The pygmy rabbit (Brachylagus idahoensis) is a rabbit species native to the United States. 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 (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. Description The pygmy rabbit is the world's smallest leporid, 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, 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. Lifecycle 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. The growth rates of juveniles are