The bighorn sheep is a species of sheep in North America named for its large horns. These horns can weigh up to 30 lb, while the sheep themselves weigh up to 300 lb. Sheep originally crossed to North America over the Bering land bridge from Siberia.
Bighorn sheep live in large flocks, and do not typically follow a single leader ram. Prior to the mating season or "rut", the rams attempt to establish a dominance hierarchy to determine access to ewes for mating.
The population in North America peaked in the millions, but by 1900, the population had crashed to several thousand, due to diseases introduced through European livestock and overhunting. Conservation efforts (in part by the Boy Scouts) have restored the population.