Antlers, unique to deer (Cervidae), are bone structures shed and regrown annually. This distinguishes them from horns, permanent keratin and bone formations found on animals like cattle and sheep. Understanding this cycle is important for observing deer populations.
The Annual Antler Growth Cycle
Antler growth in bucks begins in late spring (March-April), after previous antlers have shed. New growth emerges from bony structures on the skull called pedicles. Increasing daylight hours (photoperiod) trigger this process by influencing hormone levels.
During initial growth, antlers are covered in soft, vascularized velvet, which supplies blood and nutrients. Antler growth is rapid, among the fastest bone growth in the animal kingdom, expanding up to 1.5 inches per week during peak periods. This development continues through summer (May-August) as antlers increase in size and complexity.
By late summer or early fall (August-September), antlers harden as blood flow to the velvet ceases. The velvet dries and becomes itchy, prompting bucks to rub antlers against trees and vegetation to remove it. This leaves polished, hardened bone structures for the upcoming breeding season.
Factors Shaping Antler Development
Antler size, shape, and quality are influenced by biological and environmental factors. A buck’s age plays a role; size increases as the animal matures, peaking around 6.5 years before declining in old age. Yearling bucks display first noticeable antlers, ranging from simple spikes to complex forms.
Nutrition is another factor, as antler growth is energetically demanding. Bucks require high-quality forage rich in protein and minerals (calcium and phosphorus) to support antler development. Deficiencies can result in smaller or less developed antlers.
Genetics contribute to a buck’s antler potential, influencing characteristics like point number and antler architecture. While genetics set potential, proper nutrition and age are necessary for a buck to express its antler development. Hormones, particularly testosterone, regulate antler growth, influencing the rapid growth phase and final hardening.
The Antler Shedding Process
Following the breeding season, in late winter to early spring, bucks shed antlers. This process is triggered by a drop in testosterone levels as daylight hours decrease. The hormone reduction initiates bone tissue breakdown at the pedicle, the antler’s skull attachment point.
Demineralization weakens the connection, causing antlers to detach and fall off. Most bucks shed between January and April. Individual timing is influenced by age, physical condition, and geographical location.
Why Bucks Grow Antlers
Antlers serve several evolutionary purposes for male deer. A function is dominance displays, where bucks use antler size and appearance to intimidate rivals and establish social hierarchy. Larger, more impressive antlers signal a buck’s health and strength, deterring lesser males without direct conflict.
Antlers are used for fighting, particularly during the breeding season, when bucks spar with other males to gain access to females. These contests range from pushing and shoving to intense battles where antlers lock. Beyond combat, well-developed antlers signal genetic fitness to mates.