Editing Nipple (section)

===In male mammals===<!-- this section is target of [[:Male nipple]] redirect; update that link if you rename this section -->
[[File:Nipple of male human.jpg|thumb|Nipple of a human male]]
Almost all [[mammals]] have nipples. Why males have nipples has been the subject of scientific research.  Differences among the sexes (called [[sexual dimorphism]]) within a given species are considered by [[evolutionary biologist]]s to be mostly the result of [[sexual selection]], directly or indirectly. There is a consensus that the male nipple exists because there is no particular advantage to males losing the trait. In consequence, some biologists would call the male nipple a [[Spandrel (biology)|spandrel]].<ref>{{cite journal|last1=Lawrence|first1=Eleanor|title=Why do men have nipples?|journal=Nature News|date=5 August 1999|doi=10.1038/news990805-1|url=http://www.nature.com/news/1999/990805/full/news990805-1.html|language=en}}</ref><ref>{{cite web|last1=Burke|first1=Anna|title=Do Male Dogs Have Nipples?|url=http://www.akc.org/content/dog-care/articles/do-male-dogs-have-nipples/|website=American Kennel Club|language=en|date=July 19, 2017}}</ref><ref>{{cite news|last1=Simons|first1=Andrew M.|title=Why do men have nipples?|url=https://www.scientificamerican.com/article/why-do-men-have-nipples/|work=Scientific American|date=January 13, 2003|language=en}}</ref>

In humans, the nipples are often surrounded by [[body hair]].