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{{Short description|Primary sexual organ of male animals}}
== Basics ==
{{Other uses}}
* [[Open Source|Open-source]] project
{{Confuse|Penix}}
* A drivechain is an alternative to the [[sidechain]] vision outlined in the original [[whitepaper]]. The Drivechain protocol is an alternative to the sidechain concept because it enables multiple [[blockchain]] compatibilities but the system utilizes the same 21 million bitcoins. Sztorc’s Drivechain system claims to allow permissionless innovation without diluting the value of the main cryptocurrency. Because a Drivechain is aligned with [[Nakamoto Consensus|Nakamoto consensus]] it offers the security of the network but with an expanded set of services like [[Smart Contract|smart contracts]].
{{About|penises of animals in general|the human organ|Human penis}}
Sztorc has been working on the Drivechain project for quite some time now, and last December we reported on [https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-December/015339.html the two Drivechain] [[BIP]] proposals Sztorc submitted for review and feedback. This week Sztorc explains he is pleased to announce the first Drivechain version called Testdrive and notes that the release is in two parts.  
{{Redirect2|Penile|Penes|the community|Penile, Louisville|other uses|Penes (disambiguation)}}
* In a drivechain, miners signal the current state of a sidechain. In other words, the [[Miner|miners]] are essentially the custodian of funds, and they’re able to unfreeze funds for users who wish to move their coins back to the main chain.
{{Pp-semi-protected|small=yes}}
* One of the key tenets of drivechains is that miners are the least problematic custodians of funds being used on a sidechain from a game theory perspective. According to Sztorc, drivechains can be structured in a way in which any theft of coins frozen on the mainchain would obviously be orchestrated by miners.
{{Pp-move-indef}}
* [[Sideshift]] is one application among others created for the open-source project Drivechain 
<!--To avoid edit wars, please see relevant discussions on this article's talk page before unilaterally changing the lead picture.-->
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[[#Other mammals|Penis of an Asian elephant]]
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A '''penis''' (plural ''penises'' or ''penes'' ({{IPAc-en|-|n|iː|z}})) is the primary [[sexual organ]] that [[male]] animals use to [[inseminate]] females (or [[hermaphrodite]]s) during [[Copulation (zoology)|copulation]].<ref name="SciencesMexico2010">{{cite book|author1=Janet Leonard|author2=Alex Cordoba-Aguilar R|title=The Evolution of Primary Sexual Characters in Animals|url=https://books.google.com/books?id=PgtXj5R6OfMC|access-date=20 July 2013|date=18 June 2010|publisher=Oxford University Press|isbn=978-0-19-971703-3|url-status=live|archive-url=https://web.archive.org/web/20131011093915/http://books.google.com/books?id=PgtXj5R6OfMC&printsec=frontcover#v=onepage&q=penis&f=false|archive-date=11 October 2013}}</ref><ref>{{cite journal|title=Mating behaviour in the sea slug Elysia timida (Opisthobranchia, Sacoglossa): hypodermic injection, sperm transfer and balanced reciprocity|year=2007|pmc=1934903|last1=Schmitt|first1=V.|last2=Anthes|first2=N.|last3=Michiels|first3=N. K.|journal=Frontiers in Zoology|volume=4|page=17|doi=10.1186/1742-9994-4-17|pmid=17610714}}</ref> Such organs occur in many animals, both [[#Vertebrates|vertebrate]] and [[Invertebrates|invertebrate]], but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, the penises in the various species are not necessarily [[Homology (biology)|homologous]].
== Team, investors, etc. ==
 
* The drivechain concept was developed by [[Paul Sztorc]], who is an economist at [[Bloq]] and the creator of [[Bitcoin Hivemind]]. On September 24, 2018, [https://news.bitcoin.com/developer-paul-sztorc-launches-the-first-version-of-drivechain/ announced] the launch of the first Drivechain release.
The term ''penis'' applies to many [[intromittent organ]]s, but not to all. As an example, the intromittent organ of most [[cephalopod]]a is the [[hectocotylus]], a specialized arm, and male spiders use their [[pedipalp]]s. Even within the [[Vertebrata]] there are morphological variants with specific terminology, such as [[Hemipenis|hemipenes]].
[[Category:Jargon/Various]]
 
In most species of animals in which there is an organ that might reasonably be described as a penis, it has no major function other than intromission, or at least conveying the sperm to the female, but in the [[Eutheria|placental mammals]] the penis bears the [[distal]] part of the [[urethra]], which discharges both [[urine]] during [[urination]] and [[semen]] during copulation.<ref name="Wake1992">{{cite book|author=Marvalee H. Wake|title=Hyman's Comparative Vertebrate Anatomy|url=https://books.google.com/books?id=VKlWjdOkiMwC&pg=PA583|access-date=23 July 2013|date=15 September 1992|publisher=University of Chicago Press|isbn=978-0-226-87013-7|page=583|url-status=live|archive-url=https://web.archive.org/web/20131231143932/http://books.google.com/books?id=VKlWjdOkiMwC&pg=PA583#v=onepage&q=penis&f=false|archive-date=31 December 2013}}</ref>
{{TOC limit|5}}
 
{{Category see also|Animal penises}}
 
==Vertebrates==
 
===Birds===
{{See also|Intromittent organ#Birds|Bird anatomy#Urogenital and Endocrine systems}}
{{anchor|Birds}}
[[File:Mallard with visible pseudo-penis (cropped).jpg|thumb|right|[[Mallard]] [[pseudo-penis]]]]
Most male birds (e.g., [[rooster]]s and [[turkey (bird)|turkey]]s) have a [[cloaca]] (also present on the female), but not a penis. Among bird species with a penis are [[paleognathes]] ([[tinamou]]s and [[ratites]])<ref name="Lombardi1998">{{cite book|author=Julian Lombardi|title=Comparative Vertebrate Reproduction|url=https://books.google.com/books?id=cqQX9RMPAegC&q=penis|access-date=5 December 2012|year=1998|publisher=Springer|isbn=978-0-7923-8336-9|url-status=live|archive-url=https://web.archive.org/web/20140326171659/http://books.google.com/books?id=cqQX9RMPAegC&q=penis&f=false|archive-date=26 March 2014}}</ref> and [[Anatidae]] (ducks, geese and swans).<ref name="MobileReference2009">{{cite book|author=MobileReference|title=The Illustrated Encyclopedia of European Birds: An Essential Guide to Birds of Europe|url=https://books.google.com/books?id=RgPTUkhiSmkC&q=penis|archive-url=https://web.archive.org/web/20140326174050/http://books.google.com/books?id=RgPTUkhiSmkC&q=penis&f=false|url-status=dead|archive-date=26 March 2014|access-date=5 December 2012|date=15 December 2009|publisher=MobileReference|isbn=978-1-60501-557-6}}</ref> A bird penis is different in structure from [[#Other mammals|mammal penis]]es, being an erectile expansion of the cloacal wall and being erected by [[lymph]], not blood.<ref name="Gill2006">{{cite book|author=Frank B. Gill|title=Ornithology|url=https://books.google.com/books?id=zM0tG5ApO0UC&q=penis&pg=PA414|access-date=5 December 2012|date=6 October 2006|publisher=Macmillan|isbn=978-0-7167-4983-7|pages=414–|url-status=live|archive-url=https://web.archive.org/web/20140107223055/http://books.google.com/books?id=zM0tG5ApO0UC&pg=PA414&q=penis&f=false|archive-date=7 January 2014}}</ref> It is usually partially feathered and in some species features spines and brush-like filaments, and in flaccid [[state]] curls up inside the [[cloaca]].
 
While most male birds have no external genitalia, male waterfowl ([[Anatidae]]) have a phallus. Most birds mate with the males balancing on top of the females and touching cloacas in a "cloacal kiss"; this makes [[Sexual coercion among animals|forceful insemination]] very difficult. The phallus that male waterfowl have evolved everts out of their bodies (in a clockwise coil) and aids in inseminating females without their cooperation.<ref name="sixteen">Brennan, P. L. R. et al. Coevolution of male and female genital morphology in waterfowl. ''PLoS ONE'' 2, e418 (2007).</ref> The male waterfowl [[evolution]] of a phallus to forcefully copulate with females has led to counteradaptations in females in the form of vaginal structures called dead end sacs and clockwise coils. These structures make it harder for males to achieve intromission. The clockwise coils are significant because the male phallus everts out of their body in a counter-clockwise spiral; therefore, a clockwise vaginal structure would impede forceful copulation. Studies have shown that the longer a male's phallus is, the more elaborate the vaginal structures were.<ref name="sixteen"/>
[[File:Duck Reproduction.svg|thumb|Females have corkscrew vaginas with many blind pockets designed for difficult penetration and to prevent becoming pregnant. This reduced the likelihood of fertilization by unwanted aggressors in favor of fitter mates.]]
The [[lake duck]] is notable for possessing, in relation to body length, the [[largest body part|longest]] penis of all [[vertebrates]]; the penis, which is typically coiled up in flaccid state, can reach about the same length as the animal himself when fully erect, but is more commonly about half the bird's length.<ref>{{cite journal|last=McCracken|first=Kevin G.|year=2000|title=The 20-cm Spiny Penis of the Argentine Lake Duck (''Oxyura vittata'')|journal=[[The Auk]]|volume=117|issue=3|pages=820–825|url=http://www.bio.miami.edu/mccracken/reprints/auk-117-820.pdf|doi=10.2307/4089612|url-status=live|archive-url=https://web.archive.org/web/20150923185838/http://www.bio.miami.edu/mccracken/reprints/auk-117-820.pdf|archive-date=2015-09-23|jstor=4089612}}</ref><ref>{{cite journal|last1=McCracken|first1=Kevin G.|first2=Robert E.|last2=Wilson|first3=Pamela J.|last3=McCracken|first4=Kevin P.|last4=Johnson|year=2001|title=Sexual selection: Are ducks impressed by drakes' display?|journal=[[Nature (journal)|Nature]]|volume=413|issue=6852|page=128|doi=10.1038/35093160|url=http://www.bio.miami.edu/mccracken/reprints/nature-413-128.pdf|pmid=11557968|url-status=live|archive-url=https://web.archive.org/web/20160123225012/http://www.bio.miami.edu/mccracken/reprints/nature-413-128.pdf|archive-date=2016-01-23|bibcode=2001Natur.413..128M|s2cid=4321156|doi-access=free}}</ref> It is theorized that the remarkable size of their [[Penile spines|spiny penises]] with bristled tips may have evolved in response to competitive pressure in these highly promiscuous birds, removing sperm from previous matings in the manner of a [[brush|bottle brush]]. The lake duck has a corkscrew shaped penis.<ref>{{Cite web|url=http://www.cosmosmagazine.com/node/1277|archiveurl=https://web.archive.org/web/20080725153127/http://www.cosmosmagazine.com/node/1277|url-status=dead|title=Duck genitals locked in arms race &#124; COSMOS magazine<!-- Bot generated title -->|archivedate=July 25, 2008}}</ref>
 
Male and female [[emu]]s are similar in appearance,<ref name=e23>Eastman, p. 23.</ref> although the male's penis can become visible when it defecates.<ref name=cc366>Coddington and Cockburn, p. 366.</ref>
 
