The pronghorn's closest living relatives are the giraffe and okapi.[14] The Antilocaprids are part of the infraorder Pecora, making them distant relatives of deer, bovids, and moschids.
The pronghorn is the fastest land mammal in the Americas, with running speeds of up to 88.5km/h (55mph). It is the symbol of the American Society of Mammalogists.[15]
Etymology
The animal gets its name from its horn sheaths that branch and have a forward-pointing tine, unlike the horns of species from the ox family Bovidae.[16]
European discovery
Pronghorns were first seen and described by Spanish explorers in the 16th century, the species was not formally recorded or scrutinized until the expedition in 1804-06 by Captain Meriwether Lewis and Second Lieutenant William Clark.[17] Following the discovery of a few subspecies of the sharp-tailed grouse, Lewis and 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, and described his experience as follows:[18]
I walked on shore to find an old Vulcanoe [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; Verry 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.
Pronghorns have distinct white fur on their rumps, sides, breasts, bellies, and across their throats. Adult males are 1.3–1.5m (4ft 3in– 4ft 11in) long from nose to tail, stand 81–104cm (2ft 8in– 3ft 5in) high at the shoulder, and weigh 40–65kg (88–143lb). The females are the same height as males, but weigh 34–48kg (75–106lb). The feet have two hooves, with no dewclaws. Their body temperature is 38°C (100°F).[8][20][16][21]
Each horn of the pronghorn 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.[23] As in the Giraffidae, skin covers the bony cores, but in the pronghorn, it develops into a keratinous sheath which is shed and regrown annually. Males have a horn sheath about 12.5–43cm (5–17in) (average 25cm or 10in) long with a prong. Females have smaller horns that range from 3–15cm (1–6in) (average 12cm or 4+1⁄2in) and sometimes barely visible; they are straight and very rarely pronged.[16]
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.[8] The major chemical component in this gland's secretion is the highly odoriferous compound, 2-ethyl-3-methylpyrazine. This compound is also the major volatile component found on the animal's back in the male's medial gland. [24]
Pronghorns have well developed glands on each hoof. Like many ungulates, these interdigital (hoof) glands of pronghorn contain chemical compounds that are known to have antimicrobial activity against soil and mammalian pathogens. [25]
Movement
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 56km/h (35mph) for 6.5km (4mi), 68km/h (42mph) for 1.5km (1mi), and 88.5km/h (55mph) for 800m (1⁄2mi).[20][26] Although it is slower than the African cheetah,[27] it can sustain top speeds much longer than cheetahs.[7] The pronghorn may have evolved its running ability to escape from now-extinct predators such as the American cheetah, since its speed greatly exceeds that of all extant North American predators.[7][28]:318 Compared to its body size, the pronghorn has a large windpipe, heart, and lungs to 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.[29] They also have an extremely light bone structure and hollow hair.
Pronghorns are built for speed, not for jumping. Since their ranges are sometimes affected by sheep ranchers' fences, they can be seen going under fences, sometimes at high speed. For this reason, the Arizona Antelope Foundation and others are in the process of removing the bottom barbed wire from the fences, and/or installing a barbless bottom wire.[30]
The pronghorn has been observed to have at least 13 distinct gaits, including one reaching nearly 7.3m (23ft 11in) per stride.[7]
When a pronghorn sees something that alarms it, the white hair on the rump flairs open and exposes two highly odoriferous glands that releases a compound described as having an odour "reminiscent of buttered popcorn." This sends a message to other pronghorns by both sight and smell about a present danger. This scent has been observed by humans 20 to 30 meters downwind from alarmed animals. The major odour compound identified from this gland is 2-pyrrolidinone. [31]
Prior to the arrival of Europeans, the pronghorn was particularly abundant in the regions west of the Mississippi River (still its primary range today). Pronghorn herds filled a vital ecological niche of the prairie habitat, as well as other climatic zones. The amount of wildlife was considered to be so vast at one time that the prehistoric American Prairie—and as recently as 200 to 300 years ago—has been dubbed the "American Serengeti", due to the once-millions-strong herds of bison, elk, hundreds of thousands of pronghorn, as well as other now-extinct megafauna.
Other regional subspecies include the Rocky Mountain pronghorn (A. a. americana), Mexican pronghorn (A. a. mexicana), the Oregon pronghorn (A. a. oregona), and the critically endangered Baja California pronghorn (A. a. peninsularis).
