Tiny Mantis Shrimp Pounds Enemies, Prey With Fist-Like Club

Posted on June 7, 2012

Researchers at the University of California, Riverside's Bourns College of Engineering have been studying the bright orange fist-like club of the peacock mantis shrimp, or stomatopod, a 4-inch long crustacean found in tropical waters. The club of the stomatopod accelerates underwater faster than a 22-caliber bullet. Repeated blows of the tiny powerful club can destroy mollusk shells and crab exoskeletons, both of which have been studied for decades for their impact-resistant qualities. The force created by the mantis shrimp's impact is more than 1,000 times its own weight. It's so powerful that it needs to keep it in a special aquarium in his lab so it doesn't break the glass.

The researchers, led by David Kisailus, an assistant professor at the Bourns College of Engineering, wanted to know how the club withstands 50,000 high-velocity strikes on prey during its lifespan. They found that the club is a highly complex structure, comprised of three specialized regions that work together to create a structure tougher than many engineered ceramics.

The first region, located at the impacting surface of the club, contains a high concentration of mineral, similar to that found in human bone, which supports the impact when the mantis shrimp strikes prey. Further inside, highly organized and rotated layers of chitin fibers dispersed in mineral act as a shock absorber, absorbing energy as stress waves pass through the club. Finally, the club is encapsulated on its sides by oriented chitin fibers, which wrap around the club, keeping it intact during these high velocity impacts.

Kisailus says, "This club is stiff, yet it's light-weight and tough, making it incredibly impact tolerant and interestingly, shock resistant. That's the holy grail for materials engineers."

Kisailus thinks the club could help lead to improvements in body armor. His goal is to develop a material that is one-third the weight and thickness of existing body armor.

Kisailus says, "We have been studying these other organisms when we should have been studying this guy because he literally eats them for breakfast."

Here is a video of the mantis shrimp using its powerful tiny club to smash a clam shell. Take a look:

The research was published here in the journal, Science.

ANIMALS