The Secret of the Glass-Cracking Mantis Shrimp

The unique "herringbone" structure of a mantis shrimp claw allows it to withstand enormous force without breaking. University of California, Riverside/ADVANCED MATERIALS

Mantis shrimp may reach only about 6 inches in length, but they pack quite a punch with their "clubs," appendages they slam down on prey with incredible velocity and power. These clubs reach speeds equivalent to that of a bullet fired from a gun, and their strike can break aquarium glass and split open human thumbs. This movement also creates an imploding underwater air bubble that, ever so briefly, reaches a temperature greater than the surface of the sun.

Scientists have long wondered how these creatures' clubs could withstand such extreme force without cracking apart. A study published June 1 in the journal Advanced Materials reveals one of the shrimp's secrets: The appendages are made of a unique "herringbone" structure, consisting of interlocking units of chitin—a hard but semiflexible material found in the shells of many insects and crustaceans—and calcium phosphate, found in the bones of humans and other animals. In the claw, there are sinusoidal-shaped fibers of chitin (hence the "herringbone" description), which bind together bits of super-hard calcium phosphate. This construction allows the claw to absorb huge amounts of force without breaking, the study shows.

Researchers at the University of California, Riverside, and Purdue University are now building materials based on the design of the shrimp's claw, including a helmet that can more effectively absorb force without cracking, compared with existing materials. The team hopes to use these insights to build even more devices, like bulletproof-materials and the like.

"The smasher mantis shrimp has evolved this exceptionally strong and for one primary purpose—to be able to eat," says David Kisailus, an engineering professor at UC Riverside and lead researcher on the study, in a statement. "However, the more we learn about this tiny creature and its multilayered structural designs, the more we realize how much it can help us as we design better planes, cars, sports equipment and armor."