Ovis canadensis

The bighorn sheep, a wild sheep of the mountains of western North America, named for the massive curling horns of the rams. Males use these horns in head-butting contests for mates, which recent studies show causes concussion-like symptoms, and eventually CTE-like damage to the brains of older males. As a species they are sure-footed climbers, often favoring steep, rocky terrain that keeps them out of reach of most predators.