“The fable of ‘The Tortoise and the Hare’ is a metaphor about life, not a story about a race,” said Adrian Bejan, a Duke University professor who led a recent study on animal speed. “We see in animal life two starkly different lifestyles—one with nearly steady feeding and daily sleep and another with short bursts of intermittent feeding interspersed with day-long siestas. Both of these patterns are the rhythms of living that Aesop taught.”
Bejan examined the reported speeds of animals based on air, water, and land data. The results reveal that some of the fastest animals in the world are actually the slowest in terms of average speed throughout their lifetime.
And apparently, this result is also reflected in the aviation industry, where the general pattern is that speed and size increase hand-in-hand.
The only exception is the jet fighter, which although faster than others in short bursts, spends most of its time on the ground. And across their lifetime, they are very slow compared to transport models.
The study was created following a previous paper that utilized Bejan’s constructal theory to show that animals’ speed tends to rise with body mass.
“When I would give speeches on this topic, somebody would always bring up outliers to this principle such as the cheetah as counterexamples,” Bejan said. “But this study shows that these ‘outliers’ are to be expected and, when looked at over their lifetimes, are not so different from their lumbering cousins after all.”
The findings were published in Scientific Reports.