What is Carcharhinidae?
{{Taxobox | name = Carcharhinidae | image = Carcharhinus_perezi_at_Roatan2.jpg | image_caption = A [[bull shark]], ''Carcharhinus leucas'' | regnum = [[Animal]]ia | phylum = [[Chordata]] | classis = [[Chondrichthyes]] | ordo = [[Carcharhiniformes]] | familia = '''Carcharhinidae''' }} '''Carcharhinidae''', also known as the '''requiem sharks''', is a [[family (biology)|family]] of [[shark]]s in the [[Order (biology)|order]] [[Carcharhiniformes]]. There are currently 60 [[species]] of requiem sharks which are grouped into 12 [[genus|genera]]. Some of the most familiar species in this family are the [[lemon shark]], the [[blue shark]], the [[tiger shark]], the [[bull shark]], and the [[whitetip reef shark]]. Requiem sharks are found in [[temperate]] and [[tropical]] [[ocean]]s, and many species are worldwide. Some live in the open ocean ([[oceanic whitetip shark]]), while some live in freshwater [[river]]s and [[lake]]s ([[bull shark]]).<ref>{{Cite web|title=Facts about Requiem Sharks(Carcharhinidae)-Encyclopedia of Life|url=http://eol.org/pages/1901/details|work=eol.org|access-date= 22 June 2013}} </ref> All species of requiem sharks have a head of normal shape. Their [[eye]]s have a nictitating (winking) [[membrane]]s. They have [[caudal fin]]s with the upper lobe being larger than the lower but not very long, two spineless [[dorsal fin]]s, the first one usually much larger than the second in most of the [[Atlantic Ocean|Atlantic]] species, an [[anal fin]], a caudal peduncle which doesn't have lateral keels, and sharp, bladelike [[teeth]] with a single cusp. <ref>{{Cite web|title=Requiem sharks, family Carcharhinidae. |url=http://www.gma.org/fogm/Carcharhinidae.htm|work=gma.org|access-date=22 June 2013}} </ref> Almost all species of requiem sharks have a similar diet of [[fish]], [[octopus]], [[Marine biology|marine]] [[mammal]]s and [[seabird]]s. Since they look similar, it is usually hard to tell one species from another.<ref>{{Cite web|title=BBC Nature-Requiem sharks videos,news,and facts|url=http://www.b