Natures wonders: powerful mantis shrimp punch (Introduction)

by David Turell @, Thursday, October 18, 2018, 23:51 (415 days ago) @ David Turell

Like hit with a .22 caliber bullet:

https://www.newscientist.com/article/2182882-mantis-shrimps-punch-with-the-force-of-a-b...

The mantis shrimp packs a mean punch, smashing its victims’ shells with the force of a .22 caliber bullet. But that’s not because it has particularly powerful muscles – instead of big biceps, it has arms that are naturally spring-loaded, allowing it to swing its fistlike clubs to speeds up to 23 metres per second.

"We know that the key part of a mantis shrimp’s punch is a saddle-shaped structure on the arm just above the shrimp’s club. This shape works a bit like a bow and arrow, says Ali Miserez at Nanyang Technological University in Singapore: the muscles pull on the saddle to bend it like an archer’s bow, and when it is released that energy transfers into the club.

"Miserez and his colleagues used a series of tiny pokes and prods, as well as a computer model, to examine exactly how the shrimp’s saddle holds all that energy without snapping. They found that it works because of a two-layer structure. The top layer is made of a ceramic material similar to bone, and the bottom is made of mostly plastic-like biopolymers.

"When the saddle is bent, the top layer gets compressed and the bottom layer is stretched. The ceramic can hold a lot of energy when it is compressed, but is brittle when bent and stretched. The biopolymers are stronger and stretchier, so they hold the whole thing together.

“'It explains how the shrimps’ appendage breaks things without breaking itself,” says Foivos Koukouvinis at City University of London in the UK.

"The researchers also found that the saddle shape itself is important: a strip cut out of a mantis shrimp saddle could not store nearly as much energy, and the strain was concentrated in certain spots rather than spread out evenly. The saddle had a smooth distribution of strain, so no single spot was more likely to break."

Comment: It is used to stun sea creatures and break shells in order to eat. It is made of clever materials. Since this provided food for the shrimp, how did they survive before the claw was developed? More than likely when the shrimp appeared they were designed this way.


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