Alpheidae Rafinesque 1815

Alpheus is the most diverse shrimp genus. Some of their defining characteristics are orbital hoods and an oversized claw which they use for defense and killing prey. When this claw is snapped shut it shoots out water which creates a low pressure air bubble behind it. The bubble reaches temperatures of 5000 degrees Kelvin (half of the heat of the sun)(4). When the bubble pops it makes a loud sound and produces a flash of light. The shockwave from the pop stuns or kills the shrimp’s prey. The shrimp have developed orbital hoods to protect their eyes from the shockwave. However, this orbital hood leads to poor vision. In order to make up for this shortcoming some shrimp have developed a symbiotic relationship with gobies. The gobies protect the shrimp from predators by looking around for predators. When a goby detects a predator it moves its tail in a way that warns the shrimp. The shrimp feels the movements with its antennae and they both go hide. The shrimp and goby live in close proximity.

The pistol shrimp has evolved to have orbital hoods, which is basically permanently shut eyelids. These orbital hoods protect the shrimp’s eyes from the shock wave of the explosion of the bubble. The shock wave is strong enough to stun or kill the shrimp’s prey, and it could cause serious damage to the eyes of the shrimp. However, these orbital hoods lead to reduced vision. Some shrimp have developed a symbiotic relationship with gobies to overcome this obstacle.

Pistol Shrimp live in “crevices of coral rubble, under intertidal rocks, in self-bored tunnels in basaltic rocks, associated with sea anemones, among seagrass roots, in sponge canals, coralline algae, in excavated burrows in mangrove mud, in burrows shared with partner gobies, in tunnels of echiuran worms, in burrows in silty sediments of the deep sea, or in freshwater, in burrows made under river banks.” (1)