Figure 1: A Tiger Pistol Shrimp. Note the over sized snapping claw on its left side.

There are certain shrimp in nature that are able to make light. These shrimp are known as pistol shrimp or snapping shrimp. These types of shrimp are equipped with over sized claws that can snap shut as quick as a gunshot, releasing huge amounts of kinetic energy. That energy causes a jet of water to come out of the claw at up to sixty miles per hour.

The jet of water is followed by a cavitation bubble, which collapses. The collapse of the bubble releases a short flash of light, roughly about 10 nanoseconds long. The light is largely generated since the amount of energy inside of the bubble, exceeding 5000 degrees Kelvin, cannot dissipate quickly enough through diffusion and is instead dissipated through electromagnetic radiation.

The action of the snapping claw is much like that of a spring-loaded pistol action. The shrimp "cocks" its claw and locks it in place with a finger of tissue. To snap the claw, the shrimp retracts the finger and the claw snaps shut, releasing the jet of water. The snapping produces a loud sound that can be heard for some distance underwater and out of water. In fact, the pistol shrimp's snapping is so loud that it has been known to interfere with sonar equipment on submarines.

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