Bighorn Sheep (Ovis canadensis canadensis)

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Common Name: Rocky Mountain Bighorn Sheep Scientific Name: Ovis canadensis canadensis Class: Mammalia Order: Artiodactyla Family: Bovidae Subfamily: Caprinae Feeding Type: Herbivore Statistics: Weight: 53-140 kg; Body length: 150-180 cm; Shoulder height: 95-110 cm.

Range/Habitat: Found in the Rocky Mountains from southern Canada to Colorado and as a desert subspecies (Ovis canadensis nelsoni) from Nevada and California westward to Texas and south into Mexico. Inhabits alpine meadows, grassy mountain slopes and foothill country in proximity to rugged, rocky cliffs and bluffs. They require drier slopes where the annual snowfall is less than about 60 inches a year since they cannot paw through deep snow to feed. The have a "vertical" migration with the winter range between 2,500 - 5,000 feet in elevation with the summer range is between 6,000-8,500 feet.

Adaptations: Bighorn sheep have double-layered skulls shored with struts of bone for battle protection. They also have a massive tendon linking the skull and spine to help the head recoil from the blows received during combat with an opponent. Bighorn sheep are very alert and will watch other animals moving at distances of up to a mile away. They have excellent eyesight that allows them to accurately judge distances in jumping and locating footholds in their vertical terrain. They can zigzag up and down cliff faces with ease and use ledges only 2 inches wide for footholds. They can leap 20 feet across and can run at 30 mph. They swim easily despite their massive size and weight of their horns.

Courtship/Gestation/Birth: Rutting season begins in autumn and early winter. The males will engage in head-to-head combat, smashing into each other at speeds of 20 mph. Horn size is a symbol of rank and the winner of the duels gets to breed with the females. Females do not breed until they are 2 or 3 years old; males usually mate after they are seven years old. Gestation is 150-180 days long and 1-4 young are born in the spring. Newborns are precocial and can follow their mother over the rocky terrain after the first week. They are completely weaned by 4-6 months of age. They live an average of 9 years, but some have lived to 24 years. Lifespan for females is shortened by frequent breeding and for males from trophy hunting.

Prey/Predator: Prey

Diet: ZM-grass hay, alfalfa pellets, minerals and vitamins. Wild- a wide variety of plant life.

Status: Species of special concern. Threatened with eventual extinction, numbers are only 1/10 the population that existed when pioneers first began coming to the Rockies. Their main enemies are poachers for meat and trophies, diseases (introduced by domestic sheep), competition from livestock and continual human encroachment on their habitat. The subspecies Ovis canadensis auduboni of the Black Hills and adjacent areas is already extinct. Recovery of numbers has been very slow for these animals and the future is bleak unless further conservation efforts are taken.

Special Notes: Bighorn sheep are gregarious and herds can sometimes include over 100 individuals although small groups of 8-10 are more common. Mature males stay apart from females and their young for most of the year in bachelor flocks. Young females generally remain in their mother's group (which is led by an old ewe). Young males leave their mother's group when they are 2-4 years old and join a bachelor flock. Young sheep of both sexes learn the migratory routes and suitable habitats from the adults of the groups. Trophy hunting is especially damaging as it eliminates the dominant breeding males which shatters the cohesiveness of the bighorn groups.