Cheetah populations decline worldwide linked to human activity, study findsFlickr via Creative Commons/Ma

Humans are to blame for the decline of cheetah populations worldwide, a new study has warned.

There are now less than 10,000 cheetahs in the world, according to the Science journal.

The decline is not due to the presence of other predators, as previously thought, but to the fact that human activity leads the felines to walk for a very long time when they look for food.

Academics from Queen's School of Biological Sciences and conservation institutions discovered that while searching for prey, cheetahs incur more energy loss than in outbursts of running, which do not happen very frequently.

Researchers studied 19 free-roaming cheetahs for two weeks across two sites in southern Africa.

"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," lead researcher Dr Michael Scantlebury from Queen's School said.

Results led to the conclusion that where cheetahs' prey have been reduced or re-distributed through human impacts, the felines' ability to balance energy budgets has been severely curtailed.

"What our study showed was that their major energy costs seem to be incurred by travelling.

"If you can imagine walking up and down sand dunes in high temperatures day in, day out, with no water to drink you start to get a feel for how challenging these cats' daily lives are, and yet they remain remarkably adapted and resilient."

Co-author Dr John Wilson of North Carolina State University said: "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. Imagine how hard it must be for a small cub to follow its mother further and further through the desert to look for food, while she herself is fighting for survival."

According to another study by the Convention on International Trade in Endangered Species (CITES), the increasing trend to smuggle wild cheetahs from the Horn of Africa to the Middle East and sell them as exotic pets is also causing a dramatic decline of the felines.