Communication within C. ludovicianus as been well studied. As might be expected from such a highly social species, means of communication are varied. Black-tailed prairie dogs have 12 distinct calls, including antipredator calls, and the conspicuous "jump-yip", in which an individual stretches to its full height on hind legs, then throws the forefeet into the air as it calls. The jump-yip call of one individual seems to excite other members of the coterie, as well as individuals in adjacent coteries, into producing their own "jump-yip" calls.
In addition to vocal communication, C. ludovicianus employs physical contact (grooming, nuzzeling, playing, fighting), as well as visual signals for communication. Sniffing of other individuals occurs, and implies some chemical communication, especially in the context of mating.
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Historically, prairie dogs were villified by ranchers, and efforts were made to erradicate entire populations. Although not as common as they once were, many prairie dog colonies persist in protected areas.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
As is the case for their positive economic impact on humans, the negative impact of these animals on humans is varied. Cynomys ludovicianus has historically been considered a pest species, although most of the grounds for viewing it as such have been mistaken. Prairie dogs have been known to destroy crops of corn, wheat, alfalfa, hay, sorghum, potatoes and cantaloupes, causing some concern for agriculture. Although they are reported to compete with cattle and sheep for forage, there is actually little dietary overlap with these species. Cynomys ludovicianus burrow systems are alleged to present hazards to cattle and horses, making broken legs a threat. However, there are actually very few leg fractures in domestic livestock attributable to prairie dog burrows. Also, as discussed under "Economic Importance for Humans: Positive", the benefits of C. ludovicianus to the vegetational community may far outweigh the possible threat this species poses to agriculture. Prairie dogs may serve as a reservoir for spotted fever and bubonic plague.
Negative Impacts: injures humans; crop pest
Black-tailed prairie dogs are beneficial to humans in a variety of ways. They may help the vegetation in ways which benefit domestic cattle and horses. Because of their excavation of the soil and clipping of vegetation, as well as their fecal material and urine, many plants receive fertilization and optimal growing conditions. Bison, pronghorn antelope, and domestic livestock prefer for forage at the sites of prairie dog colonies when such are available. Beyond their utility in modifying the vegetation to the liking of livestock, black-tailed prairie dogs have been used in the laboratory for studies of gallstones. Prairie dog towns are popular among sightseers in the American west. In addition, prarie dogs are said to make excellent pets if captured young. Historically, these animals have provided food for native americans.
Positive Impacts: pet trade ; food ; ecotourism ; research and education; produces fertilizer
Black-tailed prairie dogs fall victim to a variety of predatory species. Terrestrial predators include coyotes, badgers, lynx, black-footed ferrets, rattlesnakes, and bullsnakes. Avian predators include prairie falcons, golden eagles, and a variety of hawks (Accipiter and Buteo).
The greatest defense that C. ludovicianus has against predators is exactly the same thing which makes the species so vulnerable to predators; namely, the number of animals living together in a colony. Because there are so many prairie dogs in a single colony, colonies attract the notice of predators. But, because there are so many prairie dogs present, all scanning their environment periodically, predators are readily detected by these rodents. When a predator is noticed, individual prairie dogs give alarm calls, warning their relatives that danger is near. The prairie dogs can then take shelter immediately in one of the many burrows nearby.
Known Predators:
Anti-predator Adaptations: aposematic
Cynomys ludovicianus varies in length between 352 and 415 mm. Sexual dimorphism is prevalent, with males measuring greater in total length than females (male range: 358 to 415 mm; female range: 352-375 mm). Males also tend to be between 10 and 15% heavier than females, weighing in between 850 and 1,675 g, compared to females which weigh between 705 and 1,050 g. Weight varies seasonally, with both males and females reaching their highest weights in the autumn, and lowest weights in winter.
Black-tailed prairie dogs undergo two molts per year, with slightly different pelage coloration in each molt. The general coloration is brownish to brownish-red dorsally, with whitish fur on the ventrum. During the summer, individual hairs are mixed, with some being banded (black at the base, with a whitish band, then a cinnamon band, followed by a subterminal buff band, and a black tip), and some colored either solid black or half black. The latter type of hairs are longer than banded hairs and are interspersed in the coat. In winter, the banded hairs are different, with black at the base, followed by buff, then cinnamon, and possessing a white tip. Females have 8 grayish mammae that are visible only during pregnancy and lactation.
Black-tailed prairie dogs are easily distinguished from Mexican prairie dogs because of non-overlapping geographic ranges. In addition, C. ludovicianus is easily distinguished from members of the subgenus Leucocrossuromys (including Gunnison's prairie dogs, white-tailed prairie dogs, and Utah prairie dogs). In addition to having mainly non-overlapping ranges, members of Leucocrossuromys all hibernate, have white- to gray-tipped tails, have smaller molars, and possess distinctly different territorial and antipredator vocalizations than do black-tailed prairie dogs.
Range mass: 705 to 1,675 g.
Range length: 352 to 415 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average basal metabolic rate: 2.358 W.
As is true for most mammals, most black-tailed prairie dogs die young. Only 54% of females and 47% of males who emerge from their natal burrows survive their first year of life. Females can live to be up to eight years old, whereas males don't tend to live longer than 5 years under natural conditions.
Range lifespan
Status: wild: 8 (high) years.
Average lifespan
Status: wild: 1 years.
Average lifespan
Status: captivity: 8.5 years.
Cynomys ludovicianus occupies a relatively restricted range of open, level, arid, short-grass plains. These prairie dogs are commonly found near river flats or in coulee bottomlands where sagebrush, greasewood, and prickly pear grow. They are never found in moist areas.
Range elevation: 1,300 to 2,000 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland
Cynomys ludovicianus occupies narrow bands of short to mid-grass prairies from central Texas in the south to just north of the Canadian-United States boundary. Historically, the range of black-tailed prairie dogs was greater. They were found from Nebraska in the east to Montana in the west. They ranged from Canada in the north to Mexico in the south. However, intensive efforts at eradication of these animals by ranchers have reduced the species to a few isolated populations associated mainly with protected lands.
Biogeographic Regions: nearctic (Native )
Black-tailed prairie dogs play a number of vital roles in their ecosystem. They modify the vegetational community, aerate the soil, provide food and shelter for a number of predators, and provide homes for a number of parasites. Each of these roles has extensive impact on the ecosystem.
Prairie dogs modify the vegetational community in their habitat in two distinct ways. First, and most conspicuous, the vegetation found within prairie dog colonies is dramatically shorter than the vegetation in surrounding areas. Although C. ludovicianus appears to colonize areas where the vegetation is already short, they still actively modify the landscape after colonizing an area. The short vegetation results from a combination of foraging behavior and active trimming by these rodents. Shorter vegetation seems to benefit the prairie dogs by increasing visibility, and presumably, assisting in detection of predators. Second, through some mechanism as yet unknown, the prairie dogs facilitate the growth of certain plants within their communities. Some of these plants are only rarely found on the prairie outside of prairie dog towns.
As a prey species, black-tailed prairie dogs provide food for other animals, including mammals, snakes, and birds of prey. Since they are primary consumers, they provide a vital link in food webs.
Of special note is the relationship between black-footed ferrets and C. ludovicianus. Black-footed ferrets are highly endangered mammals, the near extinction of which was intimately tied to their reliance on prairie dog colonies for food and shelter. Because of the large scale eradication of C. ludovicianus from rangelands, black-footed ferrets were unable to sustain an effective wild population. Although captive breeding of these ferrets has helped to restore the population, their continued survival depends on the availability of prairie dog colonies in which they can live. Some authors have suggested that predation by ferrets has set black-tailed prairie dogs apart from other species in the genus Cynomys, and may account for the higher levels of coloniality and sociality seen in this species.
One of the costs of coloniality that C. ludovicianus faces is a heightened level of parisitism. Black-tailed prairie dogs harbor numerous fleas, lice, and ticks. In addition to the discomfort that these parasites inflict, they infect the prairie dogs with diseases. For example, fleas transmit bubonic plague causing bacteria (Pasturella pestis). Plague, in addition to threatening the prairie dogs, can be transmitted to humans.
Ecosystem Impact: creates habitat; soil aeration ; keystone species
Black-tailed prairie dogs eat primarily leaves, stems, and roots of grasses, weeds, and forbs. Although vegetable matter comprises over 98% of the diet, animal matter may somteimes be ingested. The animals typically eaten by prairie dogs are grasshoppers, cutworms, bugs, and beetles. Black-tailed prairie dogs do not need to drink water in order to get the moisture they need to survive. They obtain all the moisture they need from their moist, leafy foods. Most prairie dogs forage close to their burrows when possible, moving into distant foraging areas only when forced to do so by local shortages of green shoots.
Cynomys ludovicianus forages selectively from the plants available in its habitat. Diet also varies seasonally. In the summer, black-tailed prairie dogs prefer to feed upon wheatgrass (g. Agopyron), buffalo grass (g. Bromus), grama (g. Bouteloua), rabbitbush (g. Chrusothamnus), and scarlet globmallow. In the winter, they eat prickly pear cactus (g. Opuntia), thistles (g. Cirsium), and various roots.
Animal Foods: insects
Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts; flowers
Primary Diet: herbivore (Folivore )
Mating is closely related to social structure in these animals. The typical mating pattern is polygynous, with a single male mating with multiple females in his home coterie. However, in some cases, more than one male may be resident in a single, large coterie. In these cases, females within the coterie may mate with both resident males. In such cases, the first male to copulate with the female sires more offspring than does the second. Additionally, there appears to be some communal nursing of young after the time they appear above ground, qualifying the species for status as a cooperative breeder.
Mating System: polygynous ; polygynandrous (promiscuous) ; cooperative breeder
Reproduction occurs once per year, with the exact timing of mating varying with latitude. In Oklahoma, breeding takes place in January; in Colorado breeding takes place in February. Between late February and March,balck-tailed prairie dogs in South Dakota breed. Finally, those animals residing in the northern portions of the species range breed in late March and early April. Females of this species are typically sexually receptive only one day of the year. Females failing to conceive after this initial estrus sometimes enter estrus a second time about 13 days after their first estrus.
Approximately 98% of matings in C. ludovicianus occur underground. This probably helps to reduce intermale competition for females. Several behaviors are associated with mating both underground and above ground. These include frequent entrance of a breeding male and estrus female into the same burrow; very high frequency of interaction between the male and female; self licking of genitals in both male and female; gathering of nesting materials by males, and transport of those materials into a burrow; and a later than normal nighttime entrance into the burrow by estrus females. In additon, male black-tailed prairie dogs have a unique vocalization that is associated only with mating behaviors.
Gestation ranges in length from 33 to 38 days, with a mean of 34.6 days. Litter sizes ate birth range from 1 to 8 young, with a mean litter size at emergence from the burrow of 3 young. Young are altricial, being born blind, naked, and mostly helpless. Neonates measure approximately 70 mm in length, and weigh an average of 15 g. Fur is evident by the age of 3 weeks, and eyes are open by approximately 5 weeks of age. The age at weaning varies with litter size, as larger litters nurse longer than smaller litters. Lactation lasts from 37 to 51 days, with a mean of 41.3 days. The termination of lactation occurs shortly after emergence from the natal burrow, and after emergence but prior to the end of lactation, pups may nurse from females other than their own mother.
Sexual dimorphism in size is already established by the time juveniles emerge from tehir natal burrows. Males weigh an average of 147 g at emergence and females weigh an average of 141 g. By October, males have acheived an average weight of 556 g, and females an average of 532 g.
Females remain in their natal coterie for life, but males disperse as yearlings. This results in minimization of inbreeding. Also, adult males rarely remain within the same coterie for more than two breeding seasons, thus reducing the possibility that they will mate with their female offspring.
The age of sexual maturity varies. Although most black-tailed prairie dogs copulate for the first time as two-year-olds, some reach maturity earlier or later. Among females, 35% breed as yearlings, 60% breed as two-year-olds, and 5% delay reproduction until they are 3 years old. Males show sexual asymmetry, being less likely than females to breed as yearlings, and more likely than females to dely reproduction until their third year. Among males, 6% breed as yearling, 70% as two-year-olds, and 24% breed in their third year.
Female C. ludovicianus who mate do not always produce litters. Successful reproduction is positively related to female age. Only 54% of yearling females who copulate subsequently give birth, compared to 89% of females over the age of 2 years who copulated. Failure to give birth results from both failure of conception, resorption of embryos, and miscarriage of pregnancies.
Breeding interval: Females of this species are able to breed once per year.
Breeding season: Breeding occurs between January and April, depending upon latitude.
Range number of offspring: 1 to 6.
Average number of offspring: 3.
Range gestation period: 33 to 38 days.
Average gestation period: 34.6 days.
Range weaning age: 27 to 51 days.
Average weaning age: 41.3 days.
Range time to independence: 1 to 2 years.
Average time to independence: 1 years.
Range age at sexual or reproductive maturity (female): 1 to 3 years.
Range age at sexual or reproductive maturity (male): 1 to 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; oviparous
Average birth mass: 15.75 g.
Average number of offspring: 4.
Cynomys lodovicianus pups are altricial. They require a large investment by parents in order to ensure their survival. Males are not directly involved in caring for young, but help to protect pups within their coteries by defending the coterie against strange males. The bulk of parental care is provided by females, who nurse, groom, and protect their offspring. Because of the prevalance of infanticide in this species, young are very vulnerable prior to emergence from their natal burrows. After emergence from the burrow, however, young are less vulnerable. They eat solid foods primarily, although they continue to nurse for about one week. Interestingly, females in the coterie frequently nurse emergent pups other than their own offspring.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Male, Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Protecting: Male, Female); post-independence association with parents; inherits maternal/paternal territory
This taxon can be found in the Colorado Plateau shrublands, as one of its North American ecoregions of occurrence. The Plateau is an elevated, northward-tilted saucer landform, characterized by its high elevation and arid to semi-arid climate. Known for the Grand Canyon, it exhibits dramatic topographic relief through the erosive action of high-gradient, swift-flowing rivers that have downcut and incised the plateau. Approximately 90 percent of the plateau is drained by the Colorado River and its tributaries, notably the lower catchment of the Green River.
A pinyon-juniper zone is extensive, dominated by a pygmy forest of Pinyon pine (Pinus edulis) and several species of juniper (Juniperus spp). Between the trees the ground is sparsely covered by grama, other grasses, herbs, and various shrubs, such as Big sagebrush (Artemisia tridentata) and Alder-leaf cercocarpus (Cercocarpus montanus).
A montane zone extends over large areas on the high plateaus and mountains, but is much smaller than the pinyon-juniper zone. The montane vegetation varies considerably, from Ponderosa pine in the south to Lodgepole pine and Aspen further north. Northern Arizona contains four distinct Douglas-fir habitat types. The lowest zone has arid grasslands but with many bare areas, as well as xeric shrubs and sagebrush. Several species of cacti and yucca are common at low elevations in the south.
Numerous mammalian species are found within the Colorado Plateau shrublands ecoregion, including the Black-tailed prairie dog (Cynomys ludovicianus); Long-eared chipmunk (Tamias quadrimaculatus); Utah prairie dog (Cynomys parvidens EN); Yellow-bellied marmot (Marmota flaviventris); and the Uinta chipmunk (Tamias umbrinus), a burrowing omnivore.
A large number of birds are seen in the ecoregion, with representative taxa: Chestnut-collared longspur (Calcarius ornatus NT); Greater sage grouse (Centrocercus urophasianus NT); Northern pygmy owl (Glaucidium gnoma); Cactus wren (Campylorhynchus brunneicapillus).
There are various snakes occurring within the Colorado Plateau, including: Black-necked garter snake (Thamnophis cyrtopsis), usually found in riparian zones; Plains Blackhead snake (Tantilla nigriceps); Black-tailed rattlesnake (Crotalus molossus), who seeks inactivity refuge in rock crevices, animal burrows and even woodrat houses. Other reptiles found here include the Common checkered whiptail (Cnemidophorus tesselatus).
There are only a limited number of anuran taxa on the Colorado Plateau; in fact, the comprehensive occcurrence list for the ecoregion is: Red-spotted toad (Anaxyrus punctatus); Canyon treefrog (Hyla arenicolor); Woodhouse's toad (Anaxyrus woodhousii); Couch's spadefoot toad (Scaphiopus couchii); Northern leopard frog (Lithobates pipiens); Plains spadefoot toad (Spea bombifrons); and Southwestern toad (Anaxyrus microscaphus). The Tiger salamander (Ambystoma tigrinum) is the sole salamander found on the Colorado Plateau shrublands.
The Colorado River fish fauna display distinctive adaptive radiations. The Humpback chub (Gila cypha), for example, is a highly specialized minnow that lives in the upper Colorado. It adapted to the water’s fast current and its extremes of temperature and flow rate. Dams and water diversion, however, have created a series of placid, stillwater lakes and side streams, and the Humpback chub may not be able to adapt to these altered conditions. The species, along with other native Colorado River fishes including the Bonytail (Gila elegans), Squawfish (Ptychocheilus lucius), and the Flannelmouth sucker (Catostomus latipinnis), may not survive much further in time.
Subterranean burrows created by black-tailed prairie dogs serve as refuges from the external environment and are one of the most important features of black-tailed prairie dog colonies. They are used for breeding, rearing young, and hiding from predators. Burrows are maintained from generation to generation and serve as stabilizers on the physical and social aspects of the colony [75]. Black-tailed prairie dog nests are located underground in burrows and are composed of fine, dried grass. Nest material is collected throughout the year by both sexes and all age classes [69,75]. Tunnel depth of black-tailed prairie dogs in central Oklahoma was typically 4 to 5 feet (50-60 inches) deep [144]. Most black-tailed prairie dog colonies contain 20 to 57 burrows/acre [20,75,81].
There are 3 types of burrow entrances- dome mounds, rimmed crater mounds, and entrances without structures around them. Entrance features may prevent flooding and/or aid in ventilation [69,75,81]. Dome mounds consist of loosely packed subterranean soil spread widely around the entrance of the burrow and tend to be vegetated by prostrate forbs. Rimmed crater mounds are cone-shaped mounds constructed of humus, litter, uprooted vegetation, and mineral soil. Black-tailed prairie dogs compact the soil of these mounds with their noses, creating poor sites for seedling establishment [23]. Rimmed crater mounds may be used as wallowing sites for American bison. Burrow entrances without structures around them are usually located on slopes >10% [75]. The density of black-tailed prairie dog burrow openings depends on both substrate and duration of occupation of an area [81].
Vegetation heights between 3 and 5 inches (7-13 cm) and a slope of 2% to 5% are optimal for detecting predators and facilitating communication amon black-tailed prairie dogs [25,27,37,75,81]. Grazing cattle keep vegetation short in the vicinity of black-tailed prairie dog colonies, reducing susceptibility to black-tailed prairie dog predators and potentially expanding colony size [59,75,81,89]. Black-tailed prairie dogs were rarely seen feeding >16 feet (5 m) from colony edges in Wind Cave National Park [50].
As of 2007, little information is available on HABITAT RELATED FIRE EFFECTS for the black-tailed prairie dog. Despite the lack of information, some generalizations may be possible based on their habitat requirements. Black-tailed prairie dogs inhabit grasslands including short-grass [26,53,70,77,91,99] and mixed-grass prairie [12,23,25,28,36,45,50,71,99], sagebrush steppe [26,79,104,105], and desert grassland [35,38,89] (see Plant Communities). The effects of fire on grasslands vary with plant community, season, weather patterns, and fire characteristics [74,83,137,149]. Information on black-tailed prairie dog ecology in sagebrush steppe and desert grasslands is sparse. The following information is from short- and mixed-grass prairie habitat. For more information on fire regime characteristics of other potential black-tailed prairie dog habitat, see the table below.
The nutrient content of grassland plants in various grassland habitat types around the world is typically higher following fire [34], and herbivores such as deer (Odocoileus spp.) seek postburn areas [138]. Black-tailed prairie dogs may also seek postburn areas for foraging. Due to the prairie dog's reliance on grass for food, low- to medium-severity fires may be beneficial, while high-severity fire may have negative impacts on the black-tailed prairie dog in the short-term.
Prairie: Blue grama, buffalo grass, and western wheatgrass are dominant grasses in shortgrass prairie and are favorite foods of black-tailed prairie dogs (see Food habits) [44,75,81,130]. Fire generally favors blue grama [2,5,41,125], and either favors or has no long-term effect on buffalo grass [143,147] and western wheatgrass [40,42,51,52]. The effects of fire on these 3 grass species vary depending on the phenological stage, season of burning, fire severity, and/or postfire weather conditions [142,148]. For more information about the effects of fire on the 3 grass species favored by black-tailed prairie dogs, see the FEIS reviews for blue grama, buffalo grass, western wheatgrass.
Blue grama [2,5,41,125], buffalo grass [143,147], and western wheatgrass [40,42,51,52] are generally favored by spring burning, which increases their frequency, biomass, and cover [40,42,62,72,76,100,142]. Spring (April) prescribed burning in mixed-grass prairie in Badlands National Park, South Dakota, favored buffalo grass. Buffalo grass began vegetative expansion and produced seed during the first growing season after fire [142]. Gartner and White [51] report that late spring and early summer burns can cause increases or decreases in western wheatgrass during the 1st growing season, but no difference between preburn and control was evident by the 2nd growing season in mixed-grass prairie communities. In the 1st and 2nd growing seasons following a spring burn in Nebraska mixed-grass prairie, blue grama experienced a significant increase (p<0.10) in basal cover on burned plots compared to unburned plots [119]. On sites in South Dakota, blue grama increased from 4% to 11% cover in the 1st growing season following a spring prescribed burn and increased from 12% to 18% cover during the 2nd growing season [41]. Following early spring prescribed burning in Texas, blue grama yield increased up to 400 lbs/acre (452 kg/ha) in the 1st growing season [147].
According to a 1980 review, during years of normal or higher than normal precipitation, timing of vegetational regrowth is quicker [60,135,147]. During dry years, grasses on the shortgrass prairie are harmed by fire [148]. In a buffalo grass-blue grama community in Hays, Kansas, it took vegetation 3 growing seasons to recover following a spring wildfire when the soil was drier than normal [86].
