Caribou, also known as reindeer, are remarkable mammals adapted to the challenging environments of the Arctic and subarctic regions. These iconic animals are recognized for their impressive antlers, which are bony growths extending from their skulls. While many associate antlers primarily with male deer, caribou possess a unique characteristic that sets them apart within the deer family.
The Unique Presence of Female Caribou Antlers
Among all species in the deer family, caribou are distinctive because both males and females typically grow antlers. This is a rare trait, as most other deer species feature antlers exclusively on males. Female caribou antlers are generally smaller and less massive than those found on males, often appearing thinner and less branched. While the presence of antlers is common, a small percentage of female caribou, approximately 3-5%, may not develop them.
The Purpose and Annual Cycle of Female Antlers
Female caribou use their antlers for survival advantages during winter. They utilize these bony structures to dig through deep snow, accessing crucial food sources like lichen buried. This ability to secure nourishment is important for pregnant females, who have increased energy demands. Antlers also help females assert dominance and defend foraging patches from other caribou, including males who may have already shed their antlers.
The annual cycle of antler growth and shedding in female caribou differs from males. Female antlers typically begin developing between June and September, becoming hardened and shedding their velvet by late September. They retain their antlers throughout the winter, providing a competitive edge when food is scarce. Pregnant females usually shed their antlers within days of calving in the spring, while barren females may shed theirs earlier in the season.
Distinguishing Caribou Antlers from Other Deer Species
Caribou stand out as the only deer species where females regularly grow antlers. In contrast, deer such as white-tailed deer, elk, and moose typically see antler growth only in males. The functional significance of female antlers for digging and defending resources is a key reason for this evolutionary difference.
While female caribou antlers are present, they are generally smaller in size compared to the expansive antlers of male caribou. The continued presence of antlers on female caribou through winter and into spring, particularly for pregnant individuals, further emphasizes their specialized role in supporting the species’ unique life cycle.