Bushy-tailed woodrats are sexually dimorphic: adult males usually weigh 300-600 g with an average of 405 g, whereas adult females usually weigh only 250-350 g with an average of 270 g. These ranges are relatively large because this species occupies a large geographic range, and its body size is closely correlated with climate (conforms to Bergmann's rule). Neotoma cinerea is the largest and most cold-tolerant species of woodrat, and the largest and most sexually dimorphic individuals of this species are found in the northern parts of its range. In addition, body size of bushy-tailed woodrats (examined via fecal pellet size in middens) has been shown to correlate with known climatic fluctuations over the past 25,000 years. Woodrats are good climbers and have sharp claws. They have hypsodont molars with enamel ridges. The color of the pelage varies across the range, but is usually buff with white areas around the feet. The bushy tail characteristic of the species is used to warm the animal. Pictures of bushy-tailed woodrats are available in Vaughan (1990), Escherich (1981), and on the web at: 
. Escherich (1981) provides pictures of both sexes at various point throughout ontogeny, as well as pictures of skulls and skins.
(Egoscue, 1962; Escherich, 1981; Finley, 1990; Hickling et al., 1991; Martin, 1973; Smith, 1995; Smith et al., 1995; Vaughan, 1990)
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 335.5 g.
Average basal metabolic rate: 1.152 W.
Perception Channels: tactile ; chemical
Bushy-tailed woodrats are the hosts for a large number of parasites, and there is a literature on Neotoma parasites (e.g. Cudmore, 1986). In Oregon, for instance, a sample of bushy-tailed woodrats had 37 species of fleas, lice, ticks, and mites associated with them.
There is also a fairly extensive literature on packrat middens and their implications. One good source for this information is Betancourt, J.L., van Devender, T.R., and Martin, P.S. 1990. Packrat middens: the last 40,000 years of biotic change. University of Arizona Press, Tucson.
Finley's (1958) monograph on woodrats in Colorado (University of Kansas Publications, Museum of Natural History, 10: 213-552) contains large sections about N. cinerea. I did not use this source in preparing this account. Instead I at looked more recent literature, much of which cited and compared their results with those of Finley (1958).
Information on this species is also available on the web in a variety of locations, including http://www.fs.fed.us/database/feis/animals/Mammal/NECI/index.html and http://www.fw.vt.edu/fishex/nmex_main/species/050645.htm.
Neotoma cinerea is not in any danger, and I did not find any literature discussing the problems of conservation of this species.
IUCN Red List of Threatened Species: least concern
Bushy-tailed woodrats are attracted to shiny items and often steal them from campsites or buildings. They can be a pest species throughout their range as they find a way into buildings and establish den sites.
Bushy-tailed woodrats are important to humans for several reasons. They are important to paleontologists and paleoclimatologists not only because their middens preserve easily-dated plant macrofossils, but also because this species incorporates lots of bones into its middens as well. Packrat middens are a major source of information about Pleistocene paleoclimates and paleoecology in the western United States.
Neotoma cinerea is also important as a prey species. For instance, the bushy-tailed woodrat is one of the major food items for northern spotted owls, a species which is in jeopardy because of range reductions due to logging. The carrying capacity of owls in a particular habitat is largely dependent upon the density of their prey. Interestingly, however, Neotoma cinerea is least frequent in old-growth forests, and found more frequently in more recently cut and open habitats.
(Frase and Sera, 1993; Rosenberg et al., 1994; Vaughan, 1990)
Because this species occupies such a wide range of habitats, its diet is variable. However, N. cinerea may best be described as a generalist herbivore. Most authors have considered it entirely herbivorous, though Johnson and Hansen (1979) believed a small component of its diet consists of arthropods. Bushy-tailed woodrats eat lots of woody vegetation, and in drier habitats also concentrate on succulents. This species gets all of its water from its food and does not need to drink. Woodrats tend to eat plant materials which have high concentrations of defensive chemicals; they combat these defenses by eating only small amounts of each species. Neotoma cinerea also tends to eat low-energy food items and plants which are high in oxalates. This has implications for the building of middens, discussed below. Neotoma cinerea has an enlarged caecum, and engages in coprophagy. Johnson and Hansen (1979) provide a list of specific food items utilized by this species in a cool, dry environment in Idaho.
(Escherich, 1981; Frase and Sera, 1993; Haufler and Nagy, 1984; Johnson and Hansen, 1979; Vaughan, 1990)
Bushy-tailed woodrats are found in western North America, ranging from arctic Canada to northern New Mexico and Arizona. This species was thought to be restricted to higher elevations until very recently, when the first reports documenting Neotoma cinerea at elevations as low as 1200 m appeared. These findings lend support to molecular evidence which had earlier indicated that bushy-tailed woodrat populations were not isolated on mountain ranges throughout the Holocene. It is currently unclear whether these lowland populations are isolated by even lower valleys, or whether this species can exist in low, xeric areas as well. Bushy-tailed woodrats are currently found at elevations up to at least 3700 m. During the Pleistocene, N. cinerea is well-known at lower elevations, and its range extended south to southern Mexico. Up to thirteen subspecies are recognized. These subspecies are primarily defined based on geography and local ecology, and are not universally accepted.
