Cheetahs to Blame Humans for their Dwindling Numbers
Most people blame competition from large predators for the drop in cheetah populations, but a new study shows that the big cats should actually be pointing the finger at humans.
By studying how cheetahs burn energy, researchers from Queen's University, Belfast have shown that human activity is the main reason wild cheetahs are down to under 10,000 from 100,000 a century ago.
It has long been assumed that as cheetahs lose more and more of their grassland habitat - mostly in eastern and southwestern Africa - competition for food with predators like lions and hyenas is becoming too exhausting for them. Sprinting for food at 60 mph, it's no surprise that their energy reserves are being tapped out.
But described in the journal Science, Queen's scientists have discovered that, for the most part, cheetahs do not use significantly more energy than other, similar-sized mammals. In fact, they actually use up more energy just searching for prey than in trying to catch it.
"Cheetahs may be Ferraris but most of the time they are driving slowly. What our study showed was that their major energy costs seem to be incurred by travelling, rather than securing prey," lead author Dr. Michael Scantlebury said in a statement.
Scantlebury and his colleagues studied 19 wild cheetahs for two weeks in southern Africa. In order to determine just how much energy they were expending each day, they injected heavy water into the animals before tracking them and collecting their feces. From these samples, they could determine how much of this heavy water the cheetahs were losing each day and calculate their energy output.
They can handle the daily struggle of competition with other species, but as humans encroach on their territory, via fences or over-hunting of cheetah prey, they are forced to travel farther distances to find food.
"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," Scantlebury explained.
"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," added co-author Dr. John Wilson of North Carolina State University.