The male tinamou has a corkscrew shaped penis, similar to those of the ratites and to the [[hemipenis]] of some reptiles. Females have a small phallic organ in the cloaca which becomes larger during the breeding season.<ref name=Cabot>{{cite encyclopedia|last1=Cabot| first1=J. |last2= Carboneras| first2= C.| last3= Folch| first3= A. |last4=de Juanca| first4= E. |last5=Llimona|first5=F. |last6=Matheu|first6=E.|year=1992 |editor-first=J.
|editor-last=del Hoyo|publisher=Lynx Edicions|location= Barcelona, Spain| volume= I: Ostrich to Ducks| encyclopedia= Handbook of the Birds of the World|title= Tinamiformes}}</ref>
 
=== Mammals ===
{{commons category|Mammal penis}}
[[File:Hundepenis.jpg|thumb|200px|External male genitalia of a [[Labrador Retriever]]]]
As with any other bodily attribute, the length and girth of the penis can be highly variable between mammals of different [[species]].<ref>{{cite book|author=Tim Birkhead|title=Promiscuity: An Evolutionary History of Sperm Competition|url=https://books.google.com/books?id=3i4Q8SvohfEC&pg=PA102|access-date=23 July 2013|year=2000|publisher=Harvard University Press|isbn=978-0-674-00666-9|page=102|url-status=live|archive-url=https://web.archive.org/web/20140326175533/http://books.google.com/books?id=3i4Q8SvohfEC&pg=PA102#v=onepage&q=penis&f=false|archive-date=26 March 2014}}</ref><ref name="HayssenTienhoven1993">{{cite book|author1=Virginia Douglass Hayssen|author2=Ari Van Tienhoven|title=Asdell's Patterns of Mammalian Reproduction: A Compendium of Species-Specific Data|url=https://archive.org/details/asdellspatternso00hays|url-access=registration|access-date=23 July 2013|year=1993|publisher=Cornell University Press|isbn=978-0-8014-1753-5}}</ref> In many mammals, the size of a flaccid penis is smaller than its [[Erection|erect]] size.
 
A bone called the [[baculum]] or ''os penis'' is present in most mammals but absent in humans, cattle and [[horse penis|horse]]s.
 
In mammals the penis is divided into three parts:<ref name="Reece"/>
 
* Roots ([[Crus of penis|crura]]): these begin at the [[Caudal (anatomical term)|caudal]] border of the [[Pubic arch|pelvic ischial arch]].
* [[Body of penis|Body]]: the part of the penis extending from the roots.
* [[Glans penis|Glans]]: the free end of the penis.
 
The internal structures of the penis consist mainly of cavernous, [[erectile tissue]], which is a collection of [[Sinusoid (blood vessel)|blood sinusoids]] separated by sheets of [[connective tissue]] (trabeculae). Some mammals have a lot of erectile tissue relative to connective tissue, for example horses. Because of this a [[horse's penis]] can enlarge more than a [[bull's penis]]. The [[urethra]] is on the ventral side of the body of the penis. As a general rule, a mammal's penis is proportional to its body size, but this varies greatly between species{{spaced ndash}}even between closely related ones. For example, an adult [[gorilla]]'s erect penis is about {{convert|4.5|cm|in|abbr=on}} in length; an adult [[Common chimpanzee|chimpanzee]], significantly smaller (in body size) than a gorilla, has a penis size about double that of the gorilla. In comparison, the [[human penis]] is larger than that of any other [[primate]], both in proportion to body size and in absolute terms.<ref name="ParkerJaffe2008">{{cite book|author1=Sue Taylor Parker|author2=Karin Enstam Jaffe|title=Darwin's Legacy: Scenarios in Human Evolution|url=https://books.google.com/books?id=gtcWrI60_zsC&pg=PA121|access-date=23 July 2013|year=2008|publisher=AltaMira Press|isbn=978-0-7591-0316-0|page=121|url-status=live|archive-url=https://web.archive.org/web/20140326182559/http://books.google.com/books?id=gtcWrI60_zsC&pg=PA121#v=onepage&q=penis&f=false|archive-date=26 March 2014}}</ref>
 
==== Artiodactyls ====
The penises of even-toed ungulates are curved in an S-shape when not erect.<ref>{{cite book|author=Uwe Gille|title=urinary and sexual apparatus, urogenital Apparatus. In: F.-V. Salomon and others (eds.): Anatomy for veterinary medicine|year=2008|pages=368–403|isbn=978-3-8304-1075-1}}</ref> In [[bull penis|bull]]s, [[Ovis|rams]] and [[boar]]s, the sigmoid flexure of the penis straightens out during erection.<ref name="BonetCasas2013">{{cite book|author1=Sergi Bonet|author2=Isabel Casas|author3=William V Holt|author4=Marc Yeste|title=Boar Reproduction: Fundamentals and New Biotechnological Trends|url=https://books.google.com/books?id=ta9GAAAAQBAJ|date=1 February 2013|publisher=Springer Science & Business Media|isbn=978-3-642-35049-8|url-status=live|archive-url=https://web.archive.org/web/20160505213256/https://books.google.com/books?id=ta9GAAAAQBAJ&printsec=frontcover#v=onepage&q=penis&f=false|archive-date=5 May 2016}}</ref>
 
When mating, the tip of a male [[pronghorn]]'s penis is often the first part to touch the female pronghorn.<ref>{{cite book|author=John A. Byers|title=American Pronghorn: Social Adaptations and the Ghosts of Predators Past|url=https://books.google.com/books?id=H170TWNKyuYC&q=penis|access-date=23 July 2013|year=1997|publisher=University of Chicago Press|isbn=978-0-226-08699-6|url-status=live|archive-url=https://web.archive.org/web/20140326172111/http://books.google.com/books?id=H170TWNKyuYC&q=penis&f=false|archive-date=26 March 2014}}</ref> The pronghorn's penis is about {{convert|5|in|cm|0|abbr=on|order=flip}} long, and is shaped like an ice pick.<ref>{{cite book|author=John A. Byers|title=Built for Speed: A Year in the Life of Pronghorn|url=https://books.google.com/books?id=R0AEkQ0jY40C&q=penis|access-date=23 July 2013|date=30 June 2009|publisher=Harvard University Press|isbn=978-0-674-02913-2|url-status=live|archive-url=https://web.archive.org/web/20140326180331/http://books.google.com/books?id=R0AEkQ0jY40C&q=penis&f=false|archive-date=26 March 2014}}</ref> The front of a pronghorn's glans penis is relatively flat, while the back is relatively thick.<ref>{{cite book|author1=Bart W. O'Gara|author2=James D. Yoakum|title=Pronghorn: ecology and management|url=https://books.google.com/books?id=mqrwAAAAMAAJ&q=penis|access-date=23 July 2013|year=2004|publisher=University Press of Colorado|isbn=978-0-87081-757-1|url-status=live|archive-url=https://web.archive.org/web/20140326182136/http://books.google.com/books?id=mqrwAAAAMAAJ&q=penis&f=false|archive-date=26 March 2014}}</ref> The male pronghorn usually [[ejaculates]] immediately after intromission.<ref name="Byers1997">{{cite book|author=John A. Byers|title=American Pronghorn: Social Adaptations and the Ghosts of Predators Past|url=https://books.google.com/books?id=H170TWNKyuYC|access-date=15 July 2013|year=1997|publisher=University of Chicago Press|isbn=978-0-226-08699-6|url-status=live|archive-url=https://web.archive.org/web/20140101052335/http://books.google.com/books?id=H170TWNKyuYC&printsec=frontcover#v=onepage&q=(ejaculate%7Cejaculates%7Cejaculation)&f=false|archive-date=1 January 2014}}</ref><ref name="Byers2009">{{cite book|author=John A. Byers|title=Built for Speed: A Year in the Life of Pronghorn|url=https://books.google.com/books?id=R0AEkQ0jY40C|access-date=15 July 2013|date=30 June 2009|publisher=Harvard University Press|isbn=978-0-674-02913-2|url-status=live|archive-url=https://web.archive.org/web/20140101045402/http://books.google.com/books?id=R0AEkQ0jY40C&printsec=frontcover#v=onepage&q=(ejaculate%7Cejaculates%7Cejaculation)&f=false|archive-date=1 January 2014}}</ref>
 
The penis of a [[dromedary]] camel is covered by a triangular penile sheath opening backwards,<ref name="Yagil1985">{{cite book|author=R. Yagil|title=The desert camel: comparative physiological adaptation|url=https://books.google.com/books?id=Nq3wAAAAMAAJ&q=penis|access-date=5 September 2013|year=1985|publisher=Karger|isbn=978-3-8055-4065-0|url-status=live|archive-url=https://web.archive.org/web/20140101072733/http://books.google.com/books?ei=OcsoUrbcIaO4sQT76YH4Bg&id=Nq3wAAAAMAAJ&q=penis#search_anchor|archive-date=1 January 2014}}</ref> and is about {{convert|60|cm|in|abbr=on}} long.<ref name=mammal>{{cite journal|last=Kohler-Rollefson|first=I. U.|title=''Camelus dromedarius''|journal=[[Mammalian Species]]|date=12 April 1991|issue=375|pages=1–8|url=http://www.science.smith.edu/msi/pdf/i0076-3519-375-01-0001.pdf|doi=10.2307/3504297|url-status=dead|archive-url=https://web.archive.org/web/20130521140058/http://www.science.smith.edu/msi/pdf/i0076-3519-375-01-0001.pdf|archive-date=21 May 2013|jstor=3504297}}</ref><ref name="SmutsBezuidenhout1987">{{cite book|author1=Malie Marie Sophie Smuts|author2=Abraham Johannes Bezuidenhout|title=Anatomy of the dromedary|url=https://books.google.com/books?id=tCtWAAAAYAAJ&q=penis|access-date=11 June 2013|year=1987|publisher=Clarendon Press|isbn=978-0-19-857188-9|url-status=live|archive-url=https://web.archive.org/web/20140326180636/http://books.google.com/books?ei=zFi3UcGMGcm30AGiqoFg&id=tCtWAAAAYAAJ&dq=penis#search_anchor|archive-date=26 March 2014}}</ref> The camelmen often aid the male to enter his penis into the female's [[vulva]], though the male is considered able to do it on his own. Copulation time ranges from 7 to 35 minutes, averaging 11–15 minutes.<ref name=mating>{{cite book|last=Mukasa-Mugerwa|first=E.|url=https://books.google.com/books?id=ipGBmdJy_5cC&q=camel+penis+mating&pg=PA20|title=The Camel (Camelus dromedarius): A Bibliographical Review|page=20|access-date=2013-11-08|url-status=live|archive-url=https://web.archive.org/web/20140326180541/http://books.google.com/books?id=ipGBmdJy_5cC&pg=PA20&dq=camel+penis+mating&hl=en&sa=X&ei=K1S3UbTTEse84AP1jYAo&ved=0CDAQ6AEwAA#v=onepage&q=camel%20penis%20mating&f=false|archive-date=2014-03-26|date=1981-01-01}}</ref><ref>{{cite book|title=Nomadic Peoples|url=https://books.google.com/books?id=1vu0AAAAIAAJ&q=penis|access-date=11 June 2013|year=1992|publisher=Commission on Nomadic Peoples|url-status=live|archive-url=https://web.archive.org/web/20140326181036/http://books.google.com/books?ei=K1S3UbTTEse84AP1jYAo&id=1vu0AAAAIAAJ&dq=penis#search_anchor|archive-date=26 March 2014}}</ref>
 
