- Dall Sheep
Taxobox
name = Dall Sheep
status = LR/lc | status_system = IUCN2.3
status_ref = [IUCN2006|assessors=Caprinae Specialist Group|year=2000|id=39250|title=Ovis dalli|downloaded=12 May 2006 ]
image_width = 250px
image_caption = Dall Sheep ram at the Alaska Zoo in Anchorage, Alaska.
regnum =Animal ia
phylum = Chordata
classis =Mammal ia
ordo = Artiodactyla
familia =Bovidae
subfamilia = Caprinae
genus = "Ovis"
species = "O. dalli"
binomial = "Ovis dalli"
binomial_authority = Nelson, 1884The Dall Sheep (originally Dall's Sheep, sometimes called Thinhorn Sheep), "Ovis dalli", is a wild sheep of the mountainous regions of northwest North America, ranging from white to slate brown and having curved yellowish brown horns. There are two putative subspecies: the northern Dall Sheep proper ("Ovis dalli dalli") which is almost pure white, and the more southern Stone Sheep (also spelled Stone's Sheep) ("Ovis dalli stonei"), which is a slaty brown with some white patches on the rump and inside the hind legs.
Research has shown that the use of these subspecies designations is questionable. Complete colour integradation occurs between white and dark morphs of the species with intermediately coloured populations, called Fannin's Sheep ("Ovis dalli fannini"), found in the
Pelly Mountains and Ogilvie Mountains of Yukon Territory.Sheldon, C. 1911. "The Wilderness of the Upper Yukon". First edition. Charles Scribner’s Sons, New York.] Mitochondrial DNA evidence has shown no molecular division along current subspecies boundariesLoehr, J., K. Worley, A. Grapputo, J. Carey, A. Veitch and D. W. Coltman. (2006) "Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA", Journal of Evolutionary Biology, 19:419-430.] , although evidence from nuclear DNA may provide some support.Worley, K., Strobeck, C., Arthur, S., Carey, J., Schwantje, H., Veitch, A. & Coltman, D.W. (2004). "Population genetic structure of North American thinhorn sheep Ovis dalli," Molcular Ecology 13: 2545–2556.] Also at the species level current taxonomy is questionable because hybrdization between "Ovis dalli" and "Ovis canadensis" has been recorded in recent evolutionary history.Loehr, J., K. Worley, A. Grapputo, J. Carey, A. Veitch and D. W. Coltman. (2006) "Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA", Journal of Evolutionary Biology, 19:419-430.]The latter half of the
Latin binomial "dalli" is derived from William Healey Dall (1845-1927), an American naturalist. The common name Dall Sheep or Dall's Sheep is often used to refer to the species "Ovis dalli". An alternative use of common name terminology is that Thinhorn Sheep refers to the species "Ovis dalli", while Dall's Sheep and Stone's Sheep refer to subspecies "Ovis dalli dalli" and "Ovis dalli stonei".The sheep inhabit the
subarctic mountain ranges ofAlaska , theYukon Territory, theMackenzie Mountains in the westernNorthwest Territories , and northernBritish 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.
The primary predators of Dall Sheep are wolves,
coyote s, black bears, and grizzly bears; golden eagles are predators of the young.Dall Sheep can often be observed along the
Alaska Highway at Muncho Lake and at Sheep Mountain inKluane National Park and Reserve , as well as nearFaro, Yukon (Fannin's Sheep).Notes
References
*A.W.F. Banfield (1974). "The Mammals of Canada". University of Toronto Press. ISBN 0-8020-2137-9
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