Back from the brink

Bighorn sheep once roamed the Western United States by the millions: Native American petroglyphs depict impossibly long caravans of the sheep, and Lewis and Clark spotted them often along their trailblaze to the Pacific. Overhunting and habitat loss brought the bighorn's US population as low as 15,000 at one point, but it's since climbed back to 70,000 or so. Some of the first work to save bighorns was done right here in Arizona (this specimen was seen in Saguaro National Park). Local boy scouts led the state's first bighorn conservation push in 1936, when only about 150 sheep survived in the state, compared to today's 6,000.