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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.

Photo of a mite.
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.

Comments

  1. Maddy
    Ohio
    October 28, 5:48 pm

    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. (:

  2. Mselem kombo
    Arusha Tanzania
    July 27, 10:45 am

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

  3. chris
    alabama
    July 8, 10:03 am

    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.

  4. Kshitij Sharma
    Indore, India
    May 16, 2:13 pm

    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.

  5. Jiremar
    Portland
    May 6, 10:08 pm

    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. ^ __ ^

  6. gravity dog
    casper wyoming
    May 5, 1:02 pm

    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

  7. gravity cat
    casper wyoming
    May 5, 12:57 pm

    do you have any more interesting things about this animal

  8. gravity cat
    casper wyoming
    May 5, 12:53 pm

    that is not an interesting topic

  9. Christine Dell'Amore
    May 5, 12:12 pm

    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!

  10. Tree Man
    Southeast
    May 4, 4:07 pm

    UH… Mites eat plant juices.

  11. Jeff
    La Verne, CA
    May 2, 12:48 pm

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

  12. DrJohn
    New Orleans
    May 2, 10:29 am

    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?

  13. DrJohn
    New Orleans
    May 2, 10:24 am

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

  14. David Leeds
    May 1, 10:34 pm

    @Vanslette – How were insects ever NOT animals?

  15. ideogram tianya
    sanya,hainan,china
    May 1, 12:08 pm

    螨虫在60°C,都能存活,真是奇迹。好像全世界都有螨虫吧!

  16. Christine Dell'Amore
    May 1, 11:39 am

    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.

  17. Matt
    May 1, 9:05 am

    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

  18. S. L. Vanslette
    New York
    May 1, 7:11 am

    The new norm…..insects are now animals.

  19. Mark
    May 1, 1:06 am

    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.

  20. sanjay
    haridwar, uttarakhand, India
    April 30, 9:19 pm

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

  21. Taylyn
    Portland
    April 30, 6:08 pm

    Cool

  22. Andrew Booth
    UK
    April 30, 1:34 pm

    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!