The mantis shrimp uses its formidable weapon to break the shells of its prey but, until recently, it was unclear how its club could receive such a severe, repetitive pounding without suffering too much damage. The club, in fact, handles as many as fifty thousands strikes during its lifespan. So how does it maintain structural integrity? Assistant professor David Kisailus from the University of California, Riverside set out to find an answer.
The club, Kisailus found, is a highly complex structure comprised of three highly specialized regions working together to create a structure tougher than many engineered ceramics.
The impact area is one millimeter thick and contains a high concentration of mineral similar to that found in human bone, except that the crystals that compose it are aligned perpendicularly to the surface of the strike to minimize cracks.
Further inside, highly organized layers of chitin fibers act as shock absorbers. The fibers are arranged in a helical structure to slow down the spreading of cracks. Here's the trick: the helix forces the cracks to constantly change direction, which disperses their energy and quickly stops them from propagating.