About 50 years ago, state wildlife officials decided to try to restore bighorn sheep to Wyoming's Seminoe Mountains. Between 1958 and 1985, they brought in six new batches -- 236 total -- from the more prolific Whiskey Mountain herd to the northwest. But the Seminoe herd failed to sustain itself, and by last fall, there appeared to be fewer than a dozen bighorns left. So officials turned to places with more Seminoe-like habitat, working with Oregon officials to helicopter-net and truck in 20 sheep from near Paisley, Ore., in December 2009. Last month, they borrowed 12 sheep from Wyoming's Devil's Canyon herd. As these maps show, efforts to reintroduce vanished herds and buoy struggling ones are widespread in the West, where factors like exotic diseases and habitat loss have taken a toll. Wyoming alone has transplanted 1,500 sheep in-state, exported 400 and imported 124.