Seahorse

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Seahorse From Wikipedia, the free encyclopedia Jump to: navigation, search This article is about the animal. For the mythological animal sea-horse, see hippocamp. For other uses, see Seahorse (disambiguation). Seahorses are a genus (Hippocampus) of fish belonging to the family Syngnathidae, which also includes pipefish and leafy sea dragons. There are over 32 species of seahorse, mainly found in shallow tropical and temperate waters throughout the world. They prefer to live in sheltered areas such as sea grass beds, coral reefs, or mangroves. Colonies have been found in European waters such as the Thames Estuary.[2] From North America down to South America there are approximately four species, ranging from very small in size (dwarf seahorses are only about an inch long) to those much larger, found off the Pacific Coast of Central America (the foot-long _Hippocampus _ingens). Hippocampus erectus are larger seahorses found anywhere from Nova Scotia down to around Uruguay. These fish form territories, with males staying in about one square meter of their habitat while females range about one hundred times that area. They bob around in sea grass meadows, mangrove stands, and coral reefs where they are camouflaged by murky brown and grey patterns that blend into the sea grass backgrounds. During social moments or in unusual surroundings, seahorses turn bright colors. Physical description Seahorses are so named for their equine profile. Although they are bony fish, they do not have scales, rather a thin skin stretched over a series of bony plates arranged in rings throughout their body. Each species has a distinct number of rings. Seahorses swim upright, another characteristic that is not shared by their close pipefish relatives, which swim horizontally. Seahorses have a coronet on their head, which is distinct to each seahorse, much like a human fingerprint. They swim very poorly by using a dorsal fin, which they rapidly flutter to propel them, and pectoral fins, located behind their eyes, which they use to steer. Seahorses have no caudal fin. Because they are poor swimmers, they are most likely to be found resting in beds of sea grass or coral reefs, with their prehensile tails wound around a stationary object. They have long snouts, which they use to suck up food, and eyes that can move independently of each other much like a chameleon. Seahorses eat small shrimp, tiny fish and plankton. {text:bookmark-start} {text:bookmark-end} volution and fossil record {text:bookmark-start} {text:bookmark-end} Courtship When two parties discover a mutual interest at the beginning of breeding season, they court for several days, even while others try to interfere. During this time they have been known to change color, swim side by side holding tails or grip the same strand of sea grass with their tails and wheel around in unison in what is known as their "pre-dawn dance”. They eventually engage in their "true courtship dance” lasting about 8 hours, during which the male pumps water through the egg pouch on his trunk which expands and cleaves open to display an appealing emptiness. When the female's eggs reach maturity, she and her mate let go of any anchors and snout-to-snout, drift upward out of the seagrass, often spiraling as they rise. "The female inserts her ovipositor into the male's brood pouch, where she deposits her eggs, which the male fertilizes. The fertilized eggs then embed in the pouch wall and become enveloped with tissues."[3] New research indicates the male releases sperm into the surrounding sea water during fertilization, and not directly into the pouch as was previously thought.[4] Most seahorse species' pregnancies lasts approximately two to three weeks. {text:bookmark-start} {text:bookmark-end} Birth The male seahorse can give birth to as few as 1 and as many as 2,000 "fry" at a time and pregnancies last anywhere from two to four weeks, depending on the species.[7] When the fry are ready to be born, the...
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