Human activities leading to reduction and redistribution of food, rather than larger predators, could be the major cause for the alarming decline in the number of cheetahs, says an analysis of how cheetahs burn energy.
Wild cheetahs are down to under 10,000 from 100,000 a century ago with conventional wisdom blaming bigger predators for monopolising available food as their habitat becomes restricted.
"They can even withstand other species, such as lions and hyenas, stealing their prey," said lead researcher Michael Scantlebury from Queen's University Belfast in Britain.
"The reality may be that human activities - for example erecting fences that inhibit free travel or over-hunting cheetah prey - are forcing cheetahs to travel ever-increasing distances and that this may be compromising their energy more than any other single factor," said Scantlebury.
The traditional thinking has been that cheetahs no longer have sufficient access to prey to fuel their enormous energy output when engaging in superfast chases.
But the new study has found that in the main, cheetahs do not use significantly more energy than other, similar-sized mammals.
The scientists also discovered that, in searching for prey, cheetahs incur more energy loss than in outbursts of running which, although spectacular, are infrequent.
"What we found was that the cats' energy expenditure was not significantly different from other mammals of similar size - cheetahs may be Ferraris but most of the time they are driving slowly," Scantlebury added.
The researchers studied 19 free-roaming cheetahs each for two weeks across two sites in southern Africa, one in the Kalahari desert and the other in a wetter area.
They injected heavy water into the animals before tracking them continuously and collecting their faeces.
From these samples, they could determine how much of this heavy water they were losing each day and calculate their energy expenditures.
"What our study showed was that their major energy costs seem to be incurred by travelling, rather than securing prey," Scantlebury said.
The study appeared in the journal Science.
