Both male and female caribou, unique among most deer species, typically grow antlers. These impressive bony structures are not permanent; caribou annually shed and regrow them. This natural cycle is a biological adaptation, allowing them to thrive.
The Antler Shedding Process
Caribou antler shedding begins with the formation of a specialized abscission layer at the antler’s base, connecting to the skull’s pedicle. This layer dissolves the bone-to-bone bond, allowing the antler to detach. The process is painless because mature antlers lack nerves and blood vessels. Antlers may fall off suddenly, sometimes both at once, or one might drop before the other. This shedding is a natural part of their life cycle, ensuring new growth.
Timing of Antler Shedding
The timing of antler shedding varies significantly between male and female caribou, aligning with their reproductive cycles and seasonal demands. Male caribou typically shed their antlers earlier, usually in late fall or early winter, after the rut. Older males may drop them as early as November, though some younger males might retain theirs until early spring.
In contrast, female caribou generally keep their antlers much longer, often throughout the winter months. Pregnant females retain their antlers until just days after calving in the spring. Non-pregnant females usually shed their antlers earlier in the spring, before calving season. This difference allows pregnant females to use their antlers for foraging in snow and defending resources during a crucial period.
Antler Growth and Purpose
Following shedding, caribou rapidly regrow new antlers each year, making antler tissue one of the fastest-growing in the animal kingdom. New antlers emerge from the pedicles, initially covered in a soft, hairy skin called velvet. This velvet contains a rich network of blood vessels and nerves, supplying necessary nutrients for rapid development and calcification. Once full size and hardened, typically by late summer or early fall, the blood supply to the velvet diminishes, and the velvet dries and is rubbed off.
Antlers serve several purposes. Males use them for display, attracting mates, and sparring during the rut to establish dominance. Females use antlers to scrape away snow for buried vegetation and to protect their calves. The annual cycle of shedding and regrowth is linked to hormonal changes and seasonal daylight.