Pronghorn Antilocapra americana americana (Ord)

Description:   The pronghorn can be distinguished by: 1) light cinnamon-brown to tan color with black to dark brown markings around the outer edges and tips of the ears, over the eyes, at the angles of the jaw, and around the muzzle, 2) white (or much lighter) patches located on the cheeks, neck, and underbelly, 3) two distinctive white patches (ca. 75 mm; long) across its rump, 4) horns in males forked or "pronged" anteriorly, while females have a smaller unforked horn or no visible horn (both sexes shed the horn sheath annually, males about a month after the breeding season, and females more variably), 5) coarse, brittle hair containing air cells which insulate the animal from winter winds.

Size:   Adults may attain the following dimensions: total length 1245-1472 mm; tail 89-178 mm; hind foot 390-430 mm; ear 142-149 mm; weigh 47-70 kilograms.

Range and Habitat:  

The pronghorn occupied the western three quarters of Kansas prior to European settlement of the state. The eastern limit of the Flint Hills was probably its eastern boundary at the time. It was nearly as numerous as the bison in early historic time. By 1933 the pronghorn had been nearly extirpated in Kansas. Only a few reports of pronghorn in western Kansas were noted after that year. In recent years a restocking program has been established (see Remarks).

Reproduction:   The breeding season of the pronghorn in Kansas is during September. Does usually breed at sixteen months of age, but are known to become pregnant as early as five months of age. The gestation period is about 230 to 250 days. Twins are produced, being born in Late May or early June. New-born fawns weigh about 3 kilograms; they remain bedded separately for about six days, while the doe returns to nurse each twin. When about a week old, the fawns begin to move about more, begin to establish a bond with their siblings, and after several weeks are fully active. Frequency of nursing declined through the summer, and the growing fawns eat more and more vegetation, until, with the onset of the breeding season in September they are fully weaned.

Habits:   The pronghorn eludes its enemies by fleetness of foot. It has been clocked at 95 km per hour for short distances. Usually they do not jump over obstacles, and where barbed-wire fences block their path, crawl or slide under the bottom strand, often very rapidly. When frightened the long white hair is raised on the rump patch and "flashes" in the sunlight. Even very young fawns can race along with adults. During summer, pronghorns disperse, browsing and sunning in small loosely formed bands. Does form groups of up to a dozen; they usually wander away from the band to give birth, and then rejoin it a few weeks later with their fawns. Young bucks form slightly larger "bachelor" herds, and in good habitat adult males stake out territories which they defend all summer against other bucks. With the onset of the rut in late summer, territorial bucks try to "hold" does within the confines of their territories, and when females become receptive, mating occurs there. In poorer habitat, territories may not be defended. Non-territorial bucks also court does, often in groups, and the does often flee from this harassment to the territory of an older male. After the rut, males cast their horn sheaths, abandon their territories, and join other males, females, and fawns in large winter herds. Long movements (100 km or more) may take place at this time from summer to winter range. They shelter below cut banks and down in ravines to avoid cold winds. They are curious animals, and will flee to a ridge top when frightened, then pause and look back.

Food:   The pronghorn consumes browse such as sagebrush, especially in winter, but utilizes a wide variety of plants as food, including cacti. Forbs are heavily used in spring and summer; grass is usually a secondary food. The pronghorn does not compete heavily with cattle for range.

Remarks:   In 1964 the Kansas Fish and Game Commission began a program of restocking pronghorns in western Kansas (Wallace and Sherman counties). In subsequent years pronghorns were also introduced into Barber, Ellsworth, Edwards, Chase, and Clark counties. By 1977 a total of 319 animals had been stocked in Kansas. Today the total population of pronghorns in Kansas numbers from 1600 to 1700 animals.

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