Pronghorns prefer open, expansive terrain at elevations varying between 900 and 1,800m (3,000 and 5,900ft), with the densest populations in areas receiving around 250–400mm (10–15+1⁄2in) of rainfall per year. They eat a wide variety of plant foods, often including plants unpalatable or toxic to domestic livestock, though they also compete with them for food.[20] In one study, forbs comprised 62% of their diet, shrubs 23%, and grasses 15%,[20] while in another, cacti comprised 40%, grass 22%, forbs 20%, and shrubs 18%.[16] Pronghorns also chew and eat (ruminate) cud.
Healthy pronghorn populations tend to stay within 5.0–6.5km (3–4mi) of a water source. The majority are found within 5mi (8km) of a water source.[36]
Cougars (Puma concolor), wolves (Canis lupus), coyotes (Canis latrans), grizzly bears (Ursus arctos horribilis) and bobcats (Lynx rufus) are major predators of pronghorns.[39]Golden eagles (Aquila chrysaetos) have been reported to prey on fawns and adults.[39][40]Jaguars (Panthera onca) also likely prey on pronghorns in their native range in the southwestern United States and in northern Mexico. In the Pleistocene, jaguars would likely be dangerous to pronghorns as a short-range ambush predator.[41]
Social behavior and reproduction
Pronghorns form mixed-sex herds in the winter. In early spring, the herds break up, with young males forming bachelor groups, females forming harems, and adult males living solitarily.[28] 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.[42] 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.[28]:228 Where precipitation is high, adult males tend to be territorial and maintain their territories with scent marking, vocalizing, and challenging intruders.[43] In these systems, territorial males have access to better resources than bachelor males.[43] 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.[44] Before fighting, males try to intimidate each other. If intimidation fails, they lock horns and try to injure each other.[16] "Quiet" females remain with a single male in an isolated area throughout estrous.[44] Females continue this mating behavior for two to three weeks.[16]
When courting an estrous female, a male pronghorn approaches her while softly vocalizing[45][28] and waving his head side to side, displaying his cheek patches.[46] The scent glands on the pronghorn are on either side of the jaw, between the hooves, and on the rump.[16] A receptive female remains motionless, sniffs his scent gland, and then allows the male to mount her.[28]
Pronghorns have a gestation period of 7–8 months, which is longer than is typical for North American ungulates. They breed in mid-September, and the doe carries her fawn until late May. The gestation period is around six weeks longer than that of the white-tailed deer. Females usually bear within a few days of each other.[20] Twin fawns are common.[29] Newborn pronghorns weigh 2–4kg (4–9lb), most commonly 3kg (7lb). In their first 21–26 days, fawns spend time hiding in vegetation.[43] Fawns interact with their mothers for 20–25 minutes a day; this continues even when the fawn joins a nursery.[43] The females nurse, groom, and lead their young to food and water, as well as keep predators away from them.[43] Females usually nurse the young about three times a day.[20] Males are weaned 2–3 weeks earlier than females.[43]Sexual maturity is reached at 15 to 16 months, though males rarely breed until three years old. Their lifespan is typically up to 10 years, rarely 15 years.[20][16][21]
Merriwether Lewis and William Clark made several other observations on the behavior of the pronghorn and how the local tribes hunted them. They described the animal, which they referred to as the "Antelope" or the "Goat", as follows:[19]
Of all the animals we have seen the Antelope seems to possess the most wonderful fleetness. Shy and timorous they generally repose only on the ridges, which command a view of all the approaches of an enemy ... When they first see the hunters they run with great velocity ... The Indians near the Rocky Mountains hunt these animals on horseback, and shoot them with arrows. The Mandans' mode of hunting them is to form a large, strong pen or fold, from which a fence made of bushes gradually widens on each side. The animals are surrounded by the hunters, and gently driven towards this pen, in which they imperceptibly find themselves enclosed, and are then at the mercy of the hunters.
