Mantis shrimp’s ‘phononic shield’ reveals clues to surviving its own .22-caliber equivalent punches

How do smasher mantis shrimp avoid self-inflicted harm from their devastating strikes? A new Northwestern University study reveals that the secret may lie in patterned armor that acts as a sound filter, selectively blocking damaging shockwaves generated by their own powerful punches. The study details how the shrimp’s armor—featuring grooves and twisted fiber bundles—selectively filters damaging high-frequency stress waves caused by its roughly .22-caliber-equivalent punches and collapsing underwater bubbles. These findings could inspire next-generation protective gear to mitigate blast injuries in military and sports applications. Sound-filtering materials for protective gear could be another application of the research.

This “phononic” shield may pave the way for next-generation protective gear, from military armor to sports equipment, by mimicking the shrimp’s self-preserving impact strategy.

As the study abstract notes (the full paper is slated for publication on February 7 in Science), this discovery shows that nature has essentially perfected a specialized “acoustic armor” to protect the shrimp’s club from self-inflicted high-frequency damage.

In this work, we explored the phononic properties of the mantis shrimp’s dactyl club using laser ultrasonic techniques and numerical simulations. Our results demonstrate that the dactyl club’s periodic region functions as a dispersive, high-quality graded system, exhibiting Bloch harmonics, flat dispersion branches, ultraslow wave modes, and wide Bragg bandgaps in the lower megahertz range. These features effectively shield the shrimp from harmful high-frequency stress waves generated by cavitation bubble collapse events during impact.

The research team emphasizes that future investigations will focus on translating these biological insights into practical applications. While the current study used 2D simulations to demonstrate the phononic filtering effect, Northwestern Engineering’s Horacio D. Espinosa (co-corresponding author of the study) notes that 3D modeling will be key for understanding how the club’s helical fiber arrangements interact with shockwaves in all dimensions. This could enable engineers to design multilayered composites that replicate both the impact-resistant herringbone pattern and the frequency-filtering Bouligand structure. Additionally, the researchers propose developing submerged testing platforms with advanced sensors to observe how the phononic mechanisms fare underwater. This could pave the way for aquatic robotics or naval armor inspired by these crustaceans. By combining materials science with fluid dynamics, the team aims to create prototype shields that mitigate blast waves in military helmets or vibration-dampening layers for athlete protective gear, potentially revolutionizing impact protection across industries