Mantis shrimp wield appendages so powerful they can impale snail shells, split open human thumbs and even shatter aquarium glass.
To decipher how these ocean predators deliver such deadly strikes, scientists created Ninjabot, an ultrafast underwater robot that mimics the shrimp’s striking motion.
The robot could shed light on how a striking shrimp produces a water bubble phenomenon called cavitation. Understanding that mysterious process could spur the development of ultrafast vessels and new materials that reduce drag underwater.
“They’re really amazing animals,” said Sheila Patek, an associate professor of biology at Duke University who studies the connection between evolution and the physics of animal movements. “For a really long time, actually since I started working on this system, I was interested in building models of how they do it.”
Before striking, the mantis shrimp bends its appendage. Milliseconds later, the appendage shoots toward the prey at about 60 miles per hour. That cavitation phenomenon created can generate shock waves powerful enough to erode boat propellers, but it’s also poorly understood.
Patek collaborated with Suzanne Cox, a PhD student in organismic and evolutionary biology at the University of Massachusetts Amherst. They found that standard engineering springs couldn’t generate the same accelerations as the mantis shrimp’s biological one.