Wildlife

Speedy Mite Is World’s Fastest Land Animal (Relative to Size)

Turns out the mite is mightier than we thought: A tiny arachnid that lives in southern California is the world’s fastest land animal relative to size, according to a new study.

At its quickest, the sesame seed-size Paratarsotomus macropalpis zips along at about 322 body lengths per second (a measure of speed that shows how quickly an animal moves relative to its size). For a human, that’d be like running 1,300 miles (2,000 kilometers) an hour.

Paratarsotomus macropalpis is small but speedy. Photograph by Samuel Rubin (W. M. Keck Science Center, Pitzer College), Dr. J. C. Wright Laboratory (Department of Biology, Pomona College), The Claremont University Consortium

The previous record-holder, the Australian tiger beetle, travels at 171 body lengths per second. By comparison, the cheetah—the fastest land animal overall—can move at only about 16 body lengths per second. (Related: “Cheetah Breaks Speed Record—Beats Usain Bolt by Seconds.”) The fastest known human, Usain Bolt, covers a little more than 6 body lengths per second.

Scientists at Pomona College, Pitzer College, and Harvey Mudd College witnessed the new record while observing P. macropalpis with high-speed cameras outside in Claremont, California, where the mite can be seen scuttling along sidewalks in the heat of the day.

A southern California native, the tiny creaturewhose legs are invisible to the naked eye—had mostly been ignored by scientists since it was identified in 1916.

“First I thought, ‘Wow, that can’t be true’—[its body lengths per second] seemed ridiculously high,” said researcher Samuel Rubin, an undergraduate in physics at Pitzer who presented the new research April 28 at the 2014 Experimental Biology meeting in San Diego. “I better redo the measurements.”

But repeated experiments showed the same result: He had found one speedy mite.

Some Like It Hot

The team filmed the mites running on concrete up to 140 degrees Fahrenheit (60 degrees Celsius)—a temperature scorching enough to kill most animals. (See “Urban Heat May Warm Faraway Places.”)

A closer look at the mites’ bodies revealed a well-sealed outer layer that acts like a barrier against extreme heat. The mite’s desert home is full of stone slabs and baked clay surfaces that would be as hot as a city sidewalk, said Rubin, who’s in the process of submitting his research paper to the Journal of Experimental Biology.

That outer layer, and the fact that the mite doesn’t take refuge in the shadows, suggests that it didn’t evolve its speediness to escape the heat. Rather, the team suspects the mite moves fast to hunt its prey, which are so small and fast that scientists haven’t seen them yet, even with high-speed cameras.

“We never observed them being fed on or feeding because it’s so infrequent, and they’re so fast,” said Rubin, who observed the mites for an entire summer and didn’t witness a single act of hunting. “It’s hard enough to get any footage on them.” The camera’s field of view is less than four inches (ten centimeters), and these mites will move that distance in less than a second.

Small and Speedy

Rubin said the team’s findings also reinforce a scientific theory called scaling, which says that relative speed increases as an animal’s body mass gets smaller. The theory holds that the smaller an animal gets, the less force it needs to move fast. And less force means not much need for muscle.

The space where a big muscle would go can instead be populated by other things, such as molecules like mitochondria—cellular powerhouses that can make an animal’s strides even faster. The mite’s stride frequency is 135 Hertz (Hz), a measurement of how many strides occur a second. By comparison, an average human runner’s stride frequency is less than 3 Hz.

Graphic on the fastest animals.

NGM STAFF. SOURCE: SAMUEL RUBIN, W.M. KECK SCIENCE DEPARTMENT OF PITZER COLLEGE

“[Until now,] no one has validated [the scaling theory] on such a small scale,” Rubin said. (Also see “World’s Fastest Bird? Chubby Snipe Snaps Nonstop Record.”)

The new research “sounds exciting,” said Walter Federle, an expert in insect biomechanics at the University of Cambridge in the U.K. who wasn’t involved in the study. “I have often wondered about the stride frequencies of rapidly running mites, and I am amazed how incredibly high they are.”

Federle agreed that smaller body sizes allow for faster speeds and acceleration, but noted that there may be a practical limit to the phenomenon: the time needed to activate muscles.

“There is clearly very little time [for the mite] to contract the leg muscles at 135 Hz,” said Federle.

As for Rubin, he’s now curious about the mite’s meals. According to the scaling theory, the mite’s prey—since it’s presumably smaller than its predator—is likely even faster.

But until such a creature is found, the mighty mite is leader of the pack.

Follow Christine Dell’Amore on Twitter and Google+.

Graphic corrected to show mite’s distance and relative speed calculated using body lengths per second, rather than miles per hour.

Christine Dell'Amore, environment writer/editor for National Geographic News, has reported from six continents, including Antarctica. She has also written for Smithsonian magazine and the Washington Post. Christine holds a masters degree in journalism with a specialty in environmental reporting from the University of Colorado at Boulder. Her book, South Pole, was published in 2012.
  • Andrew Booth

    I’m sorry to disagree with you Christine but I don’t think this mite is the fastest land creature – you obviously haven’t met my brother in his Lotus!

  • Taylyn

    Cool

  • sanjay

    I want to ask you that now what we say… fastest land animal is California Mite or cheetah……?

