“Pound of Shrimp” — The Discovery Files

The mantis shrimp is able to repeatedly pummel the shells of prey using a hammer-like appendage that can withstand rapid-fire blows by neutralizing certain frequencies of “shear waves,” according to a new research paper by the University of California, Riverside, and Purdue University engineers. The club is made of a composite material containing fibers of chitin, the same substance found in many marine crustacean shells and insect exoskeletons but arranged in a helicoidal structure that resembles a spiral staircase.