Moose, the largest members of the deer family, annually shed their impressive antlers. This natural process is a regular part of their life cycle.
The Antler Growth and Shedding Cycle
Moose antlers are bone structures that grow from bony protrusions on the skull called pedicles. The annual growth cycle begins in spring, with antlers growing rapidly. They are among the fastest-growing tissues in the animal kingdom, capable of growing an inch or more per day, or even up to a pound of bone daily.
During their growth, antlers are covered in a soft, fuzzy skin known as “velvet.” This velvet contains blood vessels and nerves that supply nutrients for the growing bone. As antlers reach full size, typically by late summer or early fall, blood flow to the velvet ceases, causing it to dry and become itchy. Moose then rub their antlers against trees and shrubs to remove the velvet, revealing the hardened, bone antlers underneath.
After the breeding season, usually in late winter or early spring, a hormonal shift, specifically a decline in testosterone, triggers shedding. A specialized layer of cells, called the abscission layer, forms at the base of the antler, weakening its connection to the pedicle. This allows the antlers to detach cleanly and painlessly. Moose then begin to regrow a new set of antlers in the following spring.
Why Moose Grow Antlers
Moose grow antlers for reproductive and social purposes, particularly during the fall mating season, known as the rut. Antlers serve as a visual display of a bull moose’s health and strength, attracting mates. Females often prefer males with larger antlers, perceiving them as more physically fit.
Beyond attracting mates, antlers establish dominance among rival males. Bull moose use their antlers for intimidation, deterring competitors. When two similarly sized bulls encounter each other, they may lock antlers to fight for mating rights. Antlers also offer a degree of defense against predators.
When Moose Shed Their Antlers
Moose shed their antlers between late winter and early spring. Timing varies based on factors like age, health, and location. Younger moose may retain their antlers longer into the winter.
Mature bull moose often shed their antlers earlier, helping them conserve energy after the demanding breeding season. Carrying large antlers requires significant energy. The shedding process can take hours or days, and both antlers rarely fall off simultaneously. After shedding, moose remain antler-less for a few months before new growth begins.
Antlers Compared to Horns
Antlers and horns are distinct types of headgear. Antlers, characteristic of the deer family (Cervidae), including moose, are bony structures shed and regrown annually. They grow from pedicles on the skull and are typically found only on males, with the exception of caribou where both sexes grow them. Antlers are made entirely of bone.
In contrast, horns are permanent structures that are not shed. They consist of a bony core covered by a sheath of keratin. Horns grow continuously throughout an animal’s life. Animals with true horns belong primarily to the Bovidae family. Horns are often present in both males and females.