Series: Dall Sheep in Alaska's National Parks

Media Included

  1. Dall Sheep Overview - Watch Dall sheep forage on the rocky slopes of the Brooks and Alaska Ranges. *This video contains no sound*

Learn the basics of Alaska's Dall Sheep.

About Dall Sheep

Dall sheep ram lays on a rocky hillside
Approximately 40% of Alaska's population of Dall sheep live in national parks.

NPS Photo / Lian Law

Real world cliff hangers, Dall sheep inhabit some of Alaska’s most rugged alpine areas. They thrive on the wind-swept exposed cliffs and peaks of mountains in central and northern Alaska. This subspecies of sheep is found only in Alaska and western Canada. Dall sheep weigh an average of 130 pounds and have white fur. Their winter coats can be up to two inches thick with coarse outer hairs covering a coat of fine wool. Rams have large horns that form a characteristic curl while females, called ewes, have smaller horns. 

In Depth

Dall Sheep Morphology
Dall sheep stand about three feet high at the shoulder. They are off-white in color, and their coat consists of a fine wool undercoat and stiff, long, and hollow guard hairs. Their winter coats can be over two inches thick. Dall’s sheep can live to be 12 to 16 years of age.

Dall sheep are sexually dimorphic, which means rams and ewes look different. Rams are larger than ewes and typically weigh between 160 and 180 pounds at maturity. Ewes weigh approximately 100 to 110 pounds on average. During the winter, adult sheep may lose up to 16% of their body mass, and lambs and yearlings as much as 40% depending on winter weather severity. Dall sheep begin growing horns at about two months old. Ewes have small, slender horns compared to the massive, curling horns of rams. Young rams resemble ewes until they are about 3 years of age. At this point, their horns begin to grow much faster and larger than ewes' horns.

Alpine Plant Communities
Dall sheep occupy wind-swept areas where snow cover is low or non-existent. They feed on grasses, sedges, forbs, lichens, and mosses, and consume a greater diversity of plant species in summer than in winter. Dall sheep will also seek out mineral licks of high calcium-phosphate or calcium-magnesium concentrations.

Predators of Dall Sheep
All living things are part of the circle of life. Just as Dall sheep eat plants, other animals depend on the sheep for food. Wolves, coyotes, bears, wolverines and lynx prey on sheep, and golden eagles also prey on lambs. 

Dall Sheep Range and Movement

Dall sheep are typically loyal to the small ranges they occupy, and their limited migration is based on snow depth, temperature, and plant availability. Some Dall sheep move very little, but others occupy distinct seasonal ranges within a 20 to 60 square mile home range. Movements and use areas are considerably smaller in winter than in summer due to snow cover.


Sources

  • Bowyer, R. T. and D. M. Leslie Jr. 1992. Ovis dalli. Mammalian Species. 393:1-7. 
  • Lawler, J. P. 2004. Demography and home ranges of Dall’s sheep in the central Brooks Range, Anaktuvuk Pass, Alaska: Gates of the Arctic National Park and Preserve. Technical Report NPS/AR/NRTR-2004-43. National Park Service, Fairbanks, Alaska.
  • Nichols, L. and F. L. Bunnell. 1999. Natural history of thinhorn sheep. Pages 23-77 in R. Valdez and P. R.Krausman, editors. Mountain sheep of North America. The University of Arizona Press, Tucson, Arizona.
  • Olson, S. T. 2008. Dall Sheep Field Notes. Alaska Department of Fish and Game. https://www.nps.gov/akso/parkwise/students/ referencelibrary/WEAR/DallSheepLifeCycle.htm