Here’s a trivia question for you: relative to its size, what is the fastest creature on the planet? You might have jumped straight to the old chestnut, “the cheetahâ€. Yes, the cheetah is quite rapid; it gets up to a speed of 16 body lengths per second while the fastest of humans can only manage about five body lengths per second. Still, the cheetah is just dawdling compared to the tiger beetle, which travels at 120 body lengths per second. If a human being travelled at that pace they would be travelling at more than 770 kilometres per hour. The tiger beetle is not actually the fastest creature on the planet…but we’ll come to that later. The tiger beetle however was the subject of a recent study that looked at how it copes with such extreme speeds.
Whereas Tom Cruise felt the “need for speed†for reasons best known to himself and the scriptwriter of the movie Top Gun, tiger beetles have a very tangible need for their amazing pace. The tiger beetle is a predator and speed is useful for a predator when it comes to catching up with dinner. However, while the tiger beetle’s body can carry it at such a pace, not all of its senses can keep up. At the equivalent of a human, 770kph vision becomes a problem, so researchers wanted to know how a tiger beetle can see the prey that it is running so fast to catch.
To test this, they used a dummy piece of prey on a string and recorded the tiger beetle’s high speed attacks in super slow motion. They found that as the beetle begins to catch up to the prey the contracting image of the prey as perceived by the beetle begins to expand under the influence of speed. Even though the beetle is not really “seeing†the prey this change is a cue for the beetle to open its jaws, then as the image receded the jaws close. So while the beetle is not genuinely “seeing†what is happening at that speed, it has learned “rules†that transcend its senses.
Life is like that; we understand what is happening at a deeper level than our senses can convey because we learn the rhymes and rhythms that underlie the world around us.
Oh, and the fastest creature? That title goes to a tiny mite called Paratarsotomus macropalpis which travels at 322 body lengths per second, equivalent to a human travelling at more than 2000 kph. A mite-y effort really.
