The annual cycle of antler growth in male deer, commonly known as bucks, culminates in the shedding of velvet. This temporary, living tissue covers the developing bone structure beneath. Observing a buck transition from full velvet to hard, polished antlers marks a significant and predictable seasonal change. This transformation signals the approach of the breeding season, making the shedding event a key part of the deer’s yearly life cycle.
The Function of Velvet in Antler Development
Velvet is a highly vascularized skin layer that acts as a life support system for rapidly growing antlers. This soft tissue is packed with blood vessels and nerves, supplying the necessary components for one of the fastest rates of bone growth in the animal kingdom. The blood flow delivers a constant stream of oxygen, protein, and minerals, such as calcium and phosphorus, to the developing bone structure beneath the skin.
The continuous supply of nutrients allows antlers to grow quickly, sometimes exceeding a quarter-inch per day for white-tailed deer. The velvet also serves a protective function, covering the soft, sensitive cartilage being replaced by hard bone. Covered in fine hair, the velvet is sensitive to touch, which helps the buck avoid damaging its developing rack.
The Hormonal Trigger and Shedding Timeline
The shedding of velvet is dictated by a precise physiological change tied to the changing seasons. The process is initiated by a spike in the buck’s testosterone levels, which are regulated by the photoperiod, or the amount of daylight hours. As days shorten in late summer and early fall, decreasing daylight triggers this hormonal surge, signaling the approach of the breeding season, or rut.
This rise in testosterone causes the blood flow to the antlers to constrict and stop at the base of the pedicle, which is where the antler attaches to the skull. Without a blood supply, the velvet tissue dies and begins to dry out. For most bucks in North America, this shedding window begins in late August and continues through mid-September. Older, more mature bucks often shed their velvet earlier than younger ones.
The Physical Process of Stripping and Hardening
Once the velvet tissue is dead and drying, the buck must physically remove the dead layer to reveal the hardened bone antler beneath. This is accomplished through a behavior known as stripping, where the buck rubs its antlers against trees, shrubs, and dense vegetation. This rubbing action is the mechanical removal of the dried, dead tissue.
The stripping process can happen quickly, with many bucks completing the removal in a matter of hours, though it may take up to a day or two. Immediately after stripping, the new hard antlers may appear bloody as the dead tissue is torn away. The clean antlers are composed of calcified bone, ready for sparring and establishing dominance during the rut. Continued rubbing also polishes the antlers and helps spread scent from the buck’s forehead glands, marking its territory.