(Escherich, 1981; Grayson and Livingston, 1989; Grayson et al., 1996; Mewaldt, 1982; Smith et al., 1995)
Biogeographic Regions: nearctic (Native )
Bushy-tailed woodrats occupy a range of habitats from boreal woodlands to deserts. They are cliff-dwellers, and are often found on isolated, high-elevation bouldery exposures under a variety of temperature and moisture regimes. They require adequate shelter inside the rocks, though they are occasionally found inhabiting abandoned buildings as well.
(Frase and Sera, 1993; Grayson and Livingston, 1989; Topping and Millar, 1996; Vaughan, 1990)
Terrestrial Biomes: taiga ; desert or dune ; savanna or grassland ; chaparral ; forest ; mountains
Some aspects of the reproductive cycle of bushy-tailed woodrats are still under debate. These animals have been considered polygamous, polygynous, and/or promiscuous by various authors. Often these conclusions have been based not on actual observed matings, but on the size and relative overlap of male and female ranges. Breeding chiefly occurs in spring and summer (May through August). Females have small litters (up to six young at a time, though litter sizes over four tend to suffer losses since the female has only four mammary glands) but may have up to three litters per year. Modal litter size is three. Females have been observed breeding as soon as twelve hours after giving birth, and be may pregnant with one litter while nursing another. Males fight for access to mates, both through scent marking and actual physical contact. Fights consist largely of biting and scratching and may result in serious injury. Gestation period in captivity is 27-32 days. Newborns weigh approximately 15 g. Eyes open at around 15 days old, and weaning occurs at 26-30 days.
Males are heavier than females from early in development on. By weaning, males weigh 120-150 g, and females weigh 85-135 g. Females do not alter their foraging movements between pregnancy, lactation, and the post-reproductive period -- even though nutrient demands are higher at certain stages. Heavier females tend to have significantly more males in their litters than lighter females. Males are larger and require more energy to raise, though after weaning female offspring tend to reap more rewards from their mothers via philopatry (see "Behavior" section below). Females breed for the first time when they are yearlings.
(Egoscue, 1962; Escherich, 1981; Finley, 1990; Hickling et al., 1991; Moses and Millar, 1992; Moses et al., 1995; Topping and Millar 1996a; 1996b)
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average birth mass: 13.5 g.
Average gestation period: 30 days.
Average number of offspring: 3.68.
Average age at sexual or reproductive maturity (female)
Sex: female: 353 days.
In addition to the plant communities listed above, occurrence of the bushy-tailed woodrat was noted in the following habitats:
Bushy-tailed woodrats were found inhabiting rock outcrops surrounded by big sagebrush (Artemisia tridentata)/cheatgrass (Bromus tectorum), big sagebrush/Sandberg bluegrass (Poa secunda), and big sagebrush/needle-and-thread (Stipa comata) community types at the Hanford Site in Washington [58].
In the Slim Buttes area of northwestern South Dakota, bushy-tailed woodrats occur in green ash (Fraxinus pennsylvanica)/chokecherry (Prunus virginianus) habitat [109].
At Bass Lake, California, 1 bushy-tailed woodrat was found in a forest dominated by incense-cedar (Calocedrus decurrens), white fir (Abies concolor), California black oak (Quercus kelloggii), ponderosa pine (Pinus ponderosa), sugar pine (Pinus lambertiana), and white alder (Alnus rhombifolia). In Lake Tahoe, California, bushy-tailed woodrats were found inhabiting a building surrounded by Jeffrey pine (Pinus jeffreyi), sugar pine, lodgepole pine (Pinus contorta), incense-cedar, white fir, western juniper (Juniperus occidentalis), California black oak, and chaparral. Chaparral consisted of greenleaf manzanita(Arctostaphylos patula), huckleberry oak (Quercus vaccinifolia), whitethorn ceanothus (Ceanothus cordulatus), bush chinquapin (Castanopsis semperivirens), bitter cherry (Prunus emarginata), big sagebrush, and other species [112].Den sites are primary limiting factors of bushy-tailed woodrat habitat [29,47,111]. Depending on the subspecies of bushy-tailed woodrat, dens may be located in openings between rocks, coarse woody debris (snags and logs), or dwarf mistletoe brooms [29]. In areas with heavy snowfall, rock shelters are the most important resource for the bushy-tailed woodrat [47]. In areas with mild climates and low availability of rock shelters, coarse woody debris, mistletoe brooms, and rock crevices along streams are utilized more often [21,26,35,66,77,82,85,94,96,124].