Fire may favor black-tailed prairie dog colony expansion if it removes woody shrubs and other visual obstructions. Prescribed burning during spring followed by mechanical brush removal in Theodore Roosevelt National Park, South Dakota, resulted in colony expansion into treated areas. Three active black-tailed prairie dog colony sites were chosen for the study: Peaceful Valley, 23.1 acres (9.34 ha); Mike Auney, 65.0 acres (26.3 ha); and Johnson's Plateau, 86.7 acres (35.1 ha). Adjacent to each active colony was a 4.9 acre (2.0 ha) treatment unit and a 4.9 acre control unit. The plant community was not described but was probably either shortgrass or mixed-grass prairie. The treatment units were burned in May 2002. The burns were patchy and incomplete, so mechanical brush removal was used to compensate for the incomplete burning. Over a 1.5 year period, black-tailed prairie dogs expanded their colonies into treated plots significantly (P<0.001) more than control plots. In the 3 treatment plots, there was an average of 335 new burrows and a mean 50.3% expansion in area, compared to 69 new burrows and a mean 1.6% expansion in control plots [98]:
Number of new black-tailed prairie dog burrows and area of colony expansion in treatment and control plots [98]
September 2002 (4 mo postfire) September 2003 (16 mo postfire) Burning and mechanical brush removal Control Burning and mechanical brush removal Control New black-tailed prairie dog burrows Peaceful Valley 192 (419)ª 40 (141) 458 (685) 41 (142) Mike Auney 315 (528) 86 (135) 358 (434) 116 (165) Johnson's Plateau 138 (304) 54 (110) 191 (357) 50 (106) mean (± 1 SE) all colonies 215 ± 52.4 60 ± 13.6 335 ± 77.9 69 ± 23.6 Area of expansion (ha) Peaceful Valley 0.89 0 1.56 -0.05 Mike Auney 1.26 0 1.09 0.10 Johnson's Plateau 0.62 0 0.31 -0.05 mean (± 1 SE) all colonies 0.92 ± 0.19 0 0.99 ± 0.36 0.001 ± 0.047 ª Numbers in parentheses are total number of burrows, including burrows present in the active black-tailed prairie dog colony encompassed by plot margins before experimental manipulations in 2002.Moderate amounts of disturbance appeared to increase plant species diversity in a mixed-grass prairie in Comanche County, Oklahoma. Plant species diversity and richness were compared in 7 treatments containing combinations of large scale, low-severity prescribed fires, light grazing by cattle, severe grazing by black-tailed prairie dogs, and wallowing by American bison. Treatments were not replicated, so significance of differences between treatments was not assessed. The 2 sites with the highest plant species diversity and richness were those with combinations of low- to moderate- severity disturbances (see table below). Plant diversity and richness was lowest on undisturbed study sites, sites that were burned frequently, and severely disturbed sites containing black-tailed prairie dogs [28]:
Plant diversity and richness in 7 undisturbed and disturbed mixed-grassland sites [28]
Treatment
Undisturbed area Lightly grazed by cattle Lightly grazed by cattle, American bison wallows Frequent, low-severity prescribed fire Low-severity prescribed fire, lightly grazed by cattle Low-severity prescribed fire, lightly grazed by cattle, American bison wallows Severe grazing by black-tailed prairie dogs DiversityThe following table provides fire regime information on vegetation communities in which black-tailed prairie dogs may occur, based on the habitat characteristics and species composition of communities black-tailed prairie dogs are known to occupy. There is not conclusive evidence that black-tailed prairie dogs occur in all the habitat types listed, and some community types, especially those used rarely, may have been omitted. Find further fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Objectives of ecologists and conservationists often conflict with those of ranchers and rural landowners regarding management of black-tailed prairie dogs [126]. Because black-tailed prairie dogs have a strong positive influence on plant and animal diversity in their native habitat, ecologists and conservationists are concerned regarding declines in their populations over the last century (e.g., [88,111]). Conversely, because black-tailed prairie dogs alter plant community structure and composition [12,29,30,71,81], they have often been regarded as competitors with livestock [18] and are subject to eradication and control efforts.
Ecological role and threats: Black-tailed prairie dogs have been called "ecosystem engineers" due to their influence on the biotic and abiotic characteristics of their habitat, landscape architecture, and ecosystem structure and function [21,35,139]. For details on their effects on vegetation and soils, see Site-scale characteristics. Research suggests that black-tailed prairie dogs are a keystone species [21,35,66,95,97] in some, but not all, geographic areas [35,101,102]. Black-tailed prairie dogs enhance the diversity of vegetation, vertebrates, and invertebrates through their foraging and burrowing activities and by their presence as prey items [21,35,103,141,144]. Grasslands inhabited by black-tailed prairie dogs support higher biodiversity than grasslands not occupied by black-tailed prairie dogs [32,95]. See Ceballos and others [21] for a simplified diagram of black-tailed prairie dog activities and impacts in grassland ecosystem function and biological diversity.
Hundreds of species of vertebrates [99,120] and invertebrates [82,124,144] are associated with black-tailed prairie dog colonies. Vertebrate species richness on black-tailed prairie dog colonies increases with colony size and density [111]. West of the Missouri River in Montana, 40% (100 species) of all vertebrate fauna in prairie habitats rely on black-tailed prairie dog colonies for food, nesting, and/or denning [48]. Rare and declining species such as the black-footed ferret [24,43,47,55,63,99,120,128], swift fox (Vulpes velox), mountain plover (Charadrius montanus) [111], and burrowing owl (Athene cunicularia) [15,69,91,93,104,106,107,131,132] are associated with black-tailed prairie dog colonies [95,99]. Because black-tailed prairie dog foraging activities keep plant development in a suppressed vegetative state with higher nutritional qualities [89,120], herbivores including elk (Cervus elaphus), American bison (Bos bison), pronghorn (Antilocarpa americana), and domestic cattle often prefer foraging in black-tailed prairie dog colonies [12,29,30,59,69,75,79,81,103,120]. Animals that depend on herbaceous cover in sagebrush habitat, such as mule deer (Odocoileus hemionus) and sage grouse (Centrocercus spp.), may be deterred by the decreased vegetative cover on black-tailed prairie dog colonies [71]. For a list of vertebrate species associated with black-tailed prairie dog colonies, see Campbell and Clark [16].
Biodiversity in shortgrass prairies may be at risk due to the reductions in distribution and occurrence of black-tailed prairie dog [82]. Threats to black-tailed prairie dogs include fragmentation and loss of habitat, unregulated eradication or control efforts, and sylvatic plague [90,99]. As a result of habitat fragmentation and prairie dog eradication programs, black-tailed prairie dog colonies are now smaller and more fragmented than in presettlement times. Agriculture, livestock use, and other development have reduced black-tailed prairie dog habitat to 2% of its former range [99]. Fragmented black-tailed prairie dog colonies are more susceptible to extirpation, primarily by sylvatic plague [95]. The effect of roads on black-tailed prairie dogs is debatable. Roads may either facilitate or hinder black-tailed prairie dog movement, depending on the landscape setting. Roads may be easy routes for dispersal, but those with heavy automobile use may increase black-tailed prairie dog mortality [26,79]. Roads, streams, and lakes may serve as barriers to sylvatic plague in black-tailed prairie dog colonies [26].
According to Reading and Beissinger [111] and Lomolino and Smith [88], a primary management goal of black-tailed prairie dog ecosystems should be the maintenance of biodiversity. Maintaining a network of native prairie reserves located in large clusters as well as large, isolated colonies across the black-tailed prairie dog's historic range is recommended [88,111]. Mulhern and Knowles [99] recommend that 1% to 3% of suitable grasslands should be occupied by black-tailed prairie dogs, and 5% to 10% of federally-owned lands should be occupied by black-tailed prairie dogs. In 1990, Miller and others [96] suggested an integrated management plan that satisfies cattle ranching needs and the conservation of grasslands. They proposed that federal money allocated to the black-tailed prairie dog poisoning program be converted into a rebate for ranchers that manage livestock and preserve black-tailed prairie dog colonies [96]. In 1970, Linder and others [87] recommended preserving black-tailed prairie dog colonies for black-footed ferrets by obtaining easements. Ranchers could continue grazing cattle in a normal manner, but an easement would stipulate that black-tailed prairie dogs could not be eliminated or controlled using methods that are detrimental to ferrets. The rancher could be compensated for an increase in the size of black-tailed prairie dog colonies [87].
A habitat suitability index model for black-tailed prairie dog was created by Clippinger [25] to produce indices for year-round habitat requirements for the black-tailed prairie dog. Possible uses of the model include the evaluation of current colony sites for habitat suitability, the evaluation of possibilities for black-tailed prairie dog colony expansion, and the suitability of sites of transplantation or rehabilitation of black-tailed prairie dog. Four habitat variables are considered: percent herbaceous cover, percent slope, height of vegetation, and soil composition. According to the model, any area of short-grass or mixed-grass prairie >6.2 acres (0.25 ha) is suitable habitat for black-tailed prairie dog. Optimal features include silty clay loam soil, ≥15% herbaceous cover with vegetation 3 to 5 inches (7-13 cm) tall, and ≤10% slope [25].
Interactions with domestic livestock: While black-tailed prairie dogs are often regarded as competitors with livestock for available forage, evidence of impacts on rangelands are mixed. Some research suggests that black-tailed prairie dogs have either neutral or beneficial effects on rangeland used by livestock [12,59,81,103]; however, effects of black-tailed prairie dogs on rangelands are not uniform [29,30,71]. In Cimarron National Grassland in southwest Kansas and adjacent private lands in Baca County, Colorado, some vegetational differences were detected between areas colonized by black-tailed prairie dogs and non-colonized areas, although not all differences were consistent among sample years. Species richness and diversity indices did not differ (P>0.05) among colonized and non-colonized sites in either year, nor did the amount of bare ground (P>0.05). The authors conclude that while prairie dogs alter shortgrass prairie such that the vegetation of colonies tends to be distinct from adjacent non-colonized areas, Âprairie dogs do not substantially alter the essential character of shortgrass vegetation [146]. Cattle neither significantly preferred nor avoided black-tailed prairie dog colonies in a study in the shortgrass steppe of northeastern Colorado. Cattle used black-tailed prairie dog colonies in proportion to the colony's availability, and grazed as intensively on colonies as on areas not occupied by black-tailed prairie dog [53].
Competitive interactions between black-tailed prairie dogs and domestic livestock for preferred forage species are unclear. Several studies suggest that black-tailed prairie dogs avoid eating many plants that livestock prefer, and prefer many plants that livestock avoid [29,30,103,136]. Conversely, on shortgrass prairie in Colorado, cattle and black-tailed prairie dogs had a 64% similarity in annual diet [59].
Some changes in plant composition brought about by black-tailed prairie dogs may benefit livestock by encouraging an increase in plants that are more tolerant of grazing, such as needleleaf sedge (Carex duriuscula), sixweeks grass (Vulpia octoflora), and scarlet globemallow [12,89,120]. Grazing by black-tailed prairie dogs may also improve the nutritional qualities of some plants [89,120]. On a shortgrass prairie near Fort Collins, Colorado, plant species diversity was greater inside black-tailed prairie dog colonies than outside of colonies, and perennial grasses such as buffalo grass and forbs increased [12]. While black-tailed prairie dog colonies at Wind Cave National Park typically had lower levels of plant biomass and were dominated by forbs, plants growing on prairie dog colonies had higher leaf nitrogen concentrations than plants in mixed-grass prairie outside colonies [39]. Foraging by black-tailed prairie dogs does not significantly (P>0.05) affect steer weights [59,103]. While forage availability and utilization by cattle decreased in black-tailed prairie dog foraging areas, there was no significant (P>0.05) reduction of steer weight in either of 2 years of study at the USDA's Southern Great Plains Experimental Range near Woodward, Oklahoma. Nutrient cycling, increased soil fertility, and subsequent changes in forage quality partly compensated for reduced forage availability [103].
Relocation: Black-tailed prairie dogs may need to be relocated for re-establishment into areas where they were extirpated, or to ensure no net loss of prairie dog habitat due to development or agriculture. Factors to consider when relocating black-tailed prairie dogs include: soil, slope, elevation, vegetation type, previous use of a site by black-tailed prairie dog, proximity to other black-tailed prairie dog colonies and adjacent landowners, and natural dispersal barriers. See Roe and Roe [116] for details. After relocation, black-tailed prairie dogs may be retained by 1) ensuring that relocation habitat is suitable, 2) use of underground nest chambers modeled after natural nest chambers, 3) acclimating black-tailed prairie dogs to release sites in large retention pens, and 4) providing supplemental food and water as necessary [117]. Survival of captive prairie dogs upon release into the wild may be enhanced by predator training at a young age [123]. In a study conducted by Shier and Owings [123], predators were presented to captive juvenile black-tailed prairie dogs in conjunction with playbacks of black-tailed prairie dog alarm vocalizations. These techniques had an immediate and lasting effect on black-tailed prairie dogs and enhanced predator avoidance once they were released [123].
Control: It is easier to discourage black-tailed prairie dogs before they inhabit an area than to try to eliminate them after they have established a colony [81]. A minimum of 77% elimination of black-tailed prairie dogs must be achieved the first year. If the remaining 23% of the population is not removed, a complete repopulation may occur within 3 years [31]. A cost-benefit analysis revealed that black-tailed prairie dog poisoning costs more than any grazing benefits accrued [95,96]. Additionally, animals such as American badgers, foxes (Vulpes spp.), coyotes, bobcats, weasels (Mustela spp.), golden eagles, and hawks (Buteo spp.) are potential indirect targets of poisoning programs [81]. Shooting black-tailed prairie dogs for population control and recreation is common across their range [69,90,99]. Shooting may decrease the health of black-tailed prairie dog colonies, fragment populations, cause the loss of non-target species, and delay recovery of colonies affected by sylvatic plague [90].
Visual barriers may be an effective, non-lethal method of black-tailed prairie dog control in mixed-grass prairies. By placing a visual obstruction at 1 side of a colony, expansion of the colony in that direction is limited due to the obstruction of the panoramic view. Physical barriers such as steep slopes and tall vegetation with grass stems about 1.5 inches (3.8 cm) apart and >1 foot (12 inches) tall are an effective barrier against black-tailed prairie dog colony expansion [81]. Koford [81] suggests changing a cattle grazing practice to alter the range vegetation and minimize the quick reoccurrence of black-tailed prairie dog damage. To establish a different plant community unsuitable to black-tailed prairie dogs, complete rest for the range or reseeding is suggested. Specialized predators of black-tailed prairie dogs could also be encouraged. For example, poles may be installed in black-tailed prairie dog colonies to encourage predatory raptors to inhabit the area [81].
Habitat preferences for the black-tailed prairie dog are influenced by vegetative cover type, slope, soil type, and amount of rainfall [111]. Black-tailed prairie dog foraging and burrowing activities influence environmental heterogeneity, hydrology, nutrient cycling, biodiversity, landscape architecture, and plant succession in grassland habitat [12,22,29,30,48,50,75,81,139,141,146].
Landscape-scale habitat characteristics: Black-tailed prairie dogs inhabit grasslands including short- and mixed-grass prairie, sagebrush steppe, and desert grasslands (see Plant Communities). Shortgrass prairies dominated by buffalo grass (Buchloe dactyloides), blue grama (Bouteloua gracilis), and western wheatgrass (Pascopyron smithii) [25,37,59,75,81], and mixed-grass prairies [12,23,25,28,36,45,50,71,99] that have been grazed by native and nonnative herbivores are preferred habitat [79,81]. Slopes of 2% to 5% and vegetation heights between 3 and 5 inches (7-13 cm) are optimal for detecting predators and facilitating communication [25,27,37,75,81].
In the Great Plains region, black-tailed prairie dog colonies commonly occur near rivers and creeks [81]. Of 86 black-tailed prairie dog colonies located in Mellette County, South Dakota, 30 were located on benches or terraces adjacent to a creek or floodplain, 30 occurred in rolling hills with a slope >5%, 20 were in flat areas, and 6 were in badland areas [64]. The slopes of playa lakes in the Texas panhandle and surrounding regions are used as habitat for the black-tailed prairie dog [108,109,110]. Black-tailed prairie dog colonies in Phillips County, Montana, were often associated with reservoirs, cattle salting grounds, and other areas affected by humans [111].
Black-tailed prairie dogs tolerate "high degrees" of disturbance over long periods of time [27,52]. New colonies are rarely created on rangeland that is in "good" to "excellent" condition; however, land that is continually heavily grazed for decades reduces habitat quality due to soil erosion [115]. Black-tailed prairie dogs may colonize heavily grazed sites but do not necessarily specialize in colonizing overgrazed areas. Overgrazing may occur subsequent to black-tailed prairie dog colonization [127]. Black-tailed prairie dogs were associated with areas intensively grazed by livestock and/or areas where topsoil had been disturbed by human activities in sagebrush-grassland habitat on the Charles M. Russell National Wildlife Refuge and Fort Belknap Indian Reservation in northeastern Montana. Roads and cattle trails were found in 150 of 154 black-tailed prairie dog colonies, and colonies were located significantly (P<0.001) closer to livestock water developments and homestead sites than randomly located points [79].
Site-scale habitat characteristics:
Vegetation: Plant community structure and species composition are impacted by black-tailed prairie dog colonization, and are related to the age of the colony and the level of expansion taking place [29,30,128]. Vegetation on black-tailed prairie dog colonies is typically of lower stature [50,75,81,146], and characterized by a higher percentage of bare ground, a higher cover of forbs and/or dwarf shrubs, and lower cover of grasses and larger woody plants than surrounding grassland [7,81,139]. As the black-tailed prairie dog colony ages, forbs and dwarf shrubs may dominate; younger colonies are dominated by grasses [29,141]. Black-tailed prairie dog colonies in Wind Cave National Park consisted of 3 vegetational zones. The interior zone was dominated by forbs, the edge zone was dominated by shortgrasses such as blue grama and buffalo grass, and the outer zone consisted of undisturbed mixed-grass prairie dominated by western wheatgrass, grama (Bouteloua spp.), and needlegrass (Stipa spp.) [50].
Shifts in vegetational structure and composition seem to occur about 10 or more years following initial colonization [23,29]. In a mixed-grass prairie in Badlands National Park, South Dakota, a buffalo grass-dominated community remained relatively unchanged 4 to 7 years after a colony was established. When cover of shortgrass (primarily buffalo grass) fell below 75%, about 11 to 13 years after colonization, abrupt vegetational changes occurred. Forbs, armed and/or sprawling grasses, aromatic dicots, and bare ground dominated the area [23]. In Wind Cave National Park, changes in relative cover of graminoids, forbs, and dwarf shrubs occurred sometime between 8 and 26 years following black-tailed prairie dog colonization, while a decrease in litter and an increase in bare ground were detectable 1 to 2 years after colonization, as shown in following table [29]:
Ground cover (%) composition before (0 years) and during 26 years of black-tailed prairie dog colonization [29]
Age (years)
0
1 to 2
3 to 8
>26
graminoids 26 26 25 1 forbs and dwarf shrubs 10 7 11 29 total vegetation 36 33 36 30 litter 48 37 39 11 bare ground 16 30 25 59According to Cid and others [22], the rate of vegetation change after the removal of grazing animals such as black-tailed prairie dogs is influenced by many factors, including grassland type, plant species composition, weather conditions, and prior intensity and duration of grazing [22]. Removal of black-tailed prairie dogs from a landscape by natural or anthropogenic factors could either release suppressed populations of woody plants or provide new habitat for woody plant colonization [4]. The removal of prairie dogs from northern mixed-grass prairies in Badlands National Park, South Dakota, did not result in rapid reestablishment of native vegetation. When seed banks were collected from black-tailed prairie dog colonies, few dominant species typical of mixed-grass prairie germinated in the laboratory compared to seed banks collected off of black-tailed prairie dog colonies. The authors suggested that unless the seed bank is restored, rapid reestablishment of representative mixed-grass prairie would be difficult [45]. In northeastern Colorado, vegetation changes following eradication of black-tailed prairie dogs were relatively minor and did not significantly (P-value not given) improve shortgrass prairie for use by cattle within 5 years. The following table shows vegetation composition on 1 active and 3 abandoned black-tailed prairie dog colonies in a shortgrass prairie. Plant species in the table were listed only if they had >0.5% cover [77]:
Vegetation cover (%) on active and inactive black-tailed prairie dog colonies [77]
Vegetation Active colony 1 year abandoned 2 years abandoned 5 years abandoned western wheatgrass 2.3 5.1 6.9 6.7 ring muhly (Muhlenbergia torreyi) 5.5 0.2 9.0 0.7 Indian ricegrass (Achnatherum hymenoides) ---- ---- ---- 0.6 purple threeawn 2.8 0.4 0.2 0.3 blue grama 20.7 22.8 9.8 22.2 buffalo grass 37.2 32.4 31.9 25.0 perennial grasses (subtotal) 68.5 60.8 57.7 55.2 annual grasses (2 species) ---- 0.1 ---- 0.5 forbs (14 species) 0.1 2.2 0.6 0.4 shrubs/half-shrubs (6 species) 2.1 2.7 1.9 2.0Total vegetation cover (27 species)
70.7 65.5 60.3 58.3Other habitat characteristics: Black-tailed prairie dog distribution is not limited by soil type, but by indirect effects of soil texture on moisture and vegetation. Black-tailed prairie dog colonies occur in many types of soil including deep, alluvial soils with medium to fine textures, and occasionally gravel. Soil that is not prone to collapsing or flooding is preferred [81]. Black-tailed prairie dogs do not select specific types of soil to dig burrows [75], but silty loam clay soils are best for tunnel construction [81]. Surface soil textures in black-tailed prairie dog colonies near Fort Collins, Colorado, varied from sandy loam to sandy clay loam in the top 6 inches (15 cm), with a sandy clay loam subsoil [11]. In northern latitudes, black-tailed prairie dog colonies commonly occur on south aspects due to the dominance of grasses over shrubs and increased solar radiation during winter. Burrows usually occur on slopes <10% [81].
