Deer, elk, and moose, all members of the Cervidae family, possess unique bony structures known as antlers. Unlike horns, which are permanent and grow continuously, antlers are shed and regrown annually. This yearly cycle of growth and shedding is a natural process, allowing for regeneration.
The Antler Growth Cycle
The annual antler cycle begins with shedding, occurring in late winter or early spring. Moose often shed first, from late November to late December, followed by white-tailed and mule deer from mid-December to early April, and elk from late February to early May. After shedding, new antler growth commences rapidly in the spring.
During this growth phase, antlers are covered in a soft skin called velvet. This velvet is rich in blood vessels and nerves, supplying the growing bone with oxygen and nutrients for rapid development. Antlers can grow very fast, with elk antlers growing about one inch per day, and moose antlers gaining as much as a pound per day. Deer antlers can grow between a quarter and a half inch daily, while yearlings might grow about 0.75 inches per week and adults up to 1.5 inches per week.
By late summer or early fall, the velvet begins to dry and peel away. This occurs because blood flow to the velvet decreases, causing the tissue to wither. Deer often rub their antlers against vegetation to help remove the velvet, a process that is not painful as the nerve density declines. Once the velvet is shed, the underlying antler bone hardens, preparing the animal for the breeding season.
The Science of Antler Regrowth
Antlers are bone structures that grow from specialized bony protrusions on the skull called pedicles. The rapid growth of antlers makes them one of the fastest growing tissues in the animal kingdom. This growth involves very fast cellular proliferation and mineralization.
The regenerative capacity of antlers is attributed to specialized stem cells located in the pedicle periosteum. These cells initiate and maintain the annual regeneration process. The growth occurs from the antler tips, with new bone forming at the distal end, while the older, hardened bone is at the base. This regenerative process is of scientific interest due to its implications for bone regeneration and repair in other mammals.
What Influences Antler Development
Several factors influence the size, shape, and quality of antler growth each year. The age of the animal plays a role, as antlers increase in size with maturity until a certain point. For white-tailed deer, antler development peaks between 5 to 7 years of age. After reaching their prime, antlers can gradually decrease in size and number of points, although thickness might still increase.
Nutrition is another factor, as adequate diet provides minerals and energy for antler growth. Antlers are composed of protein and require minerals such as calcium and phosphorus for mineralization. A deer’s body prioritizes its own development and maintenance before allocating nutrients to antler growth, which explains why younger deer might have smaller antlers. A diet rich in protein during the growing period supports antler development.
Hormonal influences, particularly testosterone, also regulate the antler cycle. Increasing testosterone levels in late summer trigger the antlers to stop growing, lose their velvet, and harden. Conversely, a decrease in testosterone levels after the breeding season in winter signals the shedding of antlers. The interplay of these factors ensures the annual regrowth and development of these bone structures.