Deer antlers, bony extensions of the skull, are primarily found on male deer. They grow and are shed annually, allowing for the development of new, often larger, antlers. While most commonly associated with male deer, caribou are a notable exception where both males and females grow antlers. This phenomenon involves biological processes governing their shedding and regrowth.
The Mechanics of Antler Shedding
The shedding of antlers is a biological event triggered by hormonal changes within the deer’s body. After the breeding season, typically in late winter or early spring, a male deer’s testosterone levels begin to decline. This decrease in testosterone is the primary signal for the antlers to detach. The exact timing can vary based on the deer’s age, health, nutrition, and geographical location.
The hormonal shift initiates the formation of a weakened bone layer at the pedicle, the permanent bony protuberance on the deer’s skull where the antler attaches. This specialized layer, known as the abscission layer, forms between the antler and the pedicle. Cells within this layer, called osteoclasts, resorb bone tissue, gradually dissolving the connective bond.
As the abscission layer deteriorates, the antler loosens and eventually falls off. This process is generally not painful for the deer, similar to a human losing a tooth. While minor bleeding or sensitivity might occur at the pedicle immediately after shedding, the area quickly scabs over and heals.
Antler Regrowth and Their Purpose
Following the shedding of old antlers, new growth begins from the pedicle within weeks, typically starting in spring. This regrowth is fast, with adult deer antlers potentially growing up to 1.5 inches per week during peak periods. During this rapid growth phase, the developing antlers are covered by a soft, fuzzy skin called “velvet.”
The velvet is highly vascularized, containing a rich network of blood vessels that supply oxygen, proteins, and minerals like calcium and phosphorus for bone formation. Once the antlers reach their full size and harden, typically by late summer or early fall, the blood flow to the velvet decreases. The velvet dries, cracks, and becomes itchy, prompting the deer to rub its antlers against trees and other vegetation to remove it.
Antlers serve several purposes in a deer’s life cycle. Their primary role is attracting mates, as larger antlers can signal health and genetic quality to female deer. Male deer also use their hardened antlers for establishing dominance among rivals, engaging in sparring matches during the breeding season. While not their primary function, antlers can also be used for defense against predators, particularly when a deer is cornered.