Black-tailed prairie dogs mix the soil horizons by raising soil from deeper layers to the surface. This may significantly affect the texture and composition of soil at different layers. Feces, urine, and carcasses of black-tailed prairie dogs also affect soil characteristics [81].
Home range and population density: The home range and territorial boundaries of black-tailed prairie dogs are determined by the area occupied by an individual coterie. Coteries typically occupy about 1.0 acre (0.4 ha) [81].
Population density and growth are influenced by habitat quality [75,111] and are restricted by topographic barriers, soil structure, tall vegetation, and social conditions [75,81]. Urbanization and other types of human development may restrict colony size and spatial distribution [70]. Most plains habitats support at least 13 black-tailed prairie dogs/ha [81]. In a mixed-grass prairie at Wind Cave National Park, black-tailed prairie dog population densities were as follows [75]:
Black-tailed prairie dog density from 1948 to 1950 [75] Sample date Area of black-tailed prairie dog ward (acres (ha)) PopulationAverage
5.6 (2.3) 50 8.8The currently accepted scientific name for the black-tailed prairie dog is Cynomys ludovicianus
(Ord) [6,54,56,145].
Although not typically distinguished, 2 subspecies were described by Hall
[54]:
Cynomys ludovicianus arizonensis Mearns
Cynomys ludovicianus ludovicianus (Ord) [54]
Age of first reproduction, pregnancy rate, litter size, juvenile growth rate, and first-year survivorship of the black-tailed prairie dog vary depending on food availability [50].
Mating: Minimum breeding age for the black-tailed prairie dog is usually 2 years [69,75,81], but yearlings may breed if space and food are abundant [75,81]. In Wind Cave National Park, South Dakota, 40% (n=213) of yearling females copulated and 9% successfully weaned a litter [66].
The mating season occurs from late February through April, but varies with latitude and site location of a black-tailed prairie dog colony [75,81]. Estrus occurs for only 1 day during the breeding season [66].
Reproductive success: In Wind Cave National Park, the mean percentage of adult females that weaned a litter each year was 47% ± 14% SD (range 30% to 73% over 10 years) [67]. Reproductive success and survival may be greater in young black-tailed prairie dog colonies that have space for expansion. In a young colony (@5 years) with space for expansion in Wind Cave National Park, 88% females were pregnant and 81% of young weaned, compared to an old colony (@30 years) with no room for expansion, where 90% of females were pregnant and 41% of young were weaned [50].
Gestation period and litter size: Black-tailed prairie dog gestation is 34 days [69,75]. Parturition occurs underground. Information about litter size at time of birth is unavailable [65]. Mean litter size observed aboveground ranges from 3.0 to 4.9 young/litter [66,67,75,81]. Only 1 litter is produced each year [66,67].
Development: In captivity, black-tailed prairie dog pups open their eyes at 30 days old [75]. Pups are altricial and remain below ground for @7 weeks to nurse [66,75,81]. Maturity is complete at 15 months old [75]. Lifespan of the black-tailed prairie dog in the wild is unknown, but males >3 years old experience high mortality. Females may live longer than males [75]. According to Hoogland and others [67], lifespan is about 5 years for males and 7 years for females.
Social organization: Black-tailed prairie dogs live in colonies. Colony size may range from 5 to thousands of individuals. Colonies are subdivided into 2 or more wards, based on topographic features, such as hills. Wards are usually subdivided into 2 or more coteries, which are composed of aggregates of highly territorial, harem-polygynous social groups [75,81]. Individuals within coteries are amicable with each other and hostile towards non-coterie individuals [49,75]. At the beginning of the breeding season, a coterie is typically composed of 1 adult male, 3 to 4 adult females, and several yearlings and juveniles of both sexes [31,75]. After the breeding season and prior to dispersal of juveniles, coterie size increases [31,75].
Habits: Black-tailed prairie dogs are diurnal [69,75,81]. Aboveground activity is reduced when rain or snow is falling and during days when the temperature exceeds 100 °F (38° C) [75,81]. They do not hibernate [61] but may become dormant for short periods [66,75,81].
Dispersal: Reasons for dispersal include new vegetative growth at colony peripheries, shortage of unrelated females in a coterie, harassment of females by juveniles, and probably an innate genetic mechanism responding to increased density within a colony [49]. Males typically leave the natal territory 12 to 14 months after weaning, during May and June [67], but dispersal may occur throughout the year [49]. Females generally remain in their natal coterie territories for their lifetime. Intercolony dispersers moved an average distance of 1.5 miles (2.4 km) from their natal site [67]. Roads and trails may facilitate black-tailed prairie dog dispersal [81].
Mortality: Major mortality factors include predation (see Predators), disease, infanticide, habitat loss, poisoning, trapping, and shooting [26,66,67,69,69]. Survivorship for the first year was 54% for females and <50% for males in Wind Cave National Park. Primary causes of death were predation and infanticide [66]. Infanticide partially or totally eliminated 39% (n=361) of all litters. Lactating females were the most common killers [66]. Mortality of young was highest due to heavy predation during the winter and early spring following birth [75]. Mortality increases with dispersal from a colony or coterie [81].
Sylvatic plague, caused by the bacterium Yersinia pestis, can quickly eliminate entire black-tailed prairie dog colonies. Once infected, death occurs within a few days [26,69]. Black-tailed prairie dogs are also susceptible to diseases transmitted by "introduced animals" (species not identified) [13,14].
Human-caused mortality of black-tailed prairie dogs is discussed in Management considerations.
Fire may have negative or positive effects on black-tailed prairie dog habitat depending on burn severity and season. Low-severity burns conducted during spring in non-drought years may stimulate the growth of black-tailed prairie dog colonies by reducing vegetational height and density at the colony periphery [40,42,62,68,72,76,78,98,100,113,133,142]. High-severity burns have the potential of altering the plant community in a black-tailed prairie dog colony, reducing its quality of habitat, at least in the short-term [128]. During the plant growing season, the absence of fire provides optimal conditions for black-tailed prairie dog colony growth [78].
Prescribed burning and mechanical brush removal around the perimeter of black-tailed prairie dog colonies may encourage their expansion. Fire exclusion may be an effective, nonlethal management tool for reducing the expansion of black-tailed prairie dog colonies [98].
El perrín de la praderes de cola negra (Cynomys ludovicianus) ye una especie de royedor esciuromorfo de la familia Sciuridae atopáu nes Grandes Llanures de Norteamérica, dende'l sur de Canadá hasta'l norte de Méxicu. A diferencia d'otros perrinos de les praderes, estos animales non enviernen.
El perrín de les praderes de cola negra tien xeneralmente un color café, siendo más claru na zona del banduyu. La so cola tien una raya negra, de la cual deriva'l nome d'esti royedor. Los adultos lleguen a pesar de 600 a 1.300 gramos, los machos suelen ser más pesaos que les femes. El llargor del cuerpu va de los 35 a los 43 centímetros, con una cola de 7 a 10 centímetros. Tienen oreyes pequeñes, pero una aguda audición, y güeyos pequeños y escuros con una bona visión.
Saskatchewan (Canadá); de Montana al este de Nebraska, oeste de Texas, Nuevu Méxicu, y sudeste d'Arizona (Estaos Xuníos); nordés de Sonora y norte de Chihuahua (Méxicu).[3]
conocense dos subespecies de Cynomys ludovicianus.[3]
El perrín de la praderes de cola negra (Cynomys ludovicianus) ye una especie de royedor esciuromorfo de la familia Sciuridae atopáu nes Grandes Llanures de Norteamérica, dende'l sur de Canadá hasta'l norte de Méxicu. A diferencia d'otros perrinos de les praderes, estos animales non enviernen.
El gosset de la prada cuanegre (Cynomys ludovicianus) és una espècie de rosegador esciüromorf de la família Sciuridae trobat en les Grans Planes de Nord-amèrica, des del sud del Canadà fins al nord de Mèxic. A diferència d'altres gossets de la prada, aquests animals no hibernen.
El gosset de les praderies cuanegre té generalment un color cafè, sent més clar a la zona del ventre. La seva cua té una ratlla negra, de la qual deriva el nom d'aquest rosegador. Els adults arriben malgrat 600 a 1.300 grams, els mascles solen ser més pesats que les femelles. La longitud del cos va dels 35 als 43 centímetres, amb una cua de 7 a 10 centímetres. Tenen orelles petites, però una aguda audició, i ulls petits i foscos amb una bona visió.
El gosset de la prada cuanegre (Cynomys ludovicianus) és una espècie de rosegador esciüromorf de la família Sciuridae trobat en les Grans Planes de Nord-amèrica, des del sud del Canadà fins al nord de Mèxic. A diferència d'altres gossets de la prada, aquests animals no hibernen.
Psoun prériový (Cynomys ludovicianus) je denní hlodavec, který žije od jihozápadní Kanady až po severní Mexiko. Jedná se o jeden z pěti druhů psounů.
Své aktivity přizpůsobují počasí, preferují travnaté biomy. Obývají planiny v nadmořských výškách 1 300–2 000 m. Dorůstají 30–40 cm. Váží kolem 0,9–1,3 kg. Ocas je dlouhý 7–11 cm. Konečky srsti jsou v zimě černé a létě bílé.
Samice rodí po 30 dnech březosti 4–5 slepých a holých mláďat. Ta opouštějí noru po 6 týdnech. Převážně mají srst pískově hnědou. Konečná třetina ocasu a hmatavé fousky jsou černé. Živí se rostlinami například: pýrem, bizoní trávou, určitými druhy slézu a v létě aromatickými keříky Chrysothamnus nauseosus, v zimě pak bodláky, kaktusy, kořeny a podzemními cibulemi. Když jsou jejich oblíbené druhy trav spaseny, nechají toto území ležet ladem, dokud tráva opět nenaroste. A naopak – jsou natolik chytří, že se snaží vyhubit druhy rostlin, které jim zrovna příliš nechutnají. Vždy ukousnou jejich výhonky a tím získají prostor pro žádané druhy rostlin.
Mláďata z obrovských kolonií jsou v omezeném počtu odchytávána a prodávána jako domácí mazlíčci. Dovoz z USA do Evropské unie byl v roce 2003 zakázán z důvodu ochrany před rizikem opičích neštovic (Monkey Pox).[zdroj?] Tato nemoc afrického tropického pralesa,[zdroj?] se v USA přirozeně nevyskytuje.[zdroj?] K nakažení jedné skupiny psounů prériových došlo lidskou nedbalostí, kdy byli umístěni do stejné ubikace s nemocnými hlodavci importovanými z Afriky.[zdroj?] V roce 2008 byl zákaz zrušen.[zdroj?]
Hlavní společenskou jednotkou psouna je rodina (rodinný klan). Je složený z jednoho samce, několika samiček a jejich potomků. Několik rodin tvoří strážní skupinu, jejichž úkol je hlídat a hájit teritoria a doupata, přičemž vyskakují, štěkají, klapou s vyceněními zuby a ježí se jim srst na ocase. Strážní skupiny vytvářejí společenství tzv. města, na ploše 65 hektarů. Každá rodina má svoji vlastní soustavu nor, jejich vchod je chráněn valem ze zeminy, aby do nor nenatekla voda.
Když se potkávají dva psouni z různých rodin, pozdraví se letmým polibkem a očichají si navzájem řitní žlázy.
Psoun prériový je chován přibližně ve 180 evropských zoo. Nejvíce přitom v Německu, kde se jedná o více jak 50 zařízení.[3] V Česku je chován v pěti zoo. Jedná se o tato zařízení:[4]
Chov tohoto druhu započal v roce 2000 a od té doby jsou jen s krátkou přestávkou (2010–2011) chováni do současnosti.[5] Ke konci roku 2017 bylo chováno devět jedinců.[4]
Psouni byli v Zoo Praha několik let chováni v horní části zoo, konkrétně ve výběhu bizonů, kde vedle bernešek doplňovali druhovou skladbu severoamerických prérijních zvířat. Relativně neomezený život skupiny přinesl její samovolný přesun do výběhu velbloudů a následně i dále do okolí (např. do tehdejších expozic jelenů lyrorohých, anoa nížinných či kiangů[6]). V tom stavu však již byla péče o tento druh velice obtížná, a tak byli přestěhováni do historické expozice ohraničené kamennou zídkou v dolní části[5], která byla dříve určená pro chov dikobrazů. Ta v roce 2018 ustoupila nově budované expozici australské fauny.
Obrázky, zvuky či videa k tématu psoun prériový ve Wikimedia Commons
Psoun prériový (Cynomys ludovicianus) je denní hlodavec, který žije od jihozápadní Kanady až po severní Mexiko. Jedná se o jeden z pěti druhů psounů.
Své aktivity přizpůsobují počasí, preferují travnaté biomy. Obývají planiny v nadmořských výškách 1 300–2 000 m. Dorůstají 30–40 cm. Váží kolem 0,9–1,3 kg. Ocas je dlouhý 7–11 cm. Konečky srsti jsou v zimě černé a létě bílé.
Samice rodí po 30 dnech březosti 4–5 slepých a holých mláďat. Ta opouštějí noru po 6 týdnech. Převážně mají srst pískově hnědou. Konečná třetina ocasu a hmatavé fousky jsou černé. Živí se rostlinami například: pýrem, bizoní trávou, určitými druhy slézu a v létě aromatickými keříky Chrysothamnus nauseosus, v zimě pak bodláky, kaktusy, kořeny a podzemními cibulemi. Když jsou jejich oblíbené druhy trav spaseny, nechají toto území ležet ladem, dokud tráva opět nenaroste. A naopak – jsou natolik chytří, že se snaží vyhubit druhy rostlin, které jim zrovna příliš nechutnají. Vždy ukousnou jejich výhonky a tím získají prostor pro žádané druhy rostlin.
Mláďata z obrovských kolonií jsou v omezeném počtu odchytávána a prodávána jako domácí mazlíčci. Dovoz z USA do Evropské unie byl v roce 2003 zakázán z důvodu ochrany před rizikem opičích neštovic (Monkey Pox).[zdroj?] Tato nemoc afrického tropického pralesa,[zdroj?] se v USA přirozeně nevyskytuje.[zdroj?] K nakažení jedné skupiny psounů prériových došlo lidskou nedbalostí, kdy byli umístěni do stejné ubikace s nemocnými hlodavci importovanými z Afriky.[zdroj?] V roce 2008 byl zákaz zrušen.[zdroj?]
Der Schwarzschwanz-Präriehund (Cynomys ludovicianus) ist eine in Nordamerika lebende, zur Ordnung der Nagetiere gehörende Art der Präriehunde aus der Unterfamilie der Erdhörnchen. Er verdankt den Namen „Präriehund“ seinem Lebensraum, der Prärie, und seinen Warnrufen, die die frühen Siedler an das Bellen von Haushunden erinnerten.[2]
Mehr als ein Jahr alte und adulte Schwarzschwanz-Präriehunde haben eine Kopf-Rumpf-Länge von 28–33 cm und eine Schwanzlänge von 7–11,5 cm. Die Gesamtlänge beträgt 35,5–41,5 cm, aufgerichtet erreichen sie eine Höhe von etwa 30 cm. Das Gewicht von 253–1390 Gramm variiert jahreszeitlich, die Männchen sind gewöhnlich 5 %–15 % schwerer als die Weibchen.[3][2][4]
Abgesehen von seltenen Albinos ist die Oberseite der Schwarzschwanz-Präriehunde braun oder rötlich braun, die Unterseite weißlich. Manchmal ähnelt die Fellfarbe durch das Graben der Farbe des Bodens. Das Fell wird zweimal im Jahr gewechselt, der Wechsel dauert etwa zwei Wochen. Die meisten Haare sind im Winter an der Basis schwarz, dann blass gelbbraun, mit subterminalem zimtfarbenen Band und weißer Spitze. Im Sommer sind die meisten Haare an der Basis schwarz, dann weißlich, anschließend zimtfarben, gefolgt von einem subterminalen gelbbraunem Band und schmal schwarzer Spitze. Die Sommerhaare sind mit zahlreichen, eher längeren, vollständig schwarzen oder zur Hälfte schwarzen Haare gemischt. Die Tasthaare und das letzte Schwanzdrittel sind schwarz.[3][2]
Schwarzschwanz-Präriehunde haben fünf Finger mit schwarzen, etwas gekrümmten Krallen. Der kantige Kopf ist breit mit großen Augen, die Iris ist dunkelbraun.[3][2]
Schwarzschwanz-Präriehunde sind primär eine Tierart der Great Plains. Ursprünglich kamen sie vom Frenchman River Valley im extremen Süden der Provinz Saskatchewan in Kanada und von Montana in den USA nach Süden durch die westlichen und zentralen Great Plains zu den Desert Grasslands von Texas, New Mexico und Südosten von Arizona in den USA bis in das nordöstliche Sonora und nördliche Chihuahua in Mexiko vor. Die Art ist heute im Südosten von Arizona, im südwestlichen New Mexico und lokal in vielen anderen Gebieten des ursprünglichen Verbreitungsgebietes ausgerottet.[5] Schwarzschwanz-Präriehunde kommen in isolierten Kolonien innerhalb des ursprünglichen Verbreitungsgebietes vor, viele davon in Nationalparks, State Parks und National Wildlife Refuge.[5][3]
Schwarzschwanz-Präriehunde bewohnen trockenes, flach oder leicht abfallendes, offenes Grasland mit niedriger, relativ spärlicher Vegetation, einschließlich von Rindern überweideten Flächen. In einigen Gebieten kommt die Art auch in unbebauten Grundstücken an Stadträndern vor. Ihr Habitat umfasst mit Langgras-, Mixedgras- und die Kurzgrasprärie alle Grünlandarten.[5]
Schwarzschwanz-Präriehunde sind tagaktiv und halten wie die Mexikanischen Präriehunde, im Gegensatz zu anderen Arten, keinen Winterschlaf. Bei extrem kaltem Wetter bleiben sie allerdings manchmal für mehrere aufeinanderfolgende Tage unter der Erde.[3] Präriehunde leben in sorgfältig ausgearbeiteten Erdhöhlen. Die Gänge haben typischerweise einen Durchmesser von 10 bis 30 cm und sind gewöhnlich 5–10 m lang und ein bis zwei Meter tief. Es gibt mehrere elliptische, mit trockenem Gras ausgepolsterte Kammern, bei den Schwarzschwanz-Präriehunden ist jede Kammer annähernd 30 cm hoch mit einer Weite von 50 cm.[2]
Mit etwa zwei Jahren sind Schwarzschwanz-Präriehunde geschlechtsreif, gewöhnlich findet die erste Kopulation im zweiten Februar oder März nach der Geburt statt. Nach einer Tragzeit von 33–38 Tagen werden bis zu acht Junge geboren.[2]
Präriehunde sind soziale, gregäre Tiere die in Kolonien, auch Städte genannt, leben. Die größte Kolonie soll sich um 1900 bei Vernon Bailey in Texas befunden und auf einer Fläche von 100 auf 250 Meilen annähernd 400 Millionen Individuen gezählt haben. Die größte heutige Kolonie mit etwa 15.000 ha liegt in der Nähe von Janos, Mexiko. Die meisten bestehenden Kolonien sind durch Landwirtschaft und Stadtentwicklung fragmentiert, die Populationsdichte variiert von 5 bis 35 Tieren pro Acre. Die Familieneinheiten, Cliquen (coteries) genannt, bestehen aus einem Männchen, bis zu fünf Weibchen und ihren Jungen.[6][4]
Die Nahrung der Schwarzschwanz-Präriehunde variiert je nach Jahreszeit. Sie ernähren sich im Sommer von Süßgräsern wie Kammquecken (Agropyron), Bouteloua Arten und Büffelgras (Buchloe dactyloides), von Chrysothamnus Arten und Sphaeralcea coccinea. Im Winter fressem sie Opuntien Arten, Kratzdisteln und unterirdische Wurzeln. Bei der Art treten auch Fälle von Kannibalismus auf. Schwarzschwanz-Präriehunde töten und fressen konspezifische Jungtiere. Gefressen werden auch Artgenossen die unter der Erde verenden.[2]
Der Wassergehalt der Nahrung ist für den täglichen Wasserbedarf ausreichend, aber auch Stoffwechselwasser trägt zur Deckung des Bedarfs bei.[4]
Vor 1975 wurden zwei Unterarten nach Hollister (1916) anerkannt:[7][2]
Basierend auf morphometrischen Analysen kam Pizzimenti (1975) zu dem Schluss, dass es keinen Grund gibt Unterarten zu befürworten. Hoffmeister (1986) folgte der Empfehlung, so dass Cynomys ludovicianus als monotypisch gilt.[2]
Auf Grund des sehr großen Verbreitungsgebietes, der geschätzten mehreren Millionen Individuen und da die Population nicht so schnell zurückgeht, dass eine Einstufung in eine höhere Kategorie gerechtfertigt wäre, wird der Schwarzschwanz-Präriehund von der International Union for Conservation of Nature and Natural Resources (IUCN) als nicht gefährdet (Least Concern, LC) eingestuft.[5]
Der Schwarzschwanz-Präriehund (Cynomys ludovicianus) ist eine in Nordamerika lebende, zur Ordnung der Nagetiere gehörende Art der Präriehunde aus der Unterfamilie der Erdhörnchen. Er verdankt den Namen „Präriehund“ seinem Lebensraum, der Prärie, und seinen Warnrufen, die die frühen Siedler an das Bellen von Haushunden erinnerten.
De Schwaarzschwanzpräriehond (Cynomys ludovicianus) gehéiert zu der Uerdnung vun de Knabberdéieren an der Gattung Präriehënn (Cynomys).
De Schwaarzschwanzpräriehond (Cynomys ludovicianus) gehéiert zu der Uerdnung vun de Knabberdéieren an der Gattung Präriehënn (Cynomys).
De swartsturtprêrjehûn (Latynske namme: Cynomys ludovicianus) is in sûchdier út it skift fan 'e kjifdieren (Rodentia), de famylje fan 'e iikhoarntsjes (Sciuridae), de tûke fan 'e grûniikhoarntsjes (Mamotini) en it skaai fan 'e prêrjehûnen (Cynomys). Dit is de meast wiid fersprate soarte prêrjehûn, dy't op 'e Grutte Flakten fan Noard-Amearika libbet, fan Kanada oant yn Meksiko. Swartsturtprêrjehûnen libje yn koloanjes dy't faak ûnbidige grut wêze kinne. Se waarden foar it earst ûntdutsen troch de Westerske wittenskip ûnder de ferneamde Ekspedysje fan Lewis en Clark.
