The second fastest land mammal is the pronghorn (Antilocapra americana), a delicate artiodactyl which ranges across the western wilderness of North America from Canada to the Baja deserts. Although they look similar to antelopes, pronghorns are actually the last surviving species of the family Antilocapridae. They can run at speeds of up to 60 miles per hour and (unlike impalas or cheetahs) they can run at full throttle for a fair distance.
Pronghorns are named for their forked horns—which are not antlers but true horns made of bone with a layer of keratin. They shed the hollow outer sheaths each year in late autumn and grow a new pair over the winter. Adult pronghorns stand 90 cm (three feet) high at the shoulders and weigh up to 50 kg (110 pounds). Although pronghorns can run swiftly, they are poor jumpers. Herds of pronghorns make great migratory treks across the country and face pressure from human developments and from fences (which they can’t jump over but must run under). If you are a rancher in pronghorn country you might consider putting a non-barbed strand of wire as the bottom wire on your fence.
Pronghorns once had many close relatives. The Antilocapridae family is most closely related to giraffes but the different family members filled many of the same niches that bovids do in the old world. These animals came in an array of shapes and were widespread across North America. There were once 22 varieties of antilocapridae (which you can explore here) but they died out ten to fourteen thousand years ago when the Clovis hunters arrived and slaughtered North America’s megafauna.
Sick or injured pronghorns are sometimes preyed upon by wolves, coyotes, or cougars, but when they are healthy, adult pronghorns can easily outrun all contemporary North American predators. Their blazing speed is not an evolutionary extravagance: pronghorns once needed their swiftness to escape Miracinonyx trumani, the American cheetah which could probably run nearly as quickly as the living African cheetahs. Like the avocado the pronghorn was molded to fit an ecosystem which has died out: today they are literally running from ghosts.
5 comments
Comments feed for this article
August 4, 2011 at 2:20 PM
ms.yin
Pronghorn is a disappointingly uncreative name, much like unicorn and tricorn and cheese corn.
August 4, 2011 at 2:44 PM
Hieronymo
I fully agree. They should have called it a zipbeast or a zoomhoof or something which better reflects its blazing speed… or perhaps they should have hired an Australian consultant to come up with a complete neologism like wongryfellow or hongabollerypanky. Unfortunately I suspect “they” were probably morphine swilling fur-traders or seal trappers or some other species of nineteenth century oddball, and creative concerns meant little to “them”.
August 9, 2011 at 1:19 PM
Diana
You just blew my mind — there were cheetahs in AMERICA?? Granted, thousands and thousands of years ago, but still.
August 9, 2011 at 10:18 PM
Hieronymo
Well it turns out that Miracinonyx wasn’t a true cheetah but was really a relative of mountain lions–convergent evolution made the two creatures look so similar that only DNA analysis revealed the true relationships.
August 11, 2011 at 11:22 PM
Diana
Oh ok. Well, still cool.