Deer antlers are living bone structures that grow annually from bony bases called pedicles on top of the skull. The process begins in spring when hormonal changes trigger growth from specialized tissue at the pedicle's tip. During the growing season, antlers are covered in soft, velvet-like skin filled with blood vessels that supply nutrients and oxygen needed for rapid bone development. This velvet skin is highly sensitive and helps regulate temperature during growth.
Antler growth is remarkably fast—some species can grow an inch per day. The antlers are composed of true bone, similar to skeletal bone but denser and harder. As summer progresses and day length decreases, hormonal shifts (particularly increased testosterone in males) cause the blood vessels in the velvet to constrict. The velvet dries up and is shed by fall, revealing the hardened antler beneath, which the deer rubs against trees and vegetation to remove remaining velvet.
Once hardened, antlers serve primarily as weapons during rutting season (mating season) when males compete for females. The size and complexity of antlers depend on the deer's age, genetics, nutrition, and overall health. After the breeding season ends, hormonal changes trigger antler shedding. The pedicles essentially "shut down" the blood supply at the base of the antler, causing them to drop off—usually between late winter and early spring. The cycle then repeats, with new antlers growing from the same pedicles. Unlike horns in other animals, antlers are shed and regrown annually, making them a unique feature of the deer family (Cervidae).