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| image = Hammerhead shark.jpg | image_width = 240px | image_caption = Scalloped hammerhead, ''Sphyrna lewini'' | regnum = Animalia | phylum = Chordata | classis = Chondrichthyes | subclassis = Elasmobranchii | superordo = Selachimorpha | ordo = Carcharhiniformes | familia = Sphyrnidae | familia_authority = T. N. Gill, 1872 | subdivision_ranks = Genera | subdivision = * ''Eusphyra'' * ''Sphyrna'' | range_map = Sphyrnidae distribution map.svg }} The hammerhead sharks are a group of sharks in the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a "hammer" shape called a cephalofoil. Most hammerhead species are placed in the genus ''Sphyrna'' while the winghead shark is placed in its own genus, ''Eusphyra''. Many not necessarily mutually exclusive functions have been proposed for the cephalofoil, including sensory reception, maneuvering, and prey manipulation. Hammerheads are found worldwide in warmer waters along coastlines and continental shelves. Unlike most sharks, hammerheads usually swim in schools during the day, becoming solitary hunters at night. Some of these schools can be found near Malpelo Island in Colombia, Cocos Island off Costa Rica, and near Molokai in Hawaii. Large schools are also seen in the waters off southern and eastern Africa. ==Description== The unknown species range from in length and weigh from .〔Hessing, S. (2000). (Sphyrna tiburo ). Animal Diversity Web. Retrieved on 2012-12-19.〕 They are usually light gray and have a greenish tint to them. Their bellies are white which allows them to blend into the ocean when viewed from the bottom and sneak up on their prey.〔(Hammerhead Shark ). Sharks-world.com. Retrieved on 2012-12-19.〕 Their heads have lateral projections which give them a hammer-like shape. Hammerheads have disproportionately small mouths and seem to do a lot of bottom-hunting. They are also known to form schools during the day, sometimes in groups of over 100. In the evening, like other sharks, they become solitary hunters. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hammerhead shark」の詳細全文を読む スポンサード リンク
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