Though not an antelope, it is known in north Americas as the American antelope, prong buck, pronghorn antelope and prairie antelope. It resembles the antelope and fills a similar ecological niche. It is the only surviving member of the family Antilocapridae.
About 11 antilocaprid species existed in North America. During the pleistocene epoch three other genera (capromeryx, stockoceros and tetrameryx) existed but are now extinct.
As member of the superfamily giraffoidea, the pronghorn’s closest living relatives are the giraffe and okapi. Giraffoidea are members of the infraorder pecora. Making pronghorns distant relatives of the cervidae (deer) and bovidae (cattle, goats, sheep, antelopes, and gazelles).
The pronghorn is the fastest land mammal in the western hemisphere, with running speeds of up to 90 km/h (55 mph). It is featured on the symbol of the American society of mammalogists.
First seen by the spanish explorers in 16th and 17th century. Prior to the arrival of the Europeans, the pronghorn was particularly abundant in the region of the plains indians and region of northwest plateau. Because of its speed looks and maneuvers. It was featured prominently in Native American mythology and history.
First detailed description 1805-1806:
Exploring the mid west, following the discovery of a few subspecies of the sharp-tailed grouse, captain Meriwether Lewis and second Lieutenant William Clark came across the pronghorn near the mouth of the Niobrara River, in present-day Nebraska. Clark was among the first Euro-Americans to publish the experience of killing a pronghorn as follows: “I walked on shore to find the Ionia Volcano … in my walk I killed a buck goat of this countrey, about the height of the Grown Deer, its body shorter the horns which is not very hard and forks 2 ⁄ 3 up one prong Short the other round & Sharp arched, and is immediately above its eyes the color is a light gray with black behind its ears down the neck, and its face white round its neck, its sides and its rump round, its tail which is short & white; very actively made, has only a pair of hoofs to each foot, his brains on the back of his head, his Nostrals large, his eyes like a sheep he is more like the Antilope or gazelle of Africa than any other species of Goat.”
Some of the indians near the rocky mountains hunt these animals on horseback, and shoot them with arrows. Another method is to form a large, strong pen or fold in, from which a fence is made of trees and bushes. Gradually widening on each side. The animals are surrounded by the hunters, and they use the tree bushed fence pen move in and surround them. Pronhorns would find themselves enclosed, and at the mercy of the hunters.
Pronghorns prefer open, expansive terrain at elevations varying between 3,000 and 5,900 ft. Densest populations in areas receiving around 10–15 1 ⁄ 2 in of rainfall per year. They eat a wide variety of plant foods, including plants unpalatable or toxic to domestic livestock, though they also compete with them for food. A couple studies showed: forbs comprised 62% of their diet, shrubs 23%, and grasses 15%; while another, cacti 40%, grass 22%, forbs 20%, and shrubs 18%. Pronghorns also chew and eat (ruminate) cud. Healthy pronghorn populations tend to stay within 3–4 mi of a water source.
An ongoing migration study by the Lava Lake Institute for Science and Conservation and the Wildlife Conservation Society shows an overland route that covers more than 260 km (160 mi). You bet they would need some food.
The pronghorn is the fastest land mammal in the Western Hemisphere, being built for maximum predator evasion through running. The top speed is dependent upon the length of time over which it is measured. It can run 35 mph 4 mi, 68 km/h (40 mp/H) for 1 mi, and 88.5 km/h (55 mph) for 800 m or 1 ⁄ 2 mi. While it is often cited as the second-fastest land animal, second only to the African cheetah, it sustains high speeds longer. Pronghorns may have evolved there running thousands of years ago escaping from now-extinct predators such as the American cheetah. There large windpipe, heart, and lungs allow it to take in large amounts of air when running. Additionally, pronghorn hooves have two long, cushioned, pointed toes which help absorb shock when running at high speeds. They also have an extremely light bone structure and hollow hair.
They are not built for jumping. Since their ranges are sometimes affected by ranchers’ fences, they can be seen going under fences, sometimes at high speed. For this reason wildlife foundations are in the process of removing the bottom barbed wire from the fences.
