Bighorn sheep (Ovis canadensis canadensis) are more widely distributed throughout the United States than Canada and are noted for their ability to survive incredibly diverse conditions. There are two subspecies of bighorn sheep; the Rocky Mountain bighorn and the California bighorn. Both species have concave hooves with rough footpads that provide traction in rocky terrain.
The two species of bighorn sheep look similar, with California bighorns being slightly darker in color than the Rocky Mountain bighorn. In late summer and autumn, bighorn sheep have a brown coat with a contrasting ivory-white rump patch, a white muzzle and white trim on the back of all four legs. By late winter, the coat fades to a gray-brown.
The horns of a California bighorn have more of an outward flare than those of the Rocky Mountain bighorn. Bighorn rams have massive, brown, spiraled horns that curl back and down. A ram’s horns can be 50 inches (127 cm) around the curve and as thick as 16 inches (40 cm) around the base, while an ewe’s horns will be around 12 inches (30 cm) long. The horns grow rapidly in the summer and slowly in the winter; this difference in this seasonal growth rate produces a ring or “annuli” that reveals the animal’s age.
A bighorn’s diet consists primarily of broad-leaved, non-woody plants and grasses. Bighorn sheep have an appetite for salt and many herds will travel miles to reach natural salt licks. In the winter, most bighorn sheep will inhabit low-elevation grassy ranges. Migratory bighorns leave their winter ranges in May or June and move to summer pastures in the alpine zone.
The weight of a bighorn sheep will range from 120 to 340 lbs (54 to 154 kg), depending on sex and age.
Photocredit: Paul Tessier