{{anchor|Bulls}}
{{Commons category|Bull penis}}
Bulls [[Bovine male reproductive system|have a fibro-elastic penis]]. Given the small amount of erectile tissue, there is little enlargement after erection. The penis is quite rigid when non-erect, and becomes even more rigid during erection. Protrusion is not affected much by erection, but more by relaxation of the [[retractor penis muscle]] and straightening of the [[sigmoid flexure]].<ref name="Sarkar">{{cite book| last =Sarkar| first = A.| title = Sexual Behaviour In Animals| publisher = Discovery Publishing House| year = 2003| isbn = 978-81-7141-746-9}}</ref><ref name="Reece">{{cite book|title=Functional Anatomy and Physiology of Domestic Animals|url=https://books.google.com/books?id=naSWWxJLcd0C&q=penis%20OR%20glans|date=2009-03-04|publisher=John Wiley & Sons|isbn=9780813814513|author=William O. Reece|url-status=live|archive-url=https://web.archive.org/web/20180320145847/https://books.google.com/books?id=naSWWxJLcd0C&q=penis%20OR%20glans&f=false|archive-date=2018-03-20}}</ref><ref>{{cite book |url=https://books.google.com/books?id=7Z9o_vGPP4cC |title=Modern Livestock and Poultry Production - James R. Gillespie, Frank B. Flanders |access-date=2012-12-02 |url-status=live |archive-url=https://web.archive.org/web/20130204074837/http://books.google.com/books?id=7Z9o_vGPP4cC&printsec=frontcover#v=onepage&q=bull%20sigmoid%20flexure&f=false |archive-date=2013-02-04 |isbn=978-1428318083 |last1=Gillespie |first1=James R. |last2=Flanders |first2=Frank |date=2009-01-28 }}</ref>
 
The male genitalia of [[mouse deer]] are similar to those of pigs.<ref>{{cite journal | last1 = Vidyadaran | first1 = M. K. | display-authors = etal | year = 1999 | title = Male genital organs and accessory glands of the lesser mouse deer, Tragulus javanicus | url = https://academic.oup.com/jmammal/article-pdf/80/1/199/2511074/80-1-199.pdf | journal = Journal of Mammalogy | volume = 80 | issue = 1| pages = 199–204 | doi = 10.2307/1383219 | jstor = 1383219 | doi-access = free }}</ref> A boar's penis, which rotates rhythmically during copulation,<ref name="Eberhard1996">{{cite book|author=William G. Eberhard|title=Female Control: Sexual Selection by Cryptic Female Choice|url=https://books.google.com/books?id=A0kcDzAlYy4C&q=penis|access-date=23 July 2013|year=1996|publisher=Princeton University Press|isbn=978-0-691-01084-7|url-status=live|archive-url=https://web.archive.org/web/20140326175332/http://books.google.com/books?id=A0kcDzAlYy4C&q=penis&f=false|archive-date=26 March 2014}}</ref> is about {{convert|18|in|cm|order=flip|abbr=on}} long, and ejaculates about a pint of semen.<ref name="Miller2011">{{cite book|author=Geoffrey Miller|title=The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature|url=https://books.google.com/books?id=QG-8PbZb4csC&q=penis|access-date=23 July 2013|date=21 December 2011|publisher=Knopf Doubleday Publishing Group|isbn=978-0-307-81374-9|url-status=live|archive-url=https://web.archive.org/web/20140326181700/http://books.google.com/books?id=QG-8PbZb4csC&q=penis&f=false|archive-date=26 March 2014}}</ref> Wild boars have a roughly egg-sized sack [[near]] the opening of the penis, which collects urine and emits a sharp odour. The purpose of this is not fully understood.<ref name=heptner1988>Heptner, V. G.; Nasimovich, A. A.; Bannikov, A. G.; Hoffman, R. S. (1988) [https://archive.org/stream/mammalsofsovietu11988gept#page/18/mode/2up ''Mammals of the Soviet Union''], Volume I, Washington, D.C. : Smithsonian Institution Libraries and National Science [[Foundation]], pp. 19-82</ref>
 
=====Deer=====
{{Main|Deer penis}}
A stag's penis forms an S-shaped [[curve]] when it is not erect, and is retracted into its sheath by the retractor penis muscle.<ref>{{cite book|url=https://books.google.com/books?id=ni6Hbqm04vIC&q=deer+penis+erect&pg=PA312 |archive-url=https://web.archive.org/web/20130528110804/http://books.google.com/books?id=ni6Hbqm04vIC&pg=PA312&dq=deer%2Bpenis%2Berect&hl=en&sa=X&ei=B1MZUd-dGofE0AGBuYHYAw&ved=0CDAQ6AEwAA |url-status=dead |archive-date=2013-05-28 |title=The Deer of North America: The Standard Reference on All North American Deer Species--Behavior, Habitat, Distribution, and More |author=Leonard Lee Rue III |year=2004 |publisher=LYONS Press |isbn=9781592284658 |access-date=2013-05-05 }}</ref> Some deer species [[Self-anointing#Ungulates|spray urine on their bodies]] by urinating from an erect penis.<ref name="Walther1984">{{cite book|author=Fritz R. Walther|title=Communication and expression in hoofed mammals|url=https://books.google.com/books?id=vTtErpxA8BYC&q=deer+penis+urinating|access-date=5 July 2013|year=1984|publisher=Indiana University Press|isbn=978-0-253-31380-5|url-status=live|archive-url=https://web.archive.org/web/20131012223637/http://books.google.com/books?id=vTtErpxA8BYC&q=deer+penis+urinating&dq=deer+penis+urinating&hl=en&sa=X&ei=f9vWUduqJqi9ywHKwYHYBw&ved=0CFkQ6AEwBzgK|archive-date=12 October 2013}}</ref> One type of scent-marking behavior in elk is known as "thrash-urination,<ref name="McCullough1969">{{cite book|author=Dale R. McCullough|title=The tule elk: its history, behavior, and ecology|url=https://archive.org/details/tuleelkitshistor0000mccu|url-access=registration|access-date=22 July 2013|year=1969|publisher=University of California Press|isbn=978-0-520-01921-8}}</ref><ref name="theriogenology">{{Cite book | url = https://books.google.com/books?id=7qogKGcOENAC | title = Current Therapy in Large Animal Theriogenology | isbn = 9781437713404 | last1 = Youngquist | first1 = Robert S | last2 = Threlfall | first2 = Walter R | date = 2006-11-23 | url-status = live | archive-url = https://web.archive.org/web/20130511035842/http://books.google.com/books?id=7qogKGcOENAC&printsec=frontcover#v=onepage&q=thrash%20urination&f=false | archive-date = 2013-05-11 }}</ref> which typically involves palpitation of the erect penis.<ref name  = "theriogenology"/><ref>{{cite book|url=https://books.google.com/books?id=EV_9pXU1EToC|title=Ultimate Elk Hunting: Strategies, Techniques & Methods|author=Jay Houston|access-date=2013-02-10|url-status=live|archive-url=https://web.archive.org/web/20130511054339/http://books.google.com/books?id=EV_9pXU1EToC&printsec=frontcover#v=onepage&q=urine%20penis%20palpitation&f=false|archive-date=2013-05-11|isbn=9781616732813|date=2008-07-07}}</ref><ref>{{Cite journal | url = https://books.google.com/books?id=WWEQAQAAMAAJ&q=elk+urine+palpitation | title = Behavior of elk (Cervus canadensis) during the rut | last1 = Struhsaker | first1 = Thomas T | year = 1967 | access-date = 2013-11-08}}</ref> A male elk's urethra points upward so that urine is sprayed almost at a right angle to the penis.<ref name = "theriogenology" /> A [[Sambar (deer)|sambar]] stag will mark himself by [[spraying urine]] directly in the face with a highly mobile penis, which is often [[erection|erect]] during its [[rut (mammalian reproduction)|rutting]] activities.<ref name="Valerius 2008">''Deer of the world: their evolution, behaviour, and ecology.'' Valerius Geist. Stackpole Books. 1998. Pg. 73-77.</ref> [[Red deer]] stags often have erect penises during combat.<ref name="SommerVasey2006">{{cite book|last1=Sommer|first1=Volker|last2=Vasey|first2=Paul L.|title=Homosexual Behaviour in Animals: An Evolutionary Perspective|url=https://books.google.com/books?id=KXM3F59y1jkC&q=penis&pg=PA166|access-date=5 May 2013|date=2006-07-27|publisher=Cambridge University Press|isbn=9780521864466|pages=166–|url-status=live|archive-url=https://web.archive.org/web/20140105050941/http://books.google.com/books?id=KXM3F59y1jkC&pg=PA166&q=penis&f=false|archive-date=5 January 2014}}</ref>
 
