by Alex Gugel , all rights reserved
Bryce Canyon National Park Service U.S. Department of the Interior Bryce Canyon National Park Pronghorn (Antilocapra americana) Their scientific name, Antilocapra americana, means “American Antelope Goat,” but they are not closely related to the antelopes of Africa and Asia. They are the fastest land animals in the western hemisphere, and they are a link to the past as one of the few remaining survivors of the last Ice Age. Pronghorns evolved when the hemisphere was home to the American Cheetah as well as other large predators and, in order to survive, they had to be fast. Vital Statistics Named for the forward facing prong on the buck’s horns, they are often referred to as antelope or Pronghorn Antelope, however, the correct common name is simply Pronghorn. Their horns are unique in the animal kingdom and shared by no living other species. Antlers are bone and shed each year, while bovine horns are permanent and are bone covered with a keratin sheath (hair and nails are keratin). The Pronghorn is similar to the bovine family in that they have bone covered with a keratin sheath, but with one major exception: the keratin sheath is shed each year after the breeding season, the regrows each Spring. Not large animals, Pronghorn have eyes as large as a horse, are able to detect movement up to 4 miles/6.5 km away, and have a field of view of more than 300 degrees. A Lone Survivor Always on the alert, a Pronghorn Doe. The males average 3 ft. (0.9 m) tall, 60 in.(1.5 m) in length, and weigh 120 pounds (55 kg). The females are approximately 10% smaller. The modern Pronghorn’s earliest ancestors appear in the fossil record from the Miocene Epoch, about 20 million years ago. The family continued to evolve and expand over the millennia and there are fossils representing at least 12 different species. Bones of the modern Pronghorn, dating to about 10,000 years ago, have been found in California’s La Brea Tar Pits. North America was a very different place and by late in the Pliocene Epoch, in addition to the pronghorns, North America was also home to several species we associate with modern Africa: lions, cheetahs, and hyenas. In addition, there were saber-toothed cats and short-faced bears that, combined with those mentioned earlier, made for some very formidable predators. For an even-toed ungulate living in such a dangerous time, speed was the only defense in the struggle for survival. When humans first arrived in North America 13,000 years ago there were five pronghorn species. By the end of the Pleistocene Epoch, about 11,000 years ago, the planet had entered the last Ice Age and North America seemed to be hardest hit. Mass extinctions during that period included mammoths, mastodons, the big cats, and all but this one surviving member of the pronghorn family. Lifestyles Pronghorn inhabit grasslands, deserts, and sagebrush flats of western North America from Canada’s prairies to northern Mexico at elevations from 4,000 to 8,000 feet (1220 to 2400 meters). Since they rely on vision and speed for predator avoidance, wide open spaces with low vegetation are critical for survival. Herds, depending on location, will migrate from just a few miles/kilometers to over 150 miles (240 km) between summer and winter forage. Pronghorn are a frequent sight in the meadows at Bryce Canyon from spring through fall, but retreat to lower elevations, where there is less snow, in the winter. Pronghorn are ruminants with fourchambered stomachs much like those of members of the deer and bovine families. Their diet consists chiefly of forbs, shrubs, and, especially in winter, sagebrush. They rarely eat grasses but will, in arid or desert environments, eat cactus. Herds tend to be larger during the winter months, then break up into smaller groups in spring and summer. Pregnant females leave the Conservation Twin fawns nursing while the doe maintains a constant vigil. herds in May or June to find a secluded location to give birth. Adults have no living natural predators except when old, sick, or injured. While vulnerable, the family heritage of speed is present even in the fawns. At the age of four days they can outrun the average human and, by three to four weeks, can already outrun a coyote or bobcat. Even with young Pronghorns, the only chance a predator has is surprise. Prior to westward expansion, the population of Pronghorns is estimated to have numbered over 40 million, and there were probably more Pronghorns than Bison. By the early 20th Century, however, their numbers had been reduced to less than 20,000. Market hunting during the last half of the 19th Century, when you could buy an entire Pronghorn for food in Denver, Colorado for 25 cents, was a major factor in their decline. In addition, as ranching grew and the “fencing of the west” began these animals, who are fast but poor jumpers, could not make their way to traditional wintering grounds. Fences left them more susceptible to predation and starvation. Conservation efforts that began in the 1920s have been successful and the population has increased to nearly one million. Though once abundant in Utah, by that same time there were less than 1,000 and in the area around Bryce Canyon they had completely disappeared. Pronghorn found at Bryce were reintroduced to the region in the 1970s and the population is doing well. EXPERIENCE YOUR AMERICA™ Pronghorn are most often seen foraging in open meadows.