Swartsturtprêrjehûnen binne lânseigen yn in grut part fan 'e Grutte Flakten fan Noard-Amearika. Yn 'e Feriene Steaten komme se foar yn sintraal en súdeastlik Montana, súdwestlik Noard-Dakota, noardlik, noardeastlik en eastlik Wyoming, eastlik Kolorado, de westlike en sintrale parten fan Súd-Dakota, Nebraska, Kansas en Oklahoma, westlik en noardwestlik Teksas en eastlik en súdlik Nij-Meksiko. Foarhinne libben se ek yn it uterste súdeastlike puntsje fan Arizona, mar dêr binne se ûnderwilens útstoarn.
Yn parten fan Kolorado en Nij-Meksiko diele se har areaal mei de besibbe Rocky-Mountainsprêrjehûn (Cynomys gunnisoni). Yn Kanada komme swartsturtprêrjehûnen foar yn it uterste suden fan 'e provinsjes Saskatchewan en Alberta, en fierders libje se ek yn in lyts gebiet yn noardlik Meksiko. Hoewol't se dêrmei hast har hiele histoaryske ferspriedingsgebiet beholden hawwe, leit it troch har besette oerflak dêrbinnen krekt as de populaasjegrutte rom ûnder it histoaryske nivo.
De swartsturtprêrjehûn hat trochinoar in kop-romplingte fan 36-43 sm, mei in sturtlingte fan 7⅔-10⅓ sm en in gewicht fan 680 g oant 1,4 kg. De mantsjes binne oer it algemien wat swierder as de wyfkes. De pels is yn 'e regel ljochtbrún oant bêzje-eftich oer har hiele liif, al skaait de bealch faak in bytsje ljochter út. De sturt, dy't foar in iikhoarntsje frij koart is, hat in swarte punt, wat dizze soarte oan syn namme holpen hat.
Swartsturtprêrjehûnen binne bewenners fan gerslân, wêrûnder de koartgerzige en de mingde prêrje, en teffens mei alsem begroeide steppes en koartgerzige healwoastinen. Op 'e langgerzige prêrje komme se lykwols net foar.
De swartsturtprêrjehûn is útslutend oerdeis aktyf, al set er net in protte út 'e wei as it reint of snijt of as it waarmer is as 38° C. Oars as guon oare soarten prêrjehûnen hâldt er gjin wintersliep en kin er midden yn it winterhealjier boppe de grûn oantroffen wurde. Wol is it mooglik dat er koarte skoften yn winterrêst giet. Swartsturtprêrjehûnen binne sosjale bisten, dy't yn koloanjes libje yn ûndergrûnsk mei-inoar yn ferbining steande eigengroeven hoalen. Sokke koloanjes kinne út fiif eksimplaren bestean, mar likegoed út ferskate tûzenen, en ien útsûnderlik grutte koloanje yn Teksas besloech 64.000 km² en telde 400 miljoen prêrjehûnen. Wat grutter oft in koloanje is, wat mear kloften oft er yn ûnderferdield is. Sokke kloften wurde foarme troch tige territoriale harem-polygyne subgroepen mei ien mantsje, in stik as trije wyfkes en ferskate ûnfolgroeide eksimplaren en jongen, wêrfan't de leden ûnderling tige sosjaal binne, mar har foar bûtensteanders oer tige agressyf opstelle.
Swartsturtprêrjehûnen hawwe in ferskaat oan fokalisaasjes en alaarmroppen. Ut ûndersyk nei har alaarmroppen hat neffens biolooch Con Slobodchikoff-en-dy bliken dien dat de bisten oer in soarte fan grammatika beskikke wêrmei't se oanjaan kinne om hokker rôfdier oft it giet, hoe grut oft dat rôfdier is en hoe fluch oft er neieroan komt. Neffens Slobodchikoff is dat bewiis dat prêrjehûnen in heech ûntwikkele kognityf fermogen hawwe. Hy beweart ek dat se inoar ynformearje kinne (en dat ek dogge) oer dingen dy't gjin gefaar foar har ynhâlde.
De peartiid kin fan ein febrewaris oant ein april rinne, mar dat fariërret mei de klimatologyske omstannichheden fan 'e oangeande koloanje. De wyfkes binne elts gefal mar ien dei djoeisk, dat it komt allegear nochal krekt. De draachtiid duorret 34 dagen, wêrnei't der 3-5 jongen smiten wurde. Elts wyfke bringt jiers mar ien nêst jongen te wrâld, dy't blyn berne wurde. Mei 30 dagen geane de eagen iepen, mar de jongen bliuwe oant 7 wiken ûnder de grûn, wêrnei't se ôfwûn wurde. Mei 15 moannen binne se folwoeksen, mar se nimme ornaris pas mei minimaal twa jier diel oan 'e fuortplanting. Hoe âld oft swartsturtprêrjehûnen yn it wyld wurde, is ûnbekend, mar yn finzenskip libje de mantsjes likernôch 5 jier en de wyfkes likernôch 7 jier. Men giet derfan út dat de wyfkes yn it wyld ek in langere libbensferwachting hawwe.
De wichtichste deadsoarsaken ûnder swartsturtprêrjehûnen binne: predaasje, sykten, ynfantiside (dat wol 39% fan 'e jongen fataal wurde kin), habitatferlies, opsetlike fergiftiging troch feehâlders, en bejaging. Op it mêd fan sykten kin de sylvatyske pest, dy't feroarsake wurdt troch de baktearje Yersinia pestis, hiel fluch hiele koloanjes útrûgje. De wichtichste natuerlike fijannen fan 'e swartsturtprêrjehûn binne de prêrjewolf, de sulverdas, de reade lynks, de keningsearn, ferskate soarten hauken en de prêrjerattelslange. Oarspronklik wie it wichtichste rôfdier de swartpoatmurd, dy't him folslein spesjalisearre hat yn 'e jacht op swartsturtprêrjehûnen. Mar dy is tsjintwurdich tige seldsum, en fan 1979 oant 1981 stied er sels as útstoarn te boek.
Swartsturtprêrjehûnen binne opportunistyske fretters, dy't benammen libje fan ferskate soarten gerzen en siggen, mar dy't oare gaadlike planten, lykas alsem, net stean litte. Ut en troch frette se ek ynsekten, wjirms en de kjitte fan 'e Amerikaanske bizon.
De swartsturtprêrjehûn hat de IUCN-status fan "net bedrige", mei't er yn syn ferspriedingsgebiet noch rûnom foarkomt en om't de populaasje stabyl liket te wêzen. Troch feehâlders wurde se faak útrûge op weidlân, mei't se as skealik ûngedierte sjoen wurde. Dat hat in oansjenlike negative ynfloed hân op 'e fersprieding binnen har areaal en op har oantal. Yn 2004 kaam út in ûndersyk nei foarren dat der yn 'e Feriene Steaten noch mar 7.450 km² grûn út koloanjes fan swartsturtprêrjehûnen bestiet, mei dêropta yn Kanada en Meksiko nochris 208,8 km².
It is lykwols mar de fraach oft weidzjend fee wol sa'n lêst hat fan swartsturtprêrjehûnekoloanjes, mei't út guon ûndersiken blykt dat de oan- of ôfwêzigens fan prêrjehûnen kij ien toetmem is, wylst Amerikaanske bizons, wapitys en gaffelantilopes se by it weidzjen just faak aktyf prêrjehûnekoloanjes opsykje. Swartsturtprêrjehûnen wiene foarhinne ek de algemienste soarte prêrjehûn dy't fongen waard om as eksoatysk húsdier ferkocht te wurden, oant it Amerikaanske regear yn 2003 it near op dy hannel lei. (It ferbod waard lykwols wer opheft yn 2008.)
De swartsturtprêrjehûn (Latynske namme: Cynomys ludovicianus) is in sûchdier út it skift fan 'e kjifdieren (Rodentia), de famylje fan 'e iikhoarntsjes (Sciuridae), de tûke fan 'e grûniikhoarntsjes (Mamotini) en it skaai fan 'e prêrjehûnen (Cynomys). Dit is de meast wiid fersprate soarte prêrjehûn, dy't op 'e Grutte Flakten fan Noard-Amearika libbet, fan Kanada oant yn Meksiko. Swartsturtprêrjehûnen libje yn koloanjes dy't faak ûnbidige grut wêze kinne. Se waarden foar it earst ûntdutsen troch de Westerske wittenskip ûnder de ferneamde Ekspedysje fan Lewis en Clark.
The black-tailed prairie dog (Cynomys ludovicianus) is a rodent of the family Sciuridae found in the Great Plains of North America from about the United States-Canada border to the United States-Mexico border. Unlike some other prairie dogs, these animals do not truly hibernate. The black-tailed prairie dog can be seen above ground in midwinter. A black-tailed prairie dog town in Texas was reported to cover 25,000 sq mi (64,000 km2) and included 400,000,000 individuals.[3] Prior to habitat destruction, the species may have been the most abundant prairie dog in central North America. It was one of two prairie dogs described by the Lewis and Clark Expedition in the journals and diaries of their expedition.
Black-tailed prairie dogs are generally tan in color, with lighter-colored bellies. They may have color variation in their pelt, such as dark fur on their back in black and brown tones. Their tails have black tips, from which their name is derived. Adults can weigh from 1.5 to 3.0 lb (0.68 to 1.36 kg), males are typically heavier than females. Body length is normally from 14 to 17 in (36 to 43 cm), with a 3-to-4 in (7.6-to-10.2 cm) tail. The black-tailed have black long claws used for digging. The body of the black-tailed prairie dog is compact, and the ears are small and close to the head.
The historic range of the black-tailed prairie dog was from southern Saskatchewan and Alberta to Chihuahua, Mexico,[4] and included portions of Montana, North Dakota, South Dakota, Wyoming, Colorado, Nebraska, Kansas, Oklahoma, Texas, Arizona, and New Mexico.[5] As of 2007, black-tailed prairie dogs occur across most of their historic range, excluding Arizona;[6][7] however, their occupied acreage and populations are well below historic levels.[8]
Black-tailed prairie dogs are diurnal.[6][9][10] Above-ground activity is reduced when rain or snow is falling and during days when the temperature exceeds 100 °F (38 °C).[9][10] During the winter months, black-tailed prairie dogs do not fully hibernate. They continue to leave the burrow to forage, but will enter a state of torpor at night to conserve energy. Torpor is categorized by a drop in metabolism, heart rate and respiration similar to hibernation, but is involuntary and shorter in duration. On average, black-tailed prairie dogs will lose twenty percent of their body weight during the fall and winter seasons when they go through bouts of torpor. As winter progressed, the amount of time spent in torpor increases. Between different colonies the overall time spent in torpor varies, independent of prairie dog body mass. This may be due to weather during the previous growing season. As black-tailed prairie dogs receive most of their water from their diet, in years with poor rainfall, the black-tailed prairie dogs spend more time in torpor.[11]
Black-tailed prairie dogs are native to grassland habitats in North America. They inhabit shortgrass prairie,[7][12][13] mixed-grass prairie,[7][14][15][16][17][18] sagebrush steppe,[12][19] and desert grassland.[4][20]
Habitat preferences for the black-tailed prairie dog are influenced by vegetative cover type, slope, soil type, and amount of rainfall.[21] Their foraging and burrowing activities influence environmental heterogeneity, hydrology, nutrient cycling, biodiversity, landscape architecture, and plant succession in grassland habitats.[9][10][15][17][22][23]
Black-tailed prairie dogs inhabit grasslands, including short- and mixed-grass prairie, sagebrush steppe, and desert grasslands. Shortgrass prairies dominated by buffalo grass (Buchloe dactyloides), blue grama (Bouteloua gracilis), and western wheatgrass (Pascopyron smithii),[9][10][14][24] and mixed-grass prairies [7][14][15][16][17][18] that have been grazed by native and non-native herbivores are their preferred habitat.[10][19] Slopes of 2% to 5% and vegetation heights between 3 and 5 in (7–13 cm) are optimal for detecting predators and facilitating communication.[9][10][14]
In the Great Plains region, black-tailed prairie dog colonies commonly occur near rivers and creeks.[10] Of 86 colonies located in Mellette County, South Dakota, 30 were located on benches or terraces adjacent to a creek or floodplain, 30 occurred in rolling hills with a slope more than 5°, 20 were in flat areas, and six were in badland areas.[25] The slopes of playa lakes in the Texas Panhandle and surrounding regions are used as habitat for the black-tailed prairie dog.[26] Colonies in Phillips County, Montana, were often associated with reservoirs, cattle salting grounds, and other areas affected by humans.[21]
Black-tailed prairie dogs tolerate "high degrees" of disturbance over long periods of time. New colonies are rarely created on rangeland in "good" to "excellent" condition; however, continuously, long-term, heavily grazed land reduces habitat quality due to soil erosion.[27] Black-tailed prairie dogs may colonize heavily grazed sites, but do not necessarily specialize in colonizing overgrazed areas. Overgrazing may occur subsequent to their colonization.[28] Black-tailed prairie dogs were associated with areas intensively grazed by livestock and/or areas where topsoil had been disturbed by human activities in sagebrush-grassland habitat on the Charles M. Russell National Wildlife Refuge and Fort Belknap Agency, Montana. Roads and cattle trails were found in 150 of 154 black-tailed prairie dog colonies, and colonies were located significantly closer to livestock water developments and homestead sites than randomly located points.[19]
Black-tailed prairie dog distribution is not limited by soil type, but by indirect effects of soil texture on moisture and vegetation. Colonies occur in many types of soil, including deep, alluvial soils with medium to fine textures, and occasionally gravel. Soil not prone to collapsing or flooding is preferred.[10] Though they do not select specific types of soil to dig burrows,[9] silty loam clay soils are best for tunnel construction.[10] Surface soil textures in colonies near Fort Collins, Colorado, varied from sandy loam to sandy clay loam in the top 6 in (15 cm), with a sandy clay loam subsoil. In northern latitudes, colonies commonly occur on south aspects due to the dominance of grasses over shrubs and increased solar radiation during winter. Burrows usually occur on slopes more than 10°.[10]
Black-tailed prairie dogs mix the soil horizons by raising soil from deeper layers to the surface. This may significantly affect the texture and composition of soil at different layers. Their feces, urine, and carcasses also affect soil characteristics.[10]
The home range and territorial boundaries of black-tailed prairie dogs are determined by the area occupied by an individual coterie. Coteries typically occupy about 1.0 acre (0.4 ha).[10]
Population density and growth are influenced by habitat quality [9] and are restricted by topographic barriers, soil structure, tall vegetation, and social conditions.[9][10] Urbanization and other types of human development may restrict colony size and spatial distribution. Most plains habitats support at least 13 black-tailed prairie dogs/ha.[10]
Burrows created by black-tailed prairie dogs serve as refuges from the external environment and are one of the most important features of their colonies. Burrows are used for breeding, rearing young, and hiding from predators, and are maintained from generation to generation, and serve as stabilizers on the physical and social aspects of the colony.[9] Black-tailed prairie dog nests are located underground in burrows and are composed of fine, dried grass. Nest material is collected throughout the year by both sexes and all age classes.[6][9] Tunnel depths in central Oklahoma were typically 50–60 in deep.[29] Most colonies contain 20 to 57 burrows/acre.[9][10]
The three types of burrow entrances are: dome mounds, rimmed crater mounds, and entrances without structures around them. Entrance features may prevent flooding and/or aid in ventilation.[6][9][10] Dome mounds consist of loosely packed subterranean soil spread widely around the entrance of the burrow, and tend to be vegetated by prostrate forbs. Rimmed crater mounds are cone-shaped and constructed of humus, litter, uprooted vegetation, and mineral soil. Black-tailed prairie dogs compact the soil of these mounds with their noses, creating poor sites for seedling establishment.[16] Rimmed crater mounds may be used as wallowing sites for American bison. Burrow entrances without structures around them are usually located on slopes more than 10°.[9] The density of burrow openings depends on both substrate and duration of occupation of an area.[10]
Vegetation heights between 3 and 5 in (7–13 cm) and a slope of 2° to 5° are optimal for detecting predators and facilitating communication among black-tailed prairie dogs.[9][10][14] Grazing cattle keep vegetation short in the vicinity of colonies, reducing susceptibility to predators and potentially expanding colony size.[9][10][20][24] Black-tailed prairie dogs were rarely seen feeding more than 16 ft (5 m) from colony edges in Wind Cave National Park.[17]
Black-tailed prairie dogs are selective opportunists, preferring certain phenological stages or types of vegetation according to their needs.[9][14][30] When forage is stressed by grazing, drought, or herbicides, they change their diets quickly. Grasses are preferred over forbs,[10][24] and may comprise more than 75% of their diets, especially during summer.[24][30] Western wheatgrass, buffalo grass, blue grama [9][10][30] and sedges (Carex spp.) are preferred during spring and summer. Scarlet globemallow (Sphaeralcea coccinea) [9][15][24][30] and Russian thistle (Salsola kali) [31] are preferred during late summer and fall, but are sought out during every season.[10][15][24] During winter, plains prickly pear (Opuntia polyacantha), Russian thistle, and underground roots are preferred.[9][30] Shrubs such as rabbitbrush (Chrysothamnus spp.), winterfat (Krascheninnikovia lanata), saltbush (Atriplex spp.), and sagebrush (Artemisia spp.) are also commonly eaten.[31] Water, which is generally not available on the short-grass prairie, is obtained from vegetation such as plains prickly pear.[30] Koford [10] estimated one black-tailed prairie dog eats about 7 lb (3 kg) of herbage per month during summer.[31] Cutworms,[31] grasshoppers,[10] and old or fresh American bison scat are occasionally eaten.[6] For a detailed list of foods eaten by black-tailed prairie dogs by month, and ratings of those foods' forage value to cattle and sheep, see.[31] For a complete list of vegetation preferred by the black-tailed prairie dog, see.[32]
Black-tailed prairie dogs live in colonies. Colony size may range from five to thousands of individuals, and may be subdivided into two or more wards, based on topographic features, such as hills. Wards are usually subdivided into two or more coteries, which are composed of aggregates of highly territorial, harem-polygynous social groups.[9][10] Individuals within coteries are amicable with each other and hostile towards outside individuals. At the beginning of the breeding season, a coterie is typically composed of one adult male, three to four adult females, and several yearlings and juveniles of both sexes. After the breeding season and prior to dispersal of juveniles, coterie size increases.[9]
Reasons for dispersal include new vegetative growth at colony peripheries, shortage of unrelated females in a coterie, harassment of females by juveniles, and probably an innate genetic mechanism responding to increased density within a colony. Males typically leave the natal territory 12 to 14 months after weaning, during May and June,[33] but dispersal may occur throughout the year. Females generally remain in their natal coterie territories for their lifetimes. Intercolony dispersers moved an average distance of 1.5 mi (2.4 km) from their natal site.[33] Roads and trails may facilitate black-tailed prairie dog dispersal.[10]
Black-tailed prairie dogs have sensory adaptions for avoiding predators. Black-tailed prairie dogs have very sensitive hearing at low frequencies that allows them to detect predators early, especially while in their burrows. Black-tailed prairie dog hearing can range from 29 Hz to 26 kHz, and can hear as low as 4 Hz.[34]
Constantine Slobodchikoff and others assert that prairie dogs use a sophisticated system of vocal communication to describe specific predators.[35] According to them, prairie dog calls contain specific information as to what the predator is, how big it is, and how fast it is approaching.[35] These have been described as a form of grammar. According to Slobodchikoff, these calls, with their individuality in response to a specific predator, imply prairie dogs have highly developed cognitive abilities.[35] He also asserts prairie dogs have calls for things that are not predators to them. This is cited as evidence that the animals have a very descriptive language and have calls for any potential threat.[35]
Debate exists over whether the alarm calling of prairie dogs is selfish or altruistic. Prairie dogs possibly alarm others to the presence of a predator so they can protect themselves. However, the calls possibly are meant to cause confusion and panic in the groups and cause the others to be more conspicuous to the predator than the caller. Studies of black-tailed prairie dogs suggest alarm calling is a form of kin selection, as a prairie dog's call alerts both offspring and kin of indirect descent, such as cousins, nephews, and nieces.[36] Prairie dogs with kin close by called more often than those without. In addition, the caller may be trying to make itself more noticeable to the predator.[36] However, a predator seems to have difficulty determining which prairie dog is making the call due to its "ventriloquistic" nature.[36] Also, when a prairie dog makes a call, the others seem not to run into the burrows, but stand on the mounds to see where the predator is, making themselves visible to the predator.[36]
Perhaps the most conspicuous prairie dog communication is the territorial call or "jump-yip" display. A prairie dog will stretch the length of its body vertically and throw its forefeet into the air while making a call.[37] A jump-yip from one prairie dog causes others nearby to do the same.[38] The instigator of the jump-yip 'wave' uses the jump-yip to assess the vigilance or watchfulness of others in the colony - a longer jump-yip wave indicates watchful neighbors and leads to increased foraging by the instigator.[39]
Age of first reproduction, pregnancy rate, litter size, juvenile growth rate, and first-year survival of the black-tailed prairie dog vary depending on food availability.[17]
Minimum breeding age for the black-tailed prairie dog is usually two years,[6][9][10] but yearlings may breed if space and food are abundant.[9][10] In Wind Cave National Park, South Dakota, 40% (213 individuals) of yearling females copulated and 9% successfully weaned a litter.[40]
The mating season occurs from late February through April, but varies with latitude and site location of the colony.[9][10] Estrus occurs for only one day during the breeding season.[40]
In Wind Cave National Park, the mean percentage of adult females that weaned a litter each year was 47% ± 14%.[33] Reproductive success and survival may be greater in young colonies that have space for expansion. In a young colony (five years) with space for expansion, in Wind Cave National Park, 88% females were pregnant and 81% of young weaned, compared to an old colony (30 years) with no room for expansion, where 90% of females were pregnant and 41% of young were weaned.[17]
Black-tailed prairie dog gestation is 34 days.[6][9] Parturition occurs underground. Information about litter size at time of birth is unavailable, but the mean litter size observed above ground ranges from 3.0 to 4.9 young/litter.[9][10][40][33] Only one litter is produced each year.[40][33]
In captivity, black-tailed prairie dog pups open their eyes at 30 days old.[9] Pups are altricial and remain below ground for up to seven weeks to nurse.[9][10][40] Maturity is complete at 15 months old.[9] Lifespan of the black-tailed prairie dog in the wild is unknown, but males more than 3 years old experience high mortality. Females may live longer than males.[9] According to Hoogland and others,[33] lifespan is about 5 years for males and 7 years for females.
