Caribou, also known as reindeer, are mammals of the deer family found across the Northern Hemisphere. They are unique among deer species because both males and females typically grow antlers, unlike most others where only males possess these bony structures. Caribou inhabit diverse environments, from the Arctic tundra to boreal forests, and their antlers play a significant role in their survival and social interactions.
Caribou Antler Characteristics
Caribou antlers have several distinct features. Most female caribou also grow antlers, though they are generally smaller and more slender than those of the males. These antlers develop from permanent bony protrusions on the skull called pedicles.
The shape of caribou antlers is distinctive, often featuring a main beam and flattened, shovel-like brow tines that extend forward over the face. The overall structure can be quite broad and palmated, especially in mature males. Antlers have a rough, textured surface, and their growth can sometimes be asymmetrical. While growing, antlers are covered in a soft, fuzzy skin called velvet, which is rich in blood vessels and nerves, supplying the bone with nutrients. This velvet is eventually shed, revealing the hardened bone underneath.
Antler Development and Function
Caribou antlers undergo an annual cycle of growth and shedding. Each spring, antlers emerge as soft, cartilage-like tissue from the pedicles. Growth is rapid, with antlers sometimes growing up to 2.5 centimeters (about 1 inch) per day, making them some of the fastest-growing tissues in the animal kingdom. As summer progresses, the antlers calcify and harden. The velvet covering dries and is rubbed off, typically by mid-September for males.
The timing of antler shedding varies between the sexes. Male caribou usually shed their antlers from late fall to early winter, typically after the mating season around November or December. Females, especially those that are pregnant, often retain their antlers throughout the winter and shed them in the spring, usually after calving. This prolonged retention provides an advantage in defending food sources during winter and early spring when nourishing calves.
Caribou use their antlers for several purposes. During the autumn breeding season, males use their large antlers for display and sparring to establish dominance and attract females. Antlers also serve as a defense mechanism against predators. Both male and female caribou use their antlers, particularly the brow tines, to dig through snow, helping them access lichen and other vegetation during winter foraging.