Pistol Shrimps

Alpheidae is a family of caridean snapping shrimp characterized by having asymmetrical claws, the larger of which is typically capable of producing a loud snapping sound. Other common names of these species include pistol shrimp or alpheid shrimp. When in colonies, the snapping shrimp can interfere with sonar and underwater communication.The shrimp are considered to be a major source of noise in the ocean. The snapping shrimp grows to only 1–2 inches (3–5 cm) long. It is distinctive for its remarkably disproportionate large claw, larger than half the shrimp's body. The claw can be on either arm of the body, and unlike most shrimp claws does not have pincers at the end. Rather, it has a pistol-like feature made of two parts. A joint allows the "hammer" part to move backward into a right-angled position. When released, it snaps into the other part of the claw, emitting an enormously powerful wave of bubbles capable of stunning larger fish and breaking small glass jars. Some pistol shrimp species share burrows with goby fishes in a symbiotic relationship. 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 smaller appendage will grow into a new snapping claw. Laboratory research has shown that severing the nerve of the snapping claw induces the conversion of the smaller limb into a second snapping claw. This phenomenon of claw symmetry in snapping shrimp has only been documented once in nature. The snapping shrimp competes with much larger animals such as the sperm whale and beluga whale for the title of loudest animal in the sea. The animal snaps a specialized claw shut to create a cavitation bubble that generates acoustic pressures of up to 80 kPa at a distance of 4 cm from the claw. As it extends out from the claw, the bubble reaches speeds of 60 miles per hour (97 km/h) and releases a sound reaching 218 decibels. The pressure is strong enough to kill small fish.

pistol shrimp and goby.