American pikas communicate via vocalizations and scent marking, and they can discriminate between individuals through calls and cheek-gland secretions. They make 2 characteristic vocalizations, short calls and long calls. Short calls are used as an alarm when predators are present or as a warning signal to potential intruders (i.e., to defend one's territory). Alarm calls are usually repetitive short calls that change in frequency depending on the type of predator seen (e.g., large vs. small). Long calls are almost exclusively given by adult males and are most common during breeding season, however, both males and females may sing in the autumn. Short call duets are also sung by mating pairs in an effort to maintain social tolerance.
American pikas use urine, feces, and cheek marks while scent marking. Cheek markings, produced from apocrine sweat glands, are used to attract potential mates and to demarcate territories. They are spread by both sexes by rubbing their jowls on rocks. During breeding season or upon colonization of a new territory, cheek marking occurs with elevated frequency. Urine and feces are usually placed by haypiles to mark ownership.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: duets ; scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
Due to its abundance and widespread distribution, the IUCN lists Ochotona princeps as a species of least concern. However, of the thirty six recognized subspecies, seven are listed as vulnerable and one, O. p. schisticeps, is listed as near threatened. The seven vulnerable subspecies (O. p. goldmani, O. p. lasalensis, O. p. nevadensis, O. p. nigrescens, O. p. obscura, O. p. sheltoni, and O. p. tutelata) are all found in the Great Basin and are currently experiencing major threats that have resulted in local extirpations. The greatest threat to American pikas, especially those in the Great Basin, is likely global climate change as they are extremely sensitive to high temperatures. American pikas can die within an hour if ambient temperatures rise above 23°C (75°F). Many populations are expected to migrate north or move to higher elevations. Unfortunately, American pikas are very poor dispersers.
Various organizations have suggested placing Ochotona princeps under the protection of the Endangered Species Act. Potential solutions to local population declines may include legislation changes to decrease the amount of global warming stressors, increasing awareness, identification of new protected areas, and re-introductions in areas where they have been extirpated.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
There are no known negative effects of American pikas on humans.
There are no known positive effects of American pikas on humans.
American pikas are considered allogenic engineers (i.e., altering the environment through their activities). Their large haypiles, containing both plant and fecal matter, are not entirely consumed during the winter, leaving large accumulations of decomposing biomass to act as fertilizer and a potential food source for other animals. As fertilizer, haypiles ultimately increase soil nitrogen, a limiting resource for vegetation at high altitude. Also, American pikas are host to many species of intestinal parasites (Coccidia) and parasitic fleas (Siphonaptera).
Ecosystem Impact: keystone species
Commensal/Parasitic Species:
American pikas are generalized herbivores that select forage by assessing its nutritional value. Preferred plants have higher protein, lipid, and water content and higher caloric value than non-preferred plants. Although certain plant species are avoided due to the presence of toxins, these plants may be cached in haypiles for winter consumption. Some toxins act as natural preservatives that wear off by the time the plant is consumed. Caching, also known as haying, occurs during summer. Haypiles generally consist of forbs and tall grasses, but up to 30 species of plants may be found in a single haypile. Most haypiles are constructed near the talus-meadow interface and serve as territory markers. When winter arrives, haypiles are moved into burrows and used as their main food supply. During winter, American pikas may also feed upon cushion plants and lichens in the subnivean zone to supplement their diet. In the summer, American pikas typically eat short alpine grasses. Forbs and shrubs constitute 78 to 87% of their diet, with alpine avens, clovers, and sedges making up the remaining 22 to 13% of their diet. Occasionally, conifer needles and bark are also eaten. They are not obligate drinkers as water is primarily obtained via ingested plants.
American pikas create two types of fecal droppings: a hard brown round pellet and a soft shiny string of material (the caecal pellet). Pikas consume the caecal pellet (which has high energy value and protein content) or store it for later consumption. Only about 68% of the ingested food is assimilated, making the caecal pellets an important part of the American pika's diet.
Plant Foods: leaves; wood, bark, or stems; flowers
Other Foods: dung
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Folivore , Lignivore); coprophage
American pikas can be found throughout the mountainous regions of western North America. Their geographic range extends as far south as New Mexico and California, as far north as British Columbia, and as far east as Colorado.
Biogeographic Regions: nearctic (Native )
American pikas inhabit areas of broken rock and talus fields fringed by alpine meadows. They are most common in cool, moist habitats above tree line. In the northern part of their range, they can be found from sea level to 3,000 meters; however, in the southern part of their range, American pikas are rarely found below 2,500 meters.
