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Has anyone actually clocked one of these ? We were driving at a steady 55 when one joined us and paced us for quite a while then put the pedal to the metal and left us in the dust ! He must have reached 75 . I see all kinds of figures but has anyone actually clocked one ?
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One of the most reliable figures available can be found in
Mammals of North America (Kays, Roland W., and Wilson, Don E. Princeton University Press. 2002.).
A combined summary of the data from that book;
American Pronghorn: Social Adaptations & the Ghosts of Predators Past (Byers, John A. University of Chicago Press. 1997.); and "Pronghorn: Survivors of the American Savanna" (
Zoogoer. December 2001.):
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Sustained speeds of up to 45 miles per hour (72 kilometers per hour) have been clocked on captive animals running up to 22 continuous miles, but wild Pronghorn have been clocked at speeds up to 61 mph (98 kph) for short sprints to outrun predatory threats. (Kays) Several scientists have suggested that the Pronghorn Antelope evolved to attain such incredible speeds due to predatory threats from now-extinct North American predators such as the North American Cheetah, Giant Short-faced Bear (faster than the name suggests), Dire Wolf, and American Lion, since no current predator presents enough of a threat to warrant the need for such speed. (Hawes, Byers)
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(emphasis mine)
It has been difficult for scientists to obtain good data for sustained speeds of wild herds, due to the logistics involved and the fact that doing something like chasing them with a helicopter will skew the data and cause undue stress.