South Californian Mite is the Fastest Land Animal

The cheetah doesn’t get a look in, and the previous record holder, the Australian tiger beetle, has been knocked off top spot as the world’s fastest animal by a mite no bigger than a sesame seed.

The mite, Paratarsotomus macropalpisis, was recently recorded running at up to 322 body lengths per second; the beetle only attains 171 body lengths. Researchers use body lengths per second to measure how fast an organism moves relative to its body length. The current record-holder for running speed is the Australian tiger beetle.

By comparison, a cheetah running at 60 miles per hour reaches a mere 16 body lengths per second. If this measure is extrapolated to the size of a human, the mite’s speed is equivalent to a person running at roughly 1,300 miles per hour.

The mite is native to South California. It was discovered in 1916, but little is known about its habitat or food habits.

According to Samuel Rubin, who documented the mite’s running abilities, the research advances understanding of animal movement.

“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,” Samuel Rubin, a junior and physics major at Pitzer College, said in a news release. “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.”

The study team accidentally discovered the mite. They were actually studying the muscle biochemistry of animal legs.

Animals tend to get faster as they get smaller. In theory, muscle physiology would limit the speed of a leg, researchers said.

“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 Jonathan Wright, Ph.D., a professor of biology at Pomona College. “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.”

The study team captured the mite’s running spree on high-speed video camera. What was even more surprising was that the mite could run on concrete in temperatures  up to 140 degrees Fahrenheit (60 degrees Celsius), a temperature that could kill most organisms.

Researchers found that the mites were good at stopping and changing directions. Researchers hope that their research can help advance designs of bio-inspired machines.

The study findings were presented at Experimental Biology 2014 meeting on Sunday, April 27, 2014.

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