Mountain cottontail

The mountain cottontail or Nuttall's cottontail (Sylvilagus nuttallii) is a species of rabbit found in western Canada and the United States. It is a medium- to small-sized rabbit with pale brown fur, white undersides, a two-colored tail, and black-tipped, rounded ears with densely furred insides. It has notably rusty-colored legs and an orange nape. The mountain cottontail appears largely among coniferous forests in mountainous regions, including the slopes of the Rocky Mountains and the Cascade-Sierra Nevada mountain ranges, and adapts to a variety of elevations and vegetation. Its diet is made up of various grasses, shrubs, and sagebrush, as well as twigs, bark, or fungi in lesser amounts or when foliage is scarce.

The mountain cottontail was first described in 1837 by naturalist John Bachman and named Lepus nuttallii; the specific name commemorates zoologist Thomas Nuttall. Marcus Ward Lyon Jr. placed the species in the genus Sylvilagus in 1904. The species is closely related to the desert cottontail, and less so to the swamp rabbit and marsh rabbit. There are three subspecies of the mountain cottontail, and limited evidence points to the three as each making up distinct species.

The range of the mountain cottontail has shrunk as a result of climate change and competition from the eastern cottontail and other leporids, though the species is sympatric with the snowshoe hare, with the mountain cottontail generally occupying lower elevations in the same region. It is a target of rabbiting and is seasonally protected by hunting authorities as game. The mountain cottontail also has many predators and is affected by various parasites and diseases such as tularemia and Rocky Mountain spotted fever. Across its entire range, the species is assessed as "least concern" by the International Union for Conservation of Nature (IUCN), but province- and state-specific conservation assessments vary, with Arizona and British Columbia marking it as "vulnerable".