Science Fair Project Encyclopedia
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Around 400 species of mantis shrimp have currently been described worldwide. They are neither shrimps nor mantids, but receive their name purely from the physical resemblance to both the terrestrial praying mantis and the shrimp.
Growing to a potential length of 20-30 cm (though most species are much smaller), these aggressive and (mostly) solitary sea creatures spend most of their time hiding within rock formations, or burrowing intricate passageways in the seabed, where they patiently wait for prey. They rarely exit their homes except to feed and relocate. Most species live in tropical and subtropical seas, for example off the Florida and California coasts and around Thailand, although some live in temperate seas.
Called "sea locusts" by ancient Assyrians, and now sometimes referred to as "thumb splitters" by modern divers - because of the relative ease the creature has in mutilating small appendages - mantis shrimp sport powerful claws, formed like jackknives, that they use to attack prey.
The species are commonly separated into two distinct groups determined by the manner of claws they possess: "spearers" are armed with spiny appendages topped with barbed tips, used to stab and snag prey and have a blunt, calcified club on the elbow, while "smashers" possess a much more developed club and a more rudimentary spear; the club is used to bludgeon and smash their meals apart. Both types strike by rapidly unfolding and swinging their raptorial claws at the prey, and are capable of inflicting serious damage on victims significantly greater in size than themselves. These two weapons are employed with blinding quickness, rapidly reaching 10 meters per second from a standing start, and can strike with a force comparable to a small-caliber bullet.
Some mantis shrimp, which are sometimes kept as aquarium pets, have managed to break through their double-paned aquarium glass with a single strike from the weapon. Smashers use this ability to attack and feast on snails, crabs, mollusks and rock oysters; their blunt clubs enabling them to crack the shells of their prey into pieces. Spearers, on the other hand, prefer the meat of softer animals, like fish, which their barbed claws can more easily slice and snag.
Mantis shrimp appear in a variety of colours, from rather pedestrian browns to stunning neon. Their eyes -- both branching from a single stalk -- are similarly variably colored, and are considered to be the most complex eyes in the animal kingdom. Each eye possesses trinocular vision, and some species have at least eight different visual pigments sensitive to various wavelengths, and three more sensitive to ultraviolet light. By comparison, humans have only three visual pigments. Mantis shrimp also have four filters that tune those visual pigments, they see two or three planes of polarized light, and each eye is capable of depth perception independently of the other eye.
Mantis shrimp are apparently highly intelligent, and exhibit very complex behavior.
In Cantonese cuisine, the mantis shrimp is a popular dish known as "pissing shrimp" due to its tendency to urinate when cooked. Because of this, mantis shrimp are speared to induce them to evacuate their bowels prior to being introduced into the cookpot. After cooking, their flesh is closer to that of lobsters than that of shrimp, and like lobsters their shells are quite hard and require some pressure to crack.
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