In the remote high country of the Pacific Northwest to Texas and Mexico and as far east as Nebraska, bighorn sheep are moving up into summer range. Rough, rubberlike pads on cloven hooves allow them to traverse trails that would challenge human climbers secured by rope and piton. Within a few days each pregnant ewe will slip away from the herd to find a sheltered ledge where she’ll deliver a lamb with soft, light-colored hair. After about a week, lambs follow their mothers, frolicking with other newborns and learning to supplement milk diets with tender grasses. Both sexes grow horns, though the ewe’s will be thinner and won’t attain a full curl. Bighorns of the Rocky Mountain race are the largest wild sheep in North America, occasionally reaching 300 pounds. By the early 20th century, bighorns had almost been eliminated, mostly by pathogens and parasites contracted from domestic sheep. But a reduction in sheep ranching, strict hunting regulations, and extensive reintroductions (like the one pictured here, in Utah) funded by sportsmen have restored the species to a large part of its natural range.