Studies show many half-rack bucks have suffered an injury to the skull or pedicel.
QUESTION: What causes bucks to grow half-racks? — Trevor B.
ANSWER: To some extent that depends on what you mean by half-racks. A buck growing only one antler could be the result of an injury or genetic mutation. An injury to the limbs often results in some sort of antler malformation, often on the opposite side of the injury. I once shot a buck that had lost the lower half of its rear leg but survived. The antler on the opposite side was malformed.
A somewhat more common occurrence is sometimes referred to as a Spike on One Side (SOOS or SOS). On a Mississippi hunt several years ago I killed bucks on successive days from the same stand. One had a spike only on the right side, the other had a spike only on the left. The opposite sides were normal 4-point racks.
While a graduate student at Auburn University, Gabe Karns investigated this phenomenon. From a sample size of 71 SOS bucks, he was able to assign “probable cause” to 44, 34 of which were the result of pedicel or skull trauma (likely due to fighting). Karns added that any damage to the pedicel, including antlers that failed to cleanly separate from the pedicels when shed, can negatively affect future antler development.
He further noted that “It is well documented that antler deformities due to skeletal injuries progressively disappear with each subsequent antler growth cycle, meaning you can expect most SOOS yearling bucks to develop normal antlers in another year or two.” He also suggested an increasing likelihood of injury with increasing buck age as a likely cause of SOS on older bucks.
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