Mustangs claim turf on the Montana-Wyoming border.

By Chris Woolston

When Spanish mustangs rule their own mountain range, there's going to be drama. "It's a constant soap opera out here," says Matt Dillon, director of the Pryor Mountain Wild Mustang Center in Lovell, a northern Wyoming ranch town. Standing on a red sandstone ridge next to an axle-busting dirt road, Dillon translates the profanities streaming from Jackson, a nearby stallion stomping around in the sagebrush and junipers. With high-pitched whinnies and deep snorts, Jackson chastises a mare for wandering away with her new foal. The mare responds by batting her saucerlike eyes.

"The foal isn't even his," says Dillon, who—unlike Jackson—knows where the mare has been spending her time. Jackson, a "coyote dun" with a dark back stripe and black mane, clearly wants others to hear. Rivalries can be fierce. Days earlier, a stallion fell to his death while battling a foe.

The 150-odd horses remain from herds released by Crow Indians in the 1800s. They are sleek and tough, well suited to a landscape that would break thoroughbreds. A few hang out along Highway 37 northeast of town, but for true wildness you can take a four-wheel-drive vehicle up Burnt Timber Ridge Road. This year the center is also offering guided tours. (307) 548-9453, www.pryormustangs.org.