Cheetah Hunting Springbok 2014 10 02
Reaching speeds of up to 60 mph, cheetahs are widely recognised as the speediest animals on the savannah. Image: Gus Mills.

In the animal Olympics, cheetahs are the gold medal sprinters – unrivalled on land. Achieving speeds of over 60mph (96.5 km/h), they also have acceleration abilities that would leave Usain Bolt in their dust. So it's been thought for some time that these speedy cats may be living on the edge when it comes to balancing their energy budgets: finding enough food to not only survive but thrive in an environment where other carnivores sometimes steal their food or drive them out of the best places to find it.

For a long time, the combined effect of this speedy lifestyle in a harsh environment and restricted access to prey was blamed for the alarming decline of wild cheetah populations, from 100,000 a century ago to an estimated 7,000-10,000 today.

In 1998, a study found incredibly high energy expenditure in African wild dogs because of their hard work of running to catch prey. The research suggested that wild dogs were vulnerable because of prey-stealing by larger carnivores (it’s a behaviour scientists call 'kleptoparasitism'). Based on that study, it was assumed that cheetahs may be similarly challenged.

But now, new research questions the idea that food stealing is a major problem for the energy budgets of cheetahs.

Queen’s University Belfast physiologist Dr David Scantlebury, lead author of the new study, along with researchers from South Africa, UK, USA and China, explored the physiology of these charismatic animals. The cats are fascinating not only for their speed – they're also active during the day and can go for several days without food, despite living in extreme landscapes like the Kalahari, which lack drinking water.

Four Large Cheetah Cubs Resting On A Dune 2014 10 02
Despite living in extreme habitats like the Kalahari Desert, cheetahs can go several days without food. Image: Gus Mills.

"People have said that cheetahs are vulnerable. They play second fiddle to lions and hyenas and leopards because they are so much smaller, and because they are quite weak – built for speed and not for grappling or bringing down prey by just fighting with it," says Scantlebury. 

"In a fight, a cheetah would always come off worse than a lion or hyena or a leopard,” he adds. As a scientist specialising in understanding how animals gain and expend energy, exploring the calorie-burning characteristics of this extreme animal athlete intrigued him.

Lion Chasing Cheetah 2014 10 02
Cheetahs must often compete with bigger cats like lions for food.Image: Gus Mills.

To measure cheetah daily energy expenditure, the team combined observations of 14 cheetahs tracked in Kgalagadi Transfrontier Park in the dry Kalahari with observations of five cheetahs from the wetter Karongwe Game Reserve near Kruger National Park over a period of ten years.

Scientists darted the animals to inject them with a small dose of what's known as doubly labeled water (a major tool for measuring energy expenditure). They then followed these radio-collared animals for two weeks and collected faecal samples. They also observed how often other carnivores snatched cheetah prey.

Cheetah Walking 2014 10 02
New research shows that most of a cheetah's calories are expended during their daily travels rather than during high-paced sprints. Image: Gus Mills.

Surprisingly, the team found that energy expenditure in these 'Ferraris of the cat world' was not much different from other similarly sized mammals. Most of their calories were used up during their daily travels rather than in hot pursuit of prey. “You may have this fast car, but you would go quite slowly and carefully with it most of the time, so it’s not actually costing you that much [energetically] to have this tremendous engine,” explains Scantlebury.

Cheetahs in the Kalahari cover around 10km per day (though one female in heat covered over 30km in a single day). From their measurements, the team calculated that cheetahs would have trouble coping with food theft from other carnivores if it reaches levels above 50%. That’s a far cry from the rates of food stealing so far observed: 14% in Kruger National Park, 11% in the Serengeti and 9.3% in the current study.

The new study suggests that it's not food stealing by competitors, but rather the energy costs of moving around (made worse by a landscape that's increasingly dominated and altered by humans) that seems to be threatening cheetah survival. “The effect of humans on wildlife is more serious than we ever thought it was,” warns Scantlebury.

That makes studies like these, which help us better understand animal 'engines' in order to inform conservation efforts, increasingly important.