====Cetaceans====
{{anchor|Whales}}
{{See also|Dolphin#anatomy}}
[[File:Penises in Jars ( 4890599548.jpg|thumb|left|Penises of [[minke whale]]s on display at the [[Icelandic Phallological Museum]]]]
{{commons category|Cetacea penis}}
[[Dolphin#Anatomy|Cetaceans' reproductive organs]] are located inside the body. Male [[cetaceans]] ([[whales]], dolphins, and porpoises) have two slits, the genital groove concealing the penis and one further behind for the [[anus]].<ref name="PerrinWursig2009">{{cite book|author1=William F. Perrin|author2=Bernd Wursig|author3=J. G.M. Thewissen|title=Encyclopedia of Marine Mammals|url=https://books.google.com/books?id=2rkHQpToi9sC|access-date=28 June 2013|date=26 February 2009|publisher=Academic Press|isbn=978-0-08-091993-5|url-status=live|archive-url=https://web.archive.org/web/20131011084144/http://books.google.com/books?id=2rkHQpToi9sC&printsec=frontcover#v=onepage&q=penis&f=false|archive-date=11 October 2013}}</ref><ref name="Tinker1988">{{cite book|author=Spencer Wilkie Tinker|title=Whales of the World|url=https://books.google.com/books?id=ASIVAAAAIAAJ|date=1 January 1988|publisher=Brill Archive|isbn=978-0-935848-47-2}}</ref><ref>{{cite book |url=https://books.google.com/books?id=KudBOfRXjWAC |title=The Dusky Dolphin: Master Acrobat Off Different Shores - Bernd G. Würsig, Bernd Wursig, Melany Wursig |access-date=2012-11-22 |url-status=live |archive-url=https://web.archive.org/web/20131011092813/http://books.google.com/books?id=KudBOfRXjWAC&printsec=frontcover#v=onepage&q=penis&f=false |archive-date=2013-10-11 |isbn=9780080920351 |last1=Würsig |first1=Bernd |last2=Wursig |first2=Melany |date=2009-07-17 }}</ref><ref>{{cite book |url=https://books.google.com/books?id=OuYcepU_YjMC&q=dolphin+penis+genital+slit&pg=PA435 |title=Conservation Endangered Spe: An Interdisciplinary Approach - Edward F. Gibbons, Jr., Barbara Susan Durrant, Jack Demarest |access-date=2012-11-22 |url-status=live |archive-url=https://web.archive.org/web/20130204074833/http://books.google.com/books?id=OuYcepU_YjMC&pg=PA435&dq=dolphin+penis+genital+slit&hl=en&sa=X&ei=R4KuUIazE7LK0AGZ6IGYAw&ved=0CDkQ6AEwAw#v=onepage&q=dolphin%20penis%20genital%20slit&f=false |archive-date=2013-02-04 |isbn=9780791419113 |last1=Gibbons |first1=Edward F. |last2=Durrant |first2=Barbara Susan |last3=Demarest |first3=Jack |year=1995 }}</ref> Cetaceans have fibroelastic penises, similar to those of [[Artiodactyla]].<ref name="Miller2016">{{cite book|author=Debra Lee Miller|title=Reproductive Biology and Phylogeny of Cetacea: Whales, Porpoises and Dolphins|url=https://books.google.com/books?id=sD3NBQAAQBAJ&q=cetacean+penis&pg=PA133|date=19 April 2016|publisher=CRC Press|isbn=978-1-4398-4257-7|pages=133–|url-status=live|archive-url=https://web.archive.org/web/20180320145847/https://books.google.com/books?id=sD3NBQAAQBAJ&pg=PA133&dq=cetacean+penis&hl=en&sa=X&ved=0ahUKEwjL3vrKiP_PAhVE2oMKHeM-CfIQ6AEIKjAC#v=snippet&q=penis&f=false|archive-date=20 March 2018}}</ref> The tapering tip of the cetacean penis is called the ''pars intrapraeputialis'' or ''terminal cone''.<ref name="Sciences1977">{{cite book|author=American Institute of Biological Sciences|title=Whales, Dolphins, and Porpoises|url=https://books.google.com/books?id=KyxELyTDlsQC|access-date=8 August 2013|year=1977|publisher=University of California Press|id=GGKEY:T3BKXB87GHT}}</ref> The [[blue whale]] has the [[Blue whale penis|largest penis of any organism]] on the planet, typically measuring {{convert|8|–|10|ft|m|order=flip|abbr=on}}.<ref name="bioweb">{{cite web|url=http://bioweb.uwlax.edu/bio203/s2012/olson_rile/reproduction.htm|title=Reproduction|publisher=[[University of Wisconsin]]|access-date=3 October 2012|url-status=live|archive-url=https://web.archive.org/web/20120730002050/http://bioweb.uwlax.edu/bio203/s2012/olson_rile/reproduction.htm|archive-date=30 July 2012}}</ref> Accurate measurements are difficult to take because its erect length can only be observed during mating,<ref name="softpedia1">{{cite web |url=http://news.softpedia.com/news/The-Largest-Penis-in-the-World-43756.shtml |title=The Largest Penis in the World – Both for humans and animals, size does matter! – Softpedia |publisher=News.softpedia.com |date=2007-01-05 |access-date=2011-05-28 |url-status=live |archive-url=https://web.archive.org/web/20110515095449/http://news.softpedia.com/news/The-Largest-Penis-in-the-World-43756.shtml |archive-date=2011-05-15 }}</ref> which occurs underwater. The penis on a [[right whale]] can be up to {{convert|2.7|m|ft|abbr=on}} – the [[testes]], at up to {{convert|2|m|ftin|abbr=on}} in length, {{convert|78|cm|ftin|abbr=on}} in diameter, and weighing up to {{convert|525|lb|kg|abbr=on|order=flip}}, are also by far the largest of any animal on Earth.<ref>{{cite book|last1=Feldhamer|first1=George A.|last2=Thompson|first2=Bruce C.|last3=Chapman|first3=Joseph A.|title=Wild mammals of North America : biology, management, and conservation|year=2003|publisher=Johns Hopkins University Press|location=Baltimore, Md.|isbn=9780801874161|url=https://books.google.com/books?id=-xQalfqP7BcC&pg=PA432|edition=2nd|page=432|access-date=2013-11-08|url-status=live|archive-url=https://web.archive.org/web/20131104003415/http://books.google.com/books?hl=en&lr=&id=-xQalfqP7BcC&oi=fnd&pg=PA432#v=onepage&q=penis&f=false|archive-date=2013-11-04}}</ref> {{anchor|Dolphins}}
On at least one occasion, a dolphin towed bathers through the water by hooking his erect penis around them.<ref name="freddy">{{cite news|title='Tougher laws' to protect friendly dolphins|url=https://www.telegraph.co.uk/earth/earthnews/3322580/Tougher-laws-to-protect-friendly-dolphins.html|author=Unwin, Brian|date=2008-01-22|newspaper=[[The Daily Telegraph|The Telegraph]]|location=London|url-status=dead|archive-url=https://web.archive.org/web/20121227064311/http://www.telegraph.co.uk/earth/earthnews/3322580/Tougher-laws-to-protect-friendly-dolphins.html|archive-date=2012-12-27}}</ref> Between male bottlenose dolphins, [[Homosexual behavior in animals|homosexual behaviour]] includes rubbing of genitals against each other, which sometimes leads to the males swimming belly to belly, inserting the penis in the other's [[genital slit]] and sometimes anus.<ref>{{cite journal|last=Wells|first=R.S.|title=Community structure of Bottlenose Dolphins near Sarasota, Florida|year=1995|series=Paper presented at the 24th International Ethological Conference, Honoluly, Hawaii}}</ref>
 
====Perissodactyls====
{{Anchor|Horses}}{{anchor|Stallion}} [[Stallion]]s (male horses) [[Horse's penis|have a vascular penis]]. When non-erect, it is quite flaccid and contained within the [[Foreskin|prepuce]] (foreskin, or sheath).
 
{{anchor|Tapiridae}}[[Tapirs]] have exceptionally long penises relative to their body size.<ref name="Endangered Wildlife and Plants of the World">{{cite book|title=Endangered Wildlife and Plants of the World|url=https://books.google.com/books?id=wFdWlrnz_uoC&q=tapiridae+penis&pg=PA1460|access-date=23 January 2013|date=1 January 2001|publisher=Marshall Cavendish|isbn=978-0-7614-7194-3|pages=1460–|url-status=live|archive-url=https://web.archive.org/web/20130528120713/http://books.google.com/books?id=wFdWlrnz_uoC&pg=PA1460&dq=tapiridae+penis&hl=en&sa=X&ei=6kgAUab1Cq670QGEloGwDA&ved=0CD0Q6AEwAw#v=onepage&q=tapiridae%20penises&f=false|archive-date=28 May 2013}}</ref><ref name="Prasad1974">{{cite book|author=M. R. N. Prasad|title=Männliche Geschlechtsorgane|url=https://books.google.com/books?id=fm7UkTFw6loC&q=tapiridae+penis&pg=PA119|access-date=23 January 2013|year=1974|publisher=Walter de Gruyter|isbn=978-3-11-004974-9|pages=119–|url-status=live|archive-url=https://web.archive.org/web/20130528094845/http://books.google.com/books?id=fm7UkTFw6loC&pg=PA119&dq=tapiridae+penis&hl=en&sa=X&ei=Rk4AUeaZK5K10QGa-4C4Bw&ved=0CE8Q6AEwBg#v=onepage&q=tapiridae%20penis&f=false|archive-date=28 May 2013}}</ref><ref name="Gade1999">{{cite book|author=Daniel W. Gade|title=Nature & Culture in the Andes|url=https://books.google.com/books?id=G01-CzUS6WgC&q=tapir+penis&pg=PA125|access-date=4 March 2013|year=1999|publisher=Univ of Wisconsin Press|isbn=978-0-299-16124-8|pages=125–|url-status=live|archive-url=https://web.archive.org/web/20130528094026/http://books.google.com/books?id=G01-CzUS6WgC&pg=PA125&dq=tapir+penis&hl=en&sa=X&ei=rC80UY-IJ5Dp0QHHrIGwDg&ved=0CC0Q6AEwAA#v=onepage&q=tapir%20penis&f=false|archive-date=28 May 2013}}</ref><ref name="Quilter2004">{{cite book|author=Jeffrey Quilter|title=Cobble Circles and Standing Stones: Archaeology at the Rivas Site, Costa Rica|url=https://books.google.com/books?id=8Y3wB33zvRkC&q=tapir+penis&pg=PA181|access-date=4 March 2013|date=1 April 2004|publisher=University of Iowa Press|isbn=978-1-58729-484-6|pages=181–|url-status=live|archive-url=https://web.archive.org/web/20130528100618/http://books.google.com/books?id=8Y3wB33zvRkC&pg=PA181&dq=tapir+penis&hl=en&sa=X&ei=eDA0UbzEE-iX0QHz_oG4CA&ved=0CFcQ6AEwBzgK#v=onepage&q=tapir%20penis&f=false|archive-date=28 May 2013}}</ref> The glans of the Malayan tapir resembles a mushroom, and is similar to the glans of the horse.<ref>{{Cite journal | last1 = Lilia | first1 = K. | last2 = Rosnina | first2 = Y. | last3 = Abd Wahid | first3 = H. | last4 = Zahari | first4 = Z. Z. | last5 = Abraham | first5 = M. | title = Gross Anatomy and Ultrasonographic Images of the Reproductive System of the Malayan Tapir (Tapirus indicus) | doi = 10.1111/j.1439-0264.2010.01030.x | journal = Anatomia, Histologia, Embryologia | volume = 39 | issue = 6 | pages = 569–575 | year = 2010 | pmid =  20809915| s2cid = 46441225 | url = http://psasir.upm.edu.my/id/eprint/14918/1/Gross%20anatomy%20and%20ultrasonographic%20images%20of%20the%20reproductive%20system%20of%20the%20Malayan%20tapir.pdf }}</ref>  The penis of the [[Sumatran rhinoceros]] contains two lateral lobes and a structure called the ''processus glandis''.<ref>Zainal Zahari, Z., et al. "[https://www.researchgate.net/publication/10805755_Gross_Anatomy_and_Ultrasonographic_Images_of_the_Reproductive_System_of_the_Sumatran_Rhinoceros_Dicerorhinus_sumatrensis Gross anatomy and ultrasonographic images of the reproductive system of the sumatran rhinoceros (Dicerorhinus sumatrensis).] {{webarchive|url=https://web.archive.org/web/20180320145847/https://www.researchgate.net/publication/10805755_Gross_Anatomy_and_Ultrasonographic_Images_of_the_Reproductive_System_of_the_Sumatran_Rhinoceros_Dicerorhinus_sumatrensis |date=2018-03-20 }}" Anatomia, histologia, embryologia 31.6 (2002): 350-354.</ref>
 