Bushy-tailed woodrat shelter consists of 2 parts, the den and the nest [29,47]. Dens refer to a shelter constructed from items such as sticks [47], leaves, grass, bark, feathers, paper, small stones [114] and human artifacts [16]. Dens are important for protection against predators and are almost never constructed in the open without a bush, rock crevice, or tree for support [47]. They are used as eating platforms, a platform for the nest, and a drying area for food [16]. Within the den are tunnels, chambers, and passages. One of the chambers may contain 2 or more nests, and other chambers are used for food storage and feeding. A lifetime may be spent using the same den [114].
Nests refer to a small cup-like structure usually located inside the den. Occasionally a nest may be found without a den [47]. On the Oregon coast and Coast Ranges, bushy-tailed woodrats may construct nests in trees up to 50 feet (15 m) above ground [29,85]. Nests are 6 to 8 inches (15-20 cm) in diameter [85] and are constructed of fibrous shredded vegetation [16,51,85].
Bushy-tailed woodrats occur from the Yukon Territory and Northwest Territories south to Arizona and New Mexico and from California east to the Badlands of the upper Missouri River drainage area of South Dakota and Nebraska [29,73,111].
The specific ranges of the 13 subspecies are listed below [63]:
Neotoma cinerea acraia: east-central California to southeastern Idaho, Utah, and northern Arizona
Neotoma cinerea alticola: southern Washington, Oregon, southern Idaho, northeastern Caliifornia, and northern Nevada
Neotoma cinerea arizonae: Utah, Colorado, New Mexico, and Arizona
Neotoma cinerea cinerea: southeastern British Columbia, southern Alberta, and southwestern Saskatchewan south to central Idaho, western Wyoming, Montana, and western North Dakota
Neotoma cinerea cinnomomea: southwestern Wyoming, northeastern Utah, and northwestern Colorado
>Neotoma cinerea drummondii: Yukon and Northwest Territories south to eastern British Columbia and western Alberta
Neotoma cinerea fusca: the Coast Ranges of Washington and Oregon
Neotoma cinerea lucida: southeastern California and southwestern Nevada
Neotoma cinerea macrodon: east-central Utah
Neotoma cinerea occidentalis: from Yukon Territory south to Washington, the Cascade Range of Oregon, and northern Idaho
Neotoma cinerea orolestes: southeastern Montana and southwestern South Dakota to northern New Mexico
Neotoma cinerea pulla: southwestern Oregon to northern California
Neotoma cinerea rupicola: southeastern Montana and North Dakota to western Nebraska and northeastern Colorado [63]
The following lists are speculative and are based on the habitat characteristics and species composition of communities bushy-tailed woodrats are known to occupy. There is not conclusive evidence that bushy-tailed woodrats occur in all the habitat types listed, and some community types, especially those used rarely, may have been omitted. See Preferred Habitat for more detail.
Bushy-tailed woodrats are herbivores [4,67,114] with a broad, flexible diet [47,55,85]. Regional specialization on certain locally abundant food items may occur [47,51]. Due to their flexible diet, food availability is likely not a limiting factor in habitats occupied by bushy-tailed woodrats. Generally, food is a more abundant resource than shelter [47]. In general, bushy-tailed woodrats do not travel far from their den to forage [55,116]. In Gunnison County, Colorado, bushy-tailed woodrats satisfied their foraging needs within a 98 foot (30 m) radius of their dens, but would occasionally travel upto 500 feet (152 m) from their den for unknown reasons [55]. Food is dried on rocks before storage [16,47,51], and is stored extensively in middens located at the periphery of the den in late August and September [16,47,51]. As plant diversity increases in bushy-tailed woodrat habitat, diversity of midden contents increases [55]. Middens may be several feet deep [51] and have been radiocarbon dated to be thousands of years old [122].
Foods eaten include cones and needles of coniferous trees [85,114], berries, leaves [47], shrubs [16,72], and forbs [67]. Fungi are a major food item in lodgepole pine and grand fir habitats in northeast Oregon. Bushy-tailed woodrats are vectors of spore dissemination of hypogeous mycorrhizal fungi in conifer forests [86].
In Canada, bushy-tailed woodrats showed a preference for the leaves of quaking aspen, cherry (Prunus spp.), rose (Rosa spp.), snowberry (Symphoricarpos spp.), currants (Ribes spp.), elderberries (Sambucus spp.), and willows (Salix spp.). The twigs and needles of western white pine (Pinus monticola), Douglas-fir, Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa), and juniper (Juniperus spp.), and the seeds and/or fruits of Douglas-fir, anemone (Anemone spp.), fireweed (Epilobium angustifolium), gentian (Gentianella spp.), honeysuckle (Lonicera spp.), cinquefoil (Potentilla spp.), gooseberry (Ribes spp.), raspberry (Rubus spp.), and elderberry were also eaten [16].
