Mammal Species of the World
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In California, S. nuttallii occurs from 1,372 m to at least 3,200 m in elevation (Chapman 1975).
The mountain cottontail lives mostly in the western part of the United States. Its range is bordered in the east by Montana’s eastern border, in the west by the Sierra Nevada Mountains, in the south by the middle of New Mexico and Arizona, and in the north by the US/Canadian border; however a small area of Canada right above Montana and Washington is also included. (Chapman, 1975)
Biogeographic Regions: nearctic (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: Western North America, from eastern slopes of Cascade-Sierra Nevada Range east to western North Dakota and Black Hills, and from southern Canada south to Arizona and New Mexico. Recently appears to have been replaced by S. FLORIDANUS in much, if not all, of southwstern North Dakota (Chapman 1975)
The mountain cottontail is of medium to large size for its genus with long hind legs and a large tail that is dark on top and light below. The top of the body is covered in grayish brown fur, and the underbelly is white. The hind legs are covered with reddish brown hairs that are long and dense. The ears are rather short and rounded. They have black tips and long hairs on their inner surfaces. The animal's whiskers are usually white. The females have eight to ten mammae. In this species there is a single annual molt. The rabbits weigh between 0.7 kg and 1.2 kg and are between 35 cm and 39 cm in body length. Females are nearly five percent larger than males.
Skull characteristics of Sylvilagus nuttallii include a long rostrum, small supraorbital processes, and long and slender postorbital processes. The animal also has a rounded braincase, and a dental formula of 2/1, 0/0, 3/2, 3/3 with rather large molariform teeth.
(Chapman, 1975) (Chapman, 1999) (Enature, online) (Schneider, 1990)
Range mass: 0.7 to 1.2 kg.
Range length: 35 to 39 cm.
Other Physical Features: endothermic ; bilateral symmetry
Length: 39 cm
Weight: 1032 grams
Size in North America
Average: 362 mm
Range: 338-390 mm
Range: 628-871 g
Habitat and Ecology
S. nuttallii feeds on sagebrush and juniper all year where this vegetation occurs, but grasses are preferred when available in spring and summer (Chapman 1975). The breeding season is variable throughout the range of S. nuttallii (Chapman and Ceballos 1990). Gestation is 28-30 days (Chapman 1999). A female may produce between two and five litters each year, with between four and six young in each litter (Chapman and Ceballos 1990). HB length is 33.8-37.1 cm (Chapman 1975).
The cottontail inhabits brushy or wooded areas on slopes or riverbanks that are often covered with grasses, willows, and most importantly, sagebrush. If vegetation is sparse, as on a rocky mountainside, these rabbits can hide in burrows or rock crevices. (Chapman, 1975) (Sibr, online)
Habitat Regions: terrestrial
Terrestrial Biomes: forest ; scrub forest ; mountains
Comments: Brushy, rocky areas; found in dense sagebrush, streamside thickets and brushy forest edges. Uses burrows and forms. May sometimes climb into junipers (Verts et al. 1984).
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
The rabbit feeds near water, in the cover of brush, or in the open near brush cover. Heavy wind and rain can reduce the likelihood that the animal will eat in the open. (Chapman, 1975) (Verts & Gehman, 1991)
Mountain cottontail prefer grasses when they are available above other food sources, but when grasses are sparse major foods are sagebrush, Western Juniper and the juniper berries. (Enature, online)
Plant Foods: leaves; fruit
Primary Diet: herbivore (Folivore , Lignivore); coprophage
Comments: Grasses and other herbaceous and woody vegetation, including sagebrush and juniper. Usually feeds in or near cover.
This cottontail eats the grass on mountainsides and keeps the vegetation sparse.
Parasites include nematodes and cestodes.
The only antipredation techniques reported are rapidly running to a safe sheltered area and restricting activity to dusk and dawn.
(Chapman, 1975) (Bull, 2000) (Sibr, online)
Mammalian predators include coyotes, bobcats, and martens. Other predators include hawks, eagles, owls, and rattlesnakes.
- coyotes (Canis latrans)
- bobcats (Lynx rufus)
- martens (Martes)
- eagles (Accipitridae)
- owls (Strigiformes)
- rattlesnakes (Crotalus)
This list may not be complete but is based on published studies.
Predators include bobcats, coyotes, great horned and long-eared owls. Gopher snake and western rattlesnake are important predators on juveniles in some areas (Diller and Johnson 1988). Population density ranged from 19 to 254 per 100 ha in Oregon (Verts et al. 1984); density in sagebrush 23-43 per 100 ha in southern British Columbia.
Life History and Behavior
Perception Channels: tactile ; chemical
Comments: May be active at any time of the day or night, but like other cottontails, is primarily crepuscular. Active throughout the year.
Status: captivity: 7.4 (high) years.
