In 1973, two Harvard scientists bought a couple of hand-reared cheetahs from an African farmer, flew the animals over to their laboratory, made them run on treadmills, and stuck thermometers up their bums. Based on the readings, they concluded that cheetahs can’t lose heat quickly enough while running. Once their body temperature hits 40.5 degrees Celsius, they’re forced to stop.

It was a groundbreaking experiment, but an incredibly artificial one. The cheetahs had lived in captivity for their entire lives, and they were running in a lab rather than a savannah. They ran at 30 kilometres per hour for 2 kilometres whereas, in the wild, they sprint for just a few hundred metres but at speeds of up to 100 km