Dr Robyn Hetem and her colleagues from the Brain Function Research Group at the University of the Witwatersrand (Wits) found that cheetah body temperature did not increase during the sprint while hunting. Their findings have been published on 24 July in the journal Biology Letters.
For superb athletes, cheetah are surprisingly poor hunters with up to 60% of hunts ending in failure. In a race over 100m, a cheetah would beat Usain Bolt by 60 meters, and easily could outsprint any antelope. But they often give up the sprint when within easy reach of their prey.
Nearly forty years ago, Harvard researchers suggested that cheetah abandon hunts because they overheat. They ran cheetah on a treadmill and found that cheetah stopped running when their body temperature reached 40.5°C. Extending their finding to real hunts, the researchers concluded that cheetah could only sprint so far before getting too hot to move. The problem was that the speed that the treadmill could reach was nowhere near that of a real hunt. Nevertheless, since then people thought that the incredible speed cheetah can develop comes at a price, an overheated 'engine' that makes them abandon the hunt. This appears now to be a myth.
So what happens in a real hunt? Answering that question had to wait until researchers could measure body temperature of hunting cheetahs. Researchers from the Brain Function Research Group at Wits, working with Professor Shane Maloney of the University of Western Australia, developed the technology needed.
“But that wasn’t enough,” said Professor Andrea Fuller, the Group’s Director. “We needed conservators who were committed to advancing cheetah research.” The Group found those conservators at the AfriCat Foundation, based at the Okonjima Nature Reserve in Namibia.
Veterinarians equipped six cheetah with body temperature and activity sensors. The researchers observed a number of hunts and their data revealed that, contrary to initial expectations, cheetah body temperature did not increase during the sprint.
Mysteriously though, cheetah temperatures did rise after the sprint was finished, more so if the hunt had been successful despite the cheetah sprinting just as hard when they got the prey as when they didn’t. What were the cheetah doing then? Typically the cheetah were resting next to their prey. Because the body temperature rise started before the first mouthful, eating could not have caused the mysterious late rise in body temperature.
This video shows the grace and force of a cheetah running at full speed. Watch the length of the cheetah’s stride (up to 8 metre).
The researchers propose that the stress of guarding the prey from more dominant carnivores, such as leopards, may account for the increase in body temperature following successful hunts. Research veterinarian, Dr Leith Meyer, confirmed that he has seen similar increases in antelope body temperature when they are stressed.
So cheetah do abandon hunts but not because they overheat, and a theory that had been in natural-history books for nearly forty years is a myth.
(Source: Wits University media release, 30.07.2013)