You might have glimpsed a wild mustang as you drove north on River to Teter Rock. But you're likely to see an entire herd from your high perch at the Rock. Look south into the valley where these horses often are contentedly grazing or running unfettered in the Flint Hills pasture. For the past 15 years mustangs have been brought to Kansas by the Bureau of Land Management from western states where the severe weather had made their living conditions in their natural habitat unstable. Today more than 4,700 wild horses roam more than 36,600 acres in the Flint Hills.