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Shrimp spring into shattering action Q: Can a mantis shrimp really punch a hole in its aquarium glass? I mean, how can it? (Lanney, Sandia Park, New Mexico) The peacock mantis shrimp peers with orange eyes and probing antennae. Her red forearm is in its up, locked position (see arrow). Courtesy of Roy Caldwell, copyright A: The sun lights the shallow seafloor off the coast of Bali. About 10 yards (10 m) down, an emerald-green body roams the bottom with blue eyestalks extended and green antennae waving. The hungry peacock mantis shrimp spots prey; she cocks her red, hammer-like forelimb — ready. A small, creamy, brown-spotted snail (confident within his thick spiral shell) inches along the seafloor in his slow-one-footed way. The predator closes fast, and hovers above the snail. The mantis shrimp (who isn't a shrimp) releases her spring-loaded hammer-like claw; it flashes forward — too fast to see — in an underhand blow that smashes the snail's shell with a loud bang. Courtesy of Roy Caldwell, copyright, used with permission The black circle indicates the location of the mantis shrimp's special saddle spring, limb lock, and limb hinge. The mantis shrimp's two eyes gaze out at the top of the picture. Her long, hammer-like claw swings forward, breaking glass in Caldwell's aquarium. The speed of the strike (up to 50 mph, or 23 m/s) creates cavitation bubbles between the shrimp's hammer-like heel and the struck snail. The bubbles collapse, and generate heat, light, and sound. The shell shatters with a flash too-fast-to-see, and a bang. Watch the flash (called shrimpoluminescence for another species) in the video, slowed by a factor of 900. (Courtesy of Sheila Patek, Wyatt Korff and Roy Caldwell/UC Berkeley) Though the mantis shrimp's tough heel is impregnated with hard minerals, still she must shed the pitted, damaged surface every few months, and grow new heel armor. Yes! Certainly, a mantis shrimp (more elegantly known as a stomatopod) can break aquarium glass. "There are a half dozen species capable of breaking a standard glass aquarium," says biologist Roy Caldwell a professor at the University of California at Berkeley. Including, of course, the peacock mantis, which gets about 7 inches (17 cm) long. Caldwell, S.N. Patek and W.L. Korff discovered how the mantis shrimp generates such powerful blows. It isn't muscle power alone. In fact, the mantis shrimp (a crustacean, distantly related to lobsters, crabs and shrimp) needs 470,000 watts of power per kilogram of muscle to do the job — orders of magnitude higher than the fastest-moving muscles can deliver. The creature's weapon needs much energy delivered fast. So, how does she do it? She stores the energy, and then releases it in a flash like a sprung jack-in-the-box. Clever. The animal latches the hammer limb so it can't move. She contracts her muscle as much as she can (compressing the jack-in-the-box). This much stored energy could hurt her limb, but doesn't because of another clever device. Mantis shrimp have evolved a special saddle-shaped spring that, due to its shape, can distribute huge loads over its surface without buckling or failing. See circled area in the second figure and the next figure, which shows the saddle and the modeled spring. When she frees her latched limb and spring, she releases the stored energy fast, and the red, hammer-like claw lashes out at blinding speeds, smashing her hapless prey. Courtesy of Roy Caldwell, copyright, used with permission The top drawing shows the actual saddle-like structure of the mantis shrimp's leg that acts like an extremely tough spring. The bottom drawing shows the modeled spring. Back to breaking glass. When mantis shrimp dig on the seafloor and run into an obstacle, they strike it to try to break it and remove the obstacle, says Caldwell. So, typically, when an animal starts digging in an aquarium corner, she encounters glass. This "usually leads to their whacking the glass, chipping it, and just causing a leak." A few mantis shrimp though, over the years, have shattered the aquariums. "This usually happens when they attack their reflection or when they try to hit a teasing finger waving at them through the glass." Further Reading: S.N. Patek, W.L. Korff, R.L Caldwell. "Deadly strike mechanism of a mantis shrimp." Nature, vol428, 22 April 2004. University of California: Secrets of the Stomatopod by Roy Caldwell Wikipedia: Pistol shrimp and shrimpoluminescence UC Berkeley News: Mantis shrimp may have swiftest kick in the animal kingdom by Robert Sanders. Edge-of-Reef.com: Peacock mantis shrimp Odontactylus scyllarus (Answered Jan. 10, 2005) April Holladay, science journalist for USATODAY.com, lives in Albuquerque, New Mexico. A few years ago Holladay retired early from computer engineering to canoe the flood-swollen Mackenzie, Canada's largest river. Now she writes a column about nature and science, which appears Fridays at USATODAY.com. To read April's past WonderQuest columns, please check out her site. If you have a question for April, visit this informational page.