The mantis shrimp is no wimp. Like a speeding bullet its claws will destroy its prey, or rip open your toe with equal enthusiasm. It comes in two basic models: the smasher (including Gonodactylus smithii) and the spearer (like Lysiosquilla maculata). In either case, when your big toe meets a mantis shrimp, it doesn't have a prayer.
By Laura Woodward

Spearers' claws impale passing fish in as little as 3 milliseconds; smashers disable prey with under-arm punches from their hammer-like elbows
Lurking in burrows on the sea bed or in cavities in coral reefs, one of the most aggressive and efficient of marine predators, the mantis shrimp (Stomatopod), is nicknamed prawn killer in Australia, and split toe or split thumb in the West Indies!
More than one unwary diver who has extended the hand of curiosity a little too far has lost a finger to the mantis shrimp's lightning stab - one of the fastest animal movements known. One species delivers punches with the force of a small-calibre bullet, and has been known to break an aquarium wall of double safety glass. Inhabiting coral reefs or coastal shallows, mantis shrimps are widely distributed around the world, and are frequently sighted waiting in ambush - so approach with caution.
It was during a photographic expedition in Manado, North Sulawesi, that my inquisitiveness about the gorlak (the Indonesian name for the local shrimp served char-grilled) was aroused. Scanning the reefs in search of something new to photograph, I stumbled across a pair of radar-shaped dishes buried in the volcanic sand. Closer examination revealed a pair of compound eyes mounted on movable stalks, protruding from a burrow and rotating independently, like the periscopes of a submarine. Each eye is capable of movement covering 360 degrees.
Few crustaceans hunt prey as a lion or a tiger does, but the mantis shrimp visually selects and stalks its victim. However, its main claim to fame is its armament of raptorial claws, bearing a strong resemblance to those of the praying mantis - hence the name. These two enlarged arms, carried folded beneath the head, divide mantis shrimps into two functional groups: the spearers (armed with a set of spines with barbed tips); and the smashers (armed with a heavily calcified and enlarged heel on the "elbow"), which attack prey with a striking motion.
The spearer dines on soft-bodied bottom-dwelling fish. Looking out from its burrow as the selected fish swims past, its claws lunge forward and, striking in as little as 3 milliseconds, trap the prey by impaling it. The velocity of this movement is calculated to be as fast as 10 metres per second.
The smasher, which lives in cavities of rocks and corals, uses its calcified heel to supply its diet of rock oysters, clams, sea snails and crabs. Delivering underarm punches with its blunt, hammer-like elbow, it disables its prey with repeated blows before wedging the stunned victim against a wall and breaking open its shell.
Fighting among stomatopods is a dangerous business, to be avoided - a single blow is sufficient to kill an enemy. Consequently, nature has provided the stomatopod with an eyespot on the inside of each raptorial claw as an aid to assessing the fighting ability of an opponent. When under threat from a rival, the claws are raised to the side, revealing the eyespots beneath the cloak in an impressive display. The colours of the eyespots are used as a visual indicator: bright colours are a warning sign to identify dominant species.
Sex too is a battle. The male makes the first move by probing each burrow, accepting rejection along the way with the occasional bash around the head, until he finds a potential mate and is allowed to enter the burrow. A ritualistic courtship of threat displays follows, until the male and female become conditioned to each other and eventually mate. Courtship lasts for a few days, when the female loses interest, and evicts the male from the burrow aggressively. In the next few days she lays eggs and then carries them for more than a month before the larvae hatch and swim away.
These fascinating predators have survived for more than 200 million years, but some populations are now being reduced by trawl nets, which indiscriminately scrape the sea floor for fish.