How cheetahs evolved springy spines and ultra-sensitive inner ears to outcompete their competitors 04 December 2018

The cheetah’s incredible speed on land is well known, but the astounding story of the evolutionary miracle behind their speed will make you gasp.

The cheetah, found in the grassy savannahs of sub-Saharan Africa, is the fastest animal on land.

These big cats can reach astounding top speeds of some 65 mph and are able to do so because their entire physiology has been designed for speed over millions of years of evolution.

Unlike our domestic cats, a cheetah’s claws are non-retractable and, in tandem with tough pads on their feet, provide maximum traction.

Instead of a tail for balance, the cheetah’s tail is long and heavy, acting as a rudder which allows them to make sharp turns at high speed.

Their long fluid body is set over extremely light bones, and every part of their physiology, from their large nasal passages, oversized lungs and liver to their gigantic hearts, is geared towards rapid physical response.

A strong, spring-like spine gives added reach to the Cheetah’s long legs, enabling them to average four strides per second – nearly twice as many as a galloping horse.

All this speed engineering allows them to outpace the competition in the pursuit of food, but the cheetahs’ exceptional biology doesn’t stop with speed.

Cheetahs are also equipped with several additional special features that are crucial to successful and efficient hunting. They have binocular vision allowing them to spot prey up to five kilometres away, and their eye is also specially developed to allow a sharp, wide-angle view.

As they hunt during the day, the distinctive black “tear marks” leading from their eyes to snout reduce glare from the sun.

Once prey has been spotted and the moment is right, a cheetah will begin the chase. But the real difficulty is to maintain their exceptional vision while their entire body moves at exceptional speed. Amazingly cheetahs are able to do this thanks to their unique inner ear.

The cheetah’s inner ear – an organ essential to balance – is unique among all big cats.

As a cheetah runs its legs, back and muscles all move with coordinated power. But its head hardly moves at all.

In the inner ear of vertebrates, the balance system consists of three semi-circular canals that contain fluid and sensory hair cells that detect movement of the head. Each of the semi-circular canals 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.

The inner ears of cheetahs differ markedly from those of all other big cats, with a greater overall volume of the vestibular system and longer anterior and posterior semi-circular canals.

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 keep their gaze locked on their prey, even at incredibly high speeds.

Sadly, like almost all other wild species, this beautiful animal is threatened by loss of habitat and conflict with humans.

As human populations grow and expand, agriculture, roads, and settlements destroy the open grasslands.

As the cheetah’s prey disappears, many will take to attacking livestock, leading to direct conflict with farmers.

The number of cheetahs in the wild has consistently dropped from approximately 100,000 in 1900, to less than 10,000 today, becoming extinct in 18 countries in its original range.

December 4, 2018 is International Cheetah Day. Join the celebrations to see how you can raise awareness of this extraordinary animal and the risks they face.