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Antler Shedding

Velvet-covered Antlers Growing

Male White-tailed Deer grow a new pair of antlers every year starting when they are one year old.  The size of the antlers depends on the age of the deer, genetics, and diet. Before antlers actually appear, structures called pedicles that connect the antlers to the skull develop.  Growth of the actual antlers begins in March or April and as more nutritious food becomes more available during May and June antlers grow more rapidly.

Antlers are one of the fastest growing bones that exist; growth is regulated by hormones which are controlled by the photoperiod, or length of day . Yearling antlers can grow about 1/8-inch a day during the summer, and adults as much as 1/4th of an inch.  While they are growing, antlers are covered with a layer of tissue called “velvet” which is dense with blood vessels that carry nutrients to the antlers. In August the supply of blood to the velvet diminishes and the antlers begin to harden. By September the velvet has dried and is falling off.  Antlers are used as weapons during rut, or the mating season, after which they fall to the ground, providing a valuable source of calcium and phosphorus for rodents. (Photo by Erin Donahue)

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White-tailed Bucks Shedding Antlers

White-tailed Deer bucks grow and shed a pair of antlers annually.  The main purpose of these bony growths is to serve as weapons against rival bucks during rut, or mating season.  During this time in the fall, prior to their 24-hour receptive period, does release chemicals to signal their readiness to bucks.  These chemicals keep the bucks’ testosterone level high, which in turn keeps antlers firmly attached to their heads.  Once rut is over, does stop emitting these chemicals, and as a consequence, the bucks’ testosterone level drops significantly.

When a buck’s testosterone level drops, it triggers cells called osteoclasts to become more active in the buck’s pedicles, the permanent bony bases which anchor the antlers to the buck’s skull. As a result, calcium is extracted from the pedicles which weakens the antlers’ connection to the buck’s skull, and eventually the antlers drop off.

It is rare that both antlers drop at the same time – usually there are four to eight days between the loss of the first and the second antler. I assumed that bucks needed to knock their antlers against something hard, such as the trunk of a tree, in order to get them to fall off.  However, years ago I witnessed a buck shedding an antler simply by dropping his head and then quickly flicking it upwards, sending an antler flying through the air. (Note pedicle where antler used to be attached. Photo by Alfred Balch)

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