It’s long been believed that Africa’s cheetah, the sleek, lithe cat seemingly tailor made for speed, was the fastest land animal on Earth. Technically, that’s still true – cheetahs can reach speeds in excess of 60 miles per hour, a top speed untouched in the animal kingdom. Look at speed from a different perspective (body lengths per second, for instance), though, and the cheetah loses hands-down to the humble mite, according to Samuel Rubin, a junior and physics major at Pitzer College.
At 60 miles per hour, the cheetah manages an impressive 116 body lengths per second. That pace is downright glacial when compared to the mite, though, which was observed covering 322 body lengths per second. To put that in perspective, to achieve the same rate of travel a human would need to run about 1300 miles per hour.
“It’s so cool to discover something that’s faster than anything else, and just to imagine, as a human, going that fast compared to your body length is really amazing,” said Rubin. “But beyond that, looking deeper into the physics of how they accomplish these speeds could help inspire revolutionary new designs for things like robots or biomimetic devices.”
According to Jonathan Wright, Ph.D., a professor of biology at Pomona College, stride frequency and speed relative to body size increase as animals get smaller, though there’s thought to be a physiological upper limit to how fast a limb can possibly move. The mite discovery has scientists rethinking that notion.
“We were looking at the overarching question of whether there is an upper limit to the relative speed or stride frequency that can be achieved,” said Wright. “When the values for mites are compared with data from other animals, they indicate that, if there is an upper limit, we haven’t found it yet.”
In filming the mites with high speed cameras, they noticed other peculiarities. For instance, mites are unusually adept at navigating surfaces well outside the lethal limit for most animals, observed traversing concrete measuring 140 degrees Fahrenheit.