Bighorn sheep and lambs eat grasses, sedges and brush, depending on the season. The lambs also suckle on their mothers for 4 to 6 months and are typically fully weaned by 6 months. Grass-eating bighorn sheep have a four-part stomach that allows them to eat and rechew their cud once they are safe from predators.
Desert bighorns eat the brush plants that are available in the desert, such as cacti and holly, and they remove the spines with their hooves before consumption, eating only the insides. Mountainous bighorn sheep consume grasses and sedges in the summer and rabbit brush, sage and willow during the winter.