Pronghorn are not antelope — they're the last surviving member of an otherwise extinct family, Antilocapridae, that's been on this continent for 20 million years. They evolved to outrun American cheetahs that disappeared at the end of the last Ice Age, which is why a pronghorn can sustain 50 miles per hour for several miles and burst past 60 in a sprint. A mature buck weighs 100 to 140 pounds with a tan-and-white coat, bold white throat bands, and black-cheek face markings. Both sexes grow horns (not antlers) — bucks carry a forward-curving prong and a hooked tip; does carry small straight spikes. The horns shed an outer sheath each fall and regrow over the bone core.
They live in open sagebrush sea — flat to rolling country where eyesight is everything. Pronghorn eyes are positioned for a 320-degree field of view and resolve detail at distances that would take a human binoculars. They graze on sage, forbs, and rabbitbrush, and they need open ground to use their speed. The rut runs in September; bucks defend either a harem of does or a stretch of preferred habitat. They will not jump fences — they crawl under them — which makes barbed-wire fences the single biggest barrier to migration across the West. Numbers are stable to growing across most core range.