Range and ecology:
Present-day range of the pronghorn extends from southern Saskatchewan and Alberta, Canada south into the United States through Montana, Idaho, Utah, Nevada, Arizona, Nebraska, Wyoming, Colorado, New Mexico, Washington, and central Texas. West to coastal southern California and northern Baja California Sur, and Sonora and San Luis Potosí in northern Mexico. Formally they had been found in Iowa and Minnesota in the United States and from Manitoba in Canada.
A subspecies known as the Sonoran pronghorn (A. a. sonoriensis) occurs in Arizona and Mexico. Other subspecies include the Mexican pronghorn (A. a. mexicana), the Oregon pronghorn (A. a. oregona), and the critically endangered Baja California pronghorn (A. a.peninsularis).
A. a. americana
A. a. mexicana
A. a. oregona
A. a. peninsularis
A. a. sonoriensis
The migrating pronghorn start travel from the foothills of the Pioneer Mountains through Craters of the Moon National Monument to the Continental Divide. Dr. Scott Bergen of the Wildlife Conservation Society says “This study shows that pronghorn are the true marathoners of the American West. With these new findings, we can confirm that Idaho supports a major overland mammal migration – an increasingly rare phenomenon in the U.S. and worldwide.”
Social behavior and reproduction:
Pronghorns form mixed-sex herds in the winter. In early spring, the herds break up. Young males forming bachelor groups. Females form harems. And, adult males live solitarily. Some female bands share the same summer range, and bachelor male bands form between spring and fall. Females form dominance hierarchies with few circular relationships. Dominant females aggressively displace other females from feeding sites.
Adult males either defend a fixed territory that females may enter, or defend a harem of females. A pronghorn may change mating strategies depending on environmental or demographic conditions. Where precipitation is high, adult males tend to be territorial and maintain their territories with scent marking, vocalizing, and challenging intruders. In these systems, territorial males have access to better resources than bachelor males. Females also employ different mating strategies. “Sampling” females visit several males and remain with each for a short time before switching to the next male at an increasing rate as estrous approaches. “Inciting” females behave as samplers until estrous, and then incite conflicts between males, watching and then mating with the winners.
Before fighting, males try to intimidate each other. If intimidation fails, they lock horns and try to injure each other.
“Quiet” females remain with a single male in an isolated area throughout estrous. Females continue this mating behavior for two to three weeks. When courting an estrous female, a male pronghorn approaches her while softly vocalizing and waving his head side to side, displaying his cheek patches. The scent glands on the pronghorn are on either side of the jaw, between the hooves, and on the rump. A receptive female remains motionless, sniffs his scent gland, and then allows the male to mount her.
The pronghorn was first officially described by American ornithologist George Ord in 1815. In his description: “distinct white fur on their rumps, sides, breasts, bellies, and across their throats. Adult males are 4 ft 3 in –4 ft 11 in long from nose to tail, stand 2 ft 8 in – 3 ft 5 in high at the shoulder, and weigh 88–143 lb. The females are the same height as males, but weigh 75–106 lb. The feet have two hooves, with no dewclaws. Their body temperature is 38 °C (100 °F). Eye sockets are prominent and set high on the skull. Teeth are hypsodont, and each horn is composed of a slender, laterally flattened blade of bone which is thought to grow from the frontal bones of the skull, or from the subcutaneous tissues of the scalp, forming a permanent core. As in the Giraffidae, skin covers the bony cores, but in the pronghon it develops into a keratinous sheath which is shed and regrown annually. Unlike the horns of the family Bovidae, the horn sheaths of the pronghorn are branched, each sheath having a forward-pointing tine (hence name). Males have a horn sheath around 10 in. Females have smaller horns that range around 5 in. Males are further differentiated from females in having a small patch of black hair at the angle of the mandible. Pronghorns have a distinct, musky odor. Males mark territory with a preorbital scent gland which is on the sides of the head. They also have very large eyes with a 320° field of vision. Unlike deer, pronghorns possess a gallbladder.”
