About 150 bighorn sheep live in Yellowstone near steep terrain where they can stay safe from predators. Bighorns are occasionally eaten by wolves but there are certainly easier meals to be had than these agile ungulates. Bighorn sheep numbers have actually increased since wolf restoration began in 1995, possibly because of the decrease in elk, a main food competitor.
Like other ungulates, males battle in autumn, ramming rivals with their big horns. Like their name says, they have horns, not antlers. Horns are not shed and keep growing. So, the bigger and curlier the horns, the older the ram.