Dall sheep

The Dall Sheep (originally Dall's Sheep, sometimes called Thinhorn sheep), Ovis dalli, is wild sheep of the mountainous regions of northwest North America, ranging from white to slate brown and having curved yellowish horns. There are two subspecies, the northern Dall sheep proper (Ovis dalli dalli) which is almost pure white, and the more southern and larger Stone sheep ((Ovis dalli stonei), which is a slaty brown with some white patches on the rump and inside the hind legs. An intermediately coloured population, called Fannin sheep, is found in the Pelly Mountains of the south-central Yukon. It is closely related to the Siberian Snow sheep (Ovis nivicola) and some taxonomists consider it the same species.

The species is named after William Healey Dall (1845–1927), an American naturalist.

The sheep inhabit the mountain ranges of Alaska, the Yukon Territory, the Mackenzie Mountains in the western Northwest Territories, and northern British Columbia. Dall sheep are found in relatively dry country and try to stay in a special combination of open alpine ridges, meadows, and steep slopes with extremely rugged ground in the immediate vicinity, in order to escape from predators that cannot travel quickly through such terrain.

Male Dall sheep have thick curling horns. The females have shorter, more slender, slightly curved horns. Males live in bands which seldom associate with female groups except during the mating season in late November and early December. Lambs are born in May.

During the summer when food is abundant, the sheep eat a wide variety of plants. During the winter diet is much more limited and consists primarily of dry, frozen grass and sedge stems available when snow is blown off, lichen and moss. Many Dall sheep populations visit mineral licks during the spring and often travel many miles to eat the soil around the licks.

Dall sheep are hunted by wolves, Grizzly bears and humans, and golden eagles are predators on the young.

Dall sheep can often be observed along the Alaska Highway at Sheep Mountain in Kluane National Park and Reserve, as well as near Faro, Yukon (Fannin sheep).

Reference

A.W.F. Banfield (1974). The Mammals of Canada. University of Toronto Press. ISBN 0802021379