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 population to about 13,000.[7] 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 help of T. Gilbert Pearson of Grinnell's National Audubon Society to create the Charles Alexander SheldonAntelope 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 and the 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 in North America.[49]
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.[1] Some recent decline has occurred in a few localized populations,[20] 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.[50]
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, and lack of recruitment.[1]
Three subspecies are considered endangered in all (A. a. sonoriensis, A. a. peninsularis), or part of their ranges (A. a. mexicana). The Sonoran pronghorn has an estimated population of fewer than 300 in the United States and 200–500 in Mexico, while there are approximately 200 Peninsula pronghorn in Baja California.[1] Populations of the Sonoran pronghorn in Arizona and Mexico are protected under the Endangered Species Act (since 1967), and a recovery plan for this subspecies has been prepared by U.S. Fish and Wildlife Service.[1] Mexican animals are listed on CITES Appendix I. Pronghorns have game-animal status in all of the western states of the United States, and permits are required to trap or hunt pronghorns.[1]
The bongo is a large, mostly nocturnal, forest-dwelling antelope, native to sub-Saharan Africa. Bongos are characterised by a striking reddish-brown coat, black and white markings, white-yellow stripes, and long slightly spiralled horns. It is the only tragelaphid in which both sexes have horns. Bongos have a complex social interaction and are found in African dense forest mosaics. They are the third-largest antelope in the world.
The springbok or springbuck is an antelope found mainly in south and southwest Africa. The sole member of the genus Antidorcas, this bovid was first described by the German zoologist Eberhard August Wilhelm von Zimmermann in 1780. Three subspecies are identified. A slender, long-legged antelope, the springbok reaches 71 to 86 cm at the shoulder and weighs between 27 and 42 kg. Both sexes have a pair of black, 35-to-50 cm (14-to-20 in) long horns that curve backwards. The springbok is characterised by a white face, a dark stripe running from the eyes to the mouth, a light-brown coat marked by a reddish-brown stripe that runs from the upper fore leg to the buttocks across the flanks like the Thomson's gazelle, and a white rump flap.
Wildebeest, also called gnu, are antelopes of the genus Connochaetes and native to Eastern and Southern Africa. They belong to the family Bovidae, which includes true antelopes, cattle, goats, sheep, and other even-toed horned ungulates. There are two species of wildebeest: the black wildebeest or white-tailed gnu, and the blue wildebeest or brindled gnu.
The term antelope refers to numerous extant or recently extinct species of the ruminant artiodactyl family Bovidae that are indigenous to most of Africa, India, the Middle East, Central Asia, and a small area of Eastern Europe. Antelopes do not form a monophyletic group, as some antelopes are more closely related to other bovid groups, like bovines, goats, and sheep, than to other antelopes.
The hirola, also called the Hunter's hartebeest or Hunter's antelope, is a critically endangered antelope species found as of now, only in Kenya along the border of Somalia. It was first described by the big game hunter and zoologist H.C.V. Hunter in 1888. It is the only living member of the genus Beatragus, though other species are known from the fossil record. The global hirola population is estimated at 300–500 animals and there are none in captivity. According to a document produced by the International Union for Conservation of Nature "the loss of the hirola would be the first extinction of a mammalian genus on mainland Africa in modern human history".
The bohor reedbuck is an antelope native to central Africa. The animal is placed under the genus Redunca and in the family Bovidae. It was first described by German zoologist and botanist Peter Simon Pallas in 1767. The bohor reedbuck has five subspecies. The head-and-body length of this medium-sized antelope is typically between 100–135 cm (39–53 in). Males reach approximately 75–89 cm (30–35 in) at the shoulder, while females reach 69–76 cm (27–30 in). Males typically weigh 43–65 kg (95–143 lb) and females 35–45 kg (77–99 lb). This sturdily built antelope has a yellow to grayish brown coat. Only the males possess horns which measure about 25–35 cm (9.8–13.8 in) long.
Thomson's gazelle is one of the best known species of gazelles. It is named after explorer Joseph Thomson and is sometimes referred to as a "tommie". It is considered by some to be a subspecies of the red-fronted gazelle and was formerly considered a member of the genus Gazella within the subgenus Eudorcas, before Eudorcas was elevated to genus status.
The oribi is a small antelope found in eastern, southern and western Africa. The sole member of its genus, it was described by the German zoologist Eberhard August Wilhelm von Zimmermann in 1783. While this is the only member in the genus Ourebia, eight subspecies are identified. The oribi reaches nearly 50–67 centimetres (20–26 in) at the shoulder and weighs 12–22 kilograms (26–49 lb). It possesses a slightly raised back, and long neck and limbs. The glossy, yellowish to rufous brown coat contrasts with the white chin, throat, underparts and rump. Only males possess horns; the thin, straight horns, 8–18 centimetres (3.1–7.1 in) long, are smooth at the tips and ringed at the base.
The gemsbok, or South African oryx, is a large antelope in the genus Oryx. It is endemic to the dry and barren regions of Botswana, Namibia, South Africa and Zimbabwe, mainly inhabiting the Kalahari and Namib Deserts, areas in which it is supremely adapted for survival. Previously, some sources classified the related East African oryx, or beisa oryx, as a subspecies.
