Deer are a family of grazing mammals that belong to the Cervidae family. They are found throughout the world, except in Antarctica and Australia, and are known for their distinctive antlers, which are unique to male deer. These antlers are shed and regrown annually, with the size and shape varying depending on the species of deer. Deer are herbivores and primarily feed on grass, leaves, and other vegetation. They are also known for their excellent sense of hearing and smell, which helps them avoid predators.