Science

Surviving the chase

By Emma Ogao

From 0 to 100 km/h in just three seconds – cheetahs stand as the fastest land animals on the planet – an incontestable record held for 10 million consecutive years. With an acceleration speed faster than most sport cars, (yes, even Lamborghinis and Ferraris), these stunning, swift and speedy cats are built for speed. With a slender build, long tail, light muscles, flexible spine, powerful legs, semi-retractable claws and pivoting hips; the aerodynamics of a cheetah ensure minimal resistance and enable them to reach impeccable speeds. Speeds so fast that scientists suggest their legs might touch the ground only half of the time that it is in motion. They are one of the successful hunters of the animal kingdom, with a success rate averaging at 50%! But is it possible to out-maneuver the fastest animal on the planet?

Over the past decade, Alan Wilson from the Royal Veterinary College, University of London, has been studying the locomotion dynamics of animals. Using specially designed radio collars fit with an accelerometer to measure speed, a GPS to record location, a gyroscope to analyze angular motion, and a magnetometer for precision in location data – Wilson and his team have crafted the perfect device to gather motion data of big cats in the grasslands, collecting an extensive data set that had left scientists in awe.

Carried out in collaboration with the University of Botswana, these specially designed collars were deployed to five cheetahs in the Okavango Delta region and observed 367 of their hunting runs over six to nine months. The study had numerous surprising results – one of which being that prey such as impala or zebra have the best chance escape such reputable hunters if they twist and turn sharply at the last minute.

“In the final stages of a hunt, it isn’t about high speed”, says Alan Wilson. “The

Optimum tactics of the prey is to run relatively slowly and turn sharply at the last moment”.

Research indicates that cheetahs, although able to reach incredible velocity, cannot turn efficiently at top speeds, as the force could potentially knock it unconscious or cause injury. What this essentially means is that if you are prey, and happen to be chased down by a cheetah, your bet for survival lays in your ability to make sharp twists and turns.

The model showed that impalas and zebras have the best chance of making a getaway if they run at moderate speeds, because that leaves more options for maneuvering away at the last second. “If you’re running flat out, there’s not much you can do to stop [your prey] from anticipating exactly where you’re going to be in two strides’ time,” Dr. Wilson said. Running at a lower speed, therefore, means an animal can speed up or slow down, reducing predictability, and increasing the chances of making an escape as opposed to running at full steam.

Professor Rory Wilson, of the University of Swansea, although not involved in the study, states that “In some senses, you can see it in rugby” – “You have to remember that your ability to turn depends on your speed and your mass. So, the lower your speed, the quicker you can turn”

Further, although cheetahs are universally more athletic than their prey in terms of speed and acceleration, Zebras and Impalas have the upper hand as they can “define the chase”. They can dictate “when to turn, how fast to run. So, it’s always one stride ahead of the predator.” says Prof. A Wilson – another advantage that increases the chances of prey evading the sharp jaws of a cheetah.

Scientists say this reflects the evolutionary arms race between predator and prey. If cheetahs were too successful in hunting, they would destabilize the balance within the ecosystem. “Your prey has to be fast enough to escape some of the time, but not all of the time”.

The results of Wilson’s work are published in the journal Nature today, and research is now underway to utilize the collar to measure locomotive dynamics of Lions, and wild dogs.

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