Mountain Cottontail

Sylvilagus nuttallii is a medium to small-sized rabbit, with a head and body length of 11 to 15 in (29 to 39 cm), though among cottontail rabbits it is relatively large. The hind legs are long; the feet are densely covered with long hair and measure from 3.1 to 4.1 in (80 to 103 mm). The ears are relatively short (2.1–3.9 in (54–100 mm)) and have rounded tips; the insides are densely furred. The tail, dark on top and white underneath, measures from 1.2 to 2.4 in (3 to 6 cm). It has pale brown fur on the back, black-tipped ears, a white-grey tail, and a white underside. The back of the head is an orange color, and the legs appear rusty on the outside. It has a distinctive cinnamon-colored ring around the eyes. Its whiskers can be either totally or partially white. Like other leporids, the mountain cottontail has a dental formula of 2.0.3.31.0.2.3 × 2 = 28, i.e. two pairs of upper and one pair of lower incisors, no canines, three upper and two lower premolars, and three upper and lower molars on either side of the jaw. The mountain cottontail can be distinguished from other rabbits that share the same habitat by its size and ear shape. It is larger than the pygmy rabbit (S. idahoensis), smaller than the eastern cottontail (S. floridanus), and has shorter, more rounded, and more densely haired ears than the desert cottontail. …

Sylvilagus nuttallii is distributed throughout the Western United States and parts of Canada. It appears from the Canadian provinces of Alberta and Saskatchewan, just north of the United States-Canada border, to the northern parts of Arizona and New Mexico. Laterally, it is known from the foothills of the eastern slopes of the Rocky Mountains and west to the eastern slopes of the Cascade-Sierra Nevada. In southwestern North Dakota, it was once prevalent, but has since been largely replaced by the eastern cottontail. It was once found as far south as Texas, but changing habitat due to climate change has resulted in the species being pushed back; in these regions, the desert cottontail and robust cottontail (S. holzneri robustus) are more prevalent. The three subspecies of mountain cottontail tend to remain separated in geographical terms. The mountain cottontail has a fairly cosmopolitan distribution, appearing at varying elevations and in regions with different vegetation. It occurs in coniferous forests, including the subalpine zone, living among rocky areas among sagebrush, in shrublands, or in wooded areas. It is more associated with sagebrush in the northern part of its distribution, and more with forests in the south. …

Sylvilagus nuttallii is not a social species and tends to live a solitary life. However, congregations do occur on popular feeding grounds. The majority of feeding occurs at dusk and dawn in clearings near cover or in brush. The mountain cottontail is also known to climb juniper trees to feed, and spends approximately half of its waking hours feeding. The most common social behavior seen is during reproductive actions or courting. It is not territorial. Males typically have a larger home range than females. When there is plenty of cover from dense vegetation, the mountain cottontail rests in shallow depressions or nests in the ground known as forms for shelter. When vegetation is sparse, it will use the burrows of other animals for shelter instead. It does not seem to dig burrows of its own. The rabbits remain active all year. When startled, a rabbit will run a couple meters to a covered area to hide, then freeze with ears erect. Predators include coyotes, bobcats, lynxes, martens, crows, ravens, hawks, owls, and rattlesnakes. Though it has been replaced in some regions by the eastern and desert cottontail, it is largely sympatric with the widely distributed snowshoe hare (Lepus americanus) and the Northern Idaho ground squirrel. Several parasites are known to affect the mountain cottontail, including nematodes, cestodes, and species of Coccidia. …