Reindeer are unique among deer because both males and females grow antlers. Unlike horns, which are permanent and made of keratin, antlers are bony growths shed and regrown annually. This adaptation helps them thrive in harsh northern environments.
Antler Growth and Shedding
Both male and female reindeer engage in an annual cycle of antler growth and shedding. The process begins with the emergence of soft, fuzzy structures covered in a layer known as “velvet,” which is rich in blood vessels and provides nutrients for rapid bone growth. This velvet stage lasts several months, with antlers growing up to an inch per day. Once the antlers reach their full size, typically by late summer or early autumn, the blood supply to the velvet diminishes, causing it to dry and peel away, revealing the hardened bone underneath.
The timing of antler shedding varies significantly between sexes. Male reindeer generally shed their antlers in late autumn or early winter, usually around November or December, after the mating season. In contrast, pregnant female reindeer retain their antlers throughout the winter months, shedding them later in the spring, often around April or May, after they have given birth to their calves. This timing difference serves a functional purpose for females during winter.
Reasons for Female Antlers
The presence of antlers in female reindeer provides significant advantages, particularly during the harsh Arctic winter. In this period, food resources become scarce and are often buried under deep snow. Female reindeer use their antlers as tools to dig through the snow, enabling them to access lichen, mosses, and other vegetation crucial for their survival. This ability to uncover buried forage is especially important for pregnant females, who require substantial nutrition to support both themselves and their developing offspring.
Beyond foraging, antlers also play a role in social dynamics and resource defense. Females with antlers can assert dominance over other reindeer, including antler-less males or those who have already shed their antlers, securing access to prime feeding spots. This competitive edge ensures they obtain the necessary calories, directly influencing their reproductive success and the health of their calves.
Reindeer Antlers Compared to Other Deer
Reindeer are distinct within the Cervidae, or deer family, because both males and females commonly grow antlers. In nearly all other deer species, such as white-tailed deer, elk, or moose, only the males possess antlers, which they typically use for competition during the breeding season.
While male reindeer generally grow larger and more branched antlers, reaching up to 51 inches in length, female antlers are typically smaller, often measuring around 9 to 20 inches. Despite the size difference, reindeer antlers are considered the largest and heaviest of all living deer species relative to their body size. This adaptation underscores their specialized existence in cold, resource-limited environments, where having antlers offers a survival benefit to both sexes.