Consumption of woody vegetation by bushy-tailed woodrats may decrease competition for food with other forb-eating small mammals. In a pinyon-juniper habitat in the Piceance Basin in Colorado, 75% of the bushy-tailed woodrat diet was composed of woody plants, primarily antelope bitterbrush (Purshia tridentata). Forbs composed 15% of their diet, but the percentage of forbs in the diet may increase in years of heavy rainfall. For a list of foods eaten by bushy-tailed woodrat in pinyon-juniper habitat in Colorado, see Haufler and Nagy [67]. In basin big sagebrush (Artemisia tridentata ssp. tridentata) habitat in south-central Idaho, plains prickly-pear (Opuntia polyacantha) was the main food eaten by bushy-tailed woodrats [72].
Fire may influence bushy-tailed woodrat populations by altering habitat structure and/or plant community composition [83]. The rapidity of recolonization of a disturbed area by small mammals depends on the size and severity of the disturbance and the presence of refugia [74].
As of this writing, no information is available on the HABITAT RELATED FIRE EFFECTS on the bushy-tailed woodrat. Despite the lack of information, some generalizations based on their habitat requirements may be possible. Coarse woody debris and mistletoe brooms are important resources for the bushy-tailed woodrat, primarily in the Pacific Northwest [21,26,34,35,39,82,85,94,96,124] (see Preferred Habitat). Conflicts in coarse woody debris management have arisen between retaining logs for wildlife use and lowering fuel levels to decrease the risk of wildfire [24]. Coarse woody debris and mistletoe brooms close to the ground torch easily and would probably be consumed by low-severity prescribed fire [69]. In ponderosa pine and dry Douglas-fir habitats, low-severity, high-frequency FIRE REGIMES will likely reduce bushy-tailed woodrat populations unless fire prescriptions mitigate the loss of coarse woody debris and mistletoe brooms [82]. In 12 vegetation types in coastal and interior British Columbia, wildlife community structure was highly correlated with FIRE REGIMES. As fire size and intensity increased, the proportion of species using woody cavities decreased due to the loss of snags and woody debris. As the interval between fires increased and downed woody debris accumulated, proportions of species using downed wood increased [27].
Bushy-tailed woodrats are found in early successional through climax stages of succession [4,29,34,125], and their presence depends more on cover and food availability than on the seral stage [47,51]. In the spruce-fir zone of northern Utah, for example, bushy-tailed woodrats were found in meadows and quaking aspen stands. These communities are commonly the first successional stages after fire [103]. In the Sierra Nevada, bushy-tailed woodrats often inhabit early postfire successional stages of Jeffrey pine and lodgepole pine communities [20,76]. Some berry-producing shrubs that provide food for bushy-tailed woodrats, such as blackberries, raspberries, and gooseberries, often thrive after fire [127]. However, severe, stand-destroying fires that consume the organic layer can kill the roots of many berry-producing shrubs, reducing the potential for sprouting and delaying revegetation [97,119]. According to Lehmkuhl and others [82], unmanaged mature forests are source habitat for bushy-tailed woodrats compared to thinned and/or burned forest stands. Closed-sapling pole habitats are also source habitat for bushy-tailed woodrats (see Stand- and landscape-level habitat) [29].
In eastern Washington and Oregon, wildlife appears to be well-adapted to mixed-severity FIRE REGIMES in mixed-conifer forests [81]. A critical habitat feature affecting wildlife habitat in mixed-severity FIRE REGIMES is the mosaic of vegetation conditions that are created [2]. Mixed-severity fires in dry forest types create mosaics of varying burn intensity and a complex of open and closed-canopy forest structure containing woody debris, snags, and understory vegetation [3,81]. Woody debris may be abundant in mixed-severity vegetation types, but availability varies over time. Consumption of woody debris on the forest floor is offset by the creation of snags in patches burned at moderate and high severities [3]. Burning to create patchy fire severity may therefore benefit the bushy-tailed woodrat [82].
Snags with large cavities are important for many species of birds and mammals including the bushy-tailed woodrat [21]. A bushy-tailed woodrat nest was found in an old-growth log with a fire scar opening 3 feet (0.9 m) high and 2 feet (0.6 m) wide [29]. Old pileated woodpecker cavities used by bushy-tailed woodrats may be at risk of destruction by high-severity fire [82]; however, high-severity fire may also create snags [26].
To reduce slash from logging operations while maintaining coarse woody debris, broadcast burning may be useful. Because of the time of year that broadcast burning is conducted, large diameter materials are usually not consumed [98,99,101]. In addition to broadcast burning, slash <6 inches (15 cm) diameter can be piled and burned to reduce fine fuels while maintaining coarse woody debris [96]. Prescribed fire has less impact on small mammals in western larch habitat than mechanical scarification [104], which destroys small mammal habitat [84].
The following table provides fire-return intervals for plant communities and ecosystems where bushy-tailed woodrats may occur. Find 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".
