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Pronghorn Antelope

Hi everyone, 

I just finished the online part of the Oregon Master Naturalist course and here’s what I learned about Pronghorn Antelope, real specialists in survival. If you’re driving around the west, you may see these fast and nimble antelope racing across the grasslands! -katie

Pronghorn antelope, Antilocarpa American, have survived since the Pleistocene and the species still displays some of the superpowers developed in that time when predators included the dire wolf (Canus dirus), short-faced bear (Arctodus simus), and North American lion (or American cave lion – Panthera leo atrox). Pronghorn antelope survived the extinctions at the end of the Pleistocene and the antelope’s adaptations—a physical structure with lightweight bones, a small digestive tract, and large lungs and heart—still help them escape predators. Easily outpacing coyotes and bobcats, the pronghorn can run up to nine miles at speeds as fast as 55 mph. Another adaptation of the pronghorn is vision that lets it see in an arc of nearly 300 degrees without moving its eyes or head and allows it to detect movement up to four miles away. The pronghorn’s advantages of speed and sight helped it survive prehistoric and modern predators—at one time 35 million pronghorn antelope roamed the North American steppes and plains. However, like the buffalo, the pronghorn was poorly adapted to outwitting hunters and the entire population was nearly annihilated by hunting (shooting) in the nineteenth century. By 1915 only 13,000 pronghorn antelope remained. Ranching, with fenced grazing lands and habitat competition with livestock, also took a toll on the pronghorn population.

The species got a second chance though with twentieth century conservation efforts and controls on hunting so by 1984 the population of pronghorn antelope had rebounded to one million. However, 1984 was the high point and since then the numbers of pronghorn from Canada to Mexico dropped to slightly less than 800,000.

In Oregon, you are most likely to see pronghorn antelope in the southern part of the Northern Basin and Range Ecoregion and in the Hart Mountain National Antelope Refuge (NAR) near Lakeview. This refuge, created in 1936 has no livestock grazing or fences and continues to be developed and groomed for habitat, recreation, and research. Pronghorn antelope fawns are most at risk of being predated by bobcats and coyotes.

In our times, pronghorn hunting is controlled (by seasons) and the antelope still face habitat conflicts due to ranching, especially fences (the pronghorn’s kryptonite) which block travel and migration routes. Unlike deer and moose, pronghorns do not jump so when faced with a fence their strategy is to try to go through it. Other threats to pronghorn antelope are habitat loss, competition with livestock, and (perhaps) hunting.

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Sources:

Photograph of antelope: US Dept. of Agriculture on commons.wikimedia.org.

American cave lion: http://www.beringia.com/research/lion.html

Hart Mountain National Antelope Refuge: http://www.fws.gov/refuges/profiles/index.cfm?id=14622

Oregon Conservation Strategy, Northern Basin and Range Ecoregion: http://www.dfw.state.or.us/conservationstrategy/docs/document_pdf/b-eco_nb.pdf

Pronghorn fawn mortality monitoring (Friends of Hart Mountain NAR): http://friendsofhartmountain.webs.com/bionotes.htm

San Diego Zoo Global Library, Pronghorn Fact Sheet: http://library.sandiegozoo.org/factsheets/pronghorn/pronghorn.htm