Editing Shark (section)

====Sexual====
Sharks practice [[internal fertilization]].<ref name="Adams">{{cite journal|last1=Adams|first1=Kye R.|last2=Fetterplace|first2=Lachlan C.|last3=Davis|first3=Andrew R.|last4=Taylor|first4=Matthew D.|last5=Knott|first5=Nathan A.|date=January 2018|title=Sharks, rays and abortion: The prevalence of capture-induced parturition in elasmobranchs|journal=Biological Conservation|volume=217|pages=11–27|doi=10.1016/j.biocon.2017.10.010|bibcode=2018BCons.217...11A |s2cid=90834034 |url=http://marxiv.org/k2qvy/|access-date=2018-11-24|archive-url=https://web.archive.org/web/20190223020619/https://marxiv.org/k2qvy/|archive-date=2019-02-23|url-status=dead}}</ref> The posterior part of a male shark's pelvic fins are modified into a pair of [[intromittent organ]]s called [[clasper]]s, analogous to a [[mammalian penis]], of which one is used to deliver [[sperm]] into the female.<ref name="Mating">{{cite web
 | url =http://elasmo-research.org/education/topics/lh_2penises.htm
 | title =Why Do Sharks Have Two Penises?
 | last =Martin
 | first =R. Aidan
 | publisher =ReefQuest Centre for Shark Research
 | archive-url =https://web.archive.org/web/20090828095620/http://www.elasmo-research.org/education/topics/lh_2penises.htm
 | archive-date =2009-08-28
 | url-status =dead
 | access-date =2009-08-22}}</ref>

[[Mating]] has rarely been observed in sharks.<ref>{{Cite news|url=http://www.andersoncabotcenterforoceanlife.org/blog/how-do-sharks-mate/|title=How Do Sharks Mate? - Center For Ocean Life|work=Center For Ocean Life|access-date=2018-09-09|archive-url=https://web.archive.org/web/20180906025855/http://www.andersoncabotcenterforoceanlife.org/blog/how-do-sharks-mate|archive-date=2018-09-06|url-status=dead}}</ref> The smaller [[Scyliorhinidae|catshark]]s often mate with the male curling around the female. In less flexible species the two sharks swim parallel to each other while the male inserts a clasper into the female's [[oviduct]]. Females in many of the larger species have bite marks that appear to be a result of a male grasping them to maintain position during [[mating]]. The bite marks may also come from courtship behavior: the male may bite the female to show his interest. In some species, females have evolved thicker skin to withstand these bites.<ref name="Mating"/>