Range elevation: sea level to 3000 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: tundra ; taiga ; mountains
Average annual mortality of American pikas is 37 to 53%, and age-specific mortality is highest for 0 to 1-year-olds and 5 to 7-year-olds. The maximum age of American pikas in the wild and in captivity is 7 years, with an average life expectancy of 3 years in the wild.
Range lifespan
Status: wild: 7 (high) years.
Range lifespan
Status: captivity: 7 (high) years.
Average lifespan
Status: wild: 3 years.
Average lifespan
Status: wild: 6.0 years.
Average lifespan
Status: wild: 7.0 years.
American pikas are intermediate in size when compared to other ochotonids. Their body mass exhibits a great deal of variation and ranges from 121 to 176 grams. In certain parts of their range, males are larger than females, but only slightly. Their body is ovoid, with short ears, long vibrissae (40-77 mm), short limbs, and no visible tail. Their back paws are digitigrade, have four toes (compared to five on the front), and range from 25 to 35 mm in length. Both sexes have a pseudocloacal openings, which must be everted to expose the penis or clitoris. Females have six mammae which do not enlarge during lactation. American pikas have a high body temperature (average of 40.1°C) and relatively low upper lethal temperature (average of 43.1°C). They have a high metabolic rate (1.53 cm^3 oxygen/hour), and thermoregulation is behavioral rather than physiological.
Pelage color of American pikas changes seasonally but maintains an off-white hue on its ventral surface (as opposed to white in Ochotona collaris). On its dorsal surface, pelage ranges from grayish to cinnamon-brown in the summer. In the winter, their dorsal pelage is gray and is twice as long as summer pelage. Their ears are round, covered with dark hair on their internal and external surfaces, and edged in white. Their paws are densely furred, including the soles, with the exception of small black naked pads at the ends of the toes. Their skull is slightly round with a flat, broad interorbital region. Other distinguishing characteristics of the American pika's skull include a slender rostrum, nasals that are widest anteriorly, maxillae with one large fenestration (rather than numerous small fenestrae of Leporidae), an elongated jugal, which forms a prominent projection from the posterior zygomatic arch, and a dental formula of 2/1, 0/0, 3/2, 2/3 totaling 26 teeth.
Range mass: 121 to 176 g.
Range length: 162 to 216 mm.
Average basal metabolic rate: 1.53 cm3.O2/g/hr.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike; male larger
Average basal metabolic rate: 0.932 W.
American pikas are moderately camouflaged and when a potential predator is detected, they emit an alarm-call informing the rest of the community of its presence. Alarm calls are emitted less frequently for small predators, as small predators may be able to chase them into the talus interstices. Small predators consist of long-tailed weasels (Mustela frenata) and ermines (Mustela erminea). Large predators, such as coyotes (Canis latrans) and American martens (Martes americana), are especially adept at capturing juveniles who are not quick enough to escape. Golden eagles (Aquila chrysaetos) also feed on American pikas, but their impact is minimal.
Known Predators:
Anti-predator Adaptations: cryptic
American pikas are monogamous, and mate pairs are formed with adults from adjacent territories. When more than one potential mate is available, females may exhibit mate choice.
Mating System: monogamous
American pikas typically mate as yearlings. Males are considered sexually active when their testes are 11 mm in length or greater (Smith and Weston, 1990). American pikas are reflex ovulators (i.e., ovulation only occurs after breeding) and are seasonally polyestrus. Each female has 2 litters per year, with an average of 3 young per litter. Breeding commences 1 month before snow-melt and gestation last approximately 30 days. At low elevations, parturition occurs as early as March but occurs from April to June at higher elevations. Pups weigh between 10 and 12 g at birth and are weaned by 28 days old. Lactation significantly reduces a female's fat reserves, and although females exhibit postpartum estrus, they only nurse the second litter if the first does not survive.
Breeding interval: American pikas breed twice yearly, during the same breeding season.
Breeding season: American pikas breed one month before snow-melt and once again following the birth of their first litter.
Range number of offspring: 1 to 6.
Average number of offspring: 3.
Average gestation period: 30 days.
Range weaning age: 18 to 35 days.
Average weaning age: 28 days.
Average time to independence: 4 weeks.
Average age at sexual or reproductive maturity (female): 347 days.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; induced ovulation ; fertilization ; viviparous ; post-partum estrous
Average birth mass: 9 g.
Average gestation period: 30 days.
Average number of offspring: 3.
Average age at sexual or reproductive maturity (female)
Sex: female: 347 days.