====Carnivores====
{{anchor|Carnivora}}
[[File:Image_from_page_91_of_"Bulletin"_(1918)_(20241179329).jpg|thumb|Genitorinary system of a [[raccoon]] (''Procyon lotor'')]]
All members of [[Carnivora#Reproductive system|Carnivora]] (except [[hyenas]]) have a baculum.<ref name="Hes1997">{{cite web|url=https://www.researchgate.net/publication/229990265|title=Baculum length and copulatory behaviour in carnivores and pinnipeds (Grand Order Ferae)|url-status=live|archive-url=https://web.archive.org/web/20160603121320/https://www.researchgate.net/profile/Alan_Dixson/publication/229990265_Baculum_length_and_copulatory-behavior_in_carnivores_and_pinnipeds_(Grand_Order_Ferae)/links/5565173508ae94e957205686.pdf|archive-date=2016-06-03}}</ref> {{anchor|Caniformia}}[[Canine penis]]es have a structure at the base called the [[bulbus glandis]].<ref name="Long2006">{{cite book|author=Susan Long|title=Veterinary Genetics and Reproductive Physiology|url=https://books.google.com/books?id=Gre0VUZuhGYC|year=2006|publisher=Churchill Livingstone Elsevier|isbn=978-0-7506-8877-2|access-date=2013-11-08|url-status=live|archive-url=https://web.archive.org/web/20140326180538/http://books.google.com/books?id=Gre0VUZuhGYC&printsec=frontcover#v=onepage&q=bulbus%20glandis&f=false|archive-date=2014-03-26}}</ref><ref name=autogenerated3/>
 
During copulation, the spotted hyena inserts his penis through [[Spotted hyena clitoris|the female's pseudo-penis]] instead of directly through the [[vagina]], which is blocked by the false scrotum and testes. Once the female retracts her clitoris, the male enters the female by sliding beneath her, an operation facilitated by the penis's upward angle.<ref name="courtship">{{cite journal | last1 = Szykman | first1 = M. | last2 = Van Horn | first2 = R. C. | last3 = Engh | first3 = A.L. Boydston | last4 = Holekamp | first4 = K. E. | year = 2007 | title = Courtship and mating in free-living spotted hyenas | url = http://tuvalu.santafe.edu/~bowles/Dominance/Papers/SzykmanetalHyenaMatingBehaviour2007.pdf | journal = Behaviour | volume = 144 | issue =  7| pages = 815–846 | doi = 10.1163/156853907781476418 | url-status = live | archive-url = https://web.archive.org/web/20121130193631/http://tuvalu.santafe.edu/~bowles/Dominance/Papers/SzykmanetalHyenaMatingBehaviour2007.pdf | archive-date = 2012-11-30 | citeseerx = 10.1.1.630.5755 }}</ref><ref name="e293">{{Harvnb|Estes|1998|p=293}}</ref> The pseudo-penis closely resembles the male hyena's penis, but can be distinguished from the male's genitalia by its greater thickness and more rounded [[glans]].<ref name="differentiation">{{cite journal | last1 = Glickman | first1 = SE | last2 = Cunha | first2 = GR | last3 = Drea | first3 = CM | last4 = Conley | first4 = AJ | last5 = Place | first5 = NJ | year = 2006 | title = Mammalian sexual differentiation: lessons from the spotted hyena | url = http://courses.washington.edu/pbio509/Glickman_etal.pdf | journal = Trends Endocrinol Metab | volume = 17 | issue =  9| pages = 349–356 | doi = 10.1016/j.tem.2006.09.005 | pmid = 17010637 | s2cid = 18227659 | url-status = live | archive-url = https://web.archive.org/web/20130222022824/http://courses.washington.edu/pbio509/Glickman_etal.pdf | archive-date = 2013-02-22 }}</ref> In male spotted hyenas, as well as females, the base of the glans is covered with [[penile spines]].<ref name="Ewer1973">{{cite book|author=R. F. Ewer|title=The Carnivores|url=https://books.google.com/books?id=IETMd3-lSlkC|access-date=9 January 2013|year=1973|publisher=Cornell University Press|isbn=978-0-8014-8493-3|url-status=live|archive-url=https://web.archive.org/web/20130528110801/http://books.google.com/books?id=IETMd3-lSlkC&printsec=frontcover#v=onepage&q=penis&f=false|archive-date=28 May 2013}}</ref><ref name="Estes1991">{{cite book|author=R. D. Estes|title=The Behavior Guide to African Mammals: Including Hoofed Mammals, Carnivores, Primates|url=https://archive.org/details/isbn_0520080858|url-access=registration|access-date=23 July 2013|year=1991|publisher=University of California Press|isbn=978-0-520-08085-0}}</ref><ref name="Blackledge2003">{{cite book|author=Catherine Blackledge|title=The Story of V: A Natural History of Female Sexuality|url=https://archive.org/details/storyofv00cath|url-access=registration|access-date=23 July 2013|year=2003|publisher=Rutgers University Press|isbn=978-0-8135-3455-8}}</ref>
 
{{anchor|Felidae}}[[Domestic cats]] have barbed penises, with about 120–150 one millimeter long [[penile spines|backwards-pointing spines]].<ref>{{Cite journal |last1=Aronson |first1=L. R. |last2=Cooper |first2=M. L. |title=Penile spines of the domestic cat: their endocrine-behavior relations |journal=Anat. Rec. |volume=157 |issue=1 |pages=71–8 |year=1967 |pmid=6030760 |doi=10.1002/ar.1091570111 |s2cid=13070242 |url=http://www.catcollection.org/files/PenileSpines.pdf |url-status=dead |archive-url=https://web.archive.org/web/20170620212227/http://www.catcollection.org/files/PenileSpines.pdf |archive-date=2017-06-20 }}</ref> Upon withdrawal of the penis, the spines rake the walls of the female's vagina, which is a trigger for [[ovulation]]. Lions [[Lion penis|also have barbed penises]].<ref>{{cite book|title=Cats of Africa|url=https://books.google.com/books?id=WBPpc7QjaVAC&q=penis|access-date=23 July 2013|year=2005|publisher=Struik|isbn=978-1-77007-063-9|url-status=live|archive-url=https://web.archive.org/web/20140326182705/http://books.google.com/books?id=WBPpc7QjaVAC&q=penis#v=snippet&q=penis&f=false|archive-date=26 March 2014}}</ref><ref name="Caputo2003">{{cite book|author=Philip Caputo|title=Ghosts of Tsavo: Stalking the Mystery Lions of East Africa|url=https://archive.org/details/ghostsoftsavosta0000capu|url-access=registration|access-date=23 July 2013|date=1 June 2003|publisher=Adventure Press, National Geographic|isbn=978-0-7922-4100-3}}</ref> Male felids [[Urination#Felidae|urinate backwards]] by curving the tip of the [[glans penis]] backward.<ref name=autogenerated3>{{cite book|author=R. F. Ewer|title=The Carnivores|url=https://books.google.com/books?id=IETMd3-lSlkC&pg=PA116|access-date=23 July 2013|year=1998|publisher=Cornell University Press|isbn=978-0-8014-8493-3|page=116|url-status=live|archive-url=https://web.archive.org/web/20140326181627/http://books.google.com/books?id=IETMd3-lSlkC&pg=PA116#v=onepage&q=penis&f=false|archive-date=26 March 2014}}</ref><ref name="Mathur2010">{{cite book|author=Reena Mathur|title=Animal Behaviour 3/e|url=https://books.google.com/books?id=QKXOCgoI6D8C&q=penis|access-date=23 July 2013|year=2009|publisher=Rastogi Publications|isbn=978-81-7133-747-7|url-status=live|archive-url=https://web.archive.org/web/20140326180352/http://books.google.com/books?id=QKXOCgoI6D8C&q=penis#v=snippet&q=penis&f=false|archive-date=26 March 2014}}</ref> When [[Cheetah penis|male cheetahs urine-mark their territories]], they stand one meter away from a tree or rock surface with the tail raised, pointing the penis either horizontally backward or 60° upward.<ref name="Caro1994">{{cite book|author=T. M. Caro|title=Cheetahs of the Serengeti Plains: Group Living in an Asocial Species|url=https://books.google.com/books?id=hcZCubO01bEC&q=penis&pg=PA203|access-date=23 July 2013|date=15 August 1994|publisher=University of Chicago Press|isbn=978-0-226-09433-5|page=203|url-status=live|archive-url=https://web.archive.org/web/20140326182439/http://books.google.com/books?id=hcZCubO01bEC&pg=PA203&q=penis&f=false|archive-date=26 March 2014}}</ref>
 
{{anchor|Fossa}}The male [[fossa (animal)|fossa]] has an unusually long penis and [[baculum]] (penis bone), reaching to between his [[front leg]]s when erect<ref name="1986Köhncke">{{cite journal | last1 = Köhncke | first1 = M. | last2 = Leonhardt | first2 = K. | title = ''Cryptoprocta ferox'' | journal = [[Mammalian Species]] | issue = 254 | pages = 1–5 | year = 1986 | url = http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-254-01-0001.pdf | access-date = 19 May 2010 | doi = 10.2307/3503919 | url-status = live | archive-url = https://web.archive.org/web/20100621003457/http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-254-01-0001.pdf | archive-date = 21 June 2010 | jstor = 3503919 }}</ref> with backwards-pointing spines along most of its length.<ref>{{cite book | editor1-last = Macdonald | editor1-first = D.W. | editor1-link = David W. Macdonald | title = The Princeton Encyclopedia of Mammals | year = 2009 | publisher = Princeton University Press | isbn = 978-0-691-14069-8 }}</ref> The male fossa has scent glands near the penis, with the penile glands emitting a strong odor.{{r|1986Köhncke}}
 
The [[beech marten]]'s penis is larger than the [[pine]] marten's, with the [[baculum|bacula]] of young beech martens often outsizing those of old pine martens.<ref name="s881">{{Harvnb|Heptner|Sludskii|2002|p=881}}</ref>
 
[[Raccoon]]s have penis bones which bend at a 90 degree angle at the tip.<ref name="Whitney1952">{{cite book|author=Leon Fradley Whitney|title=The Raccoon|url=https://books.google.com/books?id=axtBAAAAYAAJ&q=penis|access-date=24 July 2013|year=1952|publisher=Practical Science Publishing Company|url-status=live|archive-url=https://web.archive.org/web/20140326181315/http://books.google.com/books?ei=SqLwUc6KAcHhygHKjYCwDQ&id=axtBAAAAYAAJ&dq=raccoon+penis&q=penis#search_anchor|archive-date=26 March 2014}}</ref> The extrusibility of a raccoon's penis can be used to distinguish mature males from immature males.<ref name="Zeveloff2002">{{cite book|author=Samuel I. Zeveloff|title=Raccoons: A Natural History|url=https://books.google.com/books?id=vnhVibvnzvIC&q=raccoon+penis&pg=PA5|access-date=25 July 2013|year=2002|publisher=UBC Press|isbn=978-0-7748-0964-1|pages=5–|url-status=live|archive-url=https://web.archive.org/web/20140326174609/http://books.google.com/books?id=vnhVibvnzvIC&pg=PA5&dq=raccoon+penis&hl=en&sa=X&ei=CKLwUaDdIKnwyQHorYHgCQ&ved=0CC8Q6AEwAA#v=onepage&q=penis&f=false|archive-date=26 March 2014}}</ref><ref>{{cite book|author=Julie Feinstein|title=Field Guide to Urban Wildlife|url=https://books.google.com/books?id=jUUKN77Ko_0C|access-date=22 July 2013|date=January 2011|publisher=Stackpole Books|isbn=978-0-8117-0585-1|url-status=live|archive-url=https://web.archive.org/web/20140326182553/http://books.google.com/books?id=jUUKN77Ko_0C&printsec=frontcover#v=onepage&q=penis&f=false|archive-date=26 March 2014}}</ref>
 