Lifespan, longevity, and ageing
These cottontails are normally solitary unless the habitat can support more than one animal. The animals mate between March and July and almost always at night. They do not form pair bonds. (Chapman, 1975) (Schneider, 1990) (Verts & Gehman, 1991)
- The gestation period is 28-30 days and the female can have four or five litters per year. The litter size is usually 4-8 but in California it is not unusual for a litter to consist of just two babies. Female babies are slightly more abundant than male babies (1 male to 1.1 females).
- The young are able to move around outside the nest when they weigh about 75 grams and are weaned after only one month. Sexual maturity appears to be at a minimum of 3 months but probably is actually later than that. (Chapman, 1999) (Chapman, 1975)
Breeding season: March-July
Range number of offspring: 1 to 8.
Average number of offspring: 5.
Range gestation period: 28 to 30 days.
Range weaning age: 28 (high) days.
Range age at sexual or reproductive maturity (female): 90 (low) days.
Range age at sexual or reproductive maturity (male): 90 (low) days.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous
Average number of offspring: 3.6.
Before the female gives birth she makes a nest that is shaped like a cup and lines it with grass, fur, and sticks. The young are altricial with no hair, and they are blind. (Schneider, 1990) (Sibr, online)
Parental Investment: altricial
Breeds late winter spring and summer. Gestation period lasts 28-30 days (Chapman 1975). Females may produce 4-5 litters of 4-5 young per year (Jones et al. 1983).
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Lower Risk/least concern (LR/lc)
The mountain cottontail is common in its geographic range but has rapidly declined in western North Dakota. (Chapman, 1999)
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Comments: Limited in Canada primarily by loss of habitat to human settlement, agriculture, and cattle grazing (Carter and Merkens, 1994 COSEWIC report).
Relevance to Humans and Ecosystems
They graze on grasses until the area is depleted, which can cause habitat change.
Their droppings serve as fertilizer and the rabbits are potentially food for endangered species of carnivorous birds, mammals, and snakes. Like other cottontails, the mountain cottontail is valued by humans for its beauty and grace.
Positive Impacts: food ; body parts are source of valuable material
The mountain cottontail is a small rabbit but its size is relatively large for the genus. Hind legs are long; the feet are densely covered with long hair. Ears are rounded at the tips and relatively short; the inner surfaces are noticeably haired. It has pale brown fur on the back, a distinct pale brown nape on the back of the head, black-tipped ears, a white grey tail, and a white underside. A smaller size, the brown nape on the back of the head distinguish this cottontail from the Snowshoe Hare.
This species is confined to the inter mountain area of North America. It ranges from just above the Canadian border south to Arizona and New Mexico, and from the foothills of the eastern slopes of the Rocky Mountains and west to the eastern slopes of the Cascade-Sierra Nevada Range.
Mountain cottontail diet is made up in large part of grasses such as wheatgrasses, needle-and-thread, Indian ricegrass, cheatgrass brome, bluegrasses, and bottlebrush squirreltail. Dependent on the area the diet may include quantities of shrubs such as Big sagebrush, rabbitbrush, and saltbushes. As food source becomes more limited in the winter months the diet may turn to more woody plants such as bark, and twigs.
The nest of S. nuttallii is reported to be a cup-like cavity lined with fur and dried grass. The top of the nest is covered with fur, grass, and small sticks, probably placed there by the female. The average fetal sex ratio in Oregon was 1 male to 1.05 females; the adult sex ratio was 1 male to 1.18 females. Depending on location, the breeding season will vary but ranges through February to July, and possibly later in warmer climates. Mean litter sizes average 4–6 kits per litter. The gestation period for this cottontail is 28–30 days, and the female may be bred during postpartum estrous.
Most activity for these rabbits is early morning and late afternoon. They are not a social species and spend the largest quantity of time performing non social behavior. The most common social behavior seen is during reproductive actions or courting. Over 50% of the time the Mountain cottontail is active it is feeding. Some mountain cottontails eat finn's (truncation?).
- Smith, A.T. & Boyer, A.F. (2008). "Sylvilagus nuttallii". IUCN Red List of Threatened Species. Version 2009.2. International Union for Conservation of Nature. Retrieved 1 February 2010.
- Chapman, Joseph A., 1975, Sylvilagus nuttallii, Mammalian Species No. 56, The American Society of Mammalogists
- Johnson, Mark K., Richard M. Hansen, Feb 1979, Foods of Cottontails and Woodrats in South-Central Idaho, Journal of Mammalogy, Vol. 60, No. 1, pp. 213-215
- Verts, B.J. and Steven D. Gehman, Activity and Behavior of Free-Living Sylvilagus nuttallii, Department of Fisheries and Wildlife. Nash Hall, Oregon State University Corvallis, Oregon 97331