Male moose annually shed their antlers, a natural process that allows for the regrowth of new antlers each year. Understanding this phenomenon involves examining the physical mechanisms of shedding, the yearly growth cycle, and the fundamental differences between antlers and horns.
How Moose Shed Their Antlers
Moose shed their antlers in late winter to early spring, following the breeding season. Timing can vary depending on geographic location, the animal’s health, and its age.
The shedding process is triggered by a reduction in testosterone levels in bull moose after the autumn rut. This hormonal shift causes a weakening of the bone tissue at the pedicle, the bony attachment point on the skull where the antler grows. A specialized layer of cells, known as the abscission layer, forms in this area, gradually detaching the antler from the skull.
This detachment is a pain-free event for the moose. The antlers often fall off one at a time, or even simultaneously with a sudden movement. Once shed, these bony structures become a source of calcium and other minerals for rodents and other forest animals.
The Annual Antler Cycle
After shedding, moose begin growing a new set of antlers in the spring. This regrowth is remarkably rapid, making antlers one of the fastest-growing tissues in the animal kingdom. They can grow over an inch per day during peak development.
During this growth phase, the developing antlers are covered by a soft, fuzzy skin called velvet. This velvet contains a rich network of blood vessels and nerves that supply the necessary nutrients and oxygen for the antler’s rapid expansion. The velvet protects the delicate, growing bone underneath.
By late summer or early autumn, as the antlers reach their full size and harden, the blood supply to the velvet diminishes. The velvet then dries, cracks, and begins to peel off, often aided by the moose rubbing its antlers against trees and shrubs. This process reveals the hardened antlers, ready for the upcoming breeding season.
Antlers Versus Horns
Antlers and horns are distinct types of headgear found on different mammal groups. Antlers, characteristic of the deer family (Cervidae), including moose, are composed entirely of bone. They are typically found only on males, with the notable exception of caribou, where both sexes grow them.
Antlers are shed and regrown annually, a unique cycle of regeneration. Their size and complexity generally increase with the animal’s age until it reaches its prime.
In contrast, horns are permanent structures found on animals in the Bovidae family, such as cattle, sheep, and goats. Horns consist of a bony core covered by a sheath of keratin, the same material found in human fingernails. Unlike antlers, horns are never shed and continue to grow throughout the animal’s lifespan.