"Pound for pound a cheetah's acceleration power is about four times that of Usain Bolt during his world-record 100 meters," says Alan Wilson, professor of locomotor biomechanics at London's Royal Veterinary College, who led the study. "And what's more, a cheetah can still accelerate like that even when it is already doing 40 mph, then decelerate nearly as swiftly, turn hard, and sprint in another direction."

Surprisingly, the cheetahs in the study group seldom hit their top gear. The fastest speed the group recorded was 58 mph (93 kph)—well short of the anecdotal 70 mph (112.7 kph) often claimed for cheetahs in the wild. "I suspect that in more open areas like the Serengeti they may go a bit faster," says