Why Do Deer Shed Their Antlers?

Aiding males to win the favor of females and to fend off rivals, the antlers of deer renew themselves annually. A spectacular phenomenon, closely tied to the reproductive cycle of these majestic animals.

Annual Cycle

While horns are made up of a bone core surrounded by keratin, the antlers of cervids are technically branched bones. In the males of several iconic species, these impressive structures shed each year and are replaced by new ones coated in a velvet-like layer. Their friction against trees subsequently helps remove this highly vascularized and innervated specialized tissue.

Antlers are considered the fastest-growing tissue in the animal kingdom, notably triggered by the increase in sunlight and in testosterone production during the months preceding the rut, which occurs in autumn.

Their size is indicative of age, as well as the vigor and good physical and genetic condition of the animal. At the end of the mating season, punctuated by often-violent inter-male duels, testosterone levels in the blood drop significantly, which causes the antlers to fall off.

Their sustained development involves a high energy expenditure (nutrients, minerals, and proteins). Thus, shedding them at the beginning of winter helps males to endure the harshest months of the year, when food is scarce.

Croissance soutenue

À chaque repousse, ces structures se révèlent plus développées et massives. Selon le Guinness World Records, les élans mâles de l’espèce Alces alces, plus grand cervidé au monde évoluant en Eurasie, peuvent développer une paire complète de bois (pesant environ 36 kilos) en l’espace d’un seul été. Avec un gain quotidien de masse osseuse atteignant 0,5 kilo dans les cas les plus extrêmes.

S’il peut être tentant de ramasser ces « trophées », le Service américain des pêches et de la faune sauvage rappelle que les bois constituent un élément clé des écosystèmes forestiers, fournissant aux rongeurs et à d’autres animaux une précieuse source de calcium.

Pour aller plus loin, découvrez les cerfs vampires, ces animaux horriblement mignons.