White-tailed deer have antlers, bony structures that undergo an annual cycle of growth and shedding. This unique ability allows for the regeneration of significant bone mass each year.
Annual Antler Cycle Begins
Whitetail bucks typically begin growing their new antlers in late March or early April, after shedding their previous rack. This growth is primarily triggered by an increasing photoperiod, lengthening daylight hours after the winter solstice. The change in photoperiod leads to a reduction in melatonin production in deer.
This decrease in melatonin is followed by a hormonal cascade including a rise in testosterone levels post-rut, and an increase in insulin-like growth factor 1 (IGF-1) and prolactin, collectively stimulating antler growth. Initial growth starts from the pedicles, permanent bony projections on the skull. New antler growth commences at a cellular level within about 10 days of shedding, though it may not be visibly apparent for several weeks.
Key Phases of Antler Development
After emergence, antlers enter a rapid growth phase. During this period, they are covered in a soft, fuzzy skin known as velvet, rich in blood vessels and nerves. This vascularized velvet supplies oxygen and nutrients, making antlers one of the fastest-growing tissues in the animal kingdom, expanding up to 2 centimeters per day during peak periods. Growing antlers are composed of approximately 80 percent protein and 20 percent ash, primarily calcium and phosphorus.
By late summer, around August, antler growth slows significantly. The antlers then begin a process of mineralization, where the soft tissue hardens into bone. As testosterone levels increase, the blood supply to the velvet diminishes, causing it to dry and peel away, often accelerated by bucks rubbing antlers on trees and shrubs. Velvet shedding usually occurs rapidly, often within 24 to 48 hours, leaving behind hardened, polished antlers ready for the breeding season. Antlers are typically retained through winter, then shed between late December and early March, restarting the annual cycle.
Factors Influencing Growth
Several factors influence whitetail antler size and quality. Age plays a significant role, with antler size generally increasing each year until a buck reaches its peak, around 6.5 years of age, before declining in later years. Genetics also contribute, as antler development is an inherited trait, though its expression can be influenced by environmental factors.
Nutrition is important for robust antler growth. Bucks require a diet rich in protein, calcium, and phosphorus, especially during spring and summer growth. Insufficient nutrition can significantly limit a buck’s antler potential, even with superior genetics. Overall health and environmental conditions, such as drought affecting food availability, can also impact antler development.