How to Identify Pronghorn in South Dakota

An adult pronghorn is tan or reddish-brown on the back and sides, with a white or cream belly and white rump patch. The most distinctive feature is the large white rump, which flares when the animal is alarmed. Males are slightly larger and stockier than females, weighing 90 to 150 pounds compared to females at 75 to 120 pounds. The head is small and wedge-shaped, and both males and females have horns, though the male's horns are thicker and more pronounced. The horns curve backward and inward, and males have a small forward-pointing prong partway up the horn, which gives the species its name. Unlike other horned animals, pronghorns shed their horn sheaths annually.

A pronghorn stands about 3 to 3.5 feet tall at the shoulder and measures 4.5 to 5.5 feet from nose to tail tip, making them noticeably smaller than mule deer and white-tailed deer. They are sleeker and more streamlined than either deer species, with longer, thinner legs and a much smaller head in proportion to body size. From a distance, you might confuse a pronghorn with a small mule deer, but the distinctive white belly, white rump patch, and tan back are immediate giveaways. The gait is also different: pronghorns move with a stiff-legged trot, while deer bound and leap.

Four key field marks stand out even when the animal is far away. First, the white rump patch, which is large and flares when the pronghorn is alarmed or running, is visible from great distances and is unlike any other ungulate in South Dakota. Second, the tan or reddish-brown back contrasts sharply with the white belly and inner thighs, creating a two-tone pattern. Third, the horns curve backward and are visible on both males and females, setting them apart from mule deer, which have ears that seem to dominate the head profile. Fourth, the overall body shape is compact and torpedo-like, with thin legs and no visible neck thick ness. Pronghorns appear almost delicate compared to the stockier frame of a mule deer.

Male pronghorn horns are 7 to 9 inches long in adult males, while female horns are much shorter, usually under 4 inches, and may be barely visible from a distance. The male horn has a forward-pointing prong or spur about halfway up the main shaft, which is the feature that inspired the name 'pronghorn.' This prong is unique and is not seen on any other North American hoofed animal. The horns are black, and the horn sheaths are shed and regrown each year, making fall and early winter a time when some pronghorns appear hornless. Females have horns too, but they lack the forward prong and remain small and thin.

A pronghorn hoof print is small and rounded, about 1.5 to 2 inches long, and is slightly heart-shaped. The two toes leave two separate impressions, and the overall track resembles a miniature deer or elk track but is noticeably smaller. In mud or soft sand, you may see faint dew claw marks behind the main hooves, especially if the animal was running or on soft ground. Pronghorn trails are often lighter and more delicate than mule deer trails, and the hoof marks show the narrow, precise placement typical of an animal built for speed rather than power. In the sandy soils of the Badlands or around dry lake beds, pronghorn tracks remain crisp and clear, but they fade quickly on hardpan or rocky ground.

Pronghorns are often mistaken for small mule deer, but several features separate them immediately. First, pronghorns have a white rump patch that flares when alarmed, while mule deer have a white or patchy rump but never the large, flashing white rump of a pronghorn. Second, pronghorns are tan or reddish-brown, while mule deer are grayer and more uniform in color. Third, pronghorns have a small, delicate head, while mule deer have a larger, more massiv head and enormous ears. Fourth, pronghorn horns curve backward and inward, while mule deer horns branch forward and outward in a Y-shape. Elk are far larger and are not found in the same grassland habitats as pronghorns, so confusion with elk is unlikely.

Pronghorns are generally quiet animals, but they do vocalize in certain situations. A startled pronghorn may make a loud snort or whistle through its nose, which sounds like a sharp hiss or bark and carries a surprising distance across open prairie. During the fall rut, or breeding season, males make loud bleating calls. Fawns make bleating sounds to stay in contact with their mothers. In the field, you may hear these vocalizations before you see the animal, especially during the calving and rearing season from May through August. Most of the time, however, pronghorns are silent, and the first indication of their presence is often the flash of white as they raise their rump and run.

Pronghorns move with a distinctive stiff-legged trot and have a unique bouncing gait where all four feet leave the ground at once in what is called a 'stot.' This movement is different from the bounding leap of a mule deer or the gallop of an elk. When alarmed, a pronghorn often does a high-stepping trot with its tail and rump raised high, displaying the white rump patch as a warning signal to other pronghorns. The head is held low and forward, and the ears are held upright but not as prominently as a deer's. The overall impression is of an animal that is lean, fast, and built for the open plains, whereas deer appear heavier and more built for navigating brush and trees.

The pronghorn's rump patch is a large white or cream-colored patch on the rear end that stands out sharply against the tan back. The white hair on the rump can be raised and lowered by specialized muscles, and when the animal is alarmed or running, the patch flares dramatically. This flaring behavior is a warning signal that communicates danger to other pronghorns in the group. The rump patch is one of the most distinctive features of the species and is easily visible from great distances, making it one of the first clues that you are looking at a pronghorn and not a mule deer. No other large animal in South Dakota has a rump patch as large and conspicuous as this.

Most pronghorns in South Dakota follow the standard pattern of tan or reddish-brown back with white belly and rump, but slight color variations do occur. Some individuals may be slightly darker or lighter, but the basic two-tone pattern and the rump patch remain constant. Seasonal changes in fur color are minimal compared to other ungulates. Young fawns are born spotted and are smaller and more delicate, but they still show the distinctive white belly and rump patch within a few weeks of birth. Older animals may appear slightly paler in winter when their winter coat comes in, but the identifying features remain the same. No color variation in pronghorns is dramatic enough to cause confusion with other species.