sea horse

1. any fish of the genus Hippocampus, of the pipefish family, having a prehensile tail, an elongated snout, and a head bent at right angles to the body.

2. a fabled marine animal with the foreparts of a horse and the hind parts of a fish.

3. a walrus.

Also, seahorse.

[1425-75; late ME sehors walrus; cf. G Seepferd]

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Any of about 24 species (family Syngnathidae) of fishes that usually live along warm seashores, clinging to plants with their forward-curled, prehensile tail.

Species range from 1.5 to 12 in. (4–30 cm) long. Sea horses have bony rings instead of scales, and their eyes can move independently. They swim upright, propelling themselves horizontally with their fins and vertically with their swim bladder. They catch small organisms by sucking them quickly into their small mouths. The female deposits her eggs into a brood pouch beneath the male's tail, and the male expels the newly hatched young.

Sea horse (Hippocampus erectus).

Des Bartlett

Bruce Coleman Ltd.

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▪ fish

 any of about 36 species of marine fishes (fish) allied to pipefishes (pipefish) in the family Syngnathidae (order Gasterosteiformes (gasterosteiform)). Sea horses are found in shallow coastal waters in latitudes from about 52° N to 45° S. Their habitats include coral reefs (coral reef), mangroves (mangrove), sea grass beds, and estuaries (estuary). They are unique in appearance, with their horselike head, prehensile tail, independently moving eyes, and brood pouch. They have long, tubular snouts and small, toothless mouths. Their bodies are covered with consecutive rings of bony plates. The name of the genus that contains sea horses is taken from the Greek words hippos (meaning “horse”) and kampos (meaning “sea monster”).

      Sea horses vary in size, ranging in length from about 2 to 35 cm (about 0.8 to 14 inches). The smallest species, Denise's pygmy sea horse (H. denise), is found in the tropical western Pacific from Indonesia to Vanuatu. The largest species, the pot-bellied sea horse (H. abdominalis), inhabits the waters off South Australia and New Zealand.

      Sea horses are rather immobile, swimming more slowly than other fishes. When swimming they maintain a vertical position and propel themselves forward using a soft-rayed dorsal fin. They use pectoral fins located on the side of the head to maneuver. Sea horses are usually found clinging to plants or corals with their tails. Their sedentary habits coupled with excellent camouflage abilities render them successful ambush predators. When small organisms swim nearby, a sea horse may capture them by rapidly sucking them into the mouth. Sea horses also rely upon camouflage to avoid predators such as crabs (crab) and other fish.

      The reproductive behaviour of sea horses is notable in that the male carries the fertilized eggs (egg). After an elaborate courtship, the female uses an ovipositor (egg duct) to place her eggs into a brood pouch located at the base of the male's tail where the eggs are later fertilized. Depending on the species, the eggs remain in the pouch between 10 days and 6 weeks. During this time the male nurtures the developing young by regulating the chemistry of the fluid inside the pouch, slowly transforming it from that of his internal body fluids to that of salt water as pregnancy progresses. To nourish the growing young, the male also produces inorganic compounds and releases the hormone prolactin, which helps break down the proteins contributed by the female. Once the eggs hatch, the male convulses his body and expels the young through a single opening in the pouch. The young are miniature versions of their parents that receive no further care. The male can receive another brood of eggs almost immediately after giving birth. In some species a male and female will maintain a monogamous pair bond throughout the breeding season and produce many broods.

      Commercially, sea horses are traded live as aquarium animals and dead for use in traditional medicines and as curios. Threatened by direct overfishing, accidental capture (bycatch) in other fisheries, and the destruction of their coastal habitats, some species—such as the Pacific sea horse (H. ingens)—face extinction.

Elanor Bell Amanda Vincent

 

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