For every animal, survival comes down to a simple equation. The calories coming in have to exceed those going out, with enough energy left over for reproduction, escaping predators, and the acquisition of yet more calories.
As the world’s fastest land animal, you might think the cheetah spends most of its energy budget on acceleration. After all, this cat can go from 0 to 60 mph in just three seconds. That’s faster than you can power down your iPhone.
But new research paints a more laid-back picture of the cheetah's lifestyle. In fact, nearly half of its daily energy expenditure goes toward just loping around looking for something to chase. And all that walking may be wearing down the cat’s ability to survive.
In a study published in Science last month, a team of researchers found that despite being speed freaks, cheetahs don’t burn any more calories than other wild animals of similar size.
“On average, they spent 2.86 hours per day looking for prey, and this was responsible for 42 percent of the energy used that day,” says lead author Michael Scantlebury, a biologist at Queen’s University Belfast.
Scantlebury and his team injected 19 cheetahs with “heavy water,” which contains isotopes that allow scientists to calculate an animal’s metabolic rates by measuring how fast the isotopes “wash out.” (Note: “Wash out” is a delicate term for what you do after drinking a pot of coffee.)
The energy a cheetah spends looking for prey is only worthwhile if it can kill and eat its meals efficiently. A big factor in that efficiency, and the one Scantlebury set out to study, is kleptoparasitism, or the stealing of one’s lunch by other predators. Scantlebury’s cats caught prey on 52 percent of the days over the course of two weeks. That success rate isn’t too shabby, but cheetahs lose about one out of every four kills to thieving hyenas and the like.
And meals aren’t the only thing being taken from cheetahs. According to estimates by the African Wildlife Foundation, cheetah habitat has shrunk a whopping 76 percent thanks to agriculture and other development.
“If their movements are restricted because humans erect a fence or start making a road, then their energy costs will increase,” said Scantlebury. “If their energy costs increase, then they will have to hunt for even more prey to balance energy needs.”
Cheetahs once roamed across an enormous range, from South Africa up to Morocco, and across the Middle East on into India and Bangladesh. (Fun fact: Ancient cheetahs even roamed North America.) Today, Africa’s most endangered cat exists in just a handful of fragmented pockets on the continent and number fewer than 10,000.
Unlike elephants, rhinos, and other imperiled species, establishing game reserves and national parks doesn’t do cheetahs much good. While such places give the cats room to stretch their legs and help protect them from poaching, they also put them into close proximity to dense populations of their predators: lions, leopards, and hyenas. Cheetah cubs can’t run as fast as their parents, and according to the Cheetah Conservation Fund, cub mortality can be as high as 90 percent in these “protected” areas.
Outside of preserves—where about 90 percent of cheetahs live—the cats must flee another threat: angry farmers. Scared for their livestock, Namibia's farmers cut the country’s cheetah population in half during the 1980s, then halved it again in the '90s until only 2,500 remained. This is especially unfortunate, because according to the Cheetah Conservation Fund, cheetahs aren’t usually responsible for livestock deaths; they're just popular scapegoats since they are often spotted hunting during the day (while other predators prefer the night) or near the scene of the crime. Guilty or not, the CCF helps mitigate livestock losses by breeding guard dogs and distributing them to farmers across Namibia. The dogs protect both the livestock and wildlife by keeping the cheetahs (and hyenas, leopards, and jackals) away and the farmers’ guns holstered. Thanks to the program, livestock survival rates are up to 80 percent.
The cheetah has been able to withstand a lot—losing a quarter of its meals to bigger predators, living without water in the Kalahari, the rise of humans, and a genetic bottleneck that occurred when its populations took a sharp dive during the last Ice Age.
But Scantlebury’s research shows that every setback takes a quantifiable toll on this cat. A mean hyena? Calories. Another road? Calories. A new copper mine? Lots and lots of calories.
We’re used to thinking of extinction in terms of slaughters and plagues. But it can also be a war of attrition.
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