Due to their dependence on trees, arboreal rodents such as the bushy-tailed woodrat are sensitive to timber harvesting [71] and may experience population declines in intensively managed areas [13]. Huff and others [71] rated the vulnerability of arboreal mammal species to local extirpations resulting from the fragmentation or loss of old-growth Douglas-fir forests. The index ranged from "1-low vulnerability", to "10-high vulnerability". The bushy-tailed woodrat was rated a "4" [71].
Coarse woody debris is an important habitat element for the bushy-tailed woodrat, especially in the Pacific Northwest [21,26,34,35,39,82,85,94,96,124] (see Preferred Habitat). Specific information about the density and types of logs required to provide viable habitat for bushy-tailed woodrat populations is unavailable [24]; however, loss of logs due to timber management or fire should be mitigated due to their importance for cover [82]. According to Pearson [96], coarse woody debris management should focus on maintaining a diverse array of sizes and decay classes for various animal species. Suggestions for coarse woody debris management include the creation of debris piles from thinning slash, and management of streamside habitat to restore coarse woody debris and complex vegetation structure [34]. For detailed recommendations about how to manage trees and logs in the Interior Columbia River Basin, see Bull and others [26]. For information about snag management for wildlife use, see Wellersdick and Zalunardo [124] and Pearson [96].
Managing for habitat patchiness may be suitable for the bushy-tailed woodrat [26,34]. Carey and others [31,33] suggest variable-density thinning in wet Douglas-fir and western hemlock forests in western Washington, with the retention of large snags and woody debris on the scale of 0.5- to 1.2-acre (0.2 to 0.5 ha) patches.
Livestock grazing: Bushy-tailed woodrats may either be negatively or positively affected by grazing by domestic livestock in mixed-conifer and spruce (Picea spp.)-fir (Abies spp.) forests in Arizona and New Mexico, depending on the grazing regime. Seed production of shrubs and forbs could be increased by grazing; however, heavy livestock use may degrade woody cover. Bushy-tailed woodrats are a "priority species" in Arizona and New Mexico. This means that bushy-tailed woodrats should receive greater consideration than non-priority wildlife species during development of management strategies related to livestock grazing [131].
Other: When bushy-tailed woodrat density was compared between unchained and chained areas in a mature pinyon-juniper (Pinus edulis-Juniperus osteosperma) woodland in the Piceance Basin, Colorado, density was greatest (n=8 individuals) in unchained control areas. Each study area consisted of 3 trapping grids, which included 32 trap stations (4 x 8 feet (1 x 2m)) at intervals of 49 feet (15 m). In 1-year-old chained areas, bushy-tailed woodrat density was 5 per trapping grid. Bushy-tailed woodrats were absent in 8-year-old or 15-year old chained areas [93]. O'Meara and others [93] suggest interspersing blocks of chained and unchained vegetation to maintain pinyon-juniper woodland species such as the bushy-tailed woodrat.Bushy-tailed woodrats add substantially to the prey base of birds and mammals [29,34]. Their presence and abundance may affect the fitness of spotted owls (Strix occidentalis) throughout their range [29,32,34,92,117,118,123], but their importance varies locally [32]. Bushy-tailed woodrats comprised >10% relative frequency and total biomass of the Mexican spotted owl's (Strix occidentalis lucida) diet in the northern portion of its range [123]. In the Olympic Peninsula, Coast Range, Umpqua River Valley, and Klamath Mountains of Oregon, bushy-tailed woodrats comprised 2% to 70% of prey biomass for the northern spotted owl [32].
Other predators of bushy-tailed woodrats include the great-horned owl (Bubo virginianus) [16,29,78], boreal owl (Aegolius funereus) [68], American marten (Martes americana) [16,23,29], fisher (Martes pennanti) [130], and bobcat (Lynx rufus) [29].
Incidental predators include the coyote (Canis latrans) [29,45], western spotted skunk (Spilogale putorius), long-tailed weasel (Mustela frenata) [29], red-tailed hawk (Buteo jamaicensis), northern goshawk (Accipiter gentilis) [47], rattlesnake (Viperidae), wolverine (Gulo gulo) and fox (Vulpes spp. and Urocyon spp.) [16].
Due to the large amount of time spent in dens, bushy-tailed woodrats are particularly susceptible to ectoparasites such as ticks, chiggers, lice, mites, fleas, cone-nosed bugs, and warble flies [51].
Bushy-tailed woodrats are the most boreal species within the Neotoma genus [47,51]. They inhabit areas from sea level to 14,110 feet (4,300 m) and are most often associated with montane habitats [47,61,114]. Bushy-tailed woodrats are arboreal rodents [13,21,26,29,30,47], associating primarily with ponderosa pine, Douglas-fir, spruce (Abies spp.), and quaking aspen (Populus tremuloides) forests [47,51,85]. Other common habitat types inhabited by the bushy-tailed woodrat include pinyon (Pinus spp.)-juniper (Juniperusspp.) woodlands [5,22,44,50,56,67,78,93,110,125] and big sagebrush habitat [5,45,49,58,72,89,125].
