Pronghorns, often recognized as symbols of the American West, are unique North American mammals. They are celebrated for their remarkable speed, making them the fastest land animals in North America, capable of reaching speeds close to 60 miles per hour. Beyond their swiftness, their striking appearance, particularly their distinctive headgear, often sparks curiosity about whether both male and female pronghorns possess these features. This inquiry delves into the nature of pronghorn headgear and its development across both sexes.
The Unique Nature of Pronghorn Headgear
Pronghorn headgear is unique, differing from true horns (permanent and typically unbranched) and antlers (entirely bony structures shed annually). It combines characteristics of both. Each pronghorn horn consists of a permanent bony core that extends from the skull, covered by a keratinous sheath. This outer sheath, made of the same protein found in human fingernails, is uniquely shed and regrown each year.
The annual shedding of the keratinous sheath typically occurs in late fall or early winter. A new sheath begins to form underneath, pushing off the old one. This distinct cycle means that pronghorn headgear is neither a true horn nor a true antler, but rather a specialized structure found only in the Antilocapridae family, of which the pronghorn is the sole surviving member.
Horn Development in Male and Female Pronghorns
Most female pronghorns do possess horns, though they are generally much smaller and less prominent than those found on males. Male pronghorns, known as bucks, typically have larger, longer horns that often feature a distinct forward-pointing prong or fork, which gives the animal its name. These male horns can range in length from about 10 to 17 inches. Male horns often exhibit a lyre-shaped curve, sometimes curving inwards.
In contrast, the horns of female pronghorns, or does, are typically shorter, often unbranched, and sometimes barely visible, appearing as small bumps. Female horns usually measure between 1 and 6 inches in length. There is considerable variability in female horn development; some individuals may have no visible horns, while others develop small, spiky growths. Horns begin to grow in both sexes around six months of age. While male pronghorns reliably shed their horn sheaths annually after the breeding season, the shedding pattern in females can be more variable and less defined.