Major mortality factors include predation, disease, infanticide, habitat loss, poisoning, trapping, and shooting.[6][40][12][33] Survival for the first year was 54% for females and less than 50% for males in Wind Cave National Park. Primary causes of death were predation and infanticide.[40] Infanticide partially or totally eliminated 39% (361 individuals) of all litters. Lactating females were the most common killers.[40] Mortality of young was highest due to heavy predation during the winter and early spring following birth.[9] Mortality increases with dispersal from a colony or coterie.[10]
Sylvatic plague, caused by the bacterium Yersinia pestis, can quickly eliminate entire black-tailed prairie dog colonies. Once infected, death occurs within a few days.[6][12] Black-tailed prairie dogs are also susceptible to diseases transmitted by introduced animals.[41]
The most common predators of black-tailed prairie dogs are coyotes (Canis latrans),[6][9][17][42] American badgers (Taxidea taxus),[6][10][17][42] bobcats (Lynx rufus),[6][9][42] golden eagles (Aquila chrysaetos),[6][9][10][42] ferruginous hawks (Buteo regalis),[6][42] red-tailed hawks (Buteo jamaicensis),[9] and prairie rattlesnakes (Crotalus viridis).[9][10][42] Although now very rare, black-footed ferrets (Mustela nigripes) were once a major predator of the black-tailed prairie dog.[42]
Black-tailed prairie dogs have been called "ecosystem engineers" due to their influence on the biotic and abiotic characteristics of their habitat, landscape architecture, and ecosystem structure and function.[4][43] Research suggests black-tailed prairie dogs are a keystone species[4][40][43] in some, but not all, geographic areas.[4] Black-tailed prairie dogs enhance the diversity of vegetation, vertebrates, and invertebrates through their foraging and burrowing activities and by their presence as prey items.[4][29][43][44] Grasslands inhabited by black-tailed prairie dogs support higher biodiversity than grasslands not occupied by them.
Hundreds of species of vertebrates [7][45] and invertebrates[29] are associated with black-tailed prairie dog colonies. Vertebrate species richness on their colonies increases with colony size and density.[21] West of the Missouri River in Montana, 40% (100 species) of all vertebrate fauna in prairie habitats rely on black-tailed prairie dog colonies for food, nesting, and/or denning. Rare and declining species, such as the black-footed ferret,[7][42][45] swift fox (Vulpes velox), mountain plover (Charadrius montanus),[21] and burrowing owl (Athene cunicularia)[6] are associated with colonies.[7] Because their foraging activities keep plant development in a suppressed vegetative state with higher nutritional qualities,[20][45] herbivores, including American bison, pronghorn (Antilocapra americana), and domestic cattle often prefer foraging in black-tailed prairie dog colonies.[6][9][10][15][19][22][24][44][45] Animals that depend on herbaceous cover in sagebrush habitat, such as mule deer (Odocoileus hemionus) and sage grouse (Centrocercus spp.), may be deterred by the decreased vegetative cover on black-tailed prairie dog colonies.[18] For a list of vertebrate species associated with black-tailed prairie dog colonies, see.[46]
Biodiversity in shortgrass prairies may be at risk due to the reductions in distribution and occurrence of black-tailed prairie dog. Threats include fragmentation and loss of habitat, unregulated eradication or control efforts, and sylvatic plague.[7][8] As a result of habitat fragmentation and prairie dog eradication programs, colonies are now smaller and more fragmented than in presettlement times. Agriculture, livestock use, and other development have reduced habitat to 2% of its former range.[7] Fragmented colonies are more susceptible to extirpation, primarily by sylvatic plague. The effect of roads on black-tailed prairie dogs is debatable. Roads may either facilitate or hinder their movement, depending on the landscape setting. Roads may be easy routes for dispersal, but those with heavy automobile use may increase mortality.[12][19] Roads, streams, and lakes may serve as barriers to sylvatic plague.[12]
Black-tailed prairie dogs are frequently exterminated from ranchland, being viewed as pests. Their habitat has been fragmented, and their numbers have been greatly reduced. Additionally, they are remarkably susceptible to plague.[47] In 2006, all eight appearances of plague in black-tailed prairie dog colonies resulted in total colony loss. Studies in 1961 estimated only 364,000 acres (1,470 km2) of occupied black-tailed prairie dog habitat in the United States. A second study in 2000 showed 676,000 acres (2,740 km2). However, a comprehensive study between 10 states and various tribes in 2004 estimated 1,842,000 acres (7,450 km2) in the United States, plus an additional 51,589 acres (208.77 km2) in Mexico and Canada. Based on the 2004 studies, the US Fish and Wildlife Service removed the black-tailed prairie dog from the Endangered Species Act Candidate Species List in August 2004.[48]
While black-tailed prairie dogs are often regarded as competitors with livestock for available forage, evidence of impacts on rangelands are mixed. Some research suggests they have either neutral or beneficial effects on rangeland used by livestock;[10][15][24][44] however, their effects on rangelands are not uniform.[18][22] In Cimarron National Grassland in southwest Kansas and adjacent private lands in Baca County, Colorado, some vegetational differences were detected between areas colonized by black-tailed prairie dogs and uncolonized areas, although not all differences were consistent between sample years. Species richness and diversity indices did not differ among colonized and uncolonized sites in either year, nor did the amount of bare ground. The authors conclude while prairie dogs alter shortgrass prairie such that the vegetation of colonies tends to be distinct from adjacent uncolonized areas, "prairie dogs do not substantially alter the essential character of shortgrass vegetation".[23] Cattle neither significantly preferred nor avoided black-tailed prairie dog colonies in a study in the shortgrass steppe of northeastern Colorado. Cattle used colonies in proportion to the colony's availability, and grazed as intensively on colonies as on areas not occupied by black-tailed prairie dogs.[13]
Competitive interactions between black-tailed prairie dogs and domestic livestock for preferred forage species are unclear. Several studies suggest black-tailed prairie dogs avoid eating many plants that livestock prefer, and prefer many plants livestock avoid.[22][44] Conversely, on shortgrass prairie in Colorado, cattle and black-tailed prairie dogs had a 64% similarity in annual diets.[24]
Some changes in plant composition brought about by black-tailed prairie dogs may benefit livestock by encouraging an increase in plants more tolerant of grazing, such as needleleaf sedge (Carex duriuscula), sixweeks grass (Vulpia octoflora), and scarlet globemallow.[15][45] Grazing by black-tailed prairie dogs may also improve the nutritional qualities of some plants.[20][45] On a shortgrass prairie near Fort Collins, Colorado, plant species diversity was greater inside black-tailed prairie dog colonies than outside of colonies, and perennial grasses such as buffalo grass and forbs increased.[15] While black-tailed prairie dog colonies at Wind Cave National Park typically had lower levels of plant biomass and were dominated by forbs, plants growing on prairie dog colonies had higher leaf nitrogen concentrations than plants in mixed-grass prairie outside colonies. Foraging by black-tailed prairie dogs does not significantly affect steer weights.[24][44] While forage availability and use by cattle decreased in black-tailed prairie dog foraging areas, steer weight was not reduced significantly in either of two years of study at the USDA's Southern Great Plains Experimental Range near Woodward, Oklahoma. Nutrient cycling, increased soil fertility, and subsequent changes in forage quality partly compensated for reduced forage availability.[44]
Black-tailed prairie dogs were the most common prairie dog species collected in the wild for sale as exotic pets, until this trade was banned in 2003 by the United States federal government. Prairie dogs in captivity at the time of the ban are allowed to be possessed under a grandfather clause, but no more may be caught, traded, or sold, and transport is only permitted to and from a veterinarian under proper quarantine procedures. The ban was officially lifted on September 8, 2008.[49]
This article incorporates public domain material from Cynomys ludovicianus. United States Department of Agriculture.
The black-tailed prairie dog (Cynomys ludovicianus) is a rodent of the family Sciuridae found in the Great Plains of North America from about the United States-Canada border to the United States-Mexico border. Unlike some other prairie dogs, these animals do not truly hibernate. The black-tailed prairie dog can be seen above ground in midwinter. A black-tailed prairie dog town in Texas was reported to cover 25,000 sq mi (64,000 km2) and included 400,000,000 individuals. Prior to habitat destruction, the species may have been the most abundant prairie dog in central North America. It was one of two prairie dogs described by the Lewis and Clark Expedition in the journals and diaries of their expedition.
El perrito de la pradera de cola negra (Cynomys ludovicianus) es una especie de roedor esciuromorfo de la familia Sciuridae encontrado en las Grandes Llanuras de Norteamérica, desde el sur de Canadá hasta el norte de México. A diferencia de otros perritos de la pradera, estos animales no hibernan.
El perrito de la pradera de cola negra tiene generalmente un color café, siendo más claro en la zona del vientre. Su cola tiene una raya negra, de la cual deriva el nombre de este roedor. Los adultos llegan a pesar de 600 a 1.300 gramos, los machos suelen ser más pesados que las hembras. La longitud del cuerpo va de los 35 a los 43 centímetros, con una cola de 7 a 10 centímetros. Tienen orejas pequeñas, pero una aguda audición, y ojos pequeños y oscuros con una buena visión. Las patas están provistas de unas largas y poderosas uñas, perfectamente adaptadas para la excavación.
Saskatchewan (Canadá); de Montana al este de Nebraska, oeste de Texas, Nuevo México, y sudeste de Arizona (Estados Unidos); noreste de Sonora y norte de Chihuahua (México).[3]
Los perritos de la pradera de cola negra habitan en praderas de Norte América, esto incluye, zonas de hierba baja, praderas mixtas, estepas y zonas semidesérticas. La presencia de los perritos de la pradera de cola negra está más condicionada por el tipo de cobertura vegetal que por el tipo de suelo. Precisamente en el suelo construyen las madrigueras que les sirven de refugio. Estas madrigueras son utilizadas para alimentarse, para esconderse de predadores, para criar y para fijar aspectos sociales de la colonia. Estas madrigueras pueden tener miles de metros de galerías subterráneas y se mantienen de generación en generación.
Los perritos de la pradera de cola negra son oportunistas selectivos, es decir, aprovechan los recursos más abundantes de las praderas donde habitan según la época del año. Su dieta se basa en frutos y semillas de gramíneas. Durante el verano, consumen más hierba y forraje, mientras que en invierno completan su dieta con raíces. Ocasionalmente pueden alimentarse de lombrices, insectos y los huevos de aves que aniden en el suelo.
El perrito de la pradera de cola negra tiene unas fuertes costumbres sociales. Vive en colonias que pueden llegar a albergar hasta miles de individuos. Tiene una estricta jerarquía social, lo que ayuda a mantener la cohesión de los grupos. Habitualmente estas familias están formadas por un macho adulto, varias hembras y sus descendientes, tanto crías, como individuos juveniles. Forman un clan con una fuerte unión y se establecen en un territorio, tenazmente defendido de clanes ajenos. Esta unión se refuerza mediante un estrecho contacto, es frecuente ver a los perritos acariciándose, olisqueándose o lamiéndose unos a otros.
Habitualmente tiene lugar en primavera. Los nacimientos se suelen producir en abril y mayo. Las hembras tienen un período de gestación de un mes, durante el cual se hacen dueñas de una galería y no dejan acercarse a ningún otro perrito. Suelen tener de cuatro a cinco crías, aunque las camadas pueden ir desde uno hasta ocho individuos en ocasiones. Dependiendo de la disponibilidad de alimento las camadas serán más o menos numerosas. Las crías nacen muy desvalidas y abren los ojos al mes. El periodo de lactancia suele durar seis o siete semanas. A partir del mes de edad las crías comienzan a aventurarse fuera de las madrigueras, siendo muy activas y juguetonas. Los perritos de la pradera de cola negra sólo se reproducen una vez al año.
Se conocen dos subespecies de Cynomys ludovicianus.[3]
Datos: Q247142
Multimedia:
Especies: Cynomys ludovicianus
El perrito de la pradera de cola negra (Cynomys ludovicianus) es una especie de roedor esciuromorfo de la familia Sciuridae encontrado en las Grandes Llanuras de Norteamérica, desde el sur de Canadá hasta el norte de México. A diferencia de otros perritos de la pradera, estos animales no hibernan.
Cynomys ludovicianus Cynomys generoko animalia da. Karraskarien barruko Xerinae azpifamilia eta Sciuridae familian sailkatuta dago.
Cynomys ludovicianus Cynomys generoko animalia da. Karraskarien barruko Xerinae azpifamilia eta Sciuridae familian sailkatuta dago.
Mustahäntäpreeriakoira eli preeriakoira (Cynomys ludovicianus) on preeriakoirien sukuun kuuluva nisäkäs, jota tavataan Pohjois-Amerikan preerioilla aina Kanadan eteläosista Meksikon pohjoisosiin. Nimensä mustahäntäpreeriakoira on saanut koiran haukuntaa muistuttavasta ääntelystään ja sosiaalisesta elämäntavastaan, vaikkei se muuten ole läheistä sukua koiraeläimille. Nykyisin lajia pidetään jonkin verran lemmikkieläimenä, myös Suomessa.
Mustahäntäpreeriakoirat elävät valtavissa järjestäytyneissä yhteisöissä, joissa ne kaivavat laajoja tunneleita maan alle. Yhden tunnelin keskikoko on sata hehtaaria, mutta tätä paljon suurempia tunneleita tunnetaan. Kaikista laajin tunnettu yhteisö oli kaivanut elinalueeksensa 64 750 neliökilometrin kokoisen alueen.
Mustahäntäpreeriakoirat ovat hyvin sosiaalisia, mikä mahdollistaa yhteistyön niin alueiden puolustamisessa kuin yhteisöjen syntymisessä. Tällaista yhteisöä kutsutaan "kaupungiksi". Kaupunki taas on edelleen jaettu "kaupunginosiin". Kaupunginosien "väestö" on jakautuneena perhekuntiin, jotka käsittävät yleensä 8-9 - paikoin yli 20 - yksilöä.
Mustahäntäpreeriakoirat lisääntyvät vain kerran vuodessa. Lisääntymisaikana naaraat unohtavat sosiaalisuutensa ja alkavat tappaa toisten naaraiden poikasia. Lähisukulaisten tappaminen on nisäkkäiden keskuudessa harvinaista, joten mustahäntäpreeriakoiranaaraiden käytöstä on pyritty selittämään erilaisin tavoin. Todennäköisesti naaraat pyrkivät joko vähentämään liikakansoitusta, takaamaan omille poikasilleen paremmat elinolosuhteet tai sitten ne vain tarvitsevat lihaa saadakseen energiaa.
Mustahäntäpreeriakoira eli preeriakoira (Cynomys ludovicianus) on preeriakoirien sukuun kuuluva nisäkäs, jota tavataan Pohjois-Amerikan preerioilla aina Kanadan eteläosista Meksikon pohjoisosiin. Nimensä mustahäntäpreeriakoira on saanut koiran haukuntaa muistuttavasta ääntelystään ja sosiaalisesta elämäntavastaan, vaikkei se muuten ole läheistä sukua koiraeläimille. Nykyisin lajia pidetään jonkin verran lemmikkieläimenä, myös Suomessa.
Cynomys ludovicianus
Le Chien de prairie à queue noire (Cynomys ludovicianus) est une espèce de rongeur du genre Cynomys. C'est l'espèce de chien de prairie la plus répandue et celle que l'on trouve en captivité.
Cette espèce présente un dimorphisme sexuel marqué, le mâle étant 10 à 15 % plus lourd que la femelle. Le mâle mesure de 35,8 à 41,5 cm de long pour un poids allant de 850 à 1 675 g et la femelle mesure de 35,2 à 37,5 cm de long pour un poids de 705 à 1 050 g. Le poids des individus varie en fonction des saisons, atteignant un maximum en automne et un minimum à la fin de l'hiver[2].
Le chien de prairie à queue noire est un rongeur originaire d'Amérique du Nord.
C'est un animal grégaire ; en d'autres termes, il vit en groupe et ne semble véritablement s'épanouir qu'au contact de ses congénères. Ensemble, ils s'organisent en clans, comportant chacun dans la majorité des cas un mâle, quelques femelles, et les jeunes. Ils creusent de vastes galeries souterraines organisées. L'entrée est munie d'un petit dôme afin de permettre une meilleure visibilité, ces chiens de prairie étant d'excellents sentinelles prêtes à déclencher l'alerte au moindre danger[3].
Ce rongeur est essentiellement herbivore, son alimentation comprenant 98 % de matière végétale. Il se nourrit de feuilles, de tiges et de racines d'herbacées. En été, il consomme les genres Agropyron, Bromus, Bouteloua et Chrysothamnus et en hiver il se nourrit majoritairement des genres Opuntia et Cirsium[2].
Il se nourrit également de quelques insectes : criquets, chenilles et coléoptères[2].
Le Chien de prairie à queue noire est polygyne : le mâle se reproduit avec plusieurs femelles. Il y a une seule période de reproduction par an, elle a lieu entre janvier et début-avril en fonction de la latitude. L'accouplement a généralement lieu sous terre (dans 98 % des cas). La gestation dure de 33 à 38 jours. La femelle donne naissance à une portée de 1 à 8 petits qui naissent aveugles et nus. La fourrure apparaît au bout de trois semaines et les petits ouvrent les yeux après cinq semaines. La femelle allaite ses petits pendant 37 à 51 jours. Le sevrage a lieu peu après la sortie des petits du terrier[2].
Seulement 54 % des femelles et 47 % des mâles qui sortent du terrier survivent à leur première année. la femelle peut vivre jusqu'à huit ans et le mâle jusqu'à cinq ans[2].
Leurs prédateurs sont des carnivores comme le putois à pieds noirs, le Coyote, les Crotales, etc.
Sur ses terres d'origine, le chien de prairie est considéré comme nuisible[3] notamment par les éleveurs de bétail. Et ce, pour plusieurs raisons :
Dans les pays où son maintien en captivité est autorisé, le chien de prairie est un animal qui s'avère pouvoir construire une relation très personnelle avec son maître et qui se montre souvent très affectueux à son égard. Il existe désormais dans quelques rares élevages européens des sujets en mutation blanche.
Il convient de prendre au minimum deux chiens de prairie, deux femelles ou bien un couple (les portées étant extrêmement rares, surtout sans enclos), afin de conserver le mode de vie grégaire de cet animal.
Les mâles sont réputés pour être plus affectueux et les femelles plus joueuses.
Le mâle se montre particulièrement agressif au cours du rut, période de reproduction pouvant s'échelonner de novembre à février. Passée cette poussée hormonale, le mâle redevient aussi doux qu'auparavant. Les chaleurs des femelles occasionnent aussi un changement de comportement, mais bien souvent moindre, comparé à celui des mâles.
Le chien de prairie est un rongeur qui réclame de longues sorties hors de sa cage, ou simplement des moments de tendresse, même pour ceux résidant en enclos[3].
En France, d'après l'arrêté ministériel du 10 août 2004, le chien de prairie figue à l'article annexe 2, modifié par l'arrêté du 30 juillet 2010 - art. 3, qui donne la « liste des espèces non domestiques dont la détention ne peut être autorisée, avec obligation de marquage ou non, qu'au sein d'un établissement d'élevage ou de présentation au public d'animaux d'espèces non domestiques autorisé », donc avec autorisation préfectorale préalable (article 1)[4].
L'importation des chiens de prairie en provenance de pays tiers est désormais interdite, les échanges intracommunautaires n'étant pas concernés. La détention en captivité nécessite d'être titulaire d'un certificat de capacité ou bien d'avoir moins de 6 individus acquis antérieurement, de les identifier par puce et de les déclarer à la D.S.V de son département[5]. Il existe aussi des refuges destinés à recueillir ces animaux.
Cynomys ludovicianus
Le Chien de prairie à queue noire (Cynomys ludovicianus) est une espèce de rongeur du genre Cynomys. C'est l'espèce de chien de prairie la plus répandue et celle que l'on trouve en captivité.
Crnorepi prerijski pas (lat. Cynomys ludovicianus) je glodavac iz porodice Sciuridae. Živi u nekim velikim ravnicama Sjeverne Amerike u Kanadi, SAD-u i Meksiku.
Crnorepi prerijski pas općenito je prekriven tamnijim bojama, sa svjetlijom bojom trbuha. Repovi imaju crne krajeve. Odrasli mogu težiti od 0,68 do 1,4 kg, mužjaci su obično teži od ženki. Duljina tijela je obično od 36 do 43 cm s 7,6 do 10 cm repa.
Najčešće predatori crnorepog prerijskog psa su kojoti, američki jazavci, crveni ris, suri orao, njorka jastrebovi, crvenorepi jastrebovi i čegrtuše. Iako su sada vrlo rijetki crnonogi tvor je nekoć bilo glavni predator u crnorepog prerijskog psa.[2]
Za razliku od nekih drugih prerijskih pasa, ova životinja ne hibernira tijekom cijele zime. Crnorepi prerijski pas može se vidjeti iznad zemlje usred zime.
Povijesni raspon crnorepog prerijskog psa je od južnih dijelova kanadske provincije Saskatchewan do meksičke savezne države Chihuahue. Područje obuhvaća dijelove Montane, Sjeverne Dakote, Južne Dakote, Wyominga, Colorada, Nebraske, Kansasa, Oklahome, Utaha, Arizone i Novog Meksika.[3] Od 2007. godine crnorepi prerijski psi pojavljuju se diljem svog povijesnog raspona, isključujući i Arizonu. Međutim populacija je daleko ispod povijesnih razina.
