Pygmy rabbits (Brachylagus idahoensis) are the smallest members of the rabbit family in North America and are found in the sagebrush communities of the Great Basin in parts of California, Idaho, Montana, Nevada, Oregon, Utah, Washington, and Wyoming, with the greatest portion of their range in Nevada. Despite this expansive area, their specialized habitat requirements limit them to sites with deep, friable soil that will support structurally dense sagebrush stands. They weigh about 400 grams (under one pound), measure 22-28 cm (8 to 12 inches) in total length, and are brown with short rounded ears and very small, entirely brown tails.
Various types of big sagebrush—Basin, Wyoming, and mountain (all Artemisia tridentata)—account for the majority of their diet year round and may comprise up to ninety-nine percent of their winter diets. No difference in preference has been found among the different types of sagebrush, but some individual plants may be preferred over others.
Pygmy rabbits are one of only two North American rabbits that create their own burrows. The burrows are structurally simple with two or more entrances and a maximum depth of about 1 m (approximately one and one third feet). Home ranges are centered around these burrows. Due to their small size, pygmy rabbits cannot run as fast as other rabbits and rely mostly on their burrows and the surrounding canopy cover of sagebrush for protection. Pygmy rabbits can be active at any time of day, but activity outside of the burrow generally takes place at dawn and at dusk.
Pygmy rabbits typically give birth in spring or early summer. The female creates a separate natal burrow with only one entrance. Like other rabbits, the young are born blind and completely dependent on the mother. The female pygmy rabbit returns to the burrow to nurse the young and covers the burrow when she leaves. Unlike some rabbit species that show great fluctuations in population numbers, pygmy rabbits do not appear to be able to produce extra litters in response to favorable environmental conditions.
Because of their highly specific habitat requirements, only a few patches in extensive stands of sagebrush are likely to provide suitable habitat for the pygmy rabbit. Because they do not reproduce in great numbers and generally do not disperse over great distances, recolonization of available habitat is slow. As a result, small populations become isolated, making them more vulnerable to extermination. Adding to this natural threat is the continuing degradation and destruction of sagebrush habitat. Negative impacts to pygmy rabbit habitat include large wildfires, invasive exotic grasses, conversion to agricultural fields, urbanization, pinyon-juniper encroachment, and excessive livestock grazing. Pygmy rabbits also may face competition from other larger rabbit species such as cottontails.
While the pygmy rabbit is currently listed as a species of special concern in Nevada, it is still widely distributed in areas with appropriate habitat. However, with the continued fragmentation and destruction of sagebrush communities, the future of the species is uncertain.