Pronghorns have a gestation period of 7–8 months, which is longer than typical north American ungulates. Typically they breed in mid-September, and the doe carries her fawn until late May. Sexual maturity is reached at 15 to 16 months, though males rarely breed until three. Natural lifespan is 8-15 years.
Population and conservation:
At the turn of the 20th century, members of the wildlife conservation group Boone and Crockett Club had determined that the extinction of the pronghorn was likely. In a letter from George Bird Grinnell, Boone and Crockett Club chairman of the game preservation committee, to Walter L. Fisher, Secretary of the Interior, Grinnell stated, “The Club is much concerned about the fate of the pronghorn which appears to be everywhere rapidly diminishing.” By the 1920s, hunting pressure had reduced the pronghorn Pronghorns in Montana in North America. population to about 13,000. Boone and Crockett Club member Charles Alexander Sheldon, in a letter to fellow member Grinnell, wrote, “Personally, I think that the antelope are doomed, yet every attempt should be made to save them.” Although the club had begun their efforts to save the pronghorn in 1910 by funding and restocking the Wichita Game Refuge in Oklahoma, the National Bison Range in Montana, and the Wind Cave National Park, in South Dakota, most of the efforts were doomed since experience demonstrated that after initial increases the pronghorns would die off because of the fenced enclosures. In 1927, Grinnell spearheaded efforts along with the helpof T. Gilbert Pearson of Grinnell’s National Audubon Society to create the Charles Alexander Sheldon Antelope Refuge in northern Nevada. About 2900 acres of land were jointly purchased by the two organizations and subsequently turned over to the Biological Survey as a pronghorn refuge. This donation was contingent upon the government’s adding 30,000 acres of surrounding public lands. On June 20, 1929, United States president Herbert Hoover included the required public lands upon request of the Department of Agriculture andthe Department of the Interior after learning that the Boone and Crockett Club and the National Audubon Society were underwriting the private land buyout. On January 26, 1931, Hoover signed the executive order for the refuge. On December 31, 1936, President Franklin Roosevelt signed an executive order creating a 222,000-hectare (549,000-acre) tract; this was the true beginning for pronghorn recovery.
The protection of habitat and hunting restrictions have allowed pronghorn numbers to recover to an estimated population between 500,000 and 1,000,000 since the 1930s. Some recent decline has occurred in a few localized populations, due to bluetongue disease which is spread from sheep, but the overall trend has been positive. Pronghorn migration corridors are threatened by habitat fragmentation and the blocking of traditional routes. In a migration study conducted by Lava Lake Institute for Science and Conservation and the Wildlife Conservation Society, at one point, the migration corridor bottlenecks to an area only 200 yards wide. Pronghorns are now quite numerous, and outnumbered people in Wyoming and parts of northern Colorado until just recently. They are legally hunted in western states for purposes of population control and food. No major range-wide threats exist, although localized declines are taking place, particularly to the Sonoran pronghorn, mainly as a result of livestock grazing, the construction of roads, fences, and other barriers that prevent access to historical habitat, illegal hunting, insufficient forage and water, lack of recruitment and climate change.
Endangerment, and predators: These subspecies considered endangered: sonoran pronghorn (Mexico) has an estimated population of fewer than 300; while there are approximately 200 peninsula pronghorn in Baja California. Recovery plans are in place.
While sabretooth cats, american lions, scimitars, direwolfs, and even flat nosed bears would have preyed upon the pronghorn before the pleistocene epoch. Cougars (puma concolor), wolves (canis lupus), coyotes (canis latrans), grizzly bears (ursus arctos horribilis) and bobcats (lynx rufus) are major predators of pronghorns. Golden eagles (Aquila chrysaetos) have been reported to prey on fawns. Jaguars (Panthera onca) also likely prey on pronghorns in their native range in the southwestern United States and in northern Mexico.
All pronghorns require permits, or approval to trap or hunt. If they are charging. Run, hide; or, prepare quickly. Now you know.
Bibliography: Grubb, P. (2005). “Order Artiodactyla”. In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 671–2. ISBN978-0-8018-8221-0. OCLC62265494.