By keeping a level head, the cheetah wins the big cat race
The hidden secret behind cheetahs' deadly effectiveness
The world’s fastest land animal, the cheetah, has an in-built but invisible advantage as a hunter, scientists have discovered.
The lithe feline’s ability to keep its head still while pursuing prey at up to 112km/h is down to its unique inner ear, say researchers at the American Museum of Natural History.“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 co-ordinated power. But its head hardly moves at all,” said palaeontologist Camille Grohé, lead author of a study published in the journal Scientific Reports.
“The inner ear facilitates the cheetah’s remarkable ability to maintain visual and postural stability while running and capturing prey. Until now, no one has investigated the inner ear’s role in this incredible hunting specialisation.”Vertebrates’ balance system consists of three semicircular canals in the inner ear that contain fluid and sensory hair cells which detect movement of the head. Each canal is positioned at a different angle and is especially sensitive to different movements: up and down, side to side, and tilting from one side to the other.Grohé’s team used high-resolution X-ray computed tomography (CT) to scan the skulls of 21 felines, including seven modern cheetahs, a closely related extinct cheetah that lived between 2.6-million and 126,000 years ago, and more than a dozen other living species. Then they created detailed 3-D virtual images of each species’ inner ear shape and dimensions.Said co-author John Flynn: “This distinctive inner ear anatomy reflects enhanced sensitivity and more rapid responses to head motions, explaining the cheetah’s extraordinary ability to maintain visual stability and to keep their gaze locked in on prey even during incredibly high-speed hunting.”Grohé said the findings proved that the cheetah evolved relatively recently to become a high-speed hunter, probably to give it a competitive advantage over other predators.
“The living cheetah’s ancestors have evolved slender bones that would allow them to run very fast and then an inner ear ultra-sensitive to head movements to hold their head still, enabling them to run even faster,” he said.They found that the inner ears of living cheetahs differ markedly from all the others, with longer anterior and posterior semicircular canals.