Crnorepi prerijski pas većinom jede travu koja tijekom ljeta može sačinjavati i više od 75 % njegove prehrane. Vrsta trave se mijenja tijekom godina. Ponekad jede grmlje, podzemno korijenje, osobito tijekom zime, manje životinjice poput skakavca, te izmet američkog bizona.
Crnorepi prerijski pas (lat. Cynomys ludovicianus) je glodavac iz porodice Sciuridae. Živi u nekim velikim ravnicama Sjeverne Amerike u Kanadi, SAD-u i Meksiku.
Il cane della prateria dalla coda nera (Cynomys ludovicianus (Ord, 1815)) è un roditore della famiglia Sciuridae diffuso nelle Grandi Pianure del Nord America dal confine tra Stati Uniti e Canada fino al confine tra Stati Uniti e Messico. A differenza di altri cani della prateria, questi animali non vanno veramente in ibernazione e possono essere avvistati al di fuori delle loro tane anche in pieno inverno. Questi animali sono estremamente sociali costruendo delle tane comuni che possono creare delle vere e proprie "città". Una particolare città di cani della prateria, in Texas, copre 64.000 km 2, e ospitava ben 400.000.000 individui.[3] Prima che l'espansione urbana distruggesse il suo habitat naturale, la specie potrebbe essere stata il cane della prateria più abbondante nel Nord America centrale. L'animale compare anche in resoconti storici, essendo uno dei due cani della prateria descritti dalla spedizione di Lewis e Clark nei diari della loro spedizione.[4]
I cani della prateria dalla coda nera hanno generalmente un mantello di colore marrone chiaro, con il ventre più chiaro. La loro pelliccia può variare nella colorazione, con toni più scuri sul dorso. La punta della coda è invece nera, dando all'animale il suo nome comune. Gli esemplari adulti possono raggiungere un peso compreso tra 0,68 a 1,36 kg, con i maschi che sono in genere più pesanti delle femmine. La lunghezza corporea varia dai 36 ai 43 centimetri (14-17 pollici), mentre la coda è lunga dai 7,6 ai 10,2 centimetri (3-4 pollici). Questi animali presentano diverse caratteristiche tipiche di un animale fossorio, come i lunghi artigli usati per scavare, un corpo compatto e orecchie piccole e vicine alla testa.
I cani della prateria dalla coda nera sono animali diurni.[5][6][7] L'attività in superficie si riduce quando piove o nevica e durante i giorni in cui la temperatura supera i 38 °C.[6][7] Durante i mesi invernali, i cani della prateria dalla coda nera non vanno in letargo completamente. Continuano a lasciare la tana per cercare cibo, ma entreranno in uno stato di torpore durante notte per risparmiare energia. Il torpore è caratterizzato da un calo del metabolismo, della frequenza cardiaca e della respirazione simile al letargo, ma è involontario e di durata inferiore. Durante questo periodo, i cani della prateria dalla coda nera perdono in media il venti percento del loro peso corporeo. Con l'avanzare dell'inverno, il tempo che trascorrono in torpore aumenta. Tra le diverse colonie il tempo complessivo trascorso in torpore varia, indipendentemente dalla massa corporea degli esemplari. Ciò può essere dovuto al clima durante la precedente stagione di crescita. Poiché i cani della prateria dalla coda nera ricevono la maggior parte dell'acqua dalla loro dieta, nei periodi con scarse precipitazioni passano più tempo in torpore.[8]
I cani della prateria dalla coda nera vivono in colonie le cui dimensioni possono variare da cinque a migliaia di individui, e che possono essere suddivise in due o più reparti, in base a caratteristiche topografiche, come le colline. I reparti a loro volta sono solitamente suddivisi in due o più consorti, che sono composti da aggregamenti di gruppi sociali-harem poligini altamente territoriali.[6][7] Gli individui all'interno di questi consorti sono amichevoli tra di loro e ostili verso gli individui esterni. All'inizio della stagione riproduttiva, una consorteria è tipicamente composta da un maschio adulto, da tre a quattro femmine adulte e da diversi piccoli di un anno e giovani di entrambi i sessi. Dopo la stagione riproduttiva e prima della dispersione dei giovani, le dimensioni della consorteria aumenta.[6] Le ragioni della dispersione dei giovani maschi includono una nuova crescita vegetativa alle periferie della colonia, la carenza di femmine non imparentate in una consorteria, l'interessamento alle femmine dei giovani maschi e probabilmente un meccanismo genetico innato che risponde all'aumento della densità all'interno di una colonia. I maschi in genere lasciano il territorio natale da 12 a 14 mesi dopo lo svezzamento, nei mesi di maggio e giugno,[9] anche se la dispersione può verificarsi durante tutto l'anno. Le femmine generalmente rimangono nei loro territori di consorteria natale per tutta la vita. I giovani maschi possono allontanarsi dalla loro colonia natale a una distanza media di 2,4 km.[9] Strade e sentieri possono facilitare la dispersione dei cani della prateria dalla coda nera.[7]
Constantine Slobodchikoff, un comportamentista animale, e altri affermano che i cani della prateria usani un sofisticato sistema di comunicazione vocale per descrivere predatori specifici.[10] Secondo loro, i richiami dei cani della prateria contengono informazioni specifiche su cos'è il predatore, quanto è grande e quanto velocemente si sta avvicinando.[10] Questi sono stati descritti come una forma di grammatica. Secondo Slobodchikoff, questi richiami, con la loro individualità in risposta a un predatore specifico, implicano che i cani della prateria abbiano capacità cognitive altamente sviluppate.[10] Afferma inoltre che i cani della prateria hanno richiami per cose o animali che non sono predatori per loro. Questo è citato come prova che gli animali hanno un linguaggio molto descrittivo e hanno richiami diversi per qualsiasi potenziale minaccia.[10] Esiste un dibattito sul fatto che il richiamo d'allarme dei cani della prateria sia egoistico o altruistico. I cani della prateria possono allarmare gli altri della presenza di un predatore in modo che possano proteggersi. Tuttavia, le chiamate possibilmente hanno lo scopo di causare confusione e panico nei gruppi e far sì che gli altri siano più evidenti per il predatore rispetto a chi lancia l'allarme. Gli studi sui cani della prateria dalla coda nera suggeriscono che i richiami d'allarme siano una forma di selezione parentale, poiché il richiamo di un cane della prateria avverte sia la prole che i parenti di discendenza indiretta, come cugini e nipoti.[11] Inoltre, colui che lancia l'allarme si rende più evidente al predatore allontanando l'attenzione dal resto della famiglia.[11] Tuttavia, un predatore sembra avere difficoltà a determinare quale cane della prateria stia lanciando l'allarme a causa della sua natura "ventriloqua".[11] Inoltre, quando un cane della prateria lancia l'allarme, gli altri individui non corrono a nascondersi nelle tane, ma si drizzano sulle zampe posteriori per vedere dove si trova il predatore, rendendosi visibili a quest'ultimo.[11]
Forse la forma comunicazione più evidente nei cani della prateria è il richiamo territoriale o il display "jump-yip". Con questo richiamo, il cane della prateria si erge sulle zampe posteriori allungando quelle anteriori verso l'alto, lanciando un acuto squittio. Solitamente, ciò porta gli altri cani della prateria a fare lo stesso.[12] L'istigatore dell'"onda" jump-yip usa il jump-yip per valutare l'attenzione o la vigilanza degli altri membri della colonia; un'onda jump-yip più lunga membri vigili e porta, rassicurando l'istigatore che può tornare a nutrirsi in sicurezza.[13]
I cani della prateria dalla coda nera hanno, inoltre, diversi adattamenti sensoriali per evitare i predatori. Il loro udito è molto sensibile alle basse frequenze e consente loro di individuare con precisione i predatori, specialmente mentre si trovano nelle loro tane. L'udito del cane della prateria dalla coda nera può variare da 29 Hz a 26 kHz e può udire fino a 4 Hz.[14]
I cani della prateria dalla coda nera sono opportunisti selettivi, preferendo determinati stadi fenologici o tipi di vegetazione in base alle loro esigenze.[6][15][16] Quando il territorio di una colonia è usurato dal pascolo, dalla siccità o dagli erbicidi, cambiano rapidamente la loro dieta. Le erbe sono preferite alle piante grasse,[7][17] e possono costituire più del 75% della loro dieta, specialmente durante l'estate.[16][17] Graminacee occidentale, erba di bufalo, grama blu[6][7][16] e carici (Carex spp.) vengono consumati principalmente durante la primavera e l'estate. Malva scarlatta (Sphaeralcea coccinea)[6][16][17][18] e cardo russo (Salsola kali)[19] vengono invece preferiti durante la fine dell'estate e in autunno, anche se possono essere consumati in ogni stagione.[7][17][18] Durante l'inverno i cani della prateria dalla coda nera prediligono i fichi d'India di pianura (Opuntia polyacantha), il cardo russo e radici sotterranee.[6][16] Si nutrono comunemente anche di arbusti, come l'arbusto coniglio (Chrysothamnus spp.), il grasso invernale (Krascheninnikovia lanata), l'arbusto salino (Atriplex spp.) e l'artemisia (Artemisia spp.).[19] L'acqua, che generalmente scarseggia nelle prateria a erba corta, viene estratta dalla vegetazione di cui si nutrono, come il fico d'India di pianura.[16] Koford[7] ha stimato che durante l'estate un cane della prateria dalla coda nera mangia circa 7 libbre (3 kg) di erba al mese.[19] Alla loro dieta primariamente erbivora, vengono talvolta aggiunte larve di falena,[19] cavallette[7] ed escrementi di bisonte.[4][5][19][20]
L'età del primo accoppiamento, il tasso di gravidanza, le dimensioni della cucciolata, il tasso di crescita giovanile e la sopravvivenza al primo anno del cane della prateria dalla coda nera variano a seconda della disponibilità di cibo.[4][21] L'età minima per la riproduzione nei cani della prateria dalla coda nera è di solito di due anni,[5][6][7] anche se i cuccioli di un anno possono già riprodursi, se lo spazio e il cibo sono abbondanti.[6][7] Nel Parco nazionale di Wind Cave, South Dakota, il 40% (213 individui) delle femmine di un anno si era già accoppiato e il 9% aveva già svezzato con successo la loro prima cucciolata.[22] La stagione degli amori va da fine febbraio ad aprile, ma varia con la latitudine e la posizione del sito della colonia.[6][7] L'estro si verifica solo per un giorno durante la stagione riproduttiva.[22]
Nel Parco Nazionale della Grotta del Vento, la percentuale media di femmine adulte che svezzavano una cucciolata ogni anno era del 47% ± 14%.[9] Il successo riproduttivo e la sopravvivenza della prole possono essere maggiori nelle giovani colonie che hanno maggiore spazio per l'espansione. In una giovane colonia (cinque anni) con spazi di espansione, nel Parco Nazionale della Grotta del Vento, l'88% delle femmine era gravida e l'81% dei giovani svezzati, rispetto ad una colonia più vecchia (30 anni) senza margini di espansione, dove il 90% dei le femmine erano gravide e il 41% dei giovani era svezzato.[21]
La gestazione del cane della prateria dalla coda nera è di 34 giorni.[5][6] Il parto avviene in una tana sotterranea, dove le dimensioni della cucciolata possono variare da 3 a 4 cuccioli per cucciolata.[6][7][9][22] Le femmine partoriscono una sola cucciolata all'anno.[9][22] In cattività, i cuccioli di cane della prateria dalla coda nera aprono gli occhi a 30 giorni dalla nascita.[6] I cuccioli sono altriciali (completamente dipendenti dalle cure della madre) e rimangono sotto terra fino a sette settimane durante l'allattamento.[6][7][22] La maturità è completa a 15 mesi.[6] La durata della vita del cane della prateria dalla coda nera in natura è sconosciuta, ma i maschi di età superiore a 3 anni sperimentano un'elevata mortalità. Le femmine possono vivere più a lungo dei maschi.[6] Secondo Hoogland e altri,[9] la durata della vita è di circa 5 anni per i maschi e 7 per le femmine.
L'areale storico del cane della prateria dalla coda nera si estendeva dal sud del Saskatchewan fino a Chihuahua, in Messico[23], e comprendeva parti del Montana, Nord Dakota, Sud Dakota, Wyoming, Colorado, Nebraska, Kansas, Oklahoma, Texas, Arizona e Nuovo Messico.[24] A partire dal 2007, i cani della prateria dalla coda nera sono ancora diffusi nella maggior parte del loro areale storico, esclusa l'Arizona;[5][25] tuttavia, la superficie occupata e la popolazione occupante sono ben al di sotto dei livelli storici.[26]
I cani della prateria dalla coda nera sono originari delle praterie del Nord America, e prediligono le praterie ad erba corta,[25][27][28] ad erba mista,[15][18][21][25][29][30] steppe di artemisia,[27][31] e praterie desertiche.[23][32]
Le preferenze sull'habitat per il cane della prateria dalla coda nera sono influenzate dal tipo di copertura che offre la vegetazione, dalla pendenza del terreno, dal tipo di suolo e dalla frequenza delle piogge.[33] Le loro attività durante la ricerca del cibo e mentre scavano influenzano l'eterogeneità ambientale, l'idrologia, il ciclo dei nutrienti, la biodiversità, l'architettura del paesaggio e la successione delle piante negli habitat delle praterie.[6][7][18][21][34][35]
I cani della prateria dalla coda nera abitano le praterie, comprese le praterie a erba corta e mista, la steppa di artemisia e le praterie del deserto. Le praterie a erba corta dominate dall'erba di bufalo (Buchloe dactyloides), grama blu (Bouteloua gracilis) e grano occidentale (Pascopyron smithii),[6][7][15][17] e le praterie ad erba mista[15][18][21][25][29][30], che forniscono terreni di pascolo per i gran erbivori autoctoni e non, sono il loro habitat preferito.[7][31] Una pendenza del terreno del 2-5% e un'altezza della vegetazione compresa tra i 7 e i 13 centimetri sono ottimali per avvistare i predatori e facilitare la comunicazione tra i vari individui.[6][7][15]
Nella regione delle Grandi Pianure, le colonie di cani della prateria dalla coda nera si avvistano comunemente vicino a fiumi e torrenti.[7] Delle 86 colonie situate nella contea di Mellette, South Dakota, 30 erano situate su banchine o terrazze adiacenti a un torrente o a una pianura alluvionale, 30 si trovavano in basse colline con una pendenza superiore a 5°, 20 erano in aree pianeggianti e sei erano nelle zone dei calanchi.[36] Le pendici dei laghi playa nel Texas Panhandle e nelle regioni circostanti sono anch'esse un habitat ideale per questi animali.[37] Le colonie nella contea di Phillips, nel Montana, erano spesso associate a bacini idrici, terreni di salatura del bestiame e altre aree colpite dall'uomo.[33]
I cani della prateria dalla coda nera possono tollerare "elevati gradi" di disturbo per lunghi periodi di tempo. Raramente vengono create nuove colonie su pascoli in condizioni da "buone" a "eccellenti"; tuttavia, un terreno pesantemente pascolato riduce la qualità dell'habitat a causa l'erosione del suolo.[38] I cani della prateria dalla coda nera possono colonizzare siti molto pascolati, ma non sono necessariamente specializzati nella colonizzazione di aree in cui viene praticato un pascolo eccessivo. Il pascolo eccessivo può verificarsi anche dopo la loro colonizzazione.[39] I cani della prateria dalla coda nera erano associati ad aree intensamente pascolate dal bestiame e/o in aree in cui il terriccio era stato disturbato dalle attività umane nelle praterie di artemisia nel Charles M. Russell National Wildlife Refuge e nella Fort Belknap Agency, Montana. Vicino alle strade e ai sentieri utilizzati dal bestiame sono state osservate 150 delle 154 colonie di cani della prateria dalla coda nera e le colonie erano situate significativamente più vicino a corsi d'acqua e a fattorie rispetto, a zone posizionate casualmente.[31]
La distribuzione del cane della prateria dalla coda nera non è limitata dal tipo di suolo, ma dagli effetti indiretti della composizione del suolo sull'umidità e sulla vegetazione. Le colonie si trovano in molti tipi di terreno, compresi i terreni alluvionali profondi con composizioni da media a fine e occasionalmente ghiaia. È preferibile un terreno non soggetto a crolli o inondazioni.[7] Sebbene non selezionino tipi specifici di terreno per scavare le loro tane,[6] i terreni argillosi limosi sono i migliori per la costruzione di gallerie.[7] La consistenza del suolo superficiale nelle colonie vicino a Fort Collins, in Colorado, è argilloso sabbioso nei primi 15 centimetri, con un sottosuolo argilloso. Alle latitudini settentrionali, le colonie si trovano comunemente sulle esposizioni meridionali a causa del predominio delle erbe sugli arbusti e dell'aumento della radiazione solare durante l'inverno. Le tane di solito si trovano su pendii superiori a 10°.[7]
I cani della prateria dalla coda nera mescolano gli orizzonti del suolo sollevando il suolo dagli strati più profondi alla superficie. Ciò può influenzare significativamente sulla consistenza e la composizione del suolo a diversi strati. Anche le loro feci, urine e carcasse influenzano le caratteristiche del suolo in cui si stabiliscono.[7]
L'areale e i confini territoriali dei cani della prateria dalla coda nera sono determinati dall'area occupata da una consorteria individuale. Le confraternite occupano in genere circa 0,4 ettari.[7]
La densità e la crescita della popolazione sono influenzate dalla qualità dell'habitat[6] e sono limitate da barriere topografiche, struttura del suolo, vegetazione alta e condizioni sociali.[6][7] L'urbanizzazione e altri tipi di sviluppo umano possono limitare le dimensioni delle colonie e la loro distribuzione. La maggior parte degli habitat delle pianure supporta almeno 13 cani della prateria dalla coda nera per acro.[7]
Le tane create dai cani della prateria dalla coda nera fungono da rifugio dall'ambiente esterno e sono una delle caratteristiche più importanti delle loro colonie. Le tane vengono utilizzate per la riproduzione, l'allevamento dei cuccioli e per nascondersi dai predatori e vengono mantenute di generazione in generazione e fungono da stabilizzatori sugli aspetti fisici e sociali della colonia.[6] I nidi dei cani si trovano sottoterra in tane ampliate e sono composti da erba secca. Il materiale per la costruzione del nido viene raccolto durante tutto l'anno da entrambi i sessi e da tutte le classi di età.[5][6] La profondità dei tunnel nell'Oklahoma centrale erano tipicamente di 1,27-1,52 metri di profondità.[40] La maggior parte delle colonie conta dalle 20 a alle 57 tane per acro.[6][7]
I tre tipi di ingressi alle tana sono: cumuli a cupola, cumuli di crateri bordati e ingressi senza strutture esterne. Le caratteristiche dell'ingresso possono prevenire allagamenti e/o favorire la ventilazione.[5][6][7] I cumuli a cupola sono costituiti da terreno sotterraneo poco compatto diffuso ampiamente intorno all'ingresso della tana, e possono divenire terreno fertile per le piante. I tumuli craterici bordati sono a forma di cono e costruiti con humus, lettiera, vegetazione sradicata e terreno minerale. I cani della prateria dalla coda nera compattano il terreno di questi tumuli con il naso, creando siti poveri per la nascita di piante.[29] I tumuli craterici bordati vengono spesso utilizzati dai bisonti americani per i loro bagni di polvere. Gli ingressi alle tane senza strutture circostanti si trovano solitamente su pendenze superiori a 10°.[6] La densità delle aperture dei cunicoli dipende sia dal substrato che dalla durata dell'occupazione di un'area.[7]
L'altezza della vegetazione tra i 7 e i 13 centimetri e una pendenza da 2° a 5° sono ottimali per avvistare i predatori e facilitare la comunicazione tra i vari esemplari.[6][7][15] I bovini al pascolo mantengono la vegetazione corta in prossimità delle colonie, riducendo la suscettibilità degli animali ai predatori e, potenzialmente, espandendo le dimensioni delle colonie.[6][7][17][32] Raramente sono stati visti cani della prateria dalla coda nera nutrirsi a più di 5 metri dai confini della colonia nel Wind Cave National Park.[21]
I cani della prateria dalla coda nera sono spesso chiamati "ingegneri dell'ecosistema" a causa della loro influenza sulle caratteristiche biotiche e abiotiche del loro habitat, architettura del paesaggio e struttura e funzione dell'ecosistema.[23][41] La ricerca suggerisce che i cani della prateria dalla coda nera sono una specie "chiave di volta"[22][23][41] in alcune, ma non tutte, le aree geografiche in cui sono presenti.[23] I cani della prateria dalla coda nera migliorano la diversità della vegetazione, dei vertebrati e degli invertebrati attraverso le loro attività di foraggiamento e scavo e per la loro presenza come prede.[23][40][41][42] Le praterie abitate da cani della prateria dalla coda nera supportano una maggiore biodiversità rispetto alle praterie dove non sono presenti.
