The presence of headgear on female deer and antelope often causes confusion because the terms “horns” and “antlers” are frequently used interchangeably. These words describe two fundamentally different types of specialized head ornaments found on hoofed mammals. Deer (Cervidae) and antelope (Bovidae) belong to separate biological families. The presence or absence of these structures on females is determined by their family’s distinct evolutionary path and hormonal regulation.
Clarifying Terminology: Horns Versus Antlers
The family Cervidae, which includes deer, elk, and moose, grows structures known as antlers. Antlers are composed entirely of bone and are unique because they are shed and regrown annually from bony supporting structures on the skull called pedicels. During their rapid growth phase, antlers are covered in a vascularized, fuzzy skin called velvet. Once the bone hardens, the velvet dies and is scraped off, leaving the polished structure used for display and combat.
Horns, by contrast, are the characteristic headgear of the Bovidae family, which encompasses true antelopes, cattle, sheep, and goats. A horn is a two-part structure consisting of a permanent, bony core that is an extension of the skull. This core is covered by a sheath made of keratin, the same tough protein found in human fingernails and hair.
Unlike antlers, horns are never naturally shed and continue to grow throughout an animal’s life. If an animal loses a horn, it will not regrow. The sole exception to this permanency rule is the North American Pronghorn, which sheds and regrows its keratin sheath every year but is not a true antelope.
The General Rule for Female Deer and Antelope
For the Cervidae family, antler growth is linked almost exclusively to high levels of the male hormone testosterone. Consequently, female deer, or does, of species like white-tailed deer, mule deer, and elk do not grow antlers. The growth and annual casting cycle of the antlers are tightly regulated by the interplay of testicular and pituitary hormones in the males.
The Bovidae family, which includes true antelopes, follows a less restrictive pattern for horn growth in females. Horns occur in males of all bovid species, and females frequently possess them as well. In many antelope species, such as the Gazelle or Impala, the female will have horns, but they are typically thinner, shorter, or less elaborate than the male’s.
The presence of horns in both sexes is often seen in larger bovid species, where the headgear may serve defensive purposes or be used for social interactions. Horns on males are generally thicker at the base to withstand the force of head-to-head combat during the breeding season. In smaller antelope species, however, females are more likely to be entirely hornless or have only very small structures.
Notable Exceptions and Biological Anomalies
The most significant exception to the deer family’s male-only antler rule is the Reindeer, also known as Caribou. Both male and female Caribou routinely grow antlers, a highly unusual trait within the Cervidae family. The female’s antlers are generally smaller than the male’s but are retained longer into the winter months. Pregnant females hold onto their antlers until spring, sometimes as late as May or June, after their young are born. This retention is thought to give them a competitive advantage, allowing them to defend prime feeding sites beneath the snow when energy demands are highest.
In extremely rare instances, a female deer of another species may grow small, malformed antlers. These biological anomalies are typically the result of a hormonal imbalance, such as an intersex condition or a tumor causing abnormal testosterone production. Since antler growth is purely hormone-driven, a surge in male hormones can trigger the development of bony pedicels and subsequent antler growth.