Snapping Shrimp better known as Pistol shrimp are tiny finger sized creatures that are seldom seen but almost always heard! Most popularly known with divers for their ceaseless cacophony that colonies of these shrimps produce; these shrimp emit loud crackling sound almost as if a hundred people are cracking their knuckles at once.
Upon closer inspection of the snapping shrimp, it has two claws one of which is an oversized claw that resembles a boxing glove almost as big as its body that it uses to stun its prey by snapping the claw shut quickly. The action produces a loud cracking sound which produces a sort of sonic blast, the shockwave of which is sufficient to stun a passing crab.
Recent research into the Snapping shrimp has generated much interest after discovering that this tiny creature’s claw snapping motion actually shoots out a jet of water at up to 60 miles an hour which generates a low pressure bubble that bursts with a loud snap. The snap of this bubble can produce something known as sonoluminescence which is caused when the collapsing bubble reaches temperatures of over 4700 degrees Celsius or 5000K which is almost as hot as the surface of the sun which is 5778 Kelvin! The resulting snap also produces light which is of a lesser intensity and not visible to the naked eye.
Many who have tried to keep Pistol Shrimp in aquariums at home will testify that they are simply impossible to rear. The sonic blast of these tiny creatures has cracked the aquarium glass so many times, that most hobbyists simply give up.
Another fascinating fact of these amazing creatures is that Naval Submarines have been known to hide amongst beds of Pistol shrimp to hide from sonar detection. Apparently the noise they create is so much that other submarines find it impossible to pickup other noises using sonar.
Pistol Shrimp are native to the tropical waters of the Indo-Pacific and the western pacific regions around Baja California mostly inhabiting caves, bay or lagoons present on rubble at the bottom.
Another unique feature is the Pistol Shrimp shares a symbiotic association with the goby. The goby has a good eye-sight and thus, warns the shrimp of any approaching predator in the exchange of food that the shrimp provides to the goby and the burrow that the Shrimp digs for both, itself and the goby, to live in.
So the next time you hear the loud snap, crackling and pop while diving, take some time out to investigate, and you will be quite amazed at discovering its source.