The bighorn sheep originally crossed to North America over the Bering land bridge from Siberia and is named for its large horns that can weigh up to 14 kg (30 lb), while the sheep themselves weigh up to 140 kg (300 lb). The population in North America peaked in the millions, and the bighorn sheep entered into the mythology of Native Americans. By 1900, the population had crashed to several thousand, due to diseases introduced through European livestock, over-hunting, and competition from ranching.
A program of reintroduction, natural parks, and reduced hunting, together with a decrease in domesticated sheep near the end of World War II, allowed the bighorn sheep to make a comeback. (1) 
Recent genetic testing indicates three distinct subspecies, one of which is endangered – Sierra Bighorn: unique to the Sierra Nevada mountains of California and listed as a federally endangered subspecies in 2000. Today, about 500 Sierra bighorn remain in the wild. The Rocky Mountain bighorn sheep are found from British Columbia to Arizona, including Northern New Mexico.
Bighorn sheep were gone from the Rio Grande Gorge until 2006, when the Taos Pueblo released 23 onto the land. The Department of Game and Fish followed with the release of 25 additional bighorns in 2007. Since then (10 years), the population has multiplied to 280. (2)
Rocky Mountain bighorn sheep can regularly be observed within the Bureau of Land Management’s Rio Grande del Norte National Monument and are protected.
A good area to view them is the West Rim Trail that extends from the rest area west of the Rio Grande Gorge Bridge on U.S. 64 and runs south along the canyon rim to Route 567 above the Taos Junction Bridge.
Also, down into the gorge, along the river, North of Pilar, NM.
Keep in mind that while the sheep can outmaneuver smaller predators, there are mountain lions/bobcat kills.
As always, give the animals space, respect their natural habitats (no littering or destroying property), and be cautious on roads – slow down! Last year alone, three rams were killed in traffic collisions on the eastern side of the gorge. (3)
- https://en.wikipedia.org/wiki/Bighorn_sheep
- http://magazine.wildlife.state.nm.us/thriving-rio-grande-gorge/)
- http://www.taosnews.com/stories/meet-the-bighorn-sheep-of-the-ro-grande-gorge,19129
