Secret to How Cheetahs Run 60 MPH While Keeping Their Heads Stock-Still Discovered

When a cheetah runs, there's plenty of motion. After all, the animal can crack speeds of 60 miles per hour when it's sprinting after prey, making it the fastest land animal in the world. But one thing doesn't really seem to move during the rush: the cheetah's head, which lets the big cat stay focused on its target. Now scientists have discovered that may be thanks to tiny structures in its ears.

Humans have these structures, called inner ears, too—we use them to keep our balance. But researchers comparing cheetahs with other cats discovered that the speediest of the lot also had the largest inner ears, even larger than those of extinct cheetahs. That's according to a new paper published in the journal Scientific Reports.

That balance lets a cheetah keep its head stock-still while chasing after prey. "If you watch a cheetah run in slow motion, you'll see incredible feats of movement: its legs, its back, its muscles all move with such coordinated power," lead author Camille Grohé, a biologist researching at the American Museum of Natural History in New York, said in a press release. "But its head hardly moves at all."

02_02_cheetah Cheetahs use finely honed structures in their inner ears to keep their balance. Mark Probst/Flickr

So Grohé and the rest of the team decided to look at what's going on inside the cheetah's head with its inner ear. To do so, they put the skulls of 14 different species of cat through a high resolution CT machine. The other species included a tiger, a clouded leopard, and a house cat, and the researchers used seven different modern cheetah skulls to cover differences between different populations. The CT scans let the scientists gather very detailed three dimensional measurements of each cat's inner ear structures.

In the cheetah skulls, they found really weird inner ear structures: they were particularly large compared to the cat's body size, and certain sections were longer than usual. All the other skulls they looked at had less refined inner ears, even the extinct cheetah species, which likely died out about 126,000 years ago.

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That means cheetahs don't just have a nifty talent, but also that it evolved fairly recently. The researchers suggest that the improved sensory system, in conjunction with other adaptations like thin bones, was enough to let cheetahs compete against other species of big cats.

Without their inner ears, perhaps cheetahs would still be able to run quickly—but they might not be able to hunt as effectively as they do today. And all that speed burns up a lot of fuel, so successfully catching dinner is a top priority.