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Mantis shrimps are lightening-fast predators with the most complex eyes in the animal kingdom. Their powerful limbs spear or club their prey using one of the fastest responses known to man. They can deliver a blow that is equivalent to the force of a bullet.
Around 400 species occur worldwide.
They are from 2 to 30cm (1-12in) in length, depending on the species.
Mantis shrimps typically occur in the shallow waters of tropical and subtropical seas.
Most live in excavated burrows, either building their own or moving into those built by other organisms. They also inhabit rock or coral crevices.
They feed on various fish and invertebrates and are fast, efficient predators. Mantis shrimp are either 'spearers', who use their forelimbs with numerous spines to capture mainly soft-bodied prey like fish and shrimps, or 'smashers' that possess club-like appendages to crush hard-shelled animals such as crabs, clams and snails.
The strike of one of a matis shrimp forelimb is considered to be one of the fastest movements known in the animal kingdom. Larger animals can reach velocities of around 10 metres per second, producing a force approaching that of a 22 calibre bullet.
Mantis shrimp's eyes are on stalks - allowing them to size up prey, predators and competition from the comfort of the burrow or crevice. Their sense of vision is acute and more complex than any other system discovered to date. They have at least eight different type of cell involved in colour vision (compared to the human three), including several sensitive to ultraviolet wavelengths (to which humans are blind). In addition, they are able to sense and use minute information about the direction of light - known as its 'polarization'.
Mantis shrimps are very colourful and use visual display to communicate to predators and other mantis shrimp. In addition to their flamboyant red, green and blue warning coloration, some species have fluorescent patches, areas that glow yellow, increasing their conspicuousness. This coloration is hidden view when the mantis shrimp is in its burrow, but is rapidly flashed when required.
Some mantis shrimp mate for life (one pair was known to stay together for over 20 years), while others are highly promiscuous. There is usually a period of courtship, during which the male signals his intentions. The couple then come together so that sperm can be transferred, and they may mate several times. Females may store sperm for some time before using it to fertilise the eggs, or lay immediately. Some species lay their eggs in their burrows, while others carry the eggs in their forelimbs, carefully turning and cleaning the eggs until they hatch.
Larval mantis shrimps are planktonic and just as fearsome as their parents. They too have strong raptorial appendages and are effective predators, often preying on other larvae.