Occurrence of bushy-tailed woodrats is closely tied to the geology of a landscape [47]. Shelter and topography are important determinants of habitat suitability [47,51]. The availability of rock shelters may be a more important resource for the bushy-tailed woodrat than the associated plant community [34,47,51]. Preferred habitat varies depending on the subspecies of bushy-tailed woodrat; however, most subspecies are associated with rocky environments such as talus slopes [16,51,116], rockslides [47,114], boulder fields [34], rock outcrops [16,34,51,85,116], cliffs [51,116], and caves [16,51,61,106,114,116].
Due to the occasional scarcity of rocky habitats in the Pacific Northwest, hollow trees, logs, dwarf mistletoe (Arceuthobium spp.) brooms, and coarse woody debris are used for denning, foraging, and shelter [21,26,34,35,66,77,82,85,94,96,124]. In the Columbia River Basin, bushy-tailed woodrats use grand fir and white fir snags most often for den sites [77,94]. Tree cavities created by the pileated woodpecker (Dryocopus pileatus) are used by bushy-tailed woodrats in grand fir, western larch, and ponderosa pine trees [21,24,25,26].
Bushy-tailed woodrats may also associate with streamside habitats [29,34,47,82,87]. In southwestern Oregon, streamside forests provide the most suitable habitat for bushy-tailed woodrat [29]. In wet Douglas-fir and western hemlock (Tsuga heterophylla) forests in western Washington, bushy-tailed woodrats are found primarily in rocky, streamside areas [82]. Riparian quaking aspen woodlands in rangeland communities are commonly used by bushy-tailed woodrats in northeastern Nevada [87].
Human-made buildings [40,51,85,112,114] and mine tunnels are sometimes used by bushy-tailed woodrat [51].
Stand- and landscape-level habitat: Bushy-tailed woodrats may be found in early through climax stages of succession [4,29,34,82,125].
In the Pacific Northwest, one of the preferred landscapes for the bushy-tailed woodrat is closed pole-sapling stands, which are somewhat ephemeral as they succeed to small saw-log stands. Extensive areas of Douglas-fir old-growth (>200 years) may be most suitable for maintaining a viable population of bushy-tailed woodrats. Contiguous areas of suitable habitat or corridors connecting suitable habitat are also important [29].
In western Oregon and western Washington, bushy-tailed woodrats preferred mature (>80 years), unmanaged upland Douglas-fir-western hemlock streamside forests more than young (35 to 80 years), "managed" streamside forest. Streams in this habitat were narrow, deeply cut, and associated with forested boulder fields. The adjacency of streams was not sufficient to ensure occupancy by bushy-tailed woodrats.
Percent frequency of occurrence of bushy-tailed woodrats in Douglas-fir/western hemlock streamside forests [34]Stream present
Stream not present
Stands (n) % occupied Stands (n) % occupied Mature, unmanaged forest 27 78 34 21 Young, managed forest 12 33 46 17In the Pacific Northwest, Douglas-fir forests can be "sources" or "sinks" for the bushy-tailed woodrat, depending on the stand condition, presence of streams, and occurrence of predators such as the northern spotted owl (Strix occidentalis caurina) [29]. "Sources" are defined as an environment capable of sustaining a viable population. "Sinks" are defined as an environment capable of maintaining a population for a short time, but supporting low reproduction or periods of unsuitability for occupancy.
Habitat ratings for stand conditions in Douglas-fir forests in the Pacific Northwest [29] Closed sapling-poleInformation on landscape suitability for the bushy-tailed woodrat is sparse outside the Pacific Northwest. In Douglas-fir and mixed-conifer forests in southwestern Oregon and northern California, bushy-tailed woodrats were found in young and mature forests containing diverse understory vegetation [86]. Bushy-tailed woodrats were transients or ephemeral residents within the quaking aspen seral stage of a forest dominated by Engelmann spruce (Picea engelmannii) in the Wasatch Mountains in Utah [4]. In Montana, bushy-tailed woodrats are found in old-growth western larch (Larix occidentalis)/Douglas-fir forests [65]. In alluvial valleys of the Green and Yampa rivers in northwestern Colorado and northeastern Utah, bushy-tailed woodrat presence was examined in 3 habitats: high floodplain, low floodplain, and upland. Bushy-tailed woodrats were found in high floodplain and upland habitats, but the numbers in upland habitats were small. In high floodplain habitat, flooding occurred at longer intervals than in low floodplain areas, which flooded every other spring. High floodplain habitat contained the most mature cottonwood (Populus fremontii) and woody debris of the 3 habitats studied. In upland habitat, where flooding never occurred, dominant vegetation included sagebrush (Artemisia spp.), greasewood (Sarcobatus spp.), and saltbush (Atriplex spp.) [49].
