The pygmy rabbit (''Brachylagus idahoensis'') is a rabbit species native to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. It is also the only native rabbit species in North America to dig its own burrow. The pygmy rabbit differs significantly from species within either the ''

Lepus Hares and jackrabbits are mammals belonging to the genus ''Lepus''. They are herbivores, and live solitarily or in pairs. They nest in slight depressions called forms, and their young are able to fend for themselves shortly after birth. The gen ...

'' (hare) or ''

Sylvilagus Cottontail rabbits are the leporid species in the genus ''Sylvilagus'', found in the Americas. Most ''Sylvilagus'' species have stub tails with white undersides that show when they retreat, giving them their characteristic name. However, this ...

'' (cottontail) genera and is generally considered to be within the

monotypic genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

''Brachylagus''. One isolated population, the Columbia Basin pygmy rabbit, is listed as an endangered species by the U.S. Federal government, though the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...

lists the species as lower risk.

Description

The pygmy rabbit is the world's smallest

leporid Leporidae is the family of rabbits and hares, containing over 60 species of extant mammals in all. The Latin word ''Leporidae'' means "those that resemble ''lepus''" (hare). Together with the pikas, the Leporidae constitute the mammalian order ...

, with adults weighing between , and having a body length between ; females are slightly larger than males. The pygmy rabbit is distinguishable from other leporids by its small size, short ears, gray color, small hind legs, and lack of white fuzzy fur.

Distribution

The range of the pygmy rabbit includes most of the Great Basin and some of the adjacent intermountain areas of western North America. Pygmy rabbits are found in southwestern Montana from the extreme southwest corner near the Idaho border north to Dillon and Bannack in Beaverhead County. Distribution continues west to southern Idaho and southern Oregon and south to northern Utah, northern Nevada, and eastern California. Isolated populations occur in east-central Washington and Wyoming. The elevational range of pygmy rabbits in Nevada extends from and in California from . The last male purebred Columbia Basin pygmy rabbit, found only in the Columbia Basin of

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington ...

, died March 30, 2006, at the

Oregon Zoo The Oregon Zoo, originally the Portland Zoo and later the Washington Park Zoo, is a zoo located in Washington Park, Portland, Oregon, approximately southwest of downtown Portland. Founded in 1888, it is the oldest zoo west of the Mississippi R ...

in Portland. The last purebred female died in 2008. A crossbreeding program conducted by the Oregon Zoo,

Washington State University Washington State University (Washington State, WSU, or informally Wazzu) is a public land-grant research university with its flagship, and oldest, campus in Pullman, Washington. Founded in 1890, WSU is also one of the oldest land-grant uni ...

and Northwest Trek is attempting to preserve the genetic line by breeding surviving females with the Idaho pygmy rabbit.

Lifecycle

Pygmy rabbits are capable of breeding when they are about 1 year old.Wilde, Douglas B.; Keller, Barry L. (1978). An analysis of pygmy rabbit populations on the Idaho National Engineering Laboratory site. In: Markham, O. D., ed. Ecological studies on the Idaho National Engineering Laboratory site. 1978 Progress Report IDO-12087. Idaho Falls, ID: U.S. Department of Energy, Environmental Sciences Branch, Radiological and Environmental Sciences Lab: 305–316. . The breeding season of pygmy rabbits is very short. In Idaho it lasts from March through May; in Utah, from February through March.Chapman, Joseph A.; Feldhamer, George A., eds. 1982. Wild mammals of North America. Baltimore, MD: The Johns Hopkins University Press The gestation period of pygmy rabbits is unknown. It is between 27 and 30 days in various species of cottontails (''Sylvilagus'' spp.). An average of six young are born per litter and a maximum of three litters are produced per year. In Idaho the third litter is generally produced in June. It is unlikely that litters are produced in the fall. The growth rates of juveniles are dependent on the date of birth. Young from early litters grow larger due to a longer developmental period prior to their first winter. The mortality of adults is highest in late winter and early spring. Green and Flinders reported a maximum estimated annual adult mortality of 88% in Idaho. Juvenile mortality was highest from birth to 5 weeks of age. Pygmy rabbits may be active at any time of day; however, they are generally most active at dusk and dawn. They usually rest near or inside their burrows during midday.

