• Winter visitors watching geysers erupting


    National Park ID,MT,WY

Bighorn Sheep

Two bighorn sheep are alert in a sage habitat.

Although widely distributed across the Rocky Mountains, bighorn sheep (Ovis canadensis) persist chiefly in small, fragmented populations that are vulnerable to sudden declines as a result of disease, habitat loss, and disruption of their migratory routes roads and other human activities. About 10 to 13 interbreeding bands of bighorn sheep occupy steep terrain in the upper Yellowstone River drainage, including habitat that extends more than 20 miles north of the park. These sheep provide visitor enjoyment as well as revenue to local economies through tourism, guiding, and sport hunting. Mount Everts receives the most concentrated use by bighorn sheep year-round. Learn More…


Quick Facts about Bighorn Sheep in Yellowstone

  • 379 in 2012
  • Average life span: males, 9–12 years; females 10–14 years.
  • Adult male (ram): 174–319 pounds, including horns that can weigh 40 pounds. The horns of an adult ram can make up 8–12% of his total body weight
  • Adult female (ewe): up to 130 pounds bighorn sheep have horns. The rings on horns can be used to determine age, though it is easier to count the rings on a ram.
  • A chlamydia (pinkeye) epidemic in 1981–1982 reduced the northern herd by 60%.
  • Other unknown factors may be limiting the population now.

Additional Resources


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