Male [[walrus]]es possess the largest penis bones of any land mammal, both in absolute size and relative to body size.<ref name="Fay85">{{cite journal|author = Fay, F.H.|year = 1985|url = http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/default.html|title = Odobenus rosmarus|journal = [[Mammalian Species]]|pages = 1–7|doi = 10.2307/3503810|issue = 238|jstor = 3503810|url-status = live|archive-url = https://web.archive.org/web/20130915093329/http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/default.html|archive-date = 2013-09-15}}</ref><ref>{{cite book|author1= Born, E. W. |author2=Gjertz, I. |author3=Reeves, R. R.|year = 1995|title = Population assessment of Atlantic Walrus (Odobenus rosmarus rosmarus L.)|publisher = Meddelelser. Norsk Polarinstitut|location = Oslo, Norway|page = 100}}</ref>
 
The adult male [[American mink]]'s penis is {{convert|5.6|cm|in|frac=8|abbr=on}} long, and is covered by a [[penile sheath|sheath]]. The [[baculum]] is well-developed, being triangular in [[cross section (geometry)|cross section]] and curved at the tip.<ref name="f663">{{Harvnb|Feldhamer|Thompson|Chapman|2003|pp=663–664}}</ref>
 
====Bats====
 
Males of [[Racey's pipistrelle bat]] have a long, straight penis with a notch between the shaft and the narrow, egg-shaped [[glans penis]]. Near the top, the penis is haired, but the base is almost naked. In the [[baculum]] (penis bone), the shaft is long and narrow and slightly curved.<ref name=Bea304>{{harvnb|Bates|Ratrimomanarivo|Harrison|Goodman|2006|p=304}}</ref> The length of the penis and baculum distinguish ''P.&nbsp;raceyi'' from all comparably sized African and Malagasy vespertilionids.{{sfn|Bates|Ratrimomanarivo|Harrison|Goodman|2006|pp=306–307}} In males, penis length is {{convert|9.6|to|11.8|mm|in|frac=32|abbr=on}} and baculum length is {{convert|8.8|to|10.0|mm|in|frac=32|abbr=on}}.<ref name=Beat1>{{harvnb|Bates|Ratrimomanarivo|Harrison|Goodman|2006|loc=table 1}}</ref>
 
Copulation by male [[greater short-nosed fruit bat]]s is dorsoventral and the females lick the shaft or the base of the male's penis, but not the glans which has already penetrated the vagina. While the females do this, the penis is not withdrawn and research has shown a positive relationship between length of the time that the penis is licked and the duration of copulation. Post copulation genital grooming has also been observed.<ref name="plos">{{cite journal|doi=10.1371/journal.pone.0007595|last=Tan|first=Min|author2=Gareth Jones|author3=Guangjian Zhu|author4=Jianping Ye|author5=Tiyu Hong|author6=Shanyi Zhou|author7=Shuyi Zhang|author8=Libiao Zhang|date=October 28, 2009|title=Fellatio by Fruit Bats Prolongs Copulation Time|pages=e7595|journal=PLOS ONE|volume=4|issue=10|pmid=19862320|pmc=2762080|bibcode=2009PLoSO...4.7595T|editor1-last=Hosken|editor1-first=David|doi-access=free}}</ref>
 
====Rodents====
 
The glans penis of the [[marsh rice rat]] is long and robust,<ref name=HM13>{{harvnb|Hooper|Musser|1964|p=13}}</ref> averaging {{convert|7.3|mm|in|frac=32|abbr=on}} long and {{convert|4.6|mm|in|frac=32|abbr=on}} broad, and the baculum (penis bone) is {{convert|6.6|mm|in|frac=32|abbr=on}} long.{{sfn|Hooper|Musser|1964|loc=table&nbsp;1}} As is characteristic of [[Sigmodontinae]], the marsh rice rat has a complex penis, with the distal (far) end of the baculum ending in three digits.{{sfn|Weksler|2006|pp=55–56}} The central digit is notably larger than those at the sides.<ref name=HM13/> The outer surface of the penis is mostly [[penile spines|covered by small spines]], but there is a broad band of nonspinous tissue. The papilla (nipple-like projection) on the dorsal (upper) side of the penis is covered with small spines, a character the marsh rice rat shares only with ''[[Oligoryzomys]]'' and ''Oryzomys couesi'' among oryzomyines examined.{{sfnm|1a1=Hooper|1a2=Musser|1y=1964|1p=13|Weksler|2006|2p=57}} On the urethral process, located in the crater at the end of the penis,{{sfn|Hooper|Musser|1964|p=7}} a fleshy process (the subapical lobule) is present; it is absent in all other oryzomyines with studied penes except ''O.&nbsp;couesi'' and ''[[Holochilus brasiliensis]]''.{{sfn|Weksler|2006|p=57}} The baculum is deeper than it is wide.<ref name=HM13/>
 
In ''[[Transandinomys talamancae]]'', the outer surface of the penis is mostly covered by small spines, but there is a broad band of nonspinous tissue.{{sfn|Weksler|2006|pp=56–57}}
 
Some features of the accessory glands in the male genital region vary among [[oryzomyines]]. In ''Transandinomys talamancae'',<ref>Described by {{harvnb|Voss|Linzey|1981}}. Noted in {{harvnb|Weksler|2006|p=58}}, footnote&nbsp;10</ref> a single pair of [[preputial gland]]s is present at the penis. As is usual for sigmodontines, there are two pairs of [[ventral]] [[prostate]] glands and a single pair of [[anterior]] and [[dorsal (location)|dorsal]] prostate glands. Part of the end of the [[vesicular gland]] is irregularly folded, not smooth as in most oryzomyines.{{sfnm|Weksler|2006|1pp=57–58|2a1=Voss|2a2=Linzey|2y=1981|2p=13}}
 
In [[Pseudoryzomys]], the [[baculum]] (penis bone) displays large protuberances at the sides. In the [[cartilage|cartilaginous]] part of the baculum, the central digit is smaller than those at the sides.{{sfn|Weksler|2006|pp=55–56}}
 
In [[Drymoreomys]], there are three digits at the tip of the penis, of which the central one is the largest.{{Sfn|Percequillo|Weksler|Costa|2011|p=367}}
 
In ''[[Thomasomys ucucha]]'' the [[glans penis]] is rounded, short, and small and is superficially divided into left and right halves by a trough at the top and a ridge at the bottom.{{sfn|Voss|2003|p=11}}
 
The [[glans penis]] of a male [[cape ground squirrel]] is large with a prominent baculum.<ref name=Skurski2005>{{cite journal | last1 = Skurski | first1 = D. | last2 = Waterman | first2 = J. | year = 2005 | title = Xerus inauris | journal = Mammalian Species | volume = 781 | pages = 1–4 | doi=10.1644/781.1| doi-access = free }}</ref>
 
Unlike other [[squirrel]] species, [[red squirrel]]s have long, thin, and narrow penises, without a prominent baculum.<ref name="Long1995">{{cite book|author=Kim Long|title=Squirrels: A Wildlife Handbook|url=https://books.google.com/books?id=tznNYj4mTs0C&pg=PA127|access-date=23 July 2013|year=1995|publisher=Big Earth Publishing|isbn=978-1-55566-152-6|page=127|url-status=live|archive-url=https://web.archive.org/web/20140326182437/http://books.google.com/books?id=tznNYj4mTs0C&pg=PA127|archive-date=26 March 2014}}</ref><ref name="Long2008">{{cite book|author=Charles A. Long|title=The Wild Mammals of Wisconsin|url=https://books.google.com/books?id=BYHbGHp6vuEC&pg=PA341|access-date=23 July 2013|year=2008|publisher=Pensoft Publishers|isbn=978-954-642-313-9|page=341|url-status=live|archive-url=https://web.archive.org/web/20140326172856/http://books.google.com/books?id=BYHbGHp6vuEC&pg=PA341|archive-date=26 March 2014}}</ref>
 
[[Winkelmann's mouse]] can easily be distinguished from its close relatives by the shape of its penis, which has a partially corrugated [[glans penis|glans]].<ref name=Bradley1987>{{cite journal |author1=Bradley, R.D.  |author2=Schmidley, D.J.  |name-list-style=amp | year = 1987 | title = The glans penes and bacula in Latin American taxa of the ''Peromyscus boylii'' group | journal = Journal of Mammalogy | volume = 68 | issue = 3 | pages = 595–615 | doi=10.2307/1381595|jstor=1381595  }}</ref>
 
The foreskin of a [[capybara]] is attached to the anus in an unusual way, forming an anogenital invagination.<ref name="MoreiraFerraz2012">{{cite book|author1=José Roberto Moreira|author2=Katia Maria P.M.B. Ferraz|author3=Emilio A. Herrera|title=Capybara: Biology, Use and Conservation of an Exceptional Neotropical Species|url=https://books.google.com/books?id=eiPJQ0gmVrkC|access-date=25 July 2013|date=15 August 2012|publisher=Springer|isbn=978-1-4614-4000-0|url-status=live|archive-url=https://web.archive.org/web/20140326175202/http://books.google.com/books?id=eiPJQ0gmVrkC&printsec=frontcover#v=onepage&q=penis&f=false|archive-date=26 March 2014}}</ref>
 
====Primates====
{{multiple image
| align = right
|width = 150
| footer    =
External male genitalia of [[Papio hamadryas]] and [[Chlorocebus pygerythrus]]
| image1    = Papio_hamadryas-adult_penis-Lisbon_07.JPG
 
| image2    = Chlorocebus-pygerythrus-private-parts.JPG
}}
It has been postulated that the shape of the human penis may have been [[Natural selection|selected]] by [[sperm competition]]. The shape could have favored displacement of [[seminal fluid]]s implanted within the female reproductive tract by rival males: the [[pelvic thrusting|thrusting action which occurs during sexual intercourse]] can mechanically remove seminal fluid out of the [[cervix]] area from a previous mating.<ref name=Shackelford>{{Cite journal | last1 = Shackelford | first1 = T. K. | last2 = Goetz | first2 = A. T. | doi = 10.1111/j.1467-8721.2007.00473.x | title = Adaptation to Sperm Competition in Humans | journal = Current Directions in Psychological Science | volume = 16 | pages = 47–50 | year = 2007 | s2cid = 6179167 }}</ref>
 
