Pistol shrimp

Some Pistol shrimp species share burrows with goby fishes in a symbiotic relationship. The burrow is built and tended by the Pistol shrimp, and the goby provides protection by watching out for danger…

Social behavior has been discovered in the genus Synalpheus. The species Synalpheus regalis lives inside sponges in colonies that can number over 300 members… The offspring are divided into workers who care for young, and the soldiers who protect the colony with their huge claws…

Pistol shrimp have also been noted for their ability to reverse claws. When the snapping claw is lost, the missing limb will regenerate into a smaller claw and the original small claw will grow into a new snapping claw…

The snapping shrimp competes with much larger animals, like the sperm whale and beluga whale, for the title of 'loudest animal in the sea'. The shrimp snaps a specialized claw shut to create a cavitation wave that generates acoustic pressures of up to 80 kPa at a distance of 4 cm from the claw. The pressure wave is strong enough to kill small fish…

The snap can also produce sonoluminescence from a collapsing cavitation bubble. As it collapses, the cavitation bubble reaches temperatures of over 5000 K. The light is of lower intensity than the light produced by typical sonoluminescence and is not visible to the naked eye. It is most likely a by-product of the shock wave with no biological significance. However, it was the first known instance of an animal producing light by this effect. It has subsequently been discovered that another group of crustaceans, the mantis shrimp, contains species whose club-like forelimbs can strike so quickly and with such force as to induce sonoluminescent cavitation bubbles upon impact.