Sometimes women—and men—break a nail working on a tough task. Because our keratin claws are no match for the club-like appendages of a critter called the peacock mantis shrimp. They can hammer through crab exoskeletons and even mollusk shells to find a meal. They can even smash through glass.
Researchers drilled down to the nanoscale to determine what makes the tiny shrimp clubs so tough. Turns out there are three sections to the club. There’s an extremely hard impact region made of hydroxyapatite, or HA. That’s also found in vertebrate bones and teeth.
The HA is backed by an array of rods of chitosan, another hard substance found in crustacean and insect exoskeletons. The chitosan array protects against fractures. The sides of the claw are less stiff, and act sort of like shock-absorbers. The research is in the journal Science. [James C. Weaver et al., "The Stomatopod Dactyl Club: A Formidable Damage-Tolerant Biological Hammer"]
The resulting composite is optimized for high-velocity offensive strikes. It can inflict maximum damage with minimal internal cracks.
In an accompanying commentary in the journal, scientists say that understanding the structure could have implications in, for instance, designing lighter armor that’s less likely to fracture. Or perhaps an improved crab mallet.
[The above text is an exact transcript of this podcast.]