Rocky Mountain Bighorn Sheep rams (males) will band together in the spring and summer, while ewes (female bighorn sheep) and their babies will form separate groups. During winter, the separate groups will come together to form larger herds. Mating season, called the “rut”, starts in fall and rams will compete to mate with females. Ewes will have one lamb during spring to early summer. These sheep graze on grasses, sedges, and clover in warmer months and willow, holly, cactus, and sage in the cooler months. When they aren’t grazing, they lie down and chew their cud. Bighorn Sheep can go without drinking water for months at a time because they get all the necessary liquids and electrolytes from the plants that they eat.