What Causes a Moose to Lose Its Antlers?

Male members of the deer family shed their antlers each year in late fall or winter and grow new antlers beginning in the spring. Moose are the largest members of the deer family, and they grow the largest antlers. A pair of moose antlers can weigh 50 pounds. It takes only about five months for bull moose to grow this impressive amount of bone, but amazingly, they shed their antlers even faster. Several factors cause moose to shed their antlers.

  1. Shedding Factors

    • Several things, working together, cause moose to shed their antlers. After the fall mating season, moose no longer need their antlers to fight off other bulls to gain breeding rights. Large antlers are also an indication of good health, and scientists have shown that cow moose prefer to mate with large-antlered bulls. Again, this is a non-factor after the breeding season. Retaining antlers is also stressful, due to their weight, and moose certainly don't need added stress as they try to survive deep snow and cold temperatures in winter. As photoperiod (the amount of daylight) decreases in late fall, the pituitary gland produces fewer hormones. Testosterone levels drop as a result. A drop in testosterone is the major catalyst that drives antler shedding.

    Shedding Biology

    • When testosterone levels drop, special bone-eating cells called "osteoclasts" form at the pedicel, where the antler attaches to the skull. They reabsorb calcium from the antler, drawing it back into the skull. Eventually, so much calcium is reabsorbed that only tiny, threadlike connections called "spicules" hold the antler in place. When these connections become too weak to support the antler, it drops. The process happens so quickly, scientists have noted you could literally hang a moose by its antlers one day, and the antlers would fall off under their own weight the next.

    Shedding Time

    • Moose drop their antlers anytime from November until February. Bulls in the best physical condition retain their antlers the longest. Bulls that are malnourished, run down from the breeding season, or are stressed by parasites or other factors drop their antlers first. Both antlers don't necessarily fall off at the same time. For unexplained reasons, a moose may carry an antler for several days after dropping the first.

    Shed Hunting

    • Searching for shed moose antlers has become a popular activity in recent years. Shed hunters hike into moose wintering areas in late winter or spring and try to spot fallen antlers on the ground. Some leave their moose antlers unaltered for rustic decoration. Many people carve them or make crafts from them, such as belt buckles, chandeliers, fireplace tool handles and other items. Buyers may pay hundreds of dollars for a large moose antler in pristine condition.