美国科学60秒 SSS 2013-06-13（在线收听）

 　　Cheetahs reign as the fastest land mammals capable of sprinting at speeds reaching about 65 miles an hour. But when hunting in the wild, the big cats rarely reach top speed. Instead they rely on rapid acceleration and agility to catch their prey. That's according to a study in the journal Nature. Most previous research examined cheetahs running in a straight line or in a controlled habitat. To find out how the big cats move in the wild, researchers put tracking collars on five wild cheetahs in Boxwana. Each collar used GPS and other technology to measure each cat's position, velocity and acceleration. The collars recorded and uploaded data from 367 hunting runs in a 17-month-period. On these runs, the cheetahs on average topped out at only about half their maximum speed. The slower pace allowed the cats to quickly decelerate and re-accelerate into fast, tight turns, the better to avoid getting faked out by prey. So next time your kitty chases a laser pointer, tell her that maneuverability, not speed, is the key to the kill.