Habitat

Pygmy rabbits are normally found in areas on deep soils with tall, dense

sagebrush Sagebrush is the common name of several woody and herbaceous species of plants in the genus '' Artemisia''. The best known sagebrush is the shrub '' Artemisia tridentata''. Sagebrushes are native to the North American west. Following is an al ...

which they use for shelter and food.Flath, Dennis. 1994. Bunnies by the bunch. Montana Outdoors. 25(3): 8–13. Individual sagebrush plants in areas inhabited by pygmy rabbits are often 6 feet (1.8 m) or more in height. Extensive, well-used runways interlace the sage thickets and provide travel and escape routes. Dense stands of big sagebrush along streams, roads, and

fencerow In agriculture, fences are used to keep animals in or out of an area. They can be made from a wide variety of materials, depending on terrain, location and animals to be confined. Most agricultural fencing averages about high, and in some places ...

s provide dispersal corridors for pygmy rabbits. The pygmy rabbit is the only leporid native to North America that digs burrows. Juveniles use burrows more than other age groups. Early reproductive activities of adults may be concentrated at burrows. When pygmy rabbits can utilize sagebrush cover, burrow use is decreased. Pygmy rabbits use burrows more in the winter for thermal cover than at other times of the year. Burrows are usually located on slopes at the base of sagebrush plants, and face north to east. Tunnels widen below the surface, forming chambers, and extend to a maximum depth of about . Burrows typically have 4 or 5 entrances but may have as few as 2 or as many as 10. In Oregon, pygmy rabbits inhabited areas where soils were significantly deeper and looser than soils at adjacent sites. Site selection was probably related to ease of excavation of burrows. In areas where soil is shallow pygmy rabbits live in holes among volcanic rocks, in stone walls, around abandoned buildings, and in burrows made by badgers (''Taxidea taxus'') and marmots (''Marmota flaviventris''). Some researchers have found that pygmy rabbits never venture farther than from their burrows. However, Bradfield observed pygmy rabbits range up to from their burrows. Some areas inhabited by pygmy rabbits are covered with several feet of snow for up to 2 or more months during the winter. During periods when the snow has covered most of the sagebrush, pygmy rabbits tunnel beneath the snow to find food. Snow tunnels are approximately the same height and width as burrows. They are quite extensive and extend from one sagebrush to another. Above ground movement during the winter months is restricted to these tunnel systems.

Cover requirements

Pygmy rabbits are restricted to areas with heavy shrub cover. Pygmy rabbits are seldom found in areas of sparse vegetative cover and seem to be reluctant to cross open space. In southeastern Idaho, woody cover and shrub height were significantly (P<0.01) greater on sites occupied by pygmy rabbits than on other sites in the same area.

Plant communities

Pygmy rabbits are found primarily in big sagebrush (''

Artemisia tridentata ''Artemisia tridentata'', commonly called big sagebrush,MacKay, Pam (2013), ''Mojave Desert Wildflowers'', 2nd ed., , p. 264. Great Basin sagebrush or (locally) simply sagebrush, is an aromatic shrub from the family Asteraceae, which grows in ari ...

'') and rabbitbrush ('' Chrysothamnus'' spp.) dominated communities.Severaid, Joye Harold. 1950. The pigmy rabbit (Sylvilagus idahoensis) in Mono County, California. Journal of Mammalogy. 31(1): 1–4. .Welch, Bruce L.; Wagstaff, Fred J.; Roberson, Jay A. 1991. Preference of wintering sage grouse for big sagebrush. Journal of Range Management. 44(5): 462–465. . Pygmy rabbits are also found in areas where greasewood ('' Sarcobatus'' spp.) is abundant. Some woody species found on sites inhabited by pygmy rabbits in southeastern Idaho include big sagebrush, antelope bitterbrush ('' Purshia tridentata''), threetip sagebrush ('' A. tripartita''), low rabbitbrush ('' C. viscidiflorus''), gray horsebrush ('' Tetradymia canescens''), and prickly phlox ('' Leptodactylon pungens''). Grasses and forbs include thick spike wheatgrass ('' Elymus lanceolatus''), plains reedgrass ('' Calamagrostis montanensis''), sedges (''

Carex ''Carex'' is a vast genus of more than 2,000 species of grass-like plants in the family Cyperaceae, commonly known as sedges (or seg, in older books). Other members of the family Cyperaceae are also called sedges, however those of genus ''Carex'' ...

'' spp.), prairie junegrass ('' Koeleria macrantha''), Sandberg bluegrass ('' Poa secunda''), bluegrass ('' Poa'' spp.), needle-and-thread grass ('' Stipa comata''), western yarrow (''

Achillea millefolium ''Achillea millefolium'', commonly known as yarrow () or common yarrow, is a flowering plant in the family Asteraceae. Other common names include old man's pepper, devil's nettle, sanguinary, milfoil, soldier's woundwort, and thousand seal. The ...

''), rosy pussytoes ('' Antennaria microphylla''), milkvetch (''

Astragalus ''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to tempe ...

