How Soon Do Male Deer Grow Antlers?

When you compare an adorable newborn fawn to a mature buck with impressive antlers, you might wonder "When do deer start growing antlers?" Fawns grow and develop quickly, and young male deer begin growing antlers at about four or five months of age. However, these newly developing "antlers" aren't what they seem!

A young male deer begins to grow ​pedicles​ at four or five months old. Not quite antlers, the pedicles look like small hairy bumps and give young bucks the name "button bucks." The pedicle acts as the base of the antler and directly attaches to the skull of the deer. The true antler grows from the pedicle when the buck reaches about a year old.

After their first growth, all male deer follow a yearly cycle of shedding and regrowing their antlers.

During the spring, the connection between the antler and the pedicle begins to weaken. Once weakened, the deer sheds – or ​casts​ – the antler. High in protein and calcium phosphate, rodents such as squirrels typically eat the antlers after they are shed. Immediately after casting their old antlers, growth begins on the new set. New antler growth lasts through spring into summer.

The antlers continue to grow and develop throughout most of the summer. During the growing phase, a thin layer of soft velvet covers the antler. The velvet envelops a thin layer of blood vessels that nourishes the growth of the antler. Antlers of young males grow about 3/4 inch per week, while mature adults can reach growth rates of up to 1 1/2 inches per week. At the end of the summer, the antlers cease growing, and the velvet dries up and falls off.

The breeding season occurs during the fall. Male deer use their now-hardened antlers to fight one another for breeding rights over females. Unlike other members of the deer family, such as elk, white-tailed deer bucks do not protect a harem of females. The male deer fight repeatedly over an available female, using their antlers to spar with one another.

A male will remain with a female – or ​doe -​ for several days or even weeks until she is ready to breed. The gestation period for white-tailed deer lasts about six months. After their first year, most does give birth to twin fawns.

Throughout the winter, the antler begins to weaken in preparation for casting in the spring. The connection between the pedicle and the antler, known as the ​abscission line​, begins to demineralize and weaken the bone between the two. Bucks occasionally drop their antlers in late winter rather than early spring.

Antlers aren't the only type of headgear that mammals sport! Some animals, such as goats, bison, pronghorn and sheep, grow horns from their heads. Members of the deer family, also known as the Cervidae family, grow antlers. In the vast majority of cases, antlers only grow on male animals, with the exception of the caribou. Unlike antlers, horns do grow on both genders, with the females growing smaller horns than males.

While antlers fall off and regrow on a yearly basis, horns do not shed and continue to grow throughout the animal's life. The only exception to this rule is the pronghorn, which sheds the sheath around its horn every year. Antlers also consist primarily of bone and do not have blood vessels after their velvet dries up and the antlers harden. Conversely, horns consist of a keratin sheath with a bony core, with blood vessels running between the two on a permanent basis.