American pikas are born slightly altrical; they are blind, slightly haired, have fully erupted teeth, and weigh between 10 and 12 grams at birth. For the first 18 days, young are completely dependent on their mothers. Pups open their eyes at 9 days of age. Mothers spend most of their time foraging, but visit the nest once every 2 hours to nurse for an average of 10 minutes. Pups become independent by about 4 weeks old (soon after weening). American pikas exhibit a remarkable growth rates compared to other members of Lagomorpha, and can reach adult size after only 3 months.
Parental Investment: altricial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
This taxon can be found in the Montana valley and foothill grasslands ecoregions, along with some other North American ecoregions. This ecoregion occupies high valleys and foothill regions in the central Rocky Mountains of Montana in the USA and Alberta, Canada. The ecoregion the uppermost flatland reaches of the Missouri River drainage involving part of the Yellowstone River basin, and extends into the Clark Fork-Bitterroot drainage of the Columbia River system. The ecoregion, consisting of three chief disjunctive units, also extends marginally into a small portion of northern Wyoming. Having moderate vertebrate species richness, 321 different vertebrate taxa have been recorded here.
The dominant vegetation type of this ecoregion consists chiefly of wheatgrass (Agropyron spp.) and fescue (Festuca spp.). Certain valleys, notably the upper Madison, Ruby, and Red Rock drainages of southwestern Montana, are distinguished by extensive sagebrush (Artemisia spp.) communities as well. This is a reflection of semi-arid conditions caused by pronounced rain shadow effects and high elevation. Thus, near the Continental Divide in southwestern Montana, the ecoregion closely resembles the nearby Snake/Columbia shrub steppe.
A number of mammalian species are found in the ecoregion, including: American Pika (Ochotona princeps), a herbivore preferring talus habitat; Bighorn Sheep (Ovis canadensis), Black-tailed Prairie Dog (Cynomys ludovicianus), who live in underground towns that may occupy vast areas; Brown Bear (Ursos arctos); Hoary Marmot (Marmota caligata), a species who selects treeless meadows and talus as habitat; and the Northern River Otter (Lontra canadensis), a species that can tolerate fresh or brackish water and builds its den in the disused burrows of other animals.
There are six distinct anuran species that can be found in the Montana valleys and foothills grasslands, including: Canadian Toad (Anaxyrus hemiophrys); Western Toad (Anaxyrus boreas); Northern Leopard Frog (Lithobates pipiens); Plains Spadefoot Toad (Spea bombifrons); Columbia Spotted Frog (Rana luteiventris), an anuran that typically breeds in shallow quiet ponds; and the Boreal Chorus Frog (Pseudacris maculata).
Exactly two amphibian taxa occurr in the ecoregion: Long-toed Salamander (Ambystoma macrodactylum), a species who prefers lentic waters and spends most of its life hidden under bark or soil; Tiger Salamander (Ambystoma tigrinum).
Reptilian species within the ecoregion are: Milk Snake (Lampropeltis triangulum), an adaptable taxon that can be found on rocky slopes, prairie and near streambeds; Painted Turtle (Chrysemys picta); Western Plains Garter Snake (Thamnophis radix), a taxon that can hibernate in the burrows of rodents or crayfish or even hibernate underwater; Yellow-bellied Racer (Coluber constrictor); Spiny Softshell Turtle (Apalone spinifera); Western Terrestrial Garter Snake (Thamnophis elegans); Rubber Boa (Charina bottae); Western Skink (Plestiodon skiltonianus); and the Western Rattlesnake (Crotalis viridis).
The ecoregion supports endemic and relict fisheries: Westslope Cutthroat Trout (Oncorhynchus clarki lewisi), Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri), and fluvial Arctic Grayling (Thymallus arcticus), a relict species from past glaciation.
The American pika (Ochotona princeps), a diurnal species of pika, is found in the mountains of western North America, usually in boulder fields at or above the tree line. They are herbivorous, smaller relatives of rabbits and hares.[6] Pikas have two different ways of foraging; they either directly consume food or they cache food in piles for the winter (haying).
Pikas are vocal, using both calls and songs to warn when predators are nearby and during the breeding season. Predators of the pika include eagles, hawks, coyotes, bobcats, foxes, and weasels.
Recent studies suggest populations in the southwest United States are declining due to habitat loss and global warming.[7] Currently the American pika is considered a species of least concern and is still common in the northwestern United States and Canada .