  • Mark

    More half-baked science it seems. “Body length”. Humans and other bipeds have “body height”. How does one measure the body length of an ostrich, for example. A giraffe?

    How about rather comparing animal “footprint”. Or leg length. Or shadow area or dimensions from the sun directly overhead.

  • S. L. Vanslette

    The new norm…..insects are now animals.

  • Matt

    Maybe it’s just me, but I’m fairly certain that horses are bigger than people, so if they were human size, their speed would be slowed

  • Christine Dell’Amore

    Thanks for the comments! Sanjay, the mite is the fastest animal relative to its body size. The cheetah is still the fastest land animal in terms of raw speed. Mark, body length is a standard form of measurement in this field. Matt, according to the scaling theory, if horses were scaled proportionately to human size they would run faster.

  • ideogram tianya

    螨虫在60°C,都能存活,真是奇迹。好像全世界都有螨虫吧!

  • David Leeds

    @Vanslette – How were insects ever NOT animals?

  • DrJohn

    What about crazy ants? They’re really small and travel very fast.

  • DrJohn

    Wait a minute, I agree with Matt. A mites speed is increased when its size is increased? So why is a horses speed increased when its size is decreased?

  • Jeff

    Animals yes, of course…but mites are not insects. They are arachnids akin to ticks, and more distantly to spiders…

  • Tree Man

    UH… Mites eat plant juices.

  • Christine Dell’Amore

    Hi Dr. John. The scaling theory says that an animal’s speed is increased when it gets smaller. That’s why the scientists think that the mite’s prey is even faster because it’s smaller than the mite. Tree Man, many mites are parasitic, but the scientists believe this southern California mite is predatory, hence tis speed!

  • gravity cat

    that is not an interesting topic

  • gravity cat

    do you have any more interesting things about this animal

  • gravity dog

    dude you need to be more smart! if the mite is so tiny than how can it run faster than a human? they are right if the horse is bigger than a human but faster than how does it make the mite faster

  • Jiremar

    The mites are slow… You can get it in your hair with your hands… By the way their blood suckers. Maybe theyre vampires. Their pray is dwarf. ^ __ ^

  • Kshitij Sharma

    I think this is something hypothetical. If we start thinking like this way and we relate the size of an elephant to this californian mite and then check out the relative speeds of both. Obviously, the mite would be faster but what about the speed of elephant ? It would be negative and on this perception we cannot say that the elephant is running out of time.

  • chris

    So according to your theory if I race a car on my motorcycle and lose by 1 car length then I really won because if my motorcycle was the same size as the car I would have been in front….this is a stupid theory. Time a mite for 20 yards and a cheetah for 20 yards and see which can run it faster.

  • Mselem kombo

    Can you tel as who is fatest animal cheetah and mite ? We need the fact.

  • Maddy

    Mite is faster than any land animal on earth.
    Why: 322 body length per second that a mite native to California can run. For it’s size,it sprints faster than any land animal on Earth. Also this is proven in Science world current science. (:

  • Amazed

    The level of derrrrrp in these comments is astounding.

  • tush12

    never seen any animal run so fast, and i should know, because i know all about animals. that would be like me running across south america in minutes

  • Marco Flores

    You guys are focusing on body size too much. The key terms is STRIDE LENGTH and AMOUNT OF STEPS . Long legs on someone who is 6’5 give them the ability to run faster because they cover more distance with each step. A person with shorter legs would have to take more steps to cover the same distance within the same amount of time. If you have someone who has long legs and could take steps more quickly, he would be insanely quick. Stride length + steps per minute would be the equivalent to RPM of a rotating tire on a motorcycle.

    So the amazing thing about this little bug with tiny strides is how quick he takes steps. He takes a lot of steps in a short amount of time!

  • Chloe

    Peregrine Falcon Vs Cheetah Vs Mite the Peregrine Falcon goes 240mph while the Cheetah goes 68-75mph and the Mite goes .5mph, so wouldn’t the Peregrine Falcon still be the fastest land animal ( air and land )?

  • Gaynor

    I fully, fully agree!! The mite is fast. I have observed them, under magnifying glass and microscope. I can’t quite get rid of the little buggers. I knew they had super powers- like fast fairies running across my body. I have tried to catch one when I see it appear at the surface of one of the many tunnels they have constructed on my body. Impossible. What’s ever more amazing is the way they propel through skin tissue: a chemical helps them glide through effortlessly. I am also amazed how they interact in tissue paper- this is unbelievable. It was the way they interacted on tissue paper that made me realise just how fast they travelled.

  • Sven

    This comment section can’t be real.

  • Aaron

    It appears those in these comments don’t understand what the theory entails, it is simply stating that smaller animals need smaller force to move. There are many other factors that must be looked at as well.

  • Dennis

    I;m guessing most of You’all are kinda smart . On the other hand after reading most of these posts I;m pretty sure that’s not the case . Seems You don’t understand scale speed , which this study is based on . Don’t waste all that brain power on things you don’t understand & try to get a grip on scale speed first , it’s a real measurement , according to size vs distance and time . Don’t seem that confusing to Me , but I’m just a dumb high school drop out that enjoys the great outdoors and the animal kingdom .

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