Deer antlers are bony structures, typically found on males, that grow and are shed annually. Observing a deer with what appears to be “bleeding” antlers can be a puzzling sight for many. This phenomenon is a natural part of their annual cycle, linked to the intricate process of antler growth and shedding.
The Antler Growth Process
Antlers are extensions of a deer’s skull, growing from permanent bony structures called pedicles located on the frontal bone. This growth process begins in early spring, triggered by increasing daylight and a temporary rise in testosterone. Antlers grow at an extraordinary rate, making them one of the fastest-growing tissues in mammals, with some species adding over an inch per day during peak periods.
During this rapid development, the growing antlers are covered by a soft, vascular skin known as velvet. This velvet contains an extensive network of blood vessels and nerves, which supply the necessary blood, oxygen, and nutrients for the underlying bone and cartilage to form. The velvet also contains sensory nerves, making the growing antlers sensitive to touch.
Velvet Shedding: The Bleeding Phenomenon
As summer transitions into fall, the antlers approach maturity, and a significant hormonal shift occurs within the deer. Rising testosterone levels signal the end of antler growth and initiate a process called mineralization, where the soft antler tissue transforms into hardened bone. Simultaneously, the rich blood supply to the velvet is gradually restricted and eventually cut off.
With the blood supply diminished, the velvet dries up and dies. At this stage, deer begin to rub their antlers vigorously against trees, shrubs, or the ground to remove the dead, itchy velvet. The “bleeding” observed during this period is not from a wound, but rather from the remnants of the vascular velvet tissue as it is scraped away. This is a normal and healthy part of the antler cycle, generally causing minimal pain as nerve density in the velvet declines.
The Purpose and Cycle of Antlers
Once the velvet is completely shed, the hardened, bony antlers are revealed, typically in late summer or early fall. These fully developed antlers serve several biological functions, primarily for display and establishing dominance among males during the breeding season, known as the rut. Bucks use their antlers in sparring matches and fights to compete for mating rights and assert their position in the social hierarchy.
After the breeding season concludes, typically in late winter or early spring, a drop in testosterone levels triggers the annual shedding of the antlers. The connection between the antler and the skull weakens, allowing the antlers to fall off. This shedding is a natural process that does not harm the deer, and the entire growth cycle begins anew in the spring. Shed antlers also contribute to the ecosystem by providing a source of minerals for other animals.