Usually branched, antlers serve as weapons and as sexual ornaments. The male deer sheds its antlers every year between January and April. As the deer matures, the antlers become longer and acquire more points. A diet that includes certain minerals and vitamins is essential for normal antler growth. Like cattle, goats, and antelope, deer are ruminants, or cud chewers, and have a four-chambered stomach.
All deer lack a gall bladder except for the musk deer.
Teeth number 32 to 34. Through game management the white-tailed deer of North America, once hunted almost to extinction, have become the most numerous large game animal on the continent. Most deer associate in groups, although a few are solitary, usually during the non-mating season. Typically, male deer gather a harem during the breeding season. Deer mate during the autumn, and the doe usually gives birth to one or two fawns in the spring.