American pikas, known in the 19th century as "little Chief hares",[8] have a small, round, ovate body. Their body lengths range from 162 to 216 mm (6.4 to 8.5 in). Their hind feet range from 25 to 35 mm (1–1½ in).[9] They usually weigh about 170 g (6.0 oz).[10] Body size can vary among populations. In populations with sexual dimorphism, males are slightly larger than females.[11]
The American pika is intermediate in size among pikas. The hind legs of the pika do not seem to be much longer than its front legs and its hind feet are relatively short when compared to most other lagomorphs.[11] It has densely furred soles on its feet except for black pads at the ends of the toes.[11] The ears are moderately large and suborbicular, and are hairy on both surfaces, normally dark with white margins. The pika's "buried" tail is longer relative to body size compared to other lagomorphs.[11] It has a slightly rounded skull with a broad and flat preorbital region. The fur color of the pika is the same for both sexes, but varies by subspecies and season.[11] The dorsal fur of the pika ranges from grayish to cinnamon-brown, often colored with tawny or ochraceous hues, during the summer. During winter, the fur becomes grayer and longer.[11] The dense underfur is usually slate gray- or lead-colored. It also has whitish ventral fur. Males are called bucks and females are called does like rabbits.
The American pika can be found throughout the mountains of western North America, from central British Columbia and Alberta in Canada to the US states of Oregon, Washington, Idaho, Montana, Wyoming, Colorado, Utah, Nevada, California, and New Mexico.[10] Of the 30 existing species of pika, it is one of only two which inhabit North America, along with the collared pika (O. collaris). In relation to the distribution of the American pika, the collared pika is located farther north of those regions and is separated by a gap of about 500 miles (800 km) extending across British Columbia and Alberta.[12]
Pikas inhabit talus fields that are fringed by suitable vegetation on alpine areas. They also live in piles of broken rock.[11][13] Sometimes, they live in man-made substrate such as mine tailings and piles of scrap lumber. Pikas usually have their den and nest sites below rock around 0.2–1 m in diameter, but often sit on larger and more prominent rocks. They generally reside in scree near or above the tree line. Pikas are restricted to cool, moist microhabitats on high peaks or watercourses.[13] Intolerant of high diurnal temperatures, in the northern portion of their range, they may be found near sea level, but in the south they are rare below 2,500 m (8,200 ft).[11] Pikas rely on existing spaces in the talus for homes and do not dig burrows. However, they can enlarge their homes by digging.[11]
The American pika is a generalist herbivore. It eats a large variety of green plants, including different kinds of grasses, sedges, thistles, and fireweed. Although a pika can meet its water demand from the vegetation eaten, it does drink water if it is available in its environment.[14]
Pikas have two different ways of foraging; they directly consume food (feeding) or they cache food in haypiles to use for a food source in the winter (haying).[11] They feed throughout the year while haying is limited to the summer. Since they do not hibernate, pikas have greater energy demands than other montane mammals. They also make 13 trips per hour to collect vegetation when haying, up to a little over 100 trips per day.[15] The timing of haying seems to correlate to the amount of precipitation from the previous winter.[16] Pikas start and then quit haying earlier in years following little snow and early spring. In areas at lower elevations, haying begins before the snow has melted at high altitudes; at higher elevations, haying continues after it ends in lower elevations.[16]
When haying, pikas harvest plants in a deliberate sequence, corresponding to their seasonal phenology.[11] They seem to assess the nutritional value of available food and harvest accordingly. Pikas select plants that have the higher caloric, protein, lipid, and water content.[11] Forbs and tall grass tend to be hayed more than eaten directly. Haypiles tend to be stored under the talus near the talus-meadow interface, although they may be constructed on the talus surface. Males generally store more vegetation than females and adults usually store more than juveniles.[11] Pikas deposit two kinds of fecal droppings: Hard, brown, round pellets and pellets that are soft black shiny strings that form in the caecum.[11] Caecal pellets have more energy value than stored plant food and the pika may consume them directly or store them for later.[11]
The American Pika is diurnal. The total area of land that an American Pika uses is known as a home range. About 55% of its home range is territory that the Pika defends against intruders. Territory size can vary from 410–709 m² and is dependent on configuration, distance to vegetation, and quality of vegetation.[11] The home ranges of Pikas may overlap, with the distances of the home ranges of a mating pair being shorter than that of the nearest neighbors of the same sex.[11] Spatial distances between adults of a pair is greatest during early and midsummer and reduces during late summer and early autumn. Pikas defend their territories with aggression. Actual aggressive encounters are rare and usually occur between members of the same sex and those unfamiliar with each other. A Pika may intrude on another's territory, but usually when the resident is not active. During haying, territorial behavior increases.[14]
