Mantis shrimp are marine organisms that vary in size and color according to the species. They are called mantis shrimp because they bear a physical resemblance to both preying mantis insects and shrimp. Despite their name, mantis shrimp are not actually shrimp but are a type of crustacean called a stomatopod. They are aggressive predators with powerful limbs and highly developed vision.
Approximately 400 species of mantis shrimp exist. Some, like Squilla empusa, live mainly in the Chesapeake Bay in the northeastern United States but can also be found around Cape Cod in the same region as well as in the Mediterranean Sea and off the coast of Brazil. Other varieties, such as the peacock mantis shrimp, Odontodactylus scyallarus, are native to the Indo-Pacific region.
Mantis shrimp generally have flattened, segmented carapaces, or upper shells, as well as broad, segmented abdomens. Their eyes, which are on stalks, can move independently of one another. They are classified according to their forelimbs. Some species have sharp, spiny claws that they use to trap prey, and others have powerful, smashing claws that they use to crack hard objects such as mollusk shells.
Their size and coloration varies depending on the species. Squilla empusa reaches 8-10 inches (20-25 cm) in length, and Odontodactylus scyallarus grows to a length of 1-7 inches (3–18 cm). They appear in shades of green and brown as well as in vivid reds, blues and neons.
These crustaceans have compound eyes. They can see polarized light, or the direction of light, which helps them communicate with other members of their species. They also have trinocular vision, or three fields of vision that overlap with one another, as well as highly developed vision pigments that allow them to see a wider range of colors than humans can perceive.
The species reproduces sexually. Some varieties mate for life, while others have multiple partners. Depending on the species and environment, some females carry their eggs with them until they develop into larvae, and others lay their eggs in burrows. The larvae pass through several stages of development before reaching adulthood.
Most mantis shrimp live in shallow water and inhabit burrows or crevices in coral or rock. Their diet consists of mollusks, fish and other crustaceans. Larval mantis shrimp are as predatory as older member of the species, feeding primarily on other larvae.
Mantis shrimp are aggressive predators that strike rapidly and forcefully. Some aquarium hobbyists avoid keeping them in aquarium communities because they devour the other inhabitants. Their strike is powerful enough to break aquarium glass, so the species should be housed only in shatterproof acrylic tanks.