Antlers are unique bone structures that grow from the skulls of most male deer. Unlike horns, which are permanent and made of keratin, antlers are composed entirely of bone and are shed and regrown annually.
The Yearly Antler Growth Cycle
The annual antler growth cycle is regulated by changing testosterone levels, influenced by daylight length. This ensures antlers are fully developed for the breeding season, beginning with shedding of the old antlers.
Deer typically shed their antlers in late winter to early spring, usually between January and April. This natural process does not cause pain to the animal. New antler growth begins almost immediately after shedding.
In spring and summer, the antlers enter a rapid growth phase. During this time, they are covered in a soft, furry skin known as velvet, which is rich in blood vessels and nerves. The velvet supplies the growing bone with essential nutrients and oxygen, supporting an extraordinary growth rate that can reach up to 1/4 to 1/2 inch per day for white-tailed deer. Antler growth is considered one of the fastest forms of tissue growth in the animal kingdom.
As late summer and early fall approach, the antlers begin to calcify and harden. At this stage, blood flow to the antlers diminishes, causing the velvet to dry, crack, and eventually peel off. Bucks often rub their antlers against trees and shrubs to help remove the itchy, dying velvet, revealing the polished, hardened bone underneath. These hardened antlers are then retained through the breeding season and early winter.
Key Influences on Antler Development
Factors beyond the annual growth cycle influence the size and quality of antlers. The age of the buck plays a role, with antler size generally increasing as a deer matures, peaking between five and seven years of age before potentially declining in very old age. Yearling bucks, at 1.5 years old, grow their first noticeable antlers, which can vary from small spikes to multiple points.
Nutrition is another factor for antler development. A high-quality diet rich in protein, energy, and minerals like calcium and phosphorus is necessary for optimal growth. Poor nutrition leads to smaller antlers, as the body prioritizes other functions over antler growth. Deer can even mobilize calcium and phosphorus from their skeletal system to support antler formation.
Genetic traits also influence an individual deer’s potential for antler size and configuration. While nutrition allows a buck to reach its genetic potential, genetics set the upper limit for antler development. Environmental stressors, disease, or injuries can also negatively impact antler growth, reflecting the overall health and habitat quality available to the deer.
Antlers and Deer Life
Once fully developed, antlers serve several purposes in a deer’s life, especially during the autumn breeding season, known as the rut. Their primary function is for display and sparring among males. Antler size and condition can signal a buck’s age, health, and dominance status to other deer.
Bucks use their hardened antlers in ritualized sparring matches or more aggressive fights to establish a dominance hierarchy and secure breeding rights with does. These clashes are often a means for bucks to assess each other’s strength without severe injury, though serious fights can occur between equally matched individuals. Antlers are well-suited for this pushing and shoving style of combat. After the breeding season concludes and testosterone levels drop, the antlers have served their purpose for the year.