Editing Sexual intercourse (section)

==Other animals==
{{Main|Copulation (zoology)|Animal sexual behaviour}}
{{See also|Sexual coercion among animals}}
[[File:Lion sex.jpg|thumb|A pair of [[Lion#Reproduction and life cycle|lions copulating]] in the [[Maasai Mara]], [[Kenya]]]]
[[File:Housefly mating.jpg|thumb|Mating [[Housefly|houseflies]]]]
In [[zoology]], ''copulation'' often means the process in which a male introduces sperm into the female's body, especially directly into her reproductive tract.<ref name="Kent"/><ref name="Copulation1"/> [[Spider]]s have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on it. He then stores the sperm in reservoirs on his large [[pedipalp]]s, from which he transfers sperm to the female's genitals. The females can store sperm indefinitely.<ref name="RFB2004Spiders">{{cite book | author=Ruppert, E.E. | author2=Fox, R.S. | author3=Barnes, R.D. | name-list-style=amp | title=Invertebrate Zoology | publisher=Brooks/Cole | edition=7th | isbn=978-0-03-025982-1 | year=2004 | pages=[https://archive.org/details/isbn_9780030259821/page/571 571–584] | chapter=Chelicerata: Araneae | url=https://archive.org/details/isbn_9780030259821/page/571 }}</ref>

Many animals that live in water use [[external fertilization]], whereas [[internal fertilization]] may have developed from a need to maintain [[gamete]]s in a liquid medium in the [[Late Ordovician]] epoch. Internal fertilization with many vertebrates (such as [[reptile]]s, some [[fish]], and most [[bird]]s) occur via [[cloaca]]l copulation (see also [[hemipenis]]), while [[mammal]]s copulate vaginally, and many [[primitive (biology)|basal]] [[vertebrate]]s reproduce sexually with external fertilization.<ref name="Starr">{{cite book| author =Cecie Starr| author2 =Christine Evers| author3 =Lisa Starr|title=Cengage Advantage Books: Biology: A Human Emphasis|publisher =[[Cengage Learning]]| year = 2010 | pages = 630–631| access-date = December 9, 2010 |isbn =978-1-133-17005-1| url =https://books.google.com/books?id=DdU8AAAAQBAJ&pg=PA631}}</ref><ref name="Denecke">{{cite book| author =Edward J. Denecke Jr.|title=New York State Grade 8 Intermediate Level Science Test|publisher =[[Barron's Educational Series]]| year = 2006 | page = 105| access-date = December 9, 2014 |isbn = 978-0-7641-3433-3| url =https://books.google.com/books?id=dbF6g4geyfsC&pg=PA105}}</ref>

For primitive [[insect]]s, the male deposits [[spermatozoa]] on the substrate, sometimes stored within a special structure; [[Courtship display|courtship]] involves inducing the female to take up the sperm package into her genital opening, but there is no actual copulation.<ref name="Yadav">{{cite book| author =M. Yadav|title=Breeding in Insects|publisher =Discovery Publishing House| year = 2003 | page = 59| access-date = December 9, 2014 |isbn = 978-81-7141-737-7| url =https://books.google.com/books?id=ZC5obBYtusEC&pg=PA59}}</ref><ref name="Engelmann">{{cite book| author =Franz Engelmann|title=The Physiology of Insect Reproduction: International Series of Monographs in Pure and Applied Biology: Zoology|publisher =[[Elsevier]]| year = 2013 | pages = 58–59| access-date = December 9, 2014 |isbn = 978-1-4831-8653-5| url =https://books.google.com/books?id=4bXYBAAAQBAJ&pg=PA58}}</ref> In groups that have reproduction similar to spiders, such as [[dragonflies]], males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified [[sternites]] on the second abdominal segment.<ref name="Leonard">{{cite book| author =Janet Leonard| author2 =Alex Cordoba-Aguilar|title=The Evolution of Primary Sexual Characters in Animals|publisher =[[Oxford University Press]]| year = 2010 | page =334| access-date = December 9, 2014 |isbn = 978-0-19-971703-3| url =https://books.google.com/books?id=PgtXj5R6OfMC&pg=PA334}}</ref> In advanced groups of insects, the male uses its [[aedeagus]], a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a ''[[spermatophore]]'') into the female's reproductive tract.<ref name="Gullan">{{cite book| author =P. J. Gullan| author2 =P. S. Cranston|title=The Insects: An Outline of Entomology|publisher =[[John Wiley & Sons]]| year = 2009| page = 124| access-date = December 9, 2014 |isbn = 978-1-4051-4457-5| url =https://books.google.com/books?id=E_6-pGOLUgcC&pg=PA124}}</ref>

Bonobos, chimpanzees and dolphins are species known to engage in heterosexual behaviors even when the female is not in estrus, which is a point in her reproductive cycle suitable for successful impregnation. These species are also known to [[Homosexual behavior in animals|engage in same-sex sexual behaviors]].<ref name="Non-human"/> In these animals, the use of sexual intercourse has evolved beyond reproduction to apparently serve additional social functions (such as bonding).<ref name="Balcombe"/>