Humans and Not Hyenas May be Causing Cheetah Numbers to Plummet

Cheetahs are the fastest land animals on the planet, accelerating to as fast as 60 mph. Yet these large cats are in danger of disappearing, and now scientists have announced that humans could be partially to blame.

Wild cheetahs are down to under 10,000 individuals from 100,000 a century ago. In the past, many have blamed bigger predators for monopolizing available food as their habitat becomes restricted. Essentially, the idea is that cheetahs no longer have sufficient access to prey to fuel their enormous energy output when engaging in speedy chases. Yet this may not be the case.

"We 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," said Michael Scantlebury, one of the researchers, in a news release. "We injected heavy water into the animals before tracking them continuously and collecting their faeces. From these samples, we could determine how much of this heavy water they were losing each day and calculate their energy expenditures."

In the end, the researchers found that cheetahs' energy expenditure isn't significantly different from other mammals of similar size. This shows that their energy costs are mostly due to travelling rather than securing prey.

"They can even withstand other species, such as lions and hyenas, stealing their prey," said Scantlebury. "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. Our study, which is the result of ten years' worth of research, seriously questions previously held assumptions about the factors affecting populations' viability in large predators threatened by extinction."

The findings reveal that steps should be taken in order to ensure the survival of these fast, large cats. Because humans may be to blame, it's important to make sure that we institute policies that can improve current practices.

"Too often we blame lions and hyenas for decimating cheetah populations when in fact, it is likely to be us humans that drive their declines," said John Wilson, co-author of the new study. "Imagine how hard it must be for a small cub to follow its mother further and further through the desert ot look for food, while she herself is fighting for survival."

The findings are published in the journal Science.