Prong buck, Pronghorn antelope, American antelope
The pronghorn is unique amongst mammals. It does not belong to the antelope or the goat family and neither is it related to African antelopes. Its color is tan to reddish brown. Its cheeks, belly, chest, rump and the insides of its legs are white. Males have a wide black mask running from their eyes to their nose, black parches on their neck and pronged black horns. The horns of the male are shaped like a lyre, curving in towards each other. Females don’t have the black markings, and the horns are generally straight short spikes. The pronghorn possesses horns, not antlers and is the only animal with branched horns and the only animal that each year sheds its horns. The outer sheath falls off in the autumn and grows back every summer.
The pronghorn is native to North America and is distributed throughout the treeless deserts, plains and basins of western North America, across the southern prairie provinces in Canada, south into the west of the United States and to the north of Mexico. Pronghorns are typically found in grassland, chaparral, sage scrub and desert. The southern part of their range consists mostly of open prairies and arid grasslands.
Habits and lifestyle
This highly-strung animal is active day and night, alternating snatches of sleep with focused feeding. Pronghorns are opportunistic and selective foragers. The timing, length, and seasonal movement patterns vary regionally. Pronghorns come together in mixed-gender herds in winter. The herds break up in early spring and young males form bachelor groups, females join a group of females, and adult males live on their own. Females form dominance hierarchies which including circular relationships. Dominant females will aggressively displace other females at feeding sites. Pronghorns travel up to 160 km away from winter ranges to get away from very deep snow.
Diet and nutrition
In summer, pronghorns graze on grasses, cactus and forbs. In winter, they eat sagebrush and other plants that are available.
Pronghorns are polygamous. Late in summer or in early fall, a male gathers his harem of three or four does. Pronghorns are usually ready to breed at 16 to 17 months. Breeding takes place from mid-September until October. Horns are shed one month after breeding. Females usually produce twins, following gestation of about 250 days. After birth, for several days the fawns are weak and cannot keep up with the adults, so mothers and the young rest near water until they are strong enough. Females care for their fawns from birth until 1 to 1.5 years, until they are independent. Males do not help with raising offspring.
Today, there are some localized declines taking place, especially to the Sonoran Pronghorn, mostly as a result of livestock grazing, new roads, and fences and other barriers to historical habitat, insufficient food and water, illegal hunting (especially in Mexico), and lack of recruitment.
According to the IUCN Red List the total proghorn population size is around 1 million individuals. Specific populations of this species have been estimated in such areas: fewer than 300 individuals of Sonoran pronghorn in the United States; 200-500 individuals in Mexico; around 200 Peninsular pronghorn in and around breeding centres in Baja California. Overall, currently pronghorns are classifed as Least Concern (LC) and theirn numbers today remain stable.
Throughout their range, these animals live alongside cattle, sheep, bison and horses. Pronghorns improve rangeland quality for other species through eating invasive plants and noxious weeds. Introduced livestock may overgraze in areas shared with pronghorn, reducing cover and the amount of food. Reduction of cover may cause more deaths amongst the young through predation.