White-tailed deer spend their mornings and evenings grazing. They are herbivores and eat green plants and nuts. Deer live in small groups, usually composed of a female and her young. Males have beautiful antlers on their heads and live in small groups of three or four. Males and females are red-brown in summer and gray-brown in winter. In the absence of predators, deer can sometimes be so numerous that food runs out. Deer are ruminants like cattle. This means that they have four stomachs and ruminate on semi-digested food. This complicated process allows deer to eat foods such as twigs, which most animals can not digest.