Adult Pikas of the opposite sex with territories adjacent form mated pairs. When more than one male is available, females exhibit mate choice.[11] Pikas are reflex ovulators; ovulation only occurs after copulation, and they are also seasonally polyestrous. A female has two litters per year and these litters average three young each. Breeding takes place one month before the snow melts and gestation lasts around 30 days. Parturition occurs as early as March in lower elevations, but occurs from April to June at higher elevations. Lactation significantly reduces a female's fat reserves and they only nurse the second litter if the first does not survive, despite exhibiting postpartum estrus.[11] Pikas are born slightly altricial, being blind, slightly haired, and having fully erupted teeth. They weigh between 10 and 12 g at birth. At around nine days old, they are able to open their eyes.[11] Mothers forage most of the day and return to the nest once every two hours to nurse the young. Young become independent after four weeks, around the same time they are weaned.[11] Young may remain in their natal or an adjoining home range. When in their home range, young occupy areas away from their relatives as much as possible. Dispersal appears to be caused by competition for territories.[17]
Pikas are vocal, using both calls and songs to communicate among themselves. A call is used to warn when a predator is lurking nearby, and a song is used during the breeding season (males only), and during autumn (both males and females).[10] Predators of the Pika include eagles, hawks, coyotes, bobcats, foxes, and weasels.
The American pika was described in the scientific literature by John Richardson in Fauna Boreali-Americana in 1828. The original scientific name was Lepus (Lagomys) princeps.[18]
As they live in the high and cooler mountain regions, they are very sensitive to high temperatures, and are considered to be one of the best early warning systems for detecting global warming in the western United States.[19] Temperature increases are suspected to be one cause of American pikas moving higher in elevation[20] in an attempt to find suitable habitat, as well as cooler temperatures. American pikas, however, cannot easily migrate in response to climate change, as their habitat is currently restricted to small, disconnected habitat "islands" in numerous mountain ranges.[21] Pikas can die in six hours when exposed to temperatures above 25.5 °C (77.9 °F) if individuals cannot find refuge from heat. In warmer environments, such as during midday sun and at lower elevation limits, pikas typically become inactive and withdraw into cooler talus openings.[16] Because of behavioral adaptation, American pikas also persist in the hot climates of Craters of the Moon and Lava Beds National Monuments (Idaho and California, respectively). Average and extreme maximum surface temperatures in August at these sites are 32 and 38 °C (90 and 100 °F), respectively.[22]
Recent studies suggest some populations are declining due to various factors, most notably global warming.[20] A 2003 study, published in the Journal of Mammalogy, showed nine of 25 sampled populations of American pika had disappeared in the Great Basin, leading biologists to conduct further investigations to determine if the species as a whole is vulnerable.[23]
In 2010, the US government considered, then decided not to add the American pika under the US Endangered Species Act;[24] in the IUCN Red List, it is still considered a species of least concern.[3]
The Pikas in Peril Project,[25] funded through the National Park Service Climate Change Response Program, began data collection in May 2010. A large team of academic researchers and National Park Service staff - from three universities and eight national parks - worked together to address questions regarding the vulnerability of the American pika to future climate change scenarios projected for the western United States. The project concluded in 2016.[26]
More recent studies have found widespread extirpations and range retractions at lower elevations which are typically warmer and drier, patterns that have been further attributed to varying aspects of climate change such as warmer summer and winter temperatures and changes in precipitation.[27][28][29][30] For example, one study found upslope retractions in 44 of 64 watersheds surveyed in the Northern Rockies, with retractions averaging 281 meters.[31] Another study in North Cascades National Park in Washington found that a single winter of little to no snow caused drastic declines in pika abundance, highlighting how snowpack provides a necessary insulation against cold winter temperatures.[32]
The American pika (Ochotona princeps), a diurnal species of pika, is found in the mountains of western North America, usually in boulder fields at or above the tree line. They are herbivorous, smaller relatives of rabbits and hares. Pikas have two different ways of foraging; they either directly consume food or they cache food in piles for the winter (haying).
Pikas are vocal, using both calls and songs to warn when predators are nearby and during the breeding season. Predators of the pika include eagles, hawks, coyotes, bobcats, foxes, and weasels.
Recent studies suggest populations in the southwest United States are declining due to habitat loss and global warming. Currently the American pika is considered a species of least concern and is still common in the northwestern United States and Canada .