The penile morphology of some types of [[Strepsirrhini|strepsirrhine]] [[primate]]s has provided information about their taxonomy.<ref name="Dixson2012">{{cite book|author=Alan F. Dixson|title=Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans|url=https://books.google.com/books?id=khzhd2nXWM0C|access-date=6 September 2013|date=26 January 2012|publisher=Oxford University Press|isbn=978-0-19-150342-9|url-status=live|archive-url=https://web.archive.org/web/20131231131810/http://books.google.com/books?id=khzhd2nXWM0C&printsec=frontcover#v=onepage&q=penis&f=false|archive-date=31 December 2013}}</ref> Male [[galago]] species possess very distinctive penile morphology that can be used to classify species.<ref name="Anderson Comparative">{{cite journal|last=Anderson|first=MJ|title=Comparative Morphology and Speciation in Galagos|journal=Folia Primatol|year=1998|volume=69|issue=7 |pages=325–331|doi=10.1159/000052721|s2cid=202649686 }}</ref><ref name="Dixson Sexual">{{cite journal|last=Dixson|first=AF|title=Sexual Selection, Genital Morphology, and Copulatory Behavior in Male Galagos|journal=International Journal of Primatology|year=1989|volume=10|series=1|pages=47–55|doi=10.1007/bf02735703|s2cid=1129069}}</ref><ref name="Anderson Morphology">{{cite journal|last=Anderson|first=MJ|title=Penile Morphology and Classification of Bush Babies (Family Galagoninae)|journal=International Journal of Primatology|year=2000|volume=21|issue=5|series=5|pages=815–836|doi=10.1023/A:1005542609002|s2cid=9983759}}</ref>
 
The [[northern greater galago]] penis is on average {{convert|18|mm|in|frac=16|abbr=on}} in length, with doubled headed or even tridentate spines pointing towards the body. They are less densely packed than in ''Otolemur crassicaudatus''.<ref name="Anderson Comparative"/><ref name="Dixson Sexual"/><ref name="Anderson Morphology"/> The penis of the [[ring-tailed lemur]] is nearly cylindrical in shape and [[penile spines|is covered in small spines]], as well as having two pairs of larger spines on both sides.<ref name="2010Wilson&Hanlon">{{cite journal | last1 = Wilson | first1 = D.E. | last2 = Hanlon | first2 = E. | title = ''Lemur catta'' (Primates: Lemuridae) | journal = Mammalian Species | year = 2010 | volume = 42 | issue = 854 | pages = 58–74 | doi = 10.1644/854.1 | s2cid = 20361726 | url = http://www.mammalsociety.org/uploads/Wilson%20and%20Hanlon%202010.pdf | url-status = live | archive-url = https://web.archive.org/web/20130510122527/http://www.mammalsociety.org/uploads/Wilson%20and%20Hanlon%202010.pdf | archive-date = 2013-05-10 | doi-access = free }}</ref>
 
The adult male of each [[vervet monkey]] species has a pale blue [[scrotum]] and a red penis,<ref>{{Cite book |vauthors=Fedigan L, Fedigan LM |year=1988 |title=Cercopithecus aethiops: a review of field studies. |location=Cambridge (UK)|publisher=Cambridge University Press |pages=389–411}}</ref><ref name="Apps2000">{{cite book|author=Peter Apps|title=Wild Ways: Field Guide to the Behaviour of Southern African Mammals|url=https://books.google.com/books?id=CqygqDOkAj0C&q=penis|access-date=23 July 2013|year=2000|publisher=Struik|isbn=978-1-86872-443-7|url-status=live|archive-url=https://web.archive.org/web/20140326181402/http://books.google.com/books?id=CqygqDOkAj0C&q=penis&f=false|archive-date=26 March 2014}}</ref> and male [[proboscis monkey]]s have a red penis with a black scrotum.<ref name=Ankel2007>{{cite book|author=Friderun Ankel-Simons|title=Primate Anatomy: An Introduction|url=https://books.google.com/books?id=Mwl3M6c5KzoC&q=penis|access-date=23 July 2013|date=27 July 2010|publisher=Academic Press|isbn=978-0-08-046911-9|url-status=live|archive-url=https://web.archive.org/web/20140326182504/http://books.google.com/books?id=Mwl3M6c5KzoC&q=penis&f=false|archive-date=26 March 2014}}</ref>
 
Male [[baboons]] and [[squirrel monkeys]] sometimes gesture with an erect penis as both a warning of impending danger and a threat to predators.<ref name="offensive">{{cite news | first = Daniel | last = Nasaw | title = When did the middle finger become offensive? | date = February 6, 2012 | publisher = BBC | url = https://www.bbc.co.uk/news/magazine-16916263 | work = BBC News Magazine | access-date = February 7, 2012 | url-status = live | archive-url = https://web.archive.org/web/20120206231123/http://www.bbc.co.uk/news/magazine-16916263 | archive-date = February 6, 2012 }}</ref><ref name="sanjose">{{cite news|url=http://nl.newsbank.com/nl-search/we/Archives?p_product=SJ&s_site=mercurynews&p_multi=SJ&p_theme=realcities&p_action=search&p_maxdocs=200&p_topdoc=1&p_text_direct-0=0EB71FB962BD9D8F&p_field_direct-0=document_id&p_perpage=10&p_sort=YMD_date:D&s_trackval=GooglePM|newspaper=[[San Jose Mercury News]]|date=June 20, 1996|page=16A|title=Davis' Infamous Finger Salute Has Had a Big Hand in History; Folklorists: Roots Go Back At Least 2,000 Years To Ancient Rome|first=Michael|last=Oricchio|access-date=July 9, 2012|url-status=live|archive-url=https://web.archive.org/web/20130511013250/http://nl.newsbank.com/nl-search/we/Archives?p_product=SJ&s_site=mercurynews&p_multi=SJ&p_theme=realcities&p_action=search&p_maxdocs=200&p_topdoc=1&p_text_direct-0=0EB71FB962BD9D8F&p_field_direct-0=document_id&p_perpage=10&p_sort=YMD_date:D&s_trackval=GooglePM|archive-date=May 11, 2013}} {{subscription required|date=July 2012}}</ref> In male [[common squirrel monkey|squirrel monkey]]s, this gesture is used for social communication.<ref name=Blitz>{{cite journal | doi = 10.1159/000164879 |author1=Blitz J. |author2=Ploog D.W. |author3=Ploog F. | year = 1963 | title = Studies on the social and sexual behavior of the squirrel monkey (Saimiri sciureus) | journal = Folia Primatologica | volume = 1 | pages = 29–66}}</ref>
 
=====Humans=====
{{Main|Human penis}}
{{commons category|Human penis}}
[[File:Penis with Labels.jpg|thumb|Penis of a human, with pubic hair removed to show anatomical detail]]
The human penis is an external sex organ of  [[male]] [[human]]s. It is a [[reproductive]], [[intromittent organ]] that additionally serves as the [[urination|urinal duct]]. The main parts are the root of the penis ([[radix]]): It is the attached part, consisting of the [[bulb of penis]] in the middle and the [[crus of penis]], one on either side of the bulb; the body of the penis (corpus); and the [[epithelium]] of the penis consists of the shaft [[skin]], the [[foreskin]], and the [[preputial mucosa]] on the inside of the foreskin and covering the [[glans penis]].
 
The human penis is made up of three columns of [[tissue (biology)|tissue]]: two [[Corpus cavernosum penis|corpora cavernosa]] lie next to each other on the [[dorsal side]] and one [[corpus spongiosum penis|corpus spongiosum]] lies between them on the [[ventral side]]. The [[urethra]], which is the last part of the [[urinary tract]], traverses the corpus spongiosum, and its opening, known as the [[External urethral orifice (male)|meatus]] {{IPAc-en|m|iː|ˈ|eɪ|t|ə|s}}, lies on the tip of the glans penis. It is a passage both for [[urine]] and for the [[ejaculation]] of [[semen]].
 
In males, the expulsion of [[urine]] from the body is done through the penis. The [[urethra]] drains the bladder through the [[prostate gland]] where it is joined by the [[ejaculatory duct]], and then onward to the penis.
 
An erection is the stiffening and rising of the penis, which occurs during [[sexual arousal]], though it can also happen in non-sexual situations. Ejaculation is the ejecting of [[semen]] from the penis and is usually accompanied by [[orgasm]]. A series of muscular contractions delivers semen, containing male [[gametes]] known as sperm cells or [[spermatozoa]], from the penis.
 
The most common form of genital alteration is [[circumcision]], the removal of part or all of the foreskin for various cultural, religious, and more rarely medical reasons. There is controversy surrounding circumcision.
 
{{As of|2015}}, a [[systematic review]] of 15,521 men, who were measured by health professionals rather than themselves, concluded that the average length of an [[Erection|erect]] human penis is 13.12&nbsp;cm (5.17 inches) long, while the average circumference of an erect human penis is 11.66&nbsp;cm (4.59 inches).<ref>{{ cite web|url=https://www.realclearscience.com/journal_club/2015/03/03/is_your_penis_normal_theres_a_chart_for_that_109106.html|title=Is Your Penis Normal? There's a Chart for That|last=Berezow|first=Alex B.|website=RealClearScience.com|publisher=RealClearScience|date=March 2, 2015|access-date=April 12, 2019}}</ref><ref name=veale2015>{{Cite journal | doi = 10.1111/bju.13010| pmid = 25487360| title = Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15 521 men| journal = [[BJU International]]| volume = 115| issue = 6| pages = 978–986| year = 2015| last1 = Veale | first1 = D. | last2 = Miles | first2 = S. | last3 = Bramley | first3 = S. | last4 = Muir | first4 = G. | last5 = Hodsoll | first5 = J. | s2cid = 36836535}}</ref>
 
====Marsupials====
Most marsupials, except for the two largest species of kangaroos and [[marsupial mole]]s<ref>
On the Habits and Affinities of the New Australian Mammal, Notoryctes typhlops
E. D. [[Cope]]
The American Naturalist
Vol. 26, No. 302 (Feb., 1892), pp. 121-128</ref> (assuming the latter are true marsupials), [[Marsupial penis|have a bifurcated penis]], separated into two columns, so that the penis has two ends corresponding to the females' two vaginas.<ref name="Renfree1987">{{cite book|last=Renfree|first=Marilyn|title=Reproductive Physiology of Marsupials|url=https://books.google.com/books?id=HpjovN0vXW4C&q=penis|access-date=5 May 2013|date=1987-01-30|publisher=Cambridge University Press|isbn=9780521337922|author2=Hugh Tyndale-Biscoe|url-status=live|archive-url=https://web.archive.org/web/20140111213229/http://books.google.com/books?id=HpjovN0vXW4C&q=penis#v=snippet&q=penis&f=false|archive-date=11 January 2014}}</ref>
 
==== Monotremes ====
[[Monotreme]]s and [[marsupial mole]]s are the only mammals in which the penis is located inside the cloaca.<ref>Gadow, H. On the systematic position of Notoryctes typhlops. Proc. Zool. Soc. London 1892, 361–370 (1892).</ref><ref>Riedelsheimer, B., Unterberger, P., Künzle, H. and U. Welsch. 2007. Histological study of the cloacal region and associated structures in the hedgehog tenrec Echinops telfairi. Mammalian Biology 72(6): 330-341.</ref>
 
