Reindeer antlers are fuzzy, but only during their annual growth cycle. Antlers are unique bone structures that are shed and regrown each year, making them unique in the animal kingdom. During the active growth phase, these structures are covered by a specialized, furry skin known as velvet. This living tissue is fundamental to the rapid development of the bone underneath.
The Antler’s “Fuzz”: Understanding Velvet
The fuzzy covering, or velvet, is a specialized layer of skin that envelops the growing antler. This skin is densely packed with a network of blood vessels that are plainly visible just beneath the surface. It is also supplied with nerves, which makes the growing antler highly sensitive to touch and injury.
This layer of skin is rich in biological components, including proteins, minerals, and growth factors necessary for bone formation. The dense covering of short, soft hairs gives the structure its characteristic velvety appearance and texture. The velvet acts as a protective, living sheath, delivering the oxygen and nutrients required for the underlying bone to form.
The Purpose and Speed of Growth
The primary function of the velvet is to facilitate one of the fastest rates of bone growth known in nature. Reindeer antlers begin growing in the spring and can grow at a remarkable rate, sometimes up to an inch per day in adult animals. This immense growth speed demands a constant and substantial supply of building materials.
The extensive vascular system within the velvet supplies calcium, phosphorus, and other minerals directly to the rapidly ossifying bone tissue. This rapid growth phase is triggered and sustained by hormonal shifts, including high levels of growth hormones and low levels of testosterone. The velvet nourishes the bone as it expands and hardens from a cartilaginous core into solid bone.
Shedding the Velvet and Hardening
Once the antlers have reached their full size, typically in late summer, the velvet has served its purpose and must be removed. At this stage, the hormonal balance shifts, causing the blood flow to the velvet to constrict and eventually stop entirely. The lack of blood supply causes the soft, fuzzy tissue to die and dry out.
The dead velvet becomes itchy and irritating to the reindeer, prompting them to rub their antlers vigorously against trees, shrubs, and the ground. This behavior, known as “rubbing” or “stripping,” removes the dried skin, often leaving behind bloody shreds for a short period. The result is a clean, hard, polished bony antler ready for the mating season and sparring displays.
A Unique Trait: Antlers on Both Sexes
Reindeer, also known as caribou, are unique among the deer family because both males and females grow antlers. Although the growth mechanics are the same, the size and timing of the antler cycle differ between the sexes. Males grow the largest antlers, which they usually shed in late autumn after the mating season.
Female reindeer generally grow smaller antlers, but they often retain them through the winter until their calves are born in the spring. Keeping their antlers longer gives females a competitive advantage. This allows them to secure and defend feeding craters dug into the snow, ensuring access to food sources during the harshest months of the year.