Editing Shark (section)

===Teeth===
{{Main|Shark tooth}}
[[File:Tiger shark teeth.jpg|thumb|The teeth of [[tiger shark]]s are oblique and serrated to saw through flesh|alt=The serrated teeth of a [[tiger shark]], used for sawing through flesh]]

Shark teeth are embedded in the [[Gingiva|gums]] rather than directly affixed to the jaw, and are constantly replaced throughout life. Multiple rows of replacement teeth grow in a groove on the inside of the jaw and steadily move forward in comparison to a [[conveyor belt]]; some sharks lose 30,000 or more teeth in their lifetime. The rate of tooth replacement varies from once every 8 to 10 days to several months. In most species, teeth are replaced one at a time as opposed to the simultaneous replacement of an entire row, which is observed in the [[Isistius|cookiecutter shark]].<ref>{{cite web
| url = http://www.elasmo-research.org/education/white_shark/teeth.htm
| title = Teeth of the Skin
| first = R. Aidan
| last = Martin
| access-date = 2007-08-28
| archive-url = https://web.archive.org/web/20071012160555/http://elasmo-research.org/education/white_shark/teeth.htm
| archive-date = 2007-10-12
| url-status = live
}}</ref>

Tooth shape depends on the shark's diet: those that feed on [[mollusk]]s and [[crustacean]]s have dense and flattened teeth used for crushing, those that feed on fish have needle-like teeth for gripping, and those that feed on larger prey such as [[mammal]]s have pointed lower teeth for gripping and triangular upper teeth with [[serration|serrated]] edges for cutting. The teeth of plankton-feeders such as the basking shark are small and non-functional.<ref name="Gilbertson" />