The pronghorn is a remarkable North American mammal, recognized for its exceptional speed and unique appearance. Often mistaken for an antelope, it is, in fact, the sole surviving member of its own taxonomic family, Antilocapridae. A common point of curiosity regarding this animal centers on its distinctive headgear, particularly whether both sexes possess these structures.
The Pronghorn’s Distinctive Headgear
Pronghorn headgear is unique among mammals, exhibiting characteristics of both true horns and antlers. Unlike the solid bony antlers of deer that are shed and regrown annually, or the permanent, continuously growing horns of bovids like bighorn sheep, pronghorn horns have a distinct two-part structure. Each horn consists of a permanent bony core that extends from the skull. This bony core is covered by a keratinous sheath, which is made of a material similar to human fingernails.
This keratinous sheath is shed and regrown annually, between November and March. New horn growth begins underneath the existing sheath, pushing the old one off. This annual shedding cycle is a defining feature that differentiates pronghorn horns from the permanent horns of other animals.
Female Pronghorn Headgear
Female pronghorns, known as does, possess horns, but their appearance differs significantly from males. Female horns are much smaller and less developed, often appearing as small nubs or short, straight spikes, averaging about 3 to 6 inches in length. Their presence and size vary considerably; some may be barely visible or even absent. When present, they are rarely pronged or forked like those of males, presenting as simple, unbranched structures.
Variations Between Sexes
A clear distinction exists in the headgear between male and female pronghorns. Male horns are considerably larger, often reaching lengths of 10 to 17 inches, and are prominently forked with a forward-facing prong, giving the animal its name. These differ from female horns, which are shorter, simpler, and less consistently present.
These differences are not merely cosmetic; they reflect distinct roles in the animal’s biology. Male horns play a significant role in territorial defense and mating displays during the breeding season, where bucks often spar with each other to establish dominance. The smaller size and less pronounced nature of female horns suggest they do not serve the same combative or display functions. This evolutionary divergence highlights the specialized adaptations of each sex within the species.