One of the world’s most fearsome crustaceans has evolved to deliver deadly punches to its prey without damaging its own body — and now, scientists have shown how. A study published on 6 February in Science¹ reveals that the mantis shrimp’s punching limb — known as the dactyl club — has a multilayered structure that allows it to absorb the shockwaves it generates when cracking the shells of molluscs or other crustaceans.

The findings could provide inspiration for the design of artificial materials with useful properties, says study co-author Maroun Abi Ghanem, a physicist at the French National Centre for Scientific Research who studies biomaterials at the University of Lyon, France. These could be used to make surgical implants that can collect energy beamed through tissue during ultrasounds, or mechanical filters for mobile phones and other electronics.

Chitin construction

Abi Ghanem and his colleagues analysed the club of the peacock mantis shrimp (Odontodactylus scyllarus), a species native to the Indian and Pacific oceans.

The club’s exoskeleton, which contains a natural polymer called chitin and a calcium-containing mineral similar to that in human bones and teeth, has three layers. The middle layer contains the ‘Bouligand structure’: in this layer, fibres of chitin are arranged like bundles of pencils that fan out in different directions, so that some point towards the exterior layers, some are parallel to them and some are at angles in between. The fibres’ orientations aren’t random, but vary in a periodic fashion that repeats every 500 micrometres or so.