Pygmy rabbit

The pygmy rabbit (Brachylagus idahoensis) is a North American rabbit, and is one of only two rabbit species in America to dig its own burrow. The pygmy rabbit differs significantly from species within either the Lepus (hare) or Sylvilagus (cottontail) genera and is generally considered to be within the monotypic genus 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 lists the species as lower risk. The pygmy rabbit is the world's smallest leporid, which means adult weights from 375 to about 500 grams (0.827 to about 1.102 lb), and a body length from 23.5 to 29.5 centimeters (9.3 to 11.6 in); 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 fur on the tail. 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 1,370–2,135 meters (4,495–7,005 ft) and in California from 1,520–1,615 meters (4,987–5,299 ft). The last male purebred Columbia Basin pygmy rabbit, found only in the Columbia Basin of Washington State, died March 30, 2006, at the Oregon Zoo in Portland. The last purebred female died in 2008. A crossbreeding program conducted by the Oregon Zoo, Washington State University and Northwest Trek is attempting to preserve the genetic line by breeding surviving females with the Idaho pygmy rabbit. Pygmy rabbits are found primarily in big sagebrush (Artemisia tridentata) and rabbitbrush (Chrysothamnus spp.) dominated communities. 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 spp.), prairie junegrass (Koeleria macrantha), Sandberg bluegrass (Poa secunda), bluegrass (Poa spp.), needle-and-thread grass (Stipa comata), western yarrow (Achillea millefolium), rosy pussytoes (Antennaria microphylla), milkvetch (Astragalus spp.), arrowleaf balsamroot (Balsamorhiza sagittata), buckwheat (Eriogonum spp.), tailcup lupine (Lupinus caudatus), and phlox (Phlox 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). Pygmy rabbits are capable of breeding when they are about 1 year old The breeding season of pygmy rabbits is very short. In Idaho it lasts from March through May; in Utah, from February through March. 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.