Mantis shrimps are highly aggressive crustaceans that capture prey using large, raptorial claws much like that of a praying mantis.
Many are beautifully coloured in shades of red, green and blue. The ancient Assyrians called the mantis shrimps 'sea locusts'. Today, mantis shrimps are called 'shako', 'prawn killers' and 'thumb splitters'.
There are two main types of mantis shrimp: 'spearers' and 'smashers'. Both types strike by rapidly unfolding and swinging the raptorial claw at the prey. 'Spearers' have a claw lined with numerous sharp teeth and they hunt by impaling prey on these teeth. They usually feed on soft-bodied animals like worms, shrimps and fish. 'Smashers' have a claw shaped like a club, which they use to smash and hammer their prey. They usually feed on hard-bodied animals like snails and crabs. Both 'spearers' and 'smashers' have excellent binocular vision and many see in colour.
About 400 species of mantis shrimp are known worldwide. Close to 250 species occur in the Indo-West Pacific region and more than half of these occur around Australia. New species are regularly being discovered, even off the coast of New South Wales. Mantis shrimps support large fisheries in many parts of the world but they are susceptible to overfishing and habitat loss.
Most species of mantis shrimp live alone, but there are some species that live in pairs for life. Mantis shrimps can live in burrows and crevices on coral reefs, or on the seabed down to a depth of 1500 metres.
Mantis shrimps play an important role in marine ecosystems, regulating the numbers of other species and promoting higher overall species richness. Also, where the seabed is soft, the burrowing behaviour of mantis shrimps contributes to the turnover and oxygenation of sediments. Mantis shrimps are also sensitive to environmental pollutants and are good bioindicators of pollution on coral reefs.