The Bighorn sheep (Ovis canadensis) is a species of sheep in North America[4] named for its large horns. These horns can weigh up to 30 pounds (14 kg), while the sheep themselves weigh up to 300 pounds (140 kg). Recent genetic testing indicates that there are three distinct subspecies of Ovis canadensis, one of which is endangered: Ovis canadensis sierrae. Sheep originally crossed to North America over the Bering land bridge from Siberia: the population in North America peaked in the millions, and the bighorn sheep entered into the mythology of Native Americans. However, by 1900 the population had crashed to several thousand. Conservation efforts (in part by the Boy Scouts) have restored the population.