Home range and density: Bushy-tailed woodrats have a larger home range than any other Neotoma species. This may due to the requirement of existing geologic structures for den sites, such as fissures in rocky outcrops. Denning and nesting sites are usually limiting resources in bushy-tailed woodrat habitat. This may lead to concentrations of bushy-tailed woodrats in certain areas [47]. Importance of a suitable den site may outweigh the costs of maintaining a large home range [47].
Bushy-tailed woodrats occur in small, widely separated family groups [29]. The minimum habitat size needed per family group has been estimated at 80 acres (32 ha) [29]. It is rare to find more than one family group on a talus slope covering 2 to 5 acres (0.8-2.0 ha). Banfield [16] reported an average population density of 1 bushy-tailed woodrat per 20 acres (8 ha) in Canada. Bushy-tailed woodrats may forage up to 450 feet (137 m) from the den; this constitutes a 15 acre (6 ha) home range [29]. In southwestern Oregon, Carey [29] recorded movements of up to 1,250 feet (381 m) within trapping grids that were only 1,300 feet (396 m) wide, which suggests a maximum home range of about 110 acres (45 ha). The average maximum distance moved per individual was 280 feet (85.3 m).
The size of the home range is positively correlated with the number of females in the group [47]. Male bushy-tailed woodrats have larger home ranges than females [29]. In the Kananaskis Valley in southwestern Alberta, average home range size for male bushy-tailed woodrats was 6.12 ha (n=23, range 1.6 to 11.2 ha), and for females was 3.56 ha (n=27, range 0.1 to 10.4 ha) [116].
In mixed-conifer (grand fir and Douglas-fir) habitat in southwestern Oregon, bushy-tailed woodrat density was greatest (1.08 individuals/ha ? 0.51 (SE)) in streamside closed-canopy habitat. In Douglas-fir forests, bushy-tailed woodrat density was greatest (0.59 individuals/ha ? 0.57 (SE)) in rocky sites. For more details about bushy-tailed woodrat density in different habitat types in Oregon, see Carey and others [32].
Mating: Female bushy-tailed woodrats are seasonally polyoestrous [16,47,51]. The breeding period occurs from January to August [16,34,85] and peaks between March and June [16]. In southwestern Oregon, 55% (n not given) of female bushy-tailed woodrats were found lactating until fall, indicating a longer breeding period [29].
Social Organization: Bushy-tailed woodrats occur in small family groups, which are often widely separated, and distribution is often patchy [29,47]. Males are territorial and aggressively defend dens and foraging areas [16,29,47]. Bushy-tailed woodrats are considered polygynous by some authors [16,29,47]; however, this is not based on observed matings, but on the size and relative overlap of male and female ranges [34].
Gestation period and litter size: Gestation of bushy-tailed woodrats is 27 to 32 days [16,47]. On the Oregon Coast, young are born in March [85]. Litter size ranges from 1 to 6 [47,85,114], and averages 3.5 [16]. In the Sierra Nevada, mean litter size was 2.5 (n=11) [47]. Number of litters is typically 1 per year, especially in northern parts of the bushy-tailed woodrat's range [16]. In southern parts of the bushy-tailed woodrat's range, 2 litters may be produced [85].
Development: Young bushy-tailed woodrats are altricial [16,85], and the male parent does not help raise offspring [47]. Young are weaned between 26 and 30 days of age [16], and dispersal from the nest occurs at 2 months of age [114]. Bushy-tailed woodrats reach sexual maturity at 11 months [16], and breeding begins during spring and summer, ~1 year following birth [47].
Dispersal: Female bushy-tailed woodrats are generally philopatric and breed on the same rock outcrop over successive years. Male yearlings are more mobile than female yearlings and may disperse greater distances in search of suitable habitat and den sites [47]. Dispersal distances of 1.4 to 2.0 miles (2.2-3.2 km) have been recorded [29]. Once a territory is established, both sexes are relatively sedentary. The separation of family groups may attract predators and lead to extinction of the colony via emigration, predation, and random demographic processes such as death and low birth rates. Therefore, dispersal of offspring is important in the recolonization of vacated habitats [29,47].
Habits: Bushy-tailed woodrats are primarily nocturnal and are most active during the half hour after sunset and at dawn, year-round [16,29,47,51,85,114,118].
Survival: Litters produced early in the season have a greater chance of survival than litters produced later in the season [47]. Bushy-tailed woodrats may live 3 to 4 years [47,114].
Annual survival rates for bushy-tailed woodrats in dry forest cover types in the Cascade Range [82]
YearCover type
1997-1998 1998-1999 1999-2000 Open ponderosa pine 0.14 0.13 0.05 Young mixed conifer
The bushy-tailed woodrat, or packrat (Neotoma cinerea) is a species of rodent in the family Cricetidae found in Canada and the United States.[2] Its natural habitats are boreal forests, temperate forests, dry savanna, temperate shrubland, and temperate grassland.
