Pronghorn
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 A Pronghorn near Fort Rock, Oregon
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| Antilocapra americana Ord, 1815 |
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A. a. americana |
The Pronghorn (Antilocapra americana) is the only surviving member of the family Antilocapridae, and the fastest mammal in North America running at speeds of 58 mph (90 km/h) and the second-fastest land animal, second only to the Cheetah[1]. The Pronghorn is also known as the Pronghorn antelope, but is not a true antelope. It is a unique animal with no close relatives. Both the males' and the females' horns are made up of a hairlike substance that grows around a bony core; the outer sheath is shed annually.
Pronghorns have a longer gestation period than is typical for North American ungulates. Bands of pronghorns live in open grasslands, gathering into larger herds in the winter. They breed in mid-September, and the doe carries her fawn until late May. This is around six weeks longer than the Pronghorn's slightly larger distant relative, the whitetail deer.
Pronghorns were brought to scientific notice by the Lewis and Clark Expedition, which found them in what is now South Dakota, USA. The Pronghorn's range extends from southern Saskatchewan and Alberta in Canada to Sonora and Baja California in Mexico. They live on both sides of the Rocky Mountains. The eastern limit of their range is generally the Missouri River in the United States. The subspecies known as the Sonoran Pronghorn (Antilocapra americana sonoriensis) occurs in Arizona and Mexico.
Pronghorns live primarily in grasslands but also in brushland and deserts. They eat cacti, grasses, and forbs, and browse plants.
Pronghorn newborns weigh 5 to 9 lb (2 to 4 kg). Adult male Pronghorns weigh 100 to 145 lb (45 to 60 kg) while females weigh 75 to 100 lb (35 to 45 kg). The main color of adults is brown or tan, with a white rump and belly and two white stripes on the throat. A short dark mane grows along the neck, and males also sport a black mask and black patches on the sides of the neck.
Male Pronghorns have horns about 5 to 17 in (125 to 430 mm) long with a prong. Females also grow horns, though these are relatively small, ranging from 1 to 6 in (25 to 150 mm), and sometimes barely visible; they are straight rather than pronged. Pronghorns have a distinct, musky odor. Males mark territory with a scent gland located on the sides of the head. Pronghorns are commonly called "Prairie Goats", "Speed Goats", or simply "goats" for this reason (as well as their resemblance to domesticated goats.)
The Pronghorn is built for maximum predator evasion through running; its speed is surpassed only by that of the cheetah. It can sustain high speeds longer than cheetahs, however. The top recorded speed was 61 mph (98 km/h). The Pronghorn, although built for speed with an oversized heart and lungs, is a very poor jumper. Their ranges are often affected by sheep ranchers' fences. However, they can be seen going under fences. 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. The Pronghorn also sports a very large set of eyes that are said to be the equivalent of 8X binoculars, and have a 320 degree field of vision.
By 1908, hunting pressure had reduced the Pronghorn population to about 20,000. Protection of habitat and hunting restrictions have allowed them to recover to 500,000 Pronghorns. Wolves, coyotes and bobcats are the major predators. Golden eagles have been reported to prey on fawns.
Pronghorns are now numerous enough that they exceed the human population in all of Wyoming and parts of northern Colorado. The Pronghorn is widely hunted in western states for purposes of population control and food, as its meat is rich and lean.
Three subspecies are considered endangered in all (A. a. sonoriensis, A. a. peninsularis) or part of their ranges (A. a. mexicana)
[edit] References
- ^ Klessius, Michael (2007), "Losing Ground", National Geographic 211(1): 22, ISSN 0027-9358
- Antelope Specialist Group (1996). Antilocapra americana. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006.
- Antilocapra americana (TSN 180717). Integrated Taxonomic Information System. Accessed on 23 March 2006.
