Instead they designed a steel robot that amplifies power like a bow and arrow or a pole-vaulter. The robot contains a long beam spring, which is a kind of flat spring. To load it, the scientists used a hand crank that slowly puts pressure on one end of the beam, flexing it. Then a lever releases and the bent metal is suddenly freed. Cox dubbed it Ninjabot after its ninja-like strike.
The resulting ninja-like strike, quite as fast as an actual mantis shrimp, is two orders of magnitude greater than previous underwater models.
With Ninjabot, the scientists can do controlled experiments to study factors that influence how the bubbles form. The robot can be outfitted with a real mantis shrimp appendage for testing, according to Patek.
Roy Caldwell, a professor of integrative biology at the University of California Berkeley, was Patek's postdoctoral advisor. He's been studying mantis shrimp since 1965. "It will take a little bit of tweaking to get into the biological realm of capability that she needs, but I think it's a good start," he said.
California State University Long Beach biology professor Christopher Lowe has noticed cavitation bubbles form around the hydrophones he uses to record sound underwater while tracking sharks. Although he doesn't have an engineering background, Lowe thinks the Ninjabot could help us develop materials with new properties, leading to stronger ship propellers and ultrafast underwater vessels.
"It's just cool that we're using animals that have solved these problems evolutionarily," he said.
Patek and Cox described their work in the March 2014 issue of the journal Bioinspiration & Biomimetics.