It is widely understood that only male deer, often referred to as bucks, grow antlers. This perception holds true for most deer species. However, female deer, or does, can sometimes develop antlers under specific circumstances, challenging this typical understanding.
Typical Antler Development in Deer
Antlers are bone structures that grow from pedicles, permanent bony outgrowths on a deer’s skull. Unlike horns, which are permanent and keratin-based, antlers are shed and regrown annually. The growth process typically begins in late spring, with antlers rapidly forming while covered in a highly vascular, sensitive skin known as velvet. This velvet supplies essential nutrients and oxygen for the antler’s rapid development.
Testosterone, an androgen hormone, is the primary driving force behind antler growth and the annual cycle in male deer. As fall approaches and daylight decreases, testosterone levels in bucks rise, causing blood flow to the velvet to cease. The velvet then dries, cracks, and is shed, revealing the hardened, calcified antlers used during the breeding season. After the breeding season, a sharp decline in testosterone levels triggers the weakening of the connection between the antler and the skull, leading to the antlers falling off, usually between late December and early March.
When Females Grow Antlers
The occurrence of antlers on female deer is a rare phenomenon in most species. The most frequent biological reason for antler growth in does is a hormonal imbalance, specifically elevated levels of testosterone or other androgen hormones. This imbalance can stem from various factors, including ovarian abnormalities or the presence of tumors affecting the ovaries or adrenal glands, which can lead to increased androgen production.
In some cases, female deer with antlers are pseudohermaphrodites, possessing external female genitalia but also internal male reproductive organs. Such individuals exhibit higher testosterone levels, which facilitates antler development. Genetic mutations can also predispose a female deer to antler growth by affecting hormone regulation. While less common, severe injuries to the pedicle or other body parts can sometimes trigger a hormonal response that leads to atypical antler formation in does.
Characteristics of Female Antlers
Antlers grown by female deer typically differ significantly from those found on males. They are often smaller, less robust, and may appear malformed or asymmetrical. Unlike the branched, polished antlers of bucks, female antlers frequently remain covered in velvet, or are only partially hardened. This occurs because does often do not experience the necessary surge in testosterone required to cut off blood flow and cause the velvet to shed.
Female antlers may also lack the typical branching patterns seen in males and sometimes appear as simple spikes. While male deer shed their antlers annually, female deer with antlers may not shed them at all, or do so irregularly, particularly if their hormonal levels remain consistently elevated. The only deer species where females regularly grow antlers is the caribou, also known as reindeer, where both sexes typically possess them, though female antlers are usually smaller.