'' spp.), arrowleaf balsamroot ('' Balsamorhiza sagittata''), buckwheat (''

Eriogonum ''Eriogonum'' is a genus of flowering plants in the family Polygonaceae. The genus is found in North America and is known as wild buckwheat. This is a highly species-rich genus, and indications are that active speciation is continuing. It incl ...

'' spp.), tailcup lupine ('' Lupinus caudatus''), and phlox (''

Phlox ''Phlox'' (; Greek φλόξ "flame"; plural "phlox" or "phloxes", Greek φλόγες ''phlóges'') is a genus of 67 species of perennial and annual plants in the family Polemoniaceae. They are found mostly in North America (one in Siberia) in di ...

'' spp.). In the Upper Sonoran Desert pygmy rabbits occur in desert sagebrush associations dominated by big sagebrush and rabbitbrush with bitterbrush and sulphurflower ('' Eriogonum umbellatum var. stellatum'').

Food habits

The primary food of pygmy rabbits is big sagebrush, which may comprise up to 99% of the food eaten in the winter. Grasses and forbs are also eaten from mid- to late summer.Gates, Robert J.; Eng, Robert L. (1984) Sage grouse, pronghorn, and lagomorph use of a sagebrush-grassland burn site on the Idaho National Engineering Laboratory. In: Markham, O. Doyle, ed. Idaho National Engineering Laboratory radio ecology and ecology programs: 1983 progress reports. Idaho Falls, ID: U.S. Department of Energy, Radiological and Environmental Sciences Laboratory: 220–235 In Idaho, Gates and Eng found that shrubs contributed 85.2% (unweighted mean) of pygmy rabbit diets from July to December. Shrub use was lowest in August (73.1%) and highest in December (97.9%). Big sagebrush was the most important shrub in the July to December diet (54.2%), followed by rubber rabbitbrush (''Chrysothamnus nauseosus'', 25.8%) and winterfat (''Krascheninnikovia lananta'', 4.6%). Grasses comprised 10% of the July to December diet and were consumed mostly during July and August. Indian ricegrass (''Oryzopsis hymenoides'') and needlegrass (''Stipa'' spp.) were the most important grasses consumed. Forbs contributed 4.9% of the July to December diet. In southeastern Idaho, Green and Flinders found that pygmy rabbits ate big sagebrush throughout the year but in lesser amounts in summer (51% of diet) than in winter (99% of diet). Other shrubs in the area were consumed infrequently. Grass and forb consumption was relatively constant throughout the summer (39% and 10% of diet respectively) and decreased to a trace amount through fall and winter. Thickspike wheatgrass, bluebunch wheatgrass (''Pseudoroegneria spicata''), and Sandberg bluegrass were preferred foods in the summer.

Predators

Weasels Weasels are mammals of the genus ''Mustela'' of the family Mustelidae. The genus ''Mustela'' includes the least weasels, polecats, stoats, ferrets and European mink. Members of this genus are small, active predators, with long and slender b ...

(''Mustela'' and ''Neogale'' spp.) are the principal predators of pygmy rabbits. Coyotes (''Canis latrans''), red foxes (''Vulpes vulpes''),

American badger The American badger (''Taxidea taxus'') is a North American badger similar in appearance to the European badger, although not closely related. It is found in the western, central, and northeastern United States, northern Mexico, and south-cent ...

s (''Taxidea taxus''), bobcats (''Lynx rufus''),

great horned owl The great horned owl (''Bubo virginianus''), also known as the tiger owl (originally derived from early naturalists' description as the "winged tiger" or "tiger of the air"), or the hoot owl, is a large owl native to the Americas. It is an extre ...

s (''Bubo virginianus'') and northern harriers (''Circus hudsonius'') also prey on pygmy rabbits.Bradfield, Terry D. (1975). On the behavior and ecology of the pygmy rabbit. Pocatello, ID: Idaho State University. Thesis

Listing status

On September 26, 2007, Judge Edward Lodge of the United States District Court for the District of Idaho granted litigant party Western Watersheds Project

summary judgment In law, a summary judgment (also judgment as a matter of law or summary disposition) is a judgment entered by a court for one party and against another party summarily, i.e., without a full trial. Summary judgments may be issued on the merits of ...

remanding the

United States Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...

90-day finding denying conservationist parties' listing

petition A petition is a request to do something, most commonly addressed to a government official or public entity. Petitions to a deity are a form of prayer called supplication. In the colloquial sense, a petition is a document addressed to some offi ...

. The petition sought legal protection for pygmy rabbit as an endangered or

threatened species Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of '' critical depen ...

References

External links

Washington Department of Fish and Wildlife, Pygmy Rabbit
{{Authority control Leporidae Rabbit, Pygmy Rabbit, Pygmy Mammals described in 1891 ESA endangered species Taxa named by Clinton Hart Merriam Endemic fauna of the United States