The mantis shrimp (Stomatopoda) is the Muhammad Ali of the animal kingdom and now we know the secret behind its powerful punch. According to research published in the journal iScience, it all comes down to a saddle-shaped structure in its fighting limbs.
The mantis shrimp is a colorful but aggressive little crustacean that attacks its prey with a clobbering, using its club-like appendages (dactyl clubs) to beat them to death. Charming.
Like Ali, the stomatopod relies on incredible speed, striking victims at velocities as high as 23 meters (75 feet) per second. Unlike Ali, it doesn't have particularly strong muscles – as previous research has shown, its dactyl clubs are not in themselves enough to deliver such a powerful blow.
Instead, mantis shrimps' success hinges on ingenious evolutionary design, which has blessed them with naturally spring-loaded limbs. These store and then release electric energy, enabling the critters to deal the fatal punch.
"Nature has evolved a very clever design in this saddle," Ali Miserez, a materials scientist at Nanyang Technological University in Singapore and senior author of the paper, said in a statement.
"If it was made of one homogeneous material, it would be very brittle. It would for sure break."
Miserez and colleagues examined the composition of the saddle-like structure. Using a technique called nanoindentation, they prodded and poked the materials that made up the structure to determine their hardness.
They discovered that it was actually made up of two materials. One, a relatively brittle bioceramic, formed the top layer. The second, found on the underside, was stretchier and contained a higher concentration of biopolymers. The researchers describe these as fibrous – like a rope – and very strong when pulled on.