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Bigclaw snapping shrimp (sometimes referred to as pistol shrimp) reach 1.25-1.75 inches in length.  Body color is typically a translucent green, often with bright red or orange tones on the tips of the claws, and a blue or purple margin on the uropods of the tail and along the sides.   The walking legs are pale red.   First legs have unequal chelae (claws).  Larger claw is notched along both the outer and inner edges where the fingers meet the base of the claw and generally bears whitish blotches.  The carapace is somewhat compressed, and slightly more than 1/2 the length of the abdomen.  An ocular hood arises from the carapace to cover the eyestalks.  Antennae are longer than body length.  Unlike other members of the genus, bigclaw snapping shrimp do not have cardiac grooves on the carapace. 

Bigclaw snapping shrimp are common in seagrasses, oyster reefs, and coral reefs.  In Florida, they can also be abundant in mangrove areas. 

Similar Species:
There are 11 or more members of the genus Alpheus that inhabit the Indian River Lagoon.  The bigclaw snapping shrimp is distinguished based on its color, claw shape, and its lack of grooves on the carapace.

Bigclaw snapping shrimp range from the lower Chesapeake Bay south through North Carolina, Florida, the Gulf of Mexico, and Cuba, to Brazil.





The bigclaw snapping shrimp, Alpheus heterochaelis, from the Indian River Lagoon.  Photo courtesy of K. Hill, Smithsonian Marine Station.
Body form of the bigclaw snapping shrimp.  Photo courtesy of K, Hill, Smithsonian Marine Station.

Snapping shrimp hold their large claws open while hunting, and when prey is encountered, the closing of the claw occurs so quickly that water pressure around the claw changes rapidly.  This results in cavitation - the production of a bubble in the water that implodes as the pressure returns to normal.  It is the bursting of this bubble that produces the characteristic snapping sound which stuns prey so they can be captured.