Reindeer, also known as caribou in North America, are unique within the deer family, Cervidae. Unlike most other deer species where only males grow antlers, both male and female reindeer typically develop these impressive bony structures. Antlers are distinct from horns; they are made of bone and are shed and regrown annually.
The Male Reindeer’s Antler Journey
Male reindeer shed their antlers each year, a process linked to their reproductive cycle. This shedding typically occurs in late autumn to early winter, after the intense breeding season, known as the rut. During the rut, males utilize their antlers for dominance displays and competition, but once this period concludes, the antlers are no longer needed for their function.
The shedding of antlers is a natural and painless process. Antlers are bony outgrowths from the skull’s pedicles, and during their growth phase, they are covered in a soft, fuzzy skin called velvet, which supplies nutrients. After the rut, a decrease in testosterone levels in the male reindeer triggers the formation of a specialized abscission layer at the base of the antler. This layer weakens the connection between the antler and the skull, allowing the antler to detach and fall off. New antler growth for males typically begins in February, starting the cycle anew.
Antler Differences Across Genders
While both male and female reindeer possess antlers, their shedding patterns and timing differ significantly. Male reindeer shed their antlers soon after the autumn rut, leaving them antlerless for the winter months. In contrast, female reindeer generally retain their antlers longer, keeping them through the winter and into the spring.
This extended retention is common for pregnant females, who typically shed their antlers in late spring, after giving birth. This unique adaptation provides females with an advantage during the harsh winter. Their antlers are instrumental for digging through deep snow to access food sources, such as lichen, a behavior known as cratering. Antlers allow pregnant females to defend feeding sites from other reindeer, including larger males, ensuring they maintain nutrition for themselves and their developing calves.
Beyond Shedding: The Role of Reindeer Antlers
Reindeer antlers serve multiple biological functions. For males, antlers are used as visual displays during the breeding season. Larger antlers signal a male’s health and strength, helping him attract mates and establish dominance within the herd. Males engage in sparring, locking antlers to assert dominance.
Antlers also provide defense for both sexes. They can be used to deter predators and to resolve disputes with other reindeer over resources. Antlers also aid in foraging. Both male and female reindeer use their antlers to clear snow, allowing them to reach the vegetation and lichens buried beneath. Once shed, these bony structures contribute to the ecosystem by providing a source of calcium and other minerals for other animals.