The bushy-tailed woodrat is the original "pack rat", the species in which the trading habit is most pronounced. It has a strong preference for shiny objects and will drop whatever it may be carrying in favor of a coin or a spoon.[3][4]
Bushy-tailed woodrats can be identified by their large, rounded ears, and their long, bushy tails. They are usually brown, peppered with black hairs above with white undersides and feet. The top coloration may vary from buff to almost black. The tail is squirrel-like - bushy, and flattened from base to tip.[3][5]
These woodrats are good climbers and have sharp claws. They use their long tails for balance while climbing and jumping,[3] and for added warmth.[6]
These rodents are sexually dimorphic, with the average male about 50% larger than the average female. Its adult length is 11 to 18 in (28 to 46 cm), half of which is its tail. Its weight is 1.3 lb (590 g).
The bushy-tailed woodrat is the largest and most cold-tolerant species of woodrat.[6]
Bushy-tailed woodrats are found in western North America, ranging from arctic Canada down to northern Arizona and New Mexico, and as far east as the western portions of the Dakotas and Nebraska.[3][4][5][6]
Bushy-tailed woodrats occupy a wide range of habitats, from boreal forests to deserts. Their preferred habitat is in and around rocky places, so they are often found along cliffs, canyons, talus slopes, and open rocky fields. They readily adapt to abandoned buildings and mines.[5][6][7]
They can be found from sea level up to 14,000 feet (4,300 m), but they become increasingly restricted to higher elevations toward the southern end of their range.[8]
These woodrats do not do as well in old-growth forests. They are found with greater frequency and in higher densities in more open habitats.
The bushy-tailed woodrat prefers green vegetation (leaves, needles, shoots), but it will also consume twigs, fruits, nuts, seeds, mushrooms, and some animal matter. One study[7] in southeastern Idaho found grasses, cactus, vetch, sagebrush, and mustard plants in their diets, as well as a few arthropods. In drier habitats, they will concentrate on succulent plants.
These rodents get most of their water from the plants that they eat.[9]
Males establish dominance in their territories through scent marking and physical confrontations. Fights consist largely of biting and scratching, and may result in serious injury.[4][6]
Breeding occurs in spring and summer (May through August), with a gestation period of about five weeks. A female may have one or two litters each year. Litters can range in size from two to six, with a typical litter size of three. The females have only four mammary glands, so larger litters most likely have higher attrition rates. Females have been observed breeding as soon as 12 hours after giving birth, and may be pregnant with one litter while nursing another.[3][6]
Gestation period in captivity is 27–32 days. Newborns weigh around 15 g (0.53 oz). Eyes open at about 15 days old, and weaning occurs at 26–30 days.
Males leave the mother at 2½ months. Females often stay in the same area as the mother, with an overlapping range. This is a clear exception to their territorial natures, and this relationship is not currently well understood. The daughters may share food caches with the mother, increasing their likelihood of survival, and the higher female density of the area may also help attract males.[6][7]
Females breed for the first time when they are yearlings.[6]
Bushy-tailed woodrats are active throughout the year. While primarily nocturnal, they can occasionally be seen during the day. They are usually solitary and very territorial.
These woodrats collect debris in natural crevices, and abandoned man-made structures when available, into large, quasistructures for which the archaeologists' term 'midden' has been borrowed. Middens consist of plant material, feces, and other materials which are solidified with crystallized urine. Woodrat urine contains large amounts of dissolved calcium carbonate and calcium oxalates due to the high oxalate content of many of the succulent plants upon which these animals feed.[6]
An important distinction to make is between middens and nests. Nests are the areas where the animal is often found and where the females raise their young.[6] Nests are usually within the midden, but regional variations to this rule occur. When not contained within the midden, the nest is usually concealed in a rocky crevice behind a barricade of sticks.[3]
In coniferous forests, the woodrat may build its house as high as 50 feet (15 m) up a tree.[3]
Bushy-tailed woodrats do not hibernate. They build several food caches, which they use during the winter months.[6]
The bushy-tailed woodrat engages in hind foot-drumming when alarmed. It will also drum when undisturbed, producing a slow, tapping sound.[6]
Bushy-tailed woodrats are preyed upon by many predators, including: spotted owls, bobcats, black bears, coyotes, foxes, weasels, Snakes, martens, and hawks. The sheltered conditions offered by the midden are often used by reptiles during the colder months. The rattlesnake, normally a predator of the woodrat in the warmer months, is a common lodger.[10]
The bushy-tailed woodrat, or packrat (Neotoma cinerea) is a species of rodent in the family Cricetidae found in Canada and the United States. Its natural habitats are boreal forests, temperate forests, dry savanna, temperate shrubland, and temperate grassland.
The bushy-tailed woodrat is the original "pack rat", the species in which the trading habit is most pronounced. It has a strong preference for shiny objects and will drop whatever it may be carrying in favor of a coin or a spoon.
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