Punching Shrimp

Punching Shrimp Peacock mantis shrimp.
Photo Credit: Jens Petersen [CC BY 2.5 (http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons.

Legendary boxer Muhammad Ali used to brag that he could "float like a butterfly and sting like a bee." But to be a true champion, a prizefighter should really try to "punch like a mantis shrimp."


A real tough shrimp. I'm Bob Hirshon and this is Science Update.

A crustacean called the smasher mantis shrimp may be shrimpy, but it sure isn't wimpy. It roams around underwater coral reefs looking for snails to eat. When it finds one, it drags it back to its burrow, and punches its shell in.

Sheila Patek is a postdoctoral fellow at the University of California at Berkeley. With help from the BBC, she and her colleagues, Wyatt Korff and Roy Caldwell, recently captured the shrimp's punch on high-speed video.


And what I realized very soon that they were generating feeding movements that were far faster than anything I had imagined, and in fact, faster, possibly faster than any other limb movement in the animal kingdom. And the peak speed that we measured was 23 meters per second, which is over 50 miles per hour.

The key to its knockout punch appears to be a tiny, saddle-shaped spring, which is released by the click of a latch. Dr. Patek says human engineers are interested in copying the shrimp's design.


And the folks in that world see this as a very efficient pounding mechanism, or a very efficient spring-loading mechanism, where there's relatively little material requirements, but a really incredible output.

She says that technologies that could benefit include printing presses and metal-shaping machinery. I'm Bob Hirshon for AAAS, the Science Society.

Making Sense of the Research

Nature is full of awesome engineering, and it's often found in seemingly small and delicate forms. For example, an ant can lift 50 times its own weight (if a 175-pound man could do that, he could lift an SUV). Spider silk is five times stronger than steel. And a tiny shrimp packs the meanest kick in the entire animal kingdom.

Scientists have long been interested in copying these natural engineering marvels. The science of building machines and materials that imitate nature is called biomimetics. Today, biomimetic materials can be found everywhere, from the operating room to the Space Shuttle.

Before this study, scientists already knew that mantis shrimp were tough; they've been known to shatter the glass in tanks where they're kept. As far back as the 1960's, they even knew that the shrimp's kick was controlled by some kind of latch-spring mechanism. Undo the latch, and the leg springs into action. But where exactly was the spring?

That's what Patek and her colleagues discovered while they were measuring the speed of the kick. They identified a saddle-shaped structure on the top of the leg that appears to store and release energy, just like a coiled spring, by flexing and releasing.

Engineers already know that saddle-shaped surfaces are strong. The intersection of opposing curves helps it resist buckling and collapsing. A saddle-shaped concrete roof, for example, can be very durable even if it's only a few inches thick.

But it's the idea of using the saddle shape as a spring that might lead to new innovations. Powerful springs make it possible for one machine part to pound into another. And that simple mechanism is used in all sorts of technologies, from ink presses that stamp designs onto clothing to machines that bend metal into automobile or computer parts.

Now try and answer these questions:

  1. Define biomimetics.
  2. What aspect of the mantis shrimp's kick would engineers like to copy? Why?
  3. What was known prior to Patek's experiment? What was discovered?
  4. Why would an engineer want to copy nature rather than invent something from scratch?

For Educators

The Patek Lab, at the University of Massachusetts, provides information about the dynamic interplay between evolutionary processes and basic physics. You can find more information about the mantis shrimp as well as videos.

Other targets of biomimetic projects include spider silk, bioluminescence, underwater movement, and bone and tooth enamel. Stanford University has a site devoted to biomimetic robots.

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