Editing Shark (section)

====Asexual====
There have been a number of documented cases in which a female shark who has not been in contact with a male has conceived a pup on her own through [[parthenogenesis]].<ref>{{cite journal
|author1=Chapman DD |author2=Shivji MS |author3=Louis E |author4=Sommer J |author5=Fletcher H |author6=Prodöhl PA |title=Virgin birth in a hammerhead shark
|journal=Biology Letters
|volume=3
|issue=4
|pages=425–7
|year=2007
|pmid=17519185
|pmc=2390672
|doi=10.1098/rsbl.2007.0189}}</ref><ref>''[https://www.boston.com/news/nation/articles/2008/10/10/in_shark_tank_an_asexual_birth/ In shark tank, an asexual birth] {{Webarchive|url=https://web.archive.org/web/20090709165903/http://www.boston.com/news/nation/articles/2008/10/10/in_shark_tank_an_asexual_birth/ |date=2009-07-09 }}'', Boston Globe, 10 Oct. 2008</ref> The details of this process are not well understood, but [[genetic fingerprinting]] showed that the pups had no paternal genetic contribution, ruling out [[female sperm storage|sperm storage]]. The extent of this behavior in the wild is unknown. Mammals are now the only major [[vertebrate]] group in which [[asexual reproduction]] has not been observed.

Scientists say that asexual reproduction in the wild is rare, and probably a last-ditch effort to reproduce when a mate is not present. Asexual reproduction diminishes [[genetic diversity]], which helps build defenses against threats to the species. Species that rely solely on it risk extinction. Asexual reproduction may have contributed to the [[blue shark]]'s decline off the [[Ireland|Irish]] coast.<ref>{{cite news
|url=https://www.nytimes.com/2007/05/23/science/23shark.html
|title=Female sharks reproduce without male DNA, scientists say
|newspaper=The New York Times
|access-date=2007-11-13
|first=Henry
|last=Fountain
|date=2007-05-23
|archive-url=https://web.archive.org/web/20090417112821/http://www.nytimes.com/2007/05/23/science/23shark.html
|archive-date=2009-04-17
|url-status=live
}}</ref>