Gaby
No animal packs a punch like 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 were intrigued by how these marine animals manage to remain unscathed despite the recoil. What did they discover?
One of the mantis shrimp’s secrets is the fascinating structure of its dactyl clubs. This unique design lets the shrimp filter the impact, protecting its soft tissues from injury. Lead researcher Horacio Espinosa, a mechanical engineer, says these crustaceans are known for strikes powerful enough to break mollusk shells and even crack 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,” Espinosa says. 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. They found the dactyl appendages have a layered structure that helps dissipate and filter these waves, providing protection. The structure of the club is layered, somewhat like 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 that reinforces 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 and 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.
