Why do cheetahs tire so fast?

The story told on a lot of game drives is that a cheetah is a dragster: a few hundred metres, then it has to stop or it will cook. A 1973 treadmill study on captive cheetahs is where that idea got its laboratory gloss. Guides repeated it. It is not what the free-living animals did.

In 2013 Robyn Hetem and colleagues published a biologging study in Biology Letters. They recorded body temperature every minute and activity every five minutes in four free-living cheetahs hunting on their own. The cheetahs did abandon hunts. They did not abandon them because they had overheated. Body temperature averaged 38.4°C when the chase ended. At the end of the intense part of the hunt, temperatures stayed inside the ordinary daily range and did not reach the 40.5°C treadmill limit that had been treated as the reason they quit. One male came close to a 300 metre chase without a measurable temperature rise during the run.

Temperature did rise after the hunt, and it rose more after a successful one (about 1.3°C) than after a failed one (about 0.5°C), even when the activity during the hunts was similar. The authors' proposal is stress hyperthermia: the animal has a kill, and other predators may be on the way, and the heat shows up while it waits. That is a different sentence from “the engine overheated so the chase stopped.”

A cheetah hunt is still short. Prey jinks, the cheetah misses, or the cheetah connects and the sprint is over. Short is not the same claim as “stopped by heat at a fixed distance.” Four animals is a small sample. It is enough to retire the certain version of the overheating story, not enough to describe every cheetah in every season.

The speed on the cheetah entry is a different fact again. N. C. C. Sharp timed an adult at 29 metres per second over a measured course. That trial is why the cheetah leads the mammal list. It is not a measurement of how long the animal can keep the pace, and this explainer does not replace it.