Centinaia di specie di vertebrati[25][43] e invertebrati[40] sono associate alle colonie dei cani della prateria dalla coda nera. La ricchezza delle specie di vertebrati nelle loro colonie aumenta con le dimensioni e la densità delle colonie.[33] Ad ovest del fiume Missouri, nel Montana, il 40% (100 specie) di tutta la fauna dei vertebrati negli habitat delle praterie si affida a colonie di cani della prateria dalla coda nera per il cibo, la nidificazione e/o la ricerca di un rifugio. Specie rare e in declino, come il furetto dai piedi neri (Mustela nigripes),[25][43][44] la volpe americana (Vulpes velox), il piviere montano (Charadrius montanus)[33] e la civetta delle tane (Athene cunicularia)[5] sono associati alle colonie.[25] Poiché le attività di foraggiamento dei cani della prateria mantengono lo sviluppo delle piante in uno stato vegetativo soppresso con qualità nutrizionali più elevate,[32][43] gli erbivori, tra cui il bisonte americano, l'antilocapra e il bestiame domestico prediligono i territori dove occupati dalle colonie.[5][6][7][17][18][31][34][42][43] Al contrario, animali che dipendono dalla copertura erbacea nell'habitat dell'artemisia, come il cervo mulo (Odocoileus hemionus) e il gallo della salvia (Centrocercus spp.), sono sfavoriti dalla presenza delle colonie dei cani della prateria dalla coda nera.[30][45]
I cani della prateria dalla coda nera hanno un areale molto diffuso, per questo vengono considerati una specie a Rischio minimo dalla Lista Rossa IUCN.[1] Tuttavia, la densità delle popolazioni e il numero delle colonie all'interno del suo areale sono frammentate e in declino. I principali fattori di mortalità per un cane della prateria dalla coda nera includono predazione, malattie, infanticidio, perdita di habitat, avvelenamento, cattura e caccia.[5][9][22][27] Difatti, questi animali vengono spesso sterminati dai ranch, essendo visti come parassiti per i raccolti. Inoltre, sono notevolmente suscettibili alla peste silvana.[46] La peste silvatica, causata dal batterio Yersinia pestis, può eliminare rapidamente intere colonie di cani della prateria dalla coda nera. Una volta infettato, la morte avviene entro pochi giorni.[5][27] I cani della prateria dalla coda nera sono anche suscettibili alle malattie trasmesse dagli animali introdotti nel suo habitat.[47] Nel 2006, tutte e otto le apparizioni di peste nelle colonie di cani della prateria dalla coda nera hanno portato alla perdita totale della colonia. Gli studi condotti nel 1961 hanno stimato solo 364.000 acri (1.470 km2) di habitat naturale occupato dai cani della prateria dalla coda nera negli Stati Uniti. Un secondo studio nel 2000 ne ha stimati 676.000 acri (2.740 km2). Tuttavia, uno più studio completo tra 10 stati e varie tribù nel 2004 ha stimato 1.842.000 acri (7.450 km2) negli Stati Uniti, più altri 51.589 acri (208,77 km 2) in Messico e Canada. Sulla base degli studi del 2004, l'US Fish and Wildlife Service ha rimosso il cane della prateria dalla coda nera dall'elenco delle specie candidate dell'Endangered Species Act nell'agosto 2004.[48]
Con la diminuzione delle popolazioni del cane della prateria dalla coda nera, anche biodiversità delle praterie a erba corta può essere a rischio. Un'altra seria minaccia per la sopravvivenza di questo animali è data dalla frammentazione e la perdita dell'habitat, l'eradicazione non regolamentata o gli sforzi di controllo, e la peste silvestre.[25][26] Come risultato della frammentazione dell'habitat e dei programmi di eradicazione dei cani della prateria, le colonie sono ora più piccole e più frammentate rispetto ai tempi di preinsediamento. L'agricoltura, l'uso del bestiame e altri sviluppi umani hanno ridotto l'habitat al 2% del suo precedente areale.[25] Le colonie frammentate sono più suscettibili all'estirpazione, principalmente a causa della peste silvatica. L'effetto delle strade sui cani della prateria dalla coda nera è discutibile. Le strade possono facilitare o ostacolare i loro movimenti, a seconda del paesaggio. Le strade possono essere facili vie di dispersione, ma quelle con un uso intenso delle automobili possono aumentare notevolmente la mortalità di questi animali.[27][31] Strade, ruscelli e laghi possono fungere da barriere alla peste.[27]
La sopravvivenza di un individuo nel suo primo anno di vita è del 54% per le femmine e inferiore al 50% per i maschi, nel Parco nazionale di Wind Cave. Le cause primarie di morte sono la predazione e l'infanticidio.[22] Nella colonia presa in esame, l'infanticidio aveva eliminato parzialmente o totalmente il 39% (361 individui) di tutte le cucciolate. Le femmine che allattavano erano i killer più comuni.[22] La mortalità dei giovani era più alta a causa della pesante predazione durante l'inverno e all'inizio della primavera successiva alla nascita.[6] La mortalità aumenta con la dispersione da una colonia all'altra.[7] I predatori più comuni dei cani della prateria dalla coda nera sono coyote (Canis latrans),[5][6][21][44] tassi americani (Taxidea taxus),[5][7][21][44] linci rosse (Lynx rufus),[5][6][44] aquile reali (Aquila chrysaetos),[5][6][7][44] poiane ferruginosi (Buteo regalis),[5][44] poiana dalla coda rossa (Buteo jamaicensis),[6] e serpenti a sonagli delle praterie (Crotalus viridis).[6][7][44] Anche se ora sono molto rari, i furetti dai piedi neri (Mustela nigripes) erano un tempo uno dei principali predatori del cane della prateria dalla coda nera.[44]
Mentre i cani della prateria dalla coda nera sono spesso considerati dei competitori al bestiame domestico per i prati da pascolo disponibile, le prove degli impatti sui pascoli sono miste. Alcune ricerche suggeriscono che hanno effetti neutri o benefici sui pascoli utilizzati dal bestiame;[7][17][18][42] tuttavia, i loro effetti sui pascoli non sono uniformi.[30][34] Nella prateria nazionale di Cimarron nel sud-ovest del Kansas e nelle terre private adiacenti nella contea di Baca, in Colorado, sono state notate alcune differenze di vegetazione tra le aree colonizzate dai cani della prateria dalla coda nera e le aree non colonizzate, sebbene non tutte le differenze fossero coerenti tra gli anni campionati. Gli indici di ricchezza e diversità delle specie non differivano tra i siti colonizzati e non colonizzati in entrambi gli anni, né la quantità di suolo nudo. Gli autori concludono mentre i cani della prateria alterano la prateria di erba corta in modo tale che la vegetazione delle colonie tenda a essere distinta dalle aree adiacenti non colonizzate, "i cani della prateria non alterano sostanzialmente il carattere essenziale della vegetazione ad erba corta".[35] Anche il bestiame non preferiva né evitava in modo significativo le aree in cui erano presenti delle colonie di cani della prateria dalla coda nera. Il bestiame utilizzava il territorio delle colonie in proporzione alla disponibilità di cibo, e pascolavano intensamente come nelle aree non occupate dai cani della prateria dalla coda nera.[28]
Le interazioni competitive tra i cani della prateria dalla coda nera e il bestiame domestico per le stesse risorse alimentari non sono chiare. Diversi studi suggeriscono che i cani della prateria dalla coda nera evitino di mangiare molte delle piante che il bestiame predilige e preferiscono molte delle piante che il bestiame evita.[34][42] Al contrario, nelle praterie a erba corta in Colorado, i bovini e i cani della prateria dalla coda nera avevano una somiglianza del 64% nelle diete annuali.[17]
Alcuni cambiamenti nella composizione delle piante provocati dai cani della prateria dalla coda nera possono avvantaggiare il bestiame incoraggiando un aumento delle piante più tolleranti al pascolo, come la carice agugliata (Carex duriuscula), la festuca a otto fiori (Vulpia octoflora) e la malva scarlatta.[18][43] Anche il pascolo dei cani della prateria dalla coda nera può migliorare le qualità nutrizionali di alcune piante.[32][43] In una prateria ad erba corta vicino a Fort Collins, Colorado, la diversità delle specie vegetali era maggiore all'interno del territorio delle colonie di cani della prateria dalla coda nera, e le erbe perenni come l'erba di bufalo e le forbes erano aumentate.[18] Mentre le colonie di cani della prateria dalla coda nera nel Parco nazionale di Wind Cave avevano in genere livelli più bassi di biomassa vegetale ed erano dominate da forbs, le piante che crescevano sul territorio delle colonie avevano concentrazioni di azoto fogliare più elevate rispetto alle piante nelle praterie miste al di fuori delle colonie. La ricerca del cibo dei cani della prateria dalla coda nera non influisce in modo significativo sul peso del manzo.[17][42] Mentre la disponibilità di foraggio e l'uso da parte del bestiame sono diminuiti nelle aree di foraggiamento dei cani della prateria dalla coda nera, il peso del manzo non è stato ridotto significativamente in nessuno dei due anni di studio presso il Southern Great Plains Experimental Range dell'USDA vicino a Woodward, Oklahoma. Il ciclo dei nutrienti, l'aumento della fertilità del suolo e i successivi cambiamenti nella qualità del foraggio hanno in parte compensato la ridotta disponibilità di foraggio.[42]
In passato, i cani della prateria dalla coda nera erano la specie di cani della prateria più catturata in natura per essere venduti come animali animali domestici esotici, fino a quando questo commercio non è stato vietato nel 2003 dal governo federale degli Stati Uniti. I cani della prateria in cattività al momento del divieto possono essere posseduti in base a una clausola del nonno, ma non possono più essere catturati in natura, scambiati o venduti, e il trasporto è consentito solo da e verso un veterinario nell'ambito di adeguate procedure di quarantena. Tuttavia, questo divieto è stato ufficialmente revocato l'8 settembre 2008.[49]
Il cane della prateria dalla coda nera (Cynomys ludovicianus (Ord, 1815)) è un roditore della famiglia Sciuridae diffuso nelle Grandi Pianure del Nord America dal confine tra Stati Uniti e Canada fino al confine tra Stati Uniti e Messico. A differenza di altri cani della prateria, questi animali non vanno veramente in ibernazione e possono essere avvistati al di fuori delle loro tane anche in pieno inverno. Questi animali sono estremamente sociali costruendo delle tane comuni che possono creare delle vere e proprie "città". Una particolare città di cani della prateria, in Texas, copre 64.000 km 2, e ospitava ben 400.000.000 individui. Prima che l'espansione urbana distruggesse il suo habitat naturale, la specie potrebbe essere stata il cane della prateria più abbondante nel Nord America centrale. L'animale compare anche in resoconti storici, essendo uno dei due cani della prateria descritti dalla spedizione di Lewis e Clark nei diari della loro spedizione.
De zwartstaartprairiehond (Cynomys ludovicianus) is een eekhoornachtig knaagdier uit het geslacht der prairiehonden (Cynomys). Hij komt voor op de prairies van Noord-Amerika.
De zwartstaartprairiehond heeft een zandkleurig bruine vacht, met een wittige buik. De oren zijn kort en rond en de ogen groot en zwart. De dunne, korte staart heeft een zwarte punt. Hieraan dankt de soort zijn naam. Hij wordt ongeveer dertig centimeter lang en 900 tot 1360 gram zwaar.
De prairiehond heeft een voorkeur voor met kort gras begroeide prairies, en komt voor van Oost-Montana, het zuidwesten van North Dakota en het zuiden van Saskatchewan, zuidwaarts tot Zuidoost-Arizona, New Mexico, Noordwest-Texas en het uiterste noorden van Mexico. Vroeger kwamen ze voor over de gehele Great Plains.
De zwartstaartprairiehond leeft van de groene delen van de plant, vooral grassen, maar ze eten ook insecten als sprinkhanen en zelfs een enkele keer aas. Ze eten eerst alle vegetatie rond het hol weg, om zo eventuele schuilplaatsen van roofdieren te verwijderen.
De zwartstaartprairiehond is een dagdier. Onder normale omstandigheden is hij de gehele dag actief, maar in heet weer komt de prairiehond alleen 's ochtends en 's avonds buiten zijn hol. Overdag schuilt hij dan voor de zon in de ondergrondse gangen. In koude winters blijft hij enkele dagen in zijn hol, en gaat dan voor enkele dagen in torpor. De prairiehond teert dan op een vetlaag die ze in de herfst hebben opgebouwd.
De paartijd is in februari en maart. Na een draagtijd van dertig dagen worden vier tot vijf jongen geboren. De jongen worden doof, blind en naakt geboren. Prairiehonden krijgen slechts één nestje per jaar. Na zes weken verlaten de dieren voor het eerst het ouderlijk nest. Als ze tien weken oud zijn, kunnen ze voor zichzelf zorgen, en na zes maanden zijn ze volgroeid. Als de jongen twee jaar oud zijn, verlaten ze het ouderlijk nest en stichten ze hun eigen coterie.
Prairiehonden leven in enorme groepen in ondergrondse gangenstelsels, steden of towns genaamd, die uit enkele duizenden dieren kunnen bestaan en meer dan 40 hectare kunnen beslaan. Deze steden bestaan uit enkele wijken, wards genaamd, die weer zijn onderverdeeld in enkele coteries, die bestaan uit een familiegroepje van één mannetje, één tot vier vrouwtjes en hun jongen. De prairiehonden gaan zelden ver van hun hol.
Het zijn sociale dieren, die leden van dezelfde ward begroeten met een "kus", waarbij de dieren elkaar met de snuit aanraken. Andere vormen van sociaal contact zijn het verzorgen van elkaars vacht en het samen graven van gangen. Ook houden ze contact met elkaar door middel van geluiden.
Er zijn minstens negen verschillende geluiden bekend. Het bekendste is het blaffen, waaraan het dier zijn naam ontleent. Het is echter geen hond, maar een grondeekhoorn. Ook zijn er alarmsignalen, voor het geval dat er vijanden komen.
Een in- en uitgang naar de ondergrondse stad is een kegelvormige hoop van ongeveer 30 centimeter hoog en 60 centimeter breed. Deze ingangen zijn hoger om te voorkomen dat er water in de stad loopt. Ook worden ze gebruikt als uitkijkposten, waarvanaf eventuele vijanden kunnen worden gespot. De hopen zijn van afwisselende hoogte. Hierdoor loopt er steeds lucht door de gangen, die zo worden geventileerd.
Direct onder de ingang loopt een korte, zijdelings lopende gang, die tot één tot anderhalve meter diep loopt. In deze gang luisteren de prairiehonden. Op vier meter diepte loopt een lange, horizontale tunnel. Langs deze tunnels liggen verscheidene nestkamers. De nestkamers zijn bekleed met droog gras. Ook ligt er aan deze gang een toilet, waarin de prairiehond zijn behoefte doet. De prairiehond bedekt zijn uitwerpselen met aarde. Als het toilet vol is, graaft de prairiehond een nieuw toilet.
De zwartstaartprairiehond wordt zeven tot acht jaar oud. Natuurlijke vijanden zijn vooral de vos en de zilverdas, maar ook de coyote, rode lynx, arenden, buizerds en slangen doden weleens een prairiehond. De belangrijkste natuurlijke vijand van de prairiehond was de zwartvoetbunzing, maar deze soort is in het wild uitgestorven, mede doordat het aantal prairiehonden is gedaald.
In de negentiende eeuw, toen veel prairie werd omgezet in landbouwgrond, nam het aantal prairiehonden enorm toe, mede door de afname van het aantal bizons, een voedselconcurrent. Nu waren de prairiehonden echter zelf een belangrijke voedselconcurrent voor het rundvee van de boeren. Er begon een grootschalige verdelgingscampagne, waarbij veel prairiehonden werden vergiftigd.
Tegenwoordig wordt de zwartstaartprairiehond in zijn leefgebied onder meer verstoord door autoverkeer, dat een gedragsverandering bij de dieren veroorzaakt: ze spenderen meer tijd ondergronds.[3][4]
Bronnen, noten en/of referentiesDe zwartstaartprairiehond (Cynomys ludovicianus) is een eekhoornachtig knaagdier uit het geslacht der prairiehonden (Cynomys). Hij komt voor op de prairies van Noord-Amerika.
Multimedia w Wikimedia Commons Nieświszczuk czarnoogonowy[5], dawniej: nieświszczuk[6][7] (Cynomys ludovicianus) zwany też pieskiem preriowym[7] – gatunek ssaka z rodziny wiewiórkowatych (Sciuridae)[8]. Jest jednym z pięciu gatunków gryzoni zaliczanych do rodzaju nieświszczuk (Cynomys). Zamieszkuje prerie na dużym obszarze Ameryki Północnej: od południowej części kanadyjskiej prowincji Saskatchewan po południowe regiony meksykańskiego stanu Coahuila oraz od wschodniej części stanu Nebraska po zachodnie krańce Montany[2].
W dzienniku ekspedycji Lewisa i Clarka w górę rzeki Missouri (1804–1806) kapitan armii amerykańskiej Meriwether Lewis zanotował pod datą 7 września 1804: „...odkryliśmy wieś małych zwierząt, które kopią nory w ziemi (zwierzęta te są po francusku nazywane „małymi psami”). W norze znaleźliśmy dwie żaby, martwego grzechotnika oraz ziemnego szczura [psa preriowego]. Są to zwierzęta o wielkości małego susła i przypominają susła pod każdym względem,... gdy jest zaniepokojony potrząsa ogonem i gwiżdże. Mówi się, że z tymi zwierzętami pomieszkują pewne jaszczurki i wąż...”[9][10]. Dopiero w 1815 roku amerykański zoolog George Ord opublikował pracę „North American Zoology” zawierającą pierwszy naukowy opis gatunku, który oznaczył nazwą Arctomys ludoviciana[11]. Współczesna nazwa Cynomys ludovicianus została po raz pierwszy użyta przez Spencera Bairda w 1858 roku[2].
W polskiej literaturze zoologicznej dla oznaczenia gatunku używane były nazwy zwyczajowe „nieświszczuk”[6][7], „piesek preriowy”[7]. W wydanej w 2015 roku przez Muzeum i Instytut Zoologii Polskiej Akademii Nauk publikacji „Polskie nazewnictwo ssaków świata” dla gatunku zaproponowano oznaczenie nieświszczuk czarnoogonowy, rezerwując nazwę nieświszczuk dla rodzaju Cynomys[5].
Nieświszczuk czarnoogonowy jest gryzoniem o zwartej budowie ciała, największym przedstawicielem rodzaju Cynomys[2]. Tułów wraz z głową osiąga długość do około 30 cm przy masie ciała około 1 kg. Sierść w części grzbietowej ma barwę szarawożółtą[7], brązową lub czerwonobrązową[2], zaś w części brzusznej jest jaśniejsza. Ogon osiąga długość około 10 cm i z wierzchu jest pokryty ciemnobrunatną sierścią[7].
Wymiary anatomiczneMasa ciała dorosłych nieświszczuków czarnoogonowych zmienia się w poszczególnych częściach roku:
Zmienność masy ciała nieświszczuków czarnoogonowychNieświszczuk czarnoogonowy wiedzie dzienny tryb życia[7][13], nie zapada w sen zimowy[7][2], lecz okresowo może zmniejszać swoją aktywność na powierzchni. Gdy temperatura powietrza przekracza 30 °C, nieświszczuk pozostaje w norze[14].
Nieświszczuk czarnoogonowy żyje w koloniach[7], które mogą liczyć od kilku osobników do wielu tysięcy zwierząt[14]. Jest gatunkiem socjalnym i silnie terytorialnym[7]. Kolonie dzielą się na kilka obwodów. Podział następuje naturalnie, zgodnie z lokalnym ukształtowaniem terenu. Te grupy dzielą się z kolei na koterie, w skład których wchodzi kilka rodzin[14]. Członkowie koterii wspierają i bronią się wzajemnie, lecz w relacjach zewnętrznych wykazują agresję[2]. Rodzina jest z natury poligamiczna. Na początku sezonu składa się zwykle z jednego samca i kilku samic, by wraz z dojrzewaniem młodych samców i samic rozrastać się[15]. W rok po narodzinach młode samce zazwyczaj opuszczają rodzinne terytorium i ruszają tworzyć własne rodziny. Ich nowe terytorium jest zazwyczaj zlokalizowane w promieniu 2,5 km od nory rodzinnej. Z kolei samice spędzają całe życie w jednym miejscu[16]. Samce poszukując nowych terenów poruszają się czasem wzdłuż lokalnych traktów[14].
Migracje młodych samców i zdolność kolonii do stałych ekspansji jest czynnikiem znacznie zwiększającym zdolność gatunku do zwiększania liczebności populacji. Podczas badań przeprowadzonych w Parku Narodowym Wind Cave w Dakocie Południowej stwierdzono, że w młodej kolonii odnotowywany był wyraźnie wyższy odsetek udanych ciąż, mioty były liczniejsze, młode nieświszczuki rosły wyraźnie szybciej, a jednoroczne samce wykazywały aktywność płciową. Ponadto zagęszczenie kolonii było dwukrotnie wyższe niż w kolonii starej, a umieralność zauważalnie niższa[17].
Nieświszczuk czarnoogonowy często zatrzymuje się w wyprostowanej pozycji[7]. Zaniepokojony alarmuje członków stada gwizdem[18].
Młode nieświszczuki czarnoogonowe przystępują do rozrodu po osiągnięciu wieku 2 lat[13], ale w sytuacji dobrych warunków bytowych i dostatku pożywienia mogą odbywać kopulacje i rozmnażać się już po 1 roku życia. Okres godowy trwa od końca lutego do kwietnia, lecz jest nieco zróżnicowany dla poszczególnych lokalizacji[15]. Owulacja u samic tego gatunku trwa tylko przez jeden dzień w roku[19]. Po trwającej 34 dni ciąży[13] przychodzi na świat średnio 3–4,9 młodych. Rodzą się ślepe i niezdolne do samodzielnego życia. Przez pierwsze 7 tygodni pozostają w podziemnym gnieździe pod opieką matki[19], zaś oczy otwierają się po 30. dniu życia[15]. Dojrzałość płciową osiągają w 15. miesiącu życia. Umieralność wśród nieświszczuków jest stosunkowo duża w pierwszym roku życia. Do głównych przyczyn należy działanie drapieżników, ale także dzieciobójstwo ze strony dorosłych nieświszczuków czarnoogonowych. Najczęściej sprawcami dzieciobójstwa były karmiące samice. W badanej populacji zabitych w ten sposób zostało aż 39% młodych. Badania przeprowadzone w Parku Narodowym Wind Cave w Dakocie Południowej wykazały, że pierwszy rok przeżyło 54% samic oraz mniej niż 50% samców. Wśród samców umieralność wzrasta znacząco już po osiągnięciu wieku 3 lat[19]. Samce na wolności dożywają wieku około 5 lat, zaś samice 7 lat[16].
Zamieszkuje prerie Ameryki Północnej. Żywi się trawami i ziołami. Jest szkodnikiem upraw rolnych i z tego powodu jest tępiony przez człowieka[7].
