Thanks to Kitty Leonard, who caught the error in today’s post regarding osteoclasts. They are cells, not chemicals as stated in the post, that become more active when the testosterone level drops after rut. As Kitty so astutely stated in her comment, “… osteoclasts are cells rather than chemicals. Bone has osteoclasts which break down bone and osteoblasts which build bone. The balance of the actions of the two types makes for healthy bone by continually remodeling the structure. When one predominates in its activity, there is either more build up or more break down.”
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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