Cheetahs’ Secret Weapon: A Tight Turning Radius
By Katie Hiler, NY Times, June 12, 2013
Anyone who has watched a cheetah run down an antelope knows that these cats are impressively fast. But it turns out that speed is not the secret to their prodigious hunting skills: a novel study of how cheetahs chase prey in the wild shows that it is their agility—their skill at leaping sideways, changing directions abruptly and slowing down quickly—that gives those antelope such bad odds.
"Cheetahs don’t actually go very fast when they’re hunting," said Alan M. Wilson, a professor at the Royal Veterinary College at the University of London who studied cheetahs in Botswana and published a paper about them on Wednesday in the journal Nature. "The hunt is much more about maneuvering, about acceleration, about ducking and diving to capture the prey."
Until now researchers had been able to gather data on the hunting habits of cheetahs only by studying the animals in captivity, or from direct—though relatively imprecise—observations of their movements in the wild. But Dr. Wilson and his team spent nearly 10 years designing and building a battery-powered, solar-charged tracking collar, one that uses an accelerometer, a gyroscope and GPS technology to monitor the animal’s movements.
They attached these collars to five cheetahs in the Okavango Delta region and observed 367 of their hunting runs over six to nine months. The cheetahs ran as fast as 58 miles an hour, and their average speed was 33 m.p.h. High-speed runs accounted for only a small portion of the total distance covered by the cheetahs each day, the researchers found.
They also found that a cheetah can slow down by as much as 9 m.p.h. in a single stride—a feat that proves more helpful in hunting than the ability to break highway speed records. A cheetah often decelerates before turning, the data showed, and this enables it to make the tight turns that give it an advantage over its fast and nimble prey.
"Its muscles are very powerful," Dr. Wilson said. "They’re arranged in a way that gives it the ability to accelerate very quickly."
Along with those leg muscles, cheetahs have a flexible spine and big claws that give them a great deal of grip—“more grip than even a motorbike,” as Dr. Wilson put it. This anatomy helps the cats get their feet in the right positions to turn and maneuver.
"If you’ve ever done snow skiing or skateboarding really fast, you realize that stability and maneuverability at high speeds are a real problem," said John Bertram, a professor of medicine at the University of Calgary in Alberta, who was not involved in the study. Cheetahs have adapted to handle these challenges of physics in a way "we hadn’t expected," he said.
Dr. Wilson’s paper may have also put to rest the question of how fast cheetahs can actually run. In the 1960s, researchers in Africa recorded cheetahs running as fast as 65 m.p.h., but since then a number of scientists, including Dr. Wilson, have been able to clock them at speeds of only 30 to 40 m.p.h. This made some researchers “a little bit suspicious,” Dr. Bertram said. He added that Dr. Wilson’s latest data seems to confirm that cheetahs do reach speeds approaching 60 m.p.h. “on a fairly regular basis,” making them the fastest land mammals.
What is more, the cheetah’s ability to maneuver at high speeds far surpasses that of the greyhound and the horse, its closest competitors in that category, Dr. Wilson said. “The cheetah is way out there ahead of those animals,” he added. “It’s really the all-around athlete, the all-around pursuit predator.”