No creature in the animal kingdom can boast a punch as powerful as that of the mantis shrimp (Odontodactylus scyllarus). This small, colorful crustacean, also known as the peacock mantis shrimp, can shatter the shell of its prey with its dactyl club, striking at a speed of 23 meters per second. This blow, dubbed the “royal strike” by scientists, delivers a force of 1500 newtons. Researchers at Northwestern University in the U.S. became intrigued by how these marine animals manage to remain unscathed despite the recoil effect. What did they discover?
One of the secrets of mantis shrimp lies in the fascinating structure of their dactyl clubs. This unique design allows them to filter the impact, protecting the animal from injury. According to lead researcher, mechanical engineer Horacio Espinosa, these crustaceans are renowned for their incredibly powerful strikes that can break the shells of mollusks and even aquarium glass. “However, to repeatedly deliver such a powerful blow, the peacock mantis shrimp’s club must have a reliable protective mechanism to prevent self-injury,” the scientist noted. Most previous studies on Odontodactylus scyllarus focused on the strength of the club and its resistance to cracking, treating its structure as a reinforced impact shield, as reported by Science Alert.
“We found that the mantis shrimp employs phononic mechanisms—structures that selectively filter shock waves. This enables the shrimp to maintain its striking ability over multiple hits while preventing damage to its soft tissues,” the researcher explained. His team conducted a detailed analysis of the marine animal’s strike. “When the mantis shrimp strikes, it generates pressure waves. This creates bubbles that collapse rapidly, producing shock waves in the megahertz range. The collapse of these bubbles releases intense bursts of energy that travel through the shrimp’s club. This secondary effect of the shock wave, combined with the initial striking force, makes the impact even more devastating,” Horacio Espinosa elaborated.
Yet, remarkably, the mantis shrimp does not suffer from recoil. To uncover the reason for this resilience, a team led by engineer Nicolás Alderete from Northwestern University meticulously studied the dactyl clubs of the peacock mantis shrimp. They employed techniques such as picosecond laser ultrasound and transient grating spectroscopy. It turned out that the dactyl appendages have a unique structure that helps dissipate and filter these waves, thus providing protection. The structure of the club was found to be layered, somewhat resembling lasagna. The striking surface is coated with a thin layer of hydroxyapatite, a mineral primarily composed of calcium and phosphorus, similar to the enamel on our teeth. Directly beneath this striking area lies a layer of chitin fibers arranged in a herringbone pattern, reinforcing the structure. Further down is a layer of chitin fiber bundles that twist in a spiral, which also helps resist potential damage. This layer acts as a protective shield, filtering (blocking) sound and stress waves.
In the near future, researchers plan to conduct underwater experiments to further explore the effectiveness of the mantis shrimp’s remarkable armor. This knowledge could be crucial for developing new super-strong biomaterials. The findings of this study were published in the journal Science.