The Pistol shrimp are a group of small caribbean crustaceans which are part of the snapping shrimp family. Alpheidae tend to live in colonies and most live in warm costal systems, though some live in highly specialized environments such as freshwater caves.
Pistol shrimp dig down into sediment, where it forms burrows from which to launch its characteristic predatory attacks.
(note the distinctly enlarged right claw)
Pistol shrimp distinctive because of the disproportionately large claw on only one side of its body. Unlike most shrimp, this claw doesn't have pincers, but rather has a very special apparatus from which its name is derived. The large claw functions much like a gun. The hammer portion of the claw is pulled into a a cocked, right angle position. When snapped downwards the hammer contacts the other portion of the claw (much like an anvil). When the hammer and anvil contact, a pulse of bubbles is shot from the end of the claw with enormous force, generating a shock wave powerful enough to kill small fish or break glass jars! Because of this snapping effect, Alpheidae competes with sperm whales and beluga whales for the loudest creatures of the sea!
In their coral reef habitat, pistol shrimp are known to have a symbiotic relationship with gobi fish who share their burrows. The shrimp maintains the burrow for both inhabitants while the gobi fish provides protection by spotting potential threats. The shrimp communicates with the fish using its antennae while the fish communicates using a distinctive tail movement.
The video below does an amazing job of illustrating this incredible predatory toolset!