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)