Sea cucumber

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{{Taxobox | color = pink | name = Sea Cucumbers | image = Sea_cucumber.jpg | image_width = 200px | image_caption = A Sea Cucumber | regnum = Animalia | phylum = Echinodermata | classis = Holothuroidea | subdivision_ranks = Orders | subdivision = Subclass Apodacea
Apodida
Molpadiida

Subclass Aspidochirotacea
Aspidochirotida
Elasipodida

Subclass Dendrochirotacea
Dactylochirotida
Dendrochirotida }} The sea cucumber is an echinoderm of the class Holothuroidea, with an elongated body and leathery skin and is mostly found on the sea floor. It is so named because of its cucumber-like shape. Like all echinoderms, sea cucumbers have an endoskeleton just below the skin.

Sea cucumbers are generally scavengers, feeding on debris in the benthic layer. Their diet consist of plankton and other organic matter found in the sea. One way they might get a supply of food is to position themselves in a current where they can catch food that flow by with their tentacles when they open. Another way is to sift through the bottom sediments using their tentacles. They can be found in great numbers beneath fish farms.

They have the peculiar adaptation of expelling first sticky threads, perhaps to incapacitate predators, and then their internal organs when startled by a potential predator. These organs can then be regrown.

Sea cucumbers reproduce by releasing sperm and ova into the ocean water. Depending on conditions, one organism can produce thousands of gametes.

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Sea cucumbers in art

Surprising as it may seem, sea cucumbers have inspired musical composition: in the first of his Embryons desséchés Erik Satie presents the "(desiccated embryo) of a Holothurian" and inserts a description of the animal in the score:

The Holothurian crawls across boulders and rocky surfaces.

This sea-animal purrs like a cat; also, it produces disgusting silky threads.

Light appears to have an incommodating effect on it.

Nonetheless it is the sea cucumber's closest relative (the echinoidea) that gets the most attention from scientists, both as an embryo and as a fossil.

Sea cucumbers have also inspired thousands of haiku in Japan, where they are called "namako." In haiku, they are usually called "sea slugs", for the sake of the sluggish metaphor, and there is a book with almost 1000 holothurian haiku translated from Japanese titled "Rise, Ye Sea Slugs!" by Robin D. Gill (ISBN 0974261807). According to the OED, the "sea slug" is a holothurian first, but biologists insist on using "sea slug" only for the nudibranch, a mollusc famous for its neat little brain. The sea-cucumber itself does not mind either way, for it is famous for having no brain whatsoever, not even the start of a ganglia.

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Sea cucumber as food and medicine

Sea cucumber is one of the most unique foodstuffs in Chinese cuisine. It is highly valued for its supposed medicinal properties. The flesh of the animal is "cleaned" in a process that takes several days. Trepang is often purchased dried, and rehydrated before use. The product is used in Chinese stews and braised dishes due to its gelatinous texture but is unappetising on its own. In Japanese cuisine, Konowata is made of cured sea cucumber entrails which are extracted, salted, and cured. It is considered a major delicacy in Far East countries such as Malaysia, China, Japan, and Indonesia.

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