Meriwether Lewis, jeden z pierwszych obserwatorów tych gryzoni, zwracał uwagę na szereg gatunków zwierząt, których funkcjonowanie było ściśle powiązane z koloniami piesków preriowych[10]. Obecnie nieświszczuk jest uważany za gatunek zwornikowy ekosystemu prerii[20][21]. Postępujące tępienie gatunku może mieć bezpośredni, negatywny wpływ na funkcjonowanie powiązanych gatunków: tchórza czarnołapego, myszołowa królewskiego, sieweczki preriowej czy pójdźki ziemnej[20].
Na dobór siedliska przez nieświszczuka czarnoogonowego ma wpływ rodzaj i obfitość roślinności, rodzaj gleby czy suma opadów. Lubią prerie porośnięte niską trawą (Buchloe dactyloides, Bouteloua gracilis, Pascopyron smithii), preriową roślinnością mieszaną, bylicą Artemisia tridentata lub florą pustynną[14]. Tereny młodych kolonii mogą być zdominowane przez trawy, ale wraz ze starzeniem się kolonii zaczyna dominować siedlisko porośnięte niskimi krzewami i roślinnością typową dla pastwisk [22]. W kolonii żyjącej w Parku Narodowym Wind Cave zaobserwowano trzy strefy wegetacyjne. W części zewnętrznej dominowały charakterystyczne dla prerii trawy: Pascopyron smithii, Bouteloua dactyloides oraz ostnica. Bliżej środka rosły niskie trawy B. gracilis i B. dactyloides, zaś w centralnej części królowała roślinność pastwiskowa. Nieświszczuki żerują zazwyczaj wyłącznie na terenie swojej kolonii. Naukowcy bardzo sporadycznie odnotowywali osobniki żerujące w odległości większej niż 5 m od krawędzi terenu kolonii[17].
Ze względu na potrzebę zachowania komunikacji wzrokowej z członkami stada oraz monitorowania niebezpieczeństwa ze strony drapieżników roślinność nie powinna przekraczać wysokości 13 cm. Nieświszczuk lubi tereny płaskie, a ewentualne stoki w typowym siedlisku są zazwyczaj niezbyt strome i nie przekraczają spadku około 2–5%. Ważnym czynnikiem doboru lokalizacji jest występowanie rzek, jezior lub potoków[14].
Nieświszczuki czarnoogonowe budują nory z rozległym systemem korytarzy[7] i wykorzystują je w kolejnych pokoleniach. Badane przez naukowców tunele zwierząt z kolonii w Oklahomie były zlokalizowane około 50–60 cm poniżej poziomu terenu. Nora zapewnia nieświszczukom schronienie przed drapieżnikami, służy jako miejsce do rozrodu i wychowywania młodych[15]. Wejście jest zwykle usytuowane na szczycie usypanego kopca, co podczas ulewnych opadów chroni korytarze przed zalaniem[7]. Komora gniazdowa wyścielana jest sianem, które zbierane jest na bieżąco przez wszystkich członków rodziny niezależnie od płci i wieku[13]. W przeciętnej kolonii nieświszczuki drążą 20–57 nor/akr (ok. 49–140 nor/ha)[15].
Z funkcjonowaniem kolonii nieświszczuków czarnoogonowych związane jest życie setek gatunków zwierząt. Badania przeprowadzone na zachodnim brzegu Missouri w stanie Montana wykazały, że około 40% (czyli ok. 100 gatunków) kręgowców mających swoje siedliska na prerii jest związanych z funkcjonowaniem kolonii piesków preriowych, na których mają swoje ostoje, gniazda i na terenie których żerują[23]. Podobne wyniki osiągnęli naukowcy badające populacje nieświszczuków w stanie Oklahoma[24].
W warunkach naturalnych nieświszczuk bywa głównym pokarmem wielu lokalnych drapieżników. Do naturalnych wrogów polujących na nieświszczuki należy kojot preriowy[13], borsucznik amerykański[18][14], ryś rudy, orzeł przedni, myszołów królewski[13], myszołów rdzawosterny oraz grzechotnik preriowy[14]. W przeszłości głównym wrogiem był (obecnie dość rzadko już spotykany) tchórz czarnołapy[15]. Żerowanie piesków preriowych na porastającej siedlisko roślinności zielonej skutkuje utrzymaniem flory w stłumionym stanie wegetatywnym, co z kolei powoduje, że uzyskuje wyższe wartości odżywcze. Trawy porastające kolonie nieświszczuków przyciągają więc stada bizonów, jeleni szlachetnych, widłorogi amerykańskie, ale także i bydło domowe[25].
Naukowcy podkreślają sprzeczność między poglądami i działaniami ekologów i farmerów w odniesieniu do piesków preriowych[26]. Od czasów ekspedycji Lewisa i Clarka nieświszczuki zostały w znacznym stopniu wytępione na Wielkich Równinach. Zostały zdziesiątkowane przez kampanie trucia ich jako szkodnika upraw oraz chorobę wywołaną przez pałeczkę dżumy[10]. Na terenie południowo-zachodniej części Nowego Meksyku, południowo-wschodniej Arizony oraz na innych lokalnych obszarach gatunek został już całkowicie wytępiony[3]. Siedliska nieświszczuka zostały przekształcone w pastwiska i pola uprawne[10].
Do głównych zagrożeń gatunku IUCN zalicza[3]:
W połowie XIX wieku liczebność populacji nieświszczuków czarnoogonowych była zbliżona do 5 miliardów osobników, zaś wielkość pojedynczej, rozległej kolonii szacowana była na 400 000 zwierząt[27]. Obecna liczebność populacji piesków preriowych liczona jest w milionach, lecz oszacowanie łącznej liczby zwierząt tego gatunku jest znacznie utrudnione. Poszczególne populacje są izolowane i znacznie zmniejszyły swoją liczebność. United States Fish and Wildlife Service (USFaWS) publikuje informacje na temat powierzchni zajmowanych lub potencjalnych siedlisk. Obliczono, że na terenie Stanów Zjednoczonych jest blisko 159,6 mln ha potencjalnych siedlisk nieświszczuków, z czego zasiedlone są tereny jedynie o powierzchni 0,4 mln ha. Historycznie w jednym czasie zajętych było maksymalnie 20% siedlisk[10][28], czyli około 32 mln ha (według innych źródeł 45 mln ha)[28]. Biorąc pod uwagę powyższe wyniki, National Wildlife Federation (NWF) złożyła w 1998 roku do United States Fish and Wildlife Service wniosek o objęcie gatunku ochroną prawną na podstawie „Endangered Species Act”, jednak – mimo spełnienia w opinii NWF aż czterech z pięciu wymogów, jakie muszą spełniać gatunki objęte aplikacją – wniosek został odrzucony. USFaWS potwierdziło zasadność zgłoszenia, a jako przyczynę odmowy wskazało szereg innych zagrożeń ekologicznych o wyższym priorytecie oraz brak środków finansowych[10].
W 1998 roku NWF opublikował rezolucję w sprawie spadku liczebności piesków preriowych degradacji ekosystemu prerii w Ameryce Północnej. Rezolucja została przyjęta przez American Society of Mammalogists. Druga rezolucja NWF w sprawie ochrony ekosystemu zasiedlanego przez nieświszczuki została przyjęta przez amerykańskie Society for Conservation Biology[10].
W opublikowanej w 1974 roku Czerwonej księdze gatunków zagrożonych Międzynarodowa Unia Ochrony Przyrody i Jej Zasobów (IUCN) wymieniała C. ludovicianus na liście gatunków zagrożonych wyginięciem[2]. W kolejnych edycjach księgi IUCN wskazuje że mimo zagrożeń nieświszczuk nie jest gatunkiem „silnie zagrożonym” i klasyfikuje go w grupie gatunków najmniejszej troski (LC)[3].
W Polsce nieświszczuki czarnoogonowe można zobaczyć w zoo w Opolu[29].
Nieświszczuk czarnoogonowy, dawniej: nieświszczuk (Cynomys ludovicianus) zwany też pieskiem preriowym – gatunek ssaka z rodziny wiewiórkowatych (Sciuridae). Jest jednym z pięciu gatunków gryzoni zaliczanych do rodzaju nieświszczuk (Cynomys). Zamieszkuje prerie na dużym obszarze Ameryki Północnej: od południowej części kanadyjskiej prowincji Saskatchewan po południowe regiony meksykańskiego stanu Coahuila oraz od wschodniej części stanu Nebraska po zachodnie krańce Montany.
Svartsvansad präriehund (Cynomys ludovicianus[3][4][5][6][7][8][9][10]) är en däggdjursart som först beskrevs av George Ord 1815. Cynomys ludovicianus ingår i släktet präriehundar och familjen ekorrar.[11][12]
Catalogue of Life [11]samt Wilson & Reeder (2005) skiljer mellan 2 underarter:[6]
Pälsfärgen är brunaktig till rödbrunaktig på ovansidan, vitaktig på buksidan. Sommarpälsen är tickad som hos en huskatt; de individuella håren är randiga, för denna arten svart längst ner, sedan vitaktigt, därefter kanelbrunt, gråbrunt och i spetsen svart. För vinterpälsen är tickningen annorlunda: Längst ner svart, sedan gråbrunt, kanelbrunt, och vitt i spetsen. Spenarna är 8 till antalet och gråfärgade hos honan; de syns emellertid endast under dräktighet och digivning. Morrhår och klor är svarta, medan ögonens regnbågshinna är mörkbrun. Som trivialnamnet antyder, är den yttersta tredjedelen av svansen svart.[13] Hanarna är större än honorna: Viktmässigt är de mellan 10 och 15 % tyngre. Kroppslängden varierar mellan 35 och 37,5 cm för honorna, 36 och 41,5 cm för hanarna. Hanarnas vikt varierar mellan 850 och 1 675 g, honornas mellan 705 och 1 050 g.[14]
Arten lever på öppna, torra grässlätter, gärna nära flodslätter med malörtsväxter och opuntiakaktus. Den undviker dock helt fuktiga habitat.[14] Områden med kortväxt vegetation föredras, och arten söker ofta upp markstörda habitat, som områden där kreatur utfodras. Den kan även leva på ödetomter i samhällen.[1] Som andra präriehundar bildar den stora, underjordiska samhällen med hundratals individer som lever i familjegrupper som består av en eller ett par fertila hanar, ett antal närbeslätade honor och ungar. Förekommer flera vuxna hanar i gruppen, är dessa oftast bröder. Honorna stannar hela sitt liv i samma familjegrupp, medan hanarna byter grupp.[14] Byte av familjegrupp förekommer även bland fertila hanar; de stannar oftast inte mer än ett par år i samma grupp, utan byter till en annan när deras döttrar börjar bli könsmogna.[13] Matförråden är gemensamma inom familjegruppen, och alla individerna i den hävdar revir gemensamt. Hanarna är emellertid främst aggressiva mot andra främmande hanar, och honorna mot främmande honor, speciellt när de har boungar, som främmande honor ofta försöker döda. När ungarna blivit så stora att de lämnar boet under dagarna, tolereras de dock av alla individer i samhället, och det förekommer att de följer med "fel" moder ner i boet till natten, där de tas om hand och även i förekommande fall dias som om de vore honans egna ungar.[14]
Revirhävdandet hindrar inte präriehundarna från att ha ett rikt, socialt liv i sitt samhälle; de leker ofta med och putsar varandra, och om en präriehund blir varse en fara, som ett annalkande rovdjur, ger den ifrån sig ett varningsläte, så alla individer kan ge sig under jord för skydd.[14]
Arten är dagaktiv, och sover inte vintersömn. Mycket kalla perioder under vintern kan den dock hålla sig under jord under flera dagar.[14]
Arten är inte särskilt långlivad: Honorna kan bli 8 år gamla, medan hanarna sällan blir äldre än 5 år.[14]
Den svartsvansade präriehunden är främst växtätare: Mer än 98 % av födan utgörs av blad, stjälkar och rötter av gräs som kamveten, lostor och Bouteloua samt andra örter som tistlar, opuntiaarter, Chrysothamnus och malvaväxten Sphaeralcea coccinea. Dessutom kan den ibland ta insekter som skalbaggar, gräshoppor och fjärilslarver. Arten dricker sällan; den får tillräckligt med vatten från födan.[14]
Själv utgör den byte för flera rovdjur, som prärievarg, nordamerikansk grävling, lodjur, svartfotad iller, präriefalk, kungsörn, flera hökarter, skallerormar och snoksläktet Pituophis.[14]
Arten är normalt polygyn: Djuren parar sig inom familjegruppen, där den fertila hanen parar sig med flera av de fertila honorna. Om hanarna är mer en en (vanligtvis bröder), parar sig i regel alla hanarna med honorna. Lektiden inträffar en gång per år, vanligen under senvinter till tidig vår, och själva parningen sker i regel under jord. Efter en dräktighet mellan 33 och 38 dagar föder honan mellan 1 och 8 ungar, i medeltal 3 stycken. Ungarna är helt outvecklade, blinda och nakna. En nyfödd unge är omkring 7 cm lång, och väger cirka 15 g. Ungarna diar mellan 37 och 51 dagar, och börjar visa sig ovan jord strax innan de är avvanda. De blir vanligtvis könsmogna kring tvåårsåldern, även om tiden kan variera.[14]
Denna präriehund förekommer i centrala Nordamerika från sydligaste Saskatchewan i Kanada över norra Montana och centrala North Dakota söderut till västra Texas och New Mexico i USA samt nordöstra Sonora och norra Chihuahua i norra Mexiko.[1]
IUCN kategoriserar arten globalt som livskraftig. Populationen minskar emellertid; främsta orsaken är det faktum att arten är en betydande pestreserv, och många individer dör av den sjukdomen. Andra orsaker är habitatförlust till följd av uppodling och byggnation, populationsfragmentering och mänskliga kontrollåtgärder som giftutläggning och jakt.[1]
Wikimedia Commons har media som rör Svartsvansad präriehund.
Wikispecies har information om Cynomys ludovicianus.
Svartsvansad präriehund (Cynomys ludovicianus) är en däggdjursart som först beskrevs av George Ord 1815. Cynomys ludovicianus ingår i släktet präriehundar och familjen ekorrar.
Країни поширення: Канада, Мексика, Сполучені Штати Америки. Мешкає на сухих, плоских або пологих, відкритих луках з низькою, відносно рідкісною рослинністю, в тому числі областях випасання худоби.
Веде денний спосіб життя. Утворює колонії. Молодь народжуються в підземних норах. Не впадає у сплячку. Харчується різнотрав'ям, взимку також підземними коренями. Воду отримує з рослинності. Головні хижаки: Canis latrans, Taxidea taxus, Lynx rufus, Aquila chrysaetos, Buteo regalis, Buteo jamaicensis, Crotalus viridis.
Вагітність триває 34 днів. Пологи відбуваються під землею. Розмір приплоду в середньому близько чотирьох. Самиця дає один приплід на рік.
Хутро від піщано-коричневого до червонувато-коричневого кольору зверху, і білувате знизу. Літнє хутро темніше, майже без підшерстя, зимове з густим підшерстям. Линяє двічі на рік. Альбіноси рідкісні, але бувають. Очі, кігті, вібриси й остання третина хвоста чорні. Вага від 0,68 до 1,4 кг, довжина тіла, як правило, від 36 до 43 см й від 7,6 до 10 см хвіст. Зубна формула: 1/1, 0/0, 2/1, 3/3, загалом 22 зуба.
Cầy thảo nguyên đuôi đen, còn gọi là Sóc đồng cỏ đuôi đen (danh pháp khoa học: Cynomys ludovicianus) là một loài sóc trong họ Sóc được tìm thấy ở Đại bình nguyên của Bắc Mỹ từ biên giới Hoa Kỳ-Canada đến biên giới Hoa Kỳ-México. Không giống các loài sóc đồng cỏ khác, loài này thực sự không ngủ đông. Sóc đồng cỏ đuôi đen có thể thấy trên mặt đất giữa mùa đông. Một quần thể sóc đồng cỏ đuôi đen ở Texas đã được ghi nhận có phạm vi 64.000 km² và có 400.000.000 cá thể. Trước khi môi trường sống bị phá hủy, loài này có lẽ là loài sóc đồng cỏ dồi dào nhất ở trung bộ Bắc Mỹ. Loài này là một trong hai loài được miêu tả bởi chuyến thám hiểm Lewis và Clark trong ghi chép và nhật ký về chuyến khám phá của họ.
Sóc đồng cỏ đuôi đen nhìn chung có màu vàng nhạt với bụng màu nhạt hơn. Đuôi của chúng có chóp màu đen. Con trưởng thành có cân nặng đến 1,5 đến 3 lb (0,68 đến 1,36 kg), con đực thường nặng hơn con cái. Chiều dài cơ thể thường là 14 đến 17 in (36 đến 43 cm), đuôi dài 3 đến 4 in (7,6 đến 10,2 cm).
Cầy thảo nguyên đuôi đen, còn gọi là Sóc đồng cỏ đuôi đen (danh pháp khoa học: Cynomys ludovicianus) là một loài sóc trong họ Sóc được tìm thấy ở Đại bình nguyên của Bắc Mỹ từ biên giới Hoa Kỳ-Canada đến biên giới Hoa Kỳ-México. Không giống các loài sóc đồng cỏ khác, loài này thực sự không ngủ đông. Sóc đồng cỏ đuôi đen có thể thấy trên mặt đất giữa mùa đông. Một quần thể sóc đồng cỏ đuôi đen ở Texas đã được ghi nhận có phạm vi 64.000 km² và có 400.000.000 cá thể. Trước khi môi trường sống bị phá hủy, loài này có lẽ là loài sóc đồng cỏ dồi dào nhất ở trung bộ Bắc Mỹ. Loài này là một trong hai loài được miêu tả bởi chuyến thám hiểm Lewis và Clark trong ghi chép và nhật ký về chuyến khám phá của họ.
Cynomys ludovicianus (Ord, 1815)
Подвиды Ареал
Чернохвостая луговая собачка[2] (лат. Cynomys ludovicianus) — вид из рода луговых собачек семейства беличьи.
Вид широко распространён в Северной Америке, обитая на обширной территории от южной части канадского штата Саскачеван и американского штата Монтана на севере, далее через западную и центральную часть Великих Равнин и до западной части штата Техас, Нью-Мексико и юго-восточной части Аризоны. Кроме того, обитает в северо-восточной части мексиканского штата Сонора и в северной части штата Чиуауа[3].
Естественная среда обитания — пустынно-степные ландшафты равнин и предгорий с низменной, относительно скудной растительностью. Встречаются на окраине городов[3].
Размеры средние, внешне напоминают сурков. Между самцами и самками существует половой диморфизм. Длина тела с головой колеблется от 352 до 415 мм. Вес взрослой особи — от 705 до 1675 г (подвержен сезонному колебанию). Самцы примерно на 10—15 % крупнее самок[4]. Спина бурая или красно-бурая. Брюхо имеет более светлую окраску. Наружное ухо короткое, широкое. Защёчные мешки невелики. Хвост опущен. На передних лапах имеются крупные и мощные когти. Подошвы лап покрыты шерстью[5].
Ведёт наземный образ жизни. Приспособлена к рытью нор. Живёт крупными сообществами со сложной структурой отношений между отдельными особями. Активность приходится на день. Устраивает сложные норы, глубина которых может доходить до 3—5 м. В норе имеется гнездовая камера. Часто поднимается на задние лапы, чтобы осмотреть окрестности. В случае угрозы громко кричит. С конца июля-августа впадает в спячку. Пробуждается в феврале-марте[5].
Основу рациона составляют различные травянистые растения. Иногда поедают насекомых[4].
Период размножения зависит от места обитания, но, как правило, приходится на конец зимы-начало весны. Беременность короткая, длится около 30 дней. У самки бывает всего один выводок за год. В помёте от 1 до 8 детёнышей (в среднем — 3)[4]. Примерно через 63 дня детёныши отлучаются от груди матери. Половая зрелость наступает примерно через 730 дней. Максимальная продолжительность жизни в неволе — 11 лет (в дикой природе — 8 лет у самок, и 5 лет у самцов)[6].
Чернохвостая луговая собачка (лат. Cynomys ludovicianus) — вид из рода луговых собачек семейства беличьи.
![Cynomys ludovicianus range[1]](http://zh.wikipedia.org/wiki/File:Black-tailed_Prairie_Dog_Cynomys_ludovicianus_distribution_map.png)
黑尾土撥鼠（學名Cynomys ludovicianus）又稱黑尾草原犬鼠，是松鼠科的成員，生活於北美洲大平原，範圍大約介於美加邊境與美墨邊境之間。不像其他土拨鼠，黑尾土拨鼠并不冬眠。
黑尾土拨鼠通常为浅棕色，肚子颜色稍浅。尾巴为黑色，也是名称的由来。成年黑尾土拨鼠重量为1.5至3磅（0.68至1.4公斤），雄性通常比雌性重。体长通常为14至17英寸（36至43厘米），尾巴长度为3至4英寸（7.6至10厘米）。
黑尾土拨鼠为昼行性动物。下雨下雪天以及温度超过100°F (38°C)的活动减少。它们并不冬眠，但是可能会短暂的休眠。
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검은꼬리프레리도그(Cynomys ludovicianus)는 다람쥐과에 속하는 설치류의 일종이다. 5종의 프레리도그 중의 하나이다. 미국과 캐나다 국경부터 미국과 멕시코 국경 사이의 북아메리카 그레이트플레인스에서 발견된다. 일부 다른 프레리도그와 달리 진정한 겨울잠을 자지는 않는다. 겨울 중반에 땅 위에서 관찰된다. 텍사스주에서 검은꼬리프레리도그는 넓이 64,000km2를 차지하고 개체수는 약 4억 마리에 이른다. 개체수가 파괴되기 전에는 북아메리카 중부 지역에서 가장 풍주한 프레리도그였을 것으로 추정하고 있다. 루이스 클라크 탐사의 저널과 탐사 일기를 통해 기재된 2종 중의 하나이다. 천적은 퓨마, 코요테, 늑대, 아메리카오소리, 검은발족제비 등이다.
다음은 2009년 헬겐(Helgen) 등의 연구에 기초한 계통 분류이다.[3]
마멋족 프레리도그속