Nevada State Mammal
Desert Bighorn Sheep (common name)
Ovis canadensis nelsoni (scientific name)
Bighorn sheep are named for the large, curved horns borne by males. The species originally crossed over the Bering land bridge from Siberia. The population in North America peaked in the millions, and the bighorn sheep entered into the mythology of Native Americans. However, the populations of the desert bighorn sheep declined drastically with European colonization of the American Southwest. The characteristics and behavior of desert bighorn sheep generally follow those of other bighorn sheep, except for adaptation to the lack of water in the desert. The desert bighorn has been the state animal of Nevada since 1973.
The desert bighorn sheep has a solid, stocky, and muscular body on short legs. Desert bighorns are similar in size to mule deer. Their muzzles are narrow and pointed, while their ears are short. Due to their unique padded hooves, bighorn are able to climb the steep, rocky terrain of the desert mountains with speed and agility. Their fur is smooth and composed of an outer coat of brittle guard hairs and short, gray, crimped fleece under-fur. The summer coat is a rich, glossy brown, which becomes quite faded by late winter. Both rams and ewes develop horns soon after birth, with horn growth continuing more or less throughout life. However, the ewes' horns are much smaller and lighter and do not tend to curl.
Average lifespan in the wild is 6–15 years
Range: from Nevada and California to west Texas and south into Mexico
Conservation Status: In 1939, President Franklin D. Roosevelt signed a proclamation that established two desert areas in southwestern Arizona to help preserve the desert bighorn sheep. As of 2004, the numbers of desert bighorn sheep were still very low, although the overall population trend has increased since 1960.
Desert bighorn sheep are social animals and are typically found in small scattered bands adapted to a desert mountain environment with little or no permanent water. Some of the bighorn may go without visiting water for weeks or months, sustaining their body moisture from food and from rainwater collected in temporary rock pools. They may have the ability to lose up to 30 percent of their body weight and still survive.
After drinking water, they quickly recover from their dehydrated condition. Desert bighorns utilize two mechanisms for cooling: perspiring and panting. Their acute eyesight helps them gage distances when jumping from rock to rock and enables them to detect potential predators such as mountain lions, coyotes, and bobcats.
The typical diet is mainly grasses, sedges, and forbs (herbaceous flowering plants).
Breeding interval: Annual
Birthing period: late February to May
Average litter size: 1–2 lambs
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Data Source: U.S. Fish and Wildlife Service
Author: World Trade Press