Male [[echidna]]s have a bilaterally symmetrical, rosette-like, four-headed penis.<ref name="AugeeGooden2006">{{cite book|author1=Michael L. Augee|author2=Brett A. Gooden|author3=Anne Musser|title=Echidna: Extraordinary Egg-laying Mammal|url=https://books.google.com/books?id=2UQH-YrWwCYC&q=penis|access-date=23 July 2013|date=January 2006|publisher=Csiro Publishing|isbn=978-0-643-09204-4|url-status=live|archive-url=https://web.archive.org/web/20140326182613/http://books.google.com/books?id=2UQH-YrWwCYC&q=penis&f=false|archive-date=26 March 2014}}</ref> During mating, the heads on one side "shut down" and do not grow in size; the other two are used to release semen into the female's two-branched reproductive tract. The heads used are swapped each time the mammal copulates.<ref name="nsc071026">{{cite news | url = https://www.newscientist.com/article/dn12838 | title = Exhibitionist spiny anteater reveals bizarre penis | first = N. | last = Shultz | work = [[New Scientist]] | date = 26 October 2007 | access-date = 27 October 2006 | url-status = live | archive-url = https://web.archive.org/web/20071222214027/http://www.newscientist.com/article/dn12838 | archive-date = 22 December 2007 }}</ref><ref name="a81">Augee, Gooden and Musser, p. 81.</ref><ref>{{cite journal| last1 = Johnston | first1 = S.D. | last2 = Smith | first2 = B. | last3 = Pyne | first3 = M. | last4 = Stenzel | first4 = D. | last5 = Holt | first5 = W.V. | year = 2007 | title = One-Sided Ejaculation of Echidna Sperm Bundles (''Tachyglossus aculeatus'') | url = http://espace.library.uq.edu.au/view/UQ:130591/UQ130591_OA.pdf| journal = Am. Nat. | volume = 170 | issue = 6| pages = E162–4 | doi = 10.1086/522847 | pmid=18171162| s2cid = 40632746 }}</ref> When not in use, the penis is retracted inside a preputial sac in the cloaca. The male echidna's penis is {{convert|7|cm|in|frac=2|abbr=on}} long when erect, and its shaft is covered with [[penile spines]].<ref name="VogelnestWoods2008">{{cite book|author1=Larry Vogelnest|author2=Rupert Woods|title=Medicine of Australian Mammals|url=https://books.google.com/books?id=lWbgqMsyq8UC&q=penis|access-date=23 July 2013|date=18 August 2008|publisher=Csiro Publishing|isbn=978-0-643-09928-9|url-status=live|archive-url=https://web.archive.org/web/20140326182237/http://books.google.com/books?id=lWbgqMsyq8UC&q=penis&f=false|archive-date=26 March 2014}}</ref> The penis is nearly a quarter of his body length when erect.<ref>{{cite book|title=Mammalogy|url=https://books.google.com/books?id=LD1nDlzXYicC&q=short-beaked+echidna+penis+erect&pg=PA389|access-date=5 May 2013|date=21 April 2011|publisher=Jones & Bartlett Learning|isbn=978-0-7637-6299-5|pages=389–|url-status=live|archive-url=https://web.archive.org/web/20140326182422/http://books.google.com/books?id=LD1nDlzXYicC&pg=PA389&dq=short-beaked+echidna+penis+erect&hl=en&sa=X&ei=5oGGUYflHdHK4AOxmYGIDw&ved=0CDcQ6AEwAA#v=onepage&q=short-beaked%20echidna%20penis%20erect&f=false|archive-date=26 March 2014}}</ref>
 
====Others====
{{organize section|date=June 2013}}
 
The penis of the [[bush hyrax]] is complex and distinct from that of the other hyrax genera. It has a short, thin appendage within a cup-like glans penis and measures greater than {{convert|6|cm|in|frac=2|abbr=on}} when erect. Additionally, it has been observed that the bush hyrax also has a greater distance between the anus and preputial opening in comparison to other hyraxes.<ref name=B&S>{{cite journal| last1 = Barry | first1 = R.E. | last2 = Shoshani | first2 = J. | year = 2000 | title = ''Heterohyrax brucei'' | doi = 10.1644/1545-1410(2000)645<0001:hb>2.0.co;2 | journal = Mammalian Species | volume = 645 | pages = 1–7| s2cid = 28256848 }}</ref>
 
{{Commons category|Elephant penis}}
{{anchor|Elephants}}
An adult elephant has the largest penis of any land animal.<ref name="Giustina2005">{{cite book|last=Giustina|first=Anthony|title=Sex World Records|url=https://books.google.com/books?id=_FBGVW9qKpAC&q=penis&pg=PA152|access-date=3 October 2012|date=31 December 2005|publisher=Lulu.com|isbn=978-1-4116-6774-7|page=152|url-status=live|archive-url=https://web.archive.org/web/20131011084322/http://books.google.com/books?id=_FBGVW9qKpAC&pg=PA152&q=penis&f=false|archive-date=11 October 2013}}</ref>{{sps|date=February 2020}} An elephant's penis can reach a length of {{convert|100|cm|in|-1|abbr=on}} and a diameter of {{convert|16|cm|in|0|abbr=on}} at the base.{{citation needed|date=December 2013}} It is S-shaped when fully erect and has a Y-shaped [[External urethral orifice (male)|orifice]].<ref>Shoshani, p. 80.</ref> During [[musth]], a male elephant may urinate with his penis still in the [[Penile sheath|sheath]], which causes the urine to spray on the [[hind legs]].<ref>{{cite book|url=https://books.google.com/books?id=oB4Y4dag7GwC|title=Smithers' Mammals of Southern Africa: A Field Guide|access-date=2013-06-22|url-status=live|archive-url=https://web.archive.org/web/20131011082833/http://books.google.com/books?id=oB4Y4dag7GwC&printsec=frontcover#v=onepage&q=elephant%20penis&f=false|archive-date=2013-10-11|isbn=9781868725502|last1=Smithers|first1=Reay H. N.|date=March 2008}}</ref><ref name=Sukumar100>Sukumar, pp. 100–08.</ref> An elephant's penis is very mobile, being able to [[move]] independently of the male's pelvis,<ref name="FowlerMikota2006">{{cite book|author1=Murray E. Fowler|author2=Susan K. Mikota|title=Biology, Medicine, and Surgery of Elephants|url=https://books.google.com/books?id=oCpiZA61tyQC&q=elephant+penis+mating&pg=PA353|access-date=4 May 2013|date=2 October 2006|publisher=John Wiley & Sons|isbn=978-0-8138-0676-1|pages=353–|url-status=live|archive-url=https://web.archive.org/web/20130528123057/http://books.google.com/books?id=oCpiZA61tyQC&pg=PA353&dq=elephant+penis+mating&hl=en&sa=X&ei=3KiFUa-lLc-t4AOEzYCYAw&ved=0CDkQ6AEwAg#v=onepage&q=elephant%20penis%20mating&f=false|archive-date=28 May 2013}}</ref> and the penis curves forward and upward prior to [[Mating elephants|mounting another elephant]].<ref name="Estes1991"/>
 
In [[giant anteaters]], the (retracted) penis and testes are located internally between the rectum and [[urinary bladder]].<ref name=Grzimek>{{Cite book|editor1=Hutchins, M. |editor2=Kleiman, D. G |editor3=Geist, V. |editor4=McDade, M. С. |author = Naugher, K. B.|contribution = Anteaters (''Myrmecophagidae'')| title = Grzimek's Animal Life Encyclopedia | volume = 13 | edition = 2nd | publisher = Gale | year = 2004 | pages = 171–79| isbn = 978-0-7876-7750-3}}</ref>
 
When the male armadillo ''[[Chaetophractus villosus]]'' is [[sexually aroused]], species determination is easier. Its penis can be as long as {{convert|35|mm|in|frac=4|abbr=on}}, and usually remains completely withdrawn inside a skin receptacle.<ref>"New data on armadillos (Xenarthra: Dasypodidae) for Central Patagonia, Argentina." Agustin M. Abba, et al.</ref> Scientists conducting studies on the ''C. villosus'' penis muscles revealed this species' very long penis exhibits variability. During its waking hours, it remains hidden beneath a skin receptacle, until it becomes erect and it projects outside in a [[Ipsilateral|rostral]] direction.<ref>{{Cite journal| last1 = Affanni | first1 = J. M. | last2 = Cervino | first2 = C. O. | last3 = Marcos | first3 = H. J. A. | doi = 10.1046/j.1365-2869.2001.00259.x | title = Absence of penile erections during paradoxical sleep. Peculiar penile events during wakefulness and slow wave sleep in the armadillo | journal = Journal of Sleep Research | volume = 10 | issue = 3 | pages = 219–228 | year = 2001 | pmid =  11696075| s2cid = 22421482 | doi-access = free }}</ref>
 
===Fish and reptiles===
{{See also|Intromittent organ#Vertebrata}}
 
Male [[turtle]]s and [[crocodile]]s have a penis, while male specimens of the reptile order [[Squamata]] have two paired organs called [[hemipenis|hemipenes]]. [[Tuatara]]s must use their cloacae for reproduction.<ref>Lutz, Dick (2005), Tuatara: A Living Fossil, Salem, Oregon: DIMI PRESS, {{ISBN|0-931625-43-2}}</ref> Due to [[evolutionary convergence]], turtle and mammal penises have a similar structure.<ref>{{cite journal | pmc=1810052 | year=2004 | last1=Kelly | first1=D. A. | title=Turtle and mammal penis designs are anatomically convergent | journal=Proceedings. Biological Sciences | volume=271 | issue=Suppl 5 | pages=S293–S295 | doi=10.1098/rsbl.2004.0161 | pmid=15503998 }}</ref>
 
In some fish, the [[gonopodium]], [[andropodium]], and [[clasper]]s are intromittent organs (to introduce sperm into the female) developed from modified fins.
 
==Invertebrates==
{{Further|Intromittent organ#Invertebrates}}
 
=== Arthropods ===
[[File:Callosobruchus analis penis.jpg|thumb|The spine-covered penis of ''Callosobruchus analis'', a [[bean weevil]]]]
The record for the largest penis size to body size ratio is held by the [[barnacle]]. The barnacle's penis can grow to up to forty times its own body length. This enables them to reach the nearest female for fertilization.
 
A number of invertebrate species have independently evolved the mating technique of [[traumatic insemination]] where the penis penetrates the female's abdomen, thereby creating a womb into which it deposits sperm. This has been most fully studied in [[Bed bug (insect)|bed bug]]s.
 
Some [[millipede]]s have penises.  In these species, the penis is simply one or two projections on underneath the third [[body segment]] that produce a [[spermatophore]] or sperm packet. The act of insemination, however, occurs through specialized legs called [[gonopod (millipedes)|gonopods]] which collect the spermatophore and insert it into the female.
 
==== Insects ====
{{See also|Intromittent organ#Insects}}
In male [[insect]]s, the structure analogous to a penis is known as [[aedeagus]]. The male copulatory organ of various lower invertebrate animals is often called the ''cirrus''.{{citation needed|date=June 2013}}
 
The [[Micronecta scholtzi|lesser water boatman]]'s [[mating call]], generated by rubbing the penis against the [[abdomen]], is the loudest sound, relative to body size, in the animal kingdom.<ref>{{cite journal |title=So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae) |journal=PLOS ONE |volume=6 |issue=6 |pages=e21089 |doi=10.1371/journal.pone.0021089 |pmid=21698252 |pmc=3115974 |year = 2011|last1 = Sueur|first1 = Jérôme|last2=MacKie |first2=David |last3