Alpheidae

Alpheidae (also known as the snapping shrimp, pistol shrimp, or cracker shrimp) is a family of the shrimp infraorder Caridea that is characterized by having an enlarged and highly modified chelae ("claws") on one leg of their first pair, which is used for various purposes. Around half of the species, such as those in the genus Potamalpheops, lack this trait and have been dubbed "non-snapping shrimp". The family is diverse and worldwide in distribution, consisting of about 1,119 species within 38 or more genera. The two most speciose genera are Alpheus and Synalpheus, with species numbering well over 330 and 160, respectively. Most snapping shrimp dig burrows and are common inhabitants of coral reefs, submerged seagrass flats, and oyster reefs. While most genera and species are found in tropical and temperate coastal and marine waters, Betaeus inhabits cold seas and Potamalpheops has a cosmopolitan distribution including being found in freshwater caves. When living in colonies, the sound produced by snapping shrimp can interfere with sonar and other forms of underwater communication. The shrimp are considered a major source of sound in the ocean.