The dibatag, or Clarke's gazelle, is a medium-sized slender antelope native to Ethiopia and Somalia. Though not a true gazelle, it is similarly marked, with long legs and neck. It is often confused with the gerenuk due to their striking resemblance. The typical head-and-body length is about 103 to 117 cm. They stand up to about 80 to 90 cm. Male dibatag weigh between 20 and 35 kg, whereas females range from 22 and 29 kg. The length of the curved horns, present only on males, is typically between 10 and 25 cm. The upper parts are gray to fawn, while the dorsal and lateral areas are cinnamon to rufous. The underparts, rump and the insides of the legs are all white. While markings are visible on the face, there are none on the flanks or the buttocks.
The Antilocapridae are a family of ruminant artiodactyls endemic to North America. Their closest extant relatives are the giraffids. Only one species, the pronghorn, is living today; all other members of the family are extinct. The living pronghorn is a small ruminant mammal resembling an antelope.
Damaliscus lunatus is a large African antelope of the genus Damaliscus and subfamily Alcelaphinae in the family Bovidae, with a number of recognised geographic subspecies. Some authorities have split the different populations of the species into different species, although this is seen as controversial. Common names include topi, sassaby, tiang and tsessebe.
Grant's gazelle is a relatively large species of gazelle antelope, distributed from northern Tanzania to South Sudan and Ethiopia, and from the Kenyan coast to Lake Victoria. Its Swahili name is swala granti. It was named for a 19th-century British explorer, James Grant.
The Sonoran pronghorn is an endangered subspecies of pronghorn that is endemic to the Sonoran Desert.
Ramoceros is an extinct genus of the artiodactyl family Antilocapridae endemic to Middle Miocene (Clarendonian) North America.
There are at least 14 large mammal and 50 small mammal species known to occur in Glacier National Park.
Stockoceros is an extinct genus of the North American artiodactyl family Antilocapridae (pronghorns), known from what is now Mexico and the southwestern United States. The genus survived until about 12,000 years ago, and was present when Paleo-Indians reached North America.
Heuglin's gazelle, also known as the Eritrean gazelle, is a species of gazelle found east of the Nile River in Eritrea, Ethiopia and Sudan. It was considered a subspecies of the red-fronted gazelle or conspecific with Thomson's gazelle and Mongalla gazelle by some authors in the past. This small gazelle stands nearly 67 cm (26 in) at the shoulder and weighs between 15 and 35 kg. The coat is dark reddish brown with a dark reddish stripe on the flanks, except for the underparts and the rump which are white. Horns, present in both sexes, measure 15 to 35 cm in length.
Capromeryx was a genus of dwarf pronghorns (Antilocapridae) that originated in North America during the Pliocene about 5 million years ago. The closest living relative and only surviving member of the family is the North American pronghorn.
↑ Wood, William F. (2011). "2-Ethyl-3-methylpyrazine in the subauricular and median glands of pronghorn, Antilocapra americana". Biochemical Systematics and Ecology. 39 (2): 159–169. Bibcode:2011BioSE..39..159W. doi:10.1016/j.bse.2011.01.015.
↑ Wood, William F. (2002). "2-Pyrrolidinone, a putative alerting pheromone from rump glands of pronghorn, Antilocapra Americana". Biochemical Systematics and Ecology. 30 (4): 361–363. Bibcode:2002BioSE..30..361W. doi:10.1016/S0305-1978(01)00097-7.
↑ Frank Stephens (1906). California Mammals. San Diego, California: The West Coast Publishing Company. p.56. Retrieved 2011-01-30.
↑ J. Cancino; R. Rodríguez-Estrella; A. Ortega (1995). "First Aerial Survey of Historical Range for Peninsular Pronghorn of Baja California, Mexico". Journal of the Arizona-Nevada Academy of Science. 28 (1): 46–50. JSTOR40024301.
↑ Brunton BB: Kootenai. In: Handbook of North American Indians, Volume 12: Plateau. edn. Edited by Walker DE, Jr. Washington, DC: Smithsonian Institution; 1998: 223-228. ISBN0-16-049514-8
↑ Bruchac, Joseph (1992). Native American Animal Stories. Fulcrum Publishing. ISBN978-1555911270.
↑ Sheldon, Charles (1955). A History of the Boone and Crockett Club. Boone and Crockett Club.
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