Baleen 231070 221529505 2008-06-24T22:21:04Z Xp54321 6570313 Reverted edits by [[Special:Contributions/219.89.87.136|219.89.87.136]] to last version by Tkrajcar (using [[WP:HG|Huggle]]) [[Image:Baleen.jpg|frame|Baleen hair is attached to the baleen plate]] '''Baleen''' or '''whalebone''' is the means by which [[baleen whale]]s feed. These whales do not have [[teeth]], but instead have rows of ''baleen plates'' in the upper [[jaw]] – flat, flexible plates with frayed edges, arranged in two [[Parallel (geometry)|parallel]] rows, looking like [[comb]]s of thick [[hair]]. Baleen is not bone, but is composed of [[keratin]], the same substance as hair, [[Horn (anatomy)|horn]], [[claw]]s and [[nail (anatomy)|nails]]. Whales use these combs for [[filter feeding]]. Whales are the only vertebrate group to use this method of feeding in great abundance ([[flamingos]] and [[crabeater seal]]s use similar methods, but do not have baleen), and it has allowed them to grow to immense sizes. The [[Blue Whale|blue whale]], the largest animal ever to have lived, is a baleen whale. Depending on the species of whale, a baleen plate can be 0.5 to 3.5 [[metre|m]] (2 to 12 [[Foot (unit of length)|ft]]) long, and weigh up to 90 [[kg]] (200 lb). Its hairy fringes are called baleen hair or whalebone-hair. Baleen plates are broader at the gumline (base). The plates have been compared to [[sieve]]s or [[Window blind#Venetian|Venetian blind]]s. The word "baleen" derives from [[Early Modern English]] word meaning "[[whale]]". This in turn derives from the [[Latin]] ''balaena'', related to the [[Greek language|Greek]] ''phallaina'' – both of these also mean "whale". ==Evolution of baleen== The oldest true [[fossil]]s of baleen are only 15 million years old, but baleen rarely fossilizes, and scientists believe it originated considerably earlier than that. This is indicated by skull modifications which are associated with baleen (such as a buttress of bone found beneath the eyes in the upper jaw, and loose lower jaw bones at the chin), being found in fossils from considerably earlier. Currently, baleen is believed to have evolved around thirty million years ago, possibly from a creature with a hard, gummy upper jaw, similar to that found on [[Dall's porpoise]] today, which are, at a microscopic level, almost identical to baleen. Curiously, many early baleen whales also had teeth, but these were likely used only peripherally, or perhaps not at all (again, similar to Dall's porpoise, which catches squid and fish by gripping them against its hard upper jaw). ==Baleen in filter feeding== A whale's baleen plates play the most important role in its filter feeding process. In order to feed, a baleen whale opens its mouth widely and scoops in dense [[Shoal (disambiguation)|shoal]]s of prey (such as [[krill]] (euphausiids), [[copepod]]s or small [[fish]]), together with large volumes of water. It then partly shuts its mouth and presses its tongue against its upper jaw, forcing the water to pass out sideways through the baleen, thus sieving out the prey which is then swallowed. ==Uses of baleen== Whalebone was formerly used in buggy whips and parasol ribs, and to stiffen parts of women's stays and [[dress]]es, like [[corset]]s. It was commonly used to crease [[paper]]; its flexibility keeps it from damaging the paper. Its function now has been replaced by [[plastic]]. It is also used in the [[cable-backed bow]]. ==See also== * [[Baleen whale]] ==Further reading== * St. Aubin, D.J, R.H. Stinson and J.R. Geraci 1984. "Aspects of the structure and function of baleen, and some effects of exposure to petroleum hydrocarbons". ''Canadian Journal of Zoology'' 62: 193-198 {{Whaling}} [[Category:Cetaceans]] [[Category:Whale products]] [[zh-min-nan:Keng-chhiu]] [[de:Fischbein]] [[eo:Barto]] [[fr:Fanon]] [[it:Fanone]] [[nl:Balein]] [[ja:鯨ひげ]] [[no:Hvalbarde]] [[pl:Fiszbin]] [[pt:Barbas de baleia]] [[sv:Barder]]