Cheetah Don't Overheat During Hunts
Study finds that contrary to popular opinion, cheetah don't overheat during hunts. But their body temperature rises after successful hunts due to stress that another predator may seize their prey.
In a 4,500 hectare cheetah rehabilitation camp in the middle of Namibia, researchers observe the large, spotted carnivores as they readjust to wild life. This week one such researcher, physiologist Robyn Hetem from the University of the Witwatersrand Medical School, used her observations to disprove a theory about cheetah that has been treated as common knowledge for decades, that a cheetah’s running speed causes its body to overheat while hunting.
Less than 40 percent of cheetah hunts end successfully. Most of the time they stalk and chase but don't catch, even when the prey is within striking distance. Countless safari guides and animal fact websites state that cheetah give up the hunt because their bodies overheat. But we now know that isn't true.
After hunting, cheetah lie in the shade, Hetem said, panting, sometimes for more than an hour, and they seem completely exhausted. The overheating "fact" that many safari guides share is based on a 1973 study that showed cheetah stop running when their body temperature reached 40.5º C. The researchers assumed this was the reason cheetah stop chasing prey and lie down for a rest. But that study didn't simulate natural conditions, it placed cheetah on a treadmill to run for two kilometers at a medium speed, an unrealistic comparison to a real hunt.
"That study was amazing for its time," Hetem said. "But it didn't actually answer the question."
Hetem and her research team implanted two sensors, one for temperature and one to monitor activity, into six cheetah in the Namibian rehabilitation camp. Then, over the course of months, monitored the temperature readings during hunting activities.
It turns out cheetah don’t overheat while stalking and running after prey, in fact, they don’t heat up at all.
"We were definitely surprised," Hetem said. A cheetah's body temperature after the chase is the same as its mean daily body temperature, 38.4ºC.
Hetem’s study, published in Biology Letters, states "the supposed thermal limit to exercise of 40.5º C appeared irrelevant in these free-living cheetah."
If overheating doesn't explain the failed hunting attempts, what does? Hetem said it is speculation at this point, but one likely culprit is lactic acid build-up in muscles. Just like humans, when cheetah turn on the speed, the muscles tire quickly.
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Cheetah image via Shutterstock.