The mantis shrimp is the zoological gift that keeps on giving – not just to scientific discovery, but to practical engineering.
Back in 2012, the internal structure of its terrifying and powerful claws was found to be, perhaps unsurprisingly, a potent dissipater of energy, meaning that it can attack things with incredible force without breaking. Now, a new paper in the journal Advanced Materials has revealed that a previously unseen structure found on the outside of its claws also helps to dissipate stress and prevent damage to itself.
This so-called “herringbone pattern” on the front-facing section of the claws is the first of its kind to be discovered in nature. Ultimately, the unique structure of the mantis shrimps’ biological hammers may help to form the basis of stronger armor, sports equipment, buildings, and planes.
“We knew from previous studies that the impact region allows the mantis shrimp to transfer incredible momentum to its prey while resisting fracture,” lead author Nicholas Yaraghi, a graduate student at the University of California (UC) Riverside’s Bourns College of Engineering, said in a statement. “But it was exciting to reveal through our research that the properties of this highly impact-resistant material are created by the novel herringbone structure.”
Over the last few years, researchers have discovered that the mantis shrimp not only has a very unusual sense of sight, but that it uses secret light shows to communicate its aggressive intents. Arguably, it’s this aggression than the mantis shrimp’s 400 separate species are famous for: Each of them have one of two types of claws, “smashers” or “spearers,” and both are capable of decimating prey with up to 1,500 newtons (337 pounds) of force within a split second.
Taking one of the smasher species into their laboratory in order to investigate its violent appendages, the team of researchers used a high-powered microscope to initially spot the pattern on its claws. It appeared to be made of compacted calcium phosphate and chitin fibers – the type normally found in the tough exoskeletons of a variety of insects, crustaceans, and arachnids.
Assuming it was a reinforcement structure, they ran computer simulations and printed 3D replicas of it in order to test its resistance to stress. After running both through several experiments, it was clear that any force transferred to the herringbone structures was spread out more effectively and evenly than anywhere else on the shrimp’s body.
Using this rigid, force-resistance part of its claws, this mantis shrimp could eventually break through almost any biological shield it wanted to, including that of a cornucopia of clams and crabs, its primary prey.
This semi-indestructible feature of the mantis shrimp clearly has implications outside of zoology; it’s no coincidence that this particular lab has been given $7.5 million by the US Air Force, who clearly wouldn’t mind upgrading the armor on their planes and pilots.
Image in text: The herringbone structure on the impact zone of the claws. UC Riverside.