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| Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > prawns and shrimps |
| Snapping
shrimps Family Alpheidae updated Dec 08
Where seen? You will most likely hear a snapping shrimp before you see one. These snappy but elusive creatures are often tucked away in their burrows or other hiding places such as under rocks, even under carpet anemones and within sponges. They are seen on many of our shores. What are snapping shrimps? Snapping shrimps are crustaceans that belong to Family Alpheidae. Snap, crackle and pop! These little creatures make the incessant pops that you hear at low tide. They are found on sand, mudflats and coral rubble. They range from tiny ones to rather large ones that can pack a really loud pop. Some even hide under carpet anemones and inside sponges or other animals. Features: 2-7cm long. A snapping shrimp has one of its pincers greatly enlarged. This pincer may even be as long as its entire body! The pincer has a moveable 'finger' held apart with a catch. When the catch is released, an explosive sound results. The blast stuns prey like tiny fish and cracks the shells of small clams. It is also used to ward off predators and intimidate rival pistol prawns. During the day, the snapping shrimp hides in a burrow, sometimes renovating it quietly. It forages more actively at night. The science of The Sound: The snapping sound is not made by the fingers actually hitting each other. Rather, a high-speed jet of water shoots out due to the extremely rapid compression of the fingers. This jet vapourises the water and creates a bubble. When the bubble collapses, the sound results. Not only that, a flash of light is also emitted! These findings are possibly useful for naval applications as the sound of snapping shrimps seriously interfere with sonar detection in shallow seas. In fact, snapping shrimps have been studied since World War II as their sounds interfered with the detection of hostile submarines! Shrimpy friends: Some species live in symbiosis with corals, sponges, sea fans and other animals. The most amazing must be the relationship between the snapping shrimp and goby. The shrimp goby lives in the same burrow with a snapping shrimp. With keener eyesight, the goby keeps a look-out while the shrimp busily digs out and maintains their shared home. The shrimp is literally constantly in touch with the goby with at least one of its antennae always on the goby. When the goby darts into the burrow, the shrimp is right behind it! Colonial shrimps? A kind of snapping shrimp (Synalpheaus regalis) that lives in sponges in the coral reefs of Belize were found to form colonies much like termites do. One 'queen' prawn produces all the members of the colony, which attack members of other colonies but are peaceful towards members of their own colony. Status and threats: Most of our snapping shrimps are not listed among the endangered animals of Singapore, except for the Crinoid snapping shrimp (Synalpheus stimpsoni). This tiny shrimp (about 1cm) lives in pairs on feather stars (crinoids), feeding off the mucus of its host. It is threatened by reef destruction and siltation. However, like other creatures of the intertidal zone, all our snapping shrimps are affected by human activities such as reclamation and pollution. Trampling by careless visitors also have an impact on local populations. |
 One pincer greatly enlarged. Pulau Sekudu, Jun 05  Using the small pincer to carry things. Labrador, May 02  Sideview of the shrimp St. John's Island, May 06  This shrimp shares its burrow with a brittle star. Chek Jawa, Jul 05 |
You will probably hear one than see one on the shores.
Listen out for them!
 Kusu Island, Aug 08 |
| Family
Alpheidae recorded for Singapore from Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. *in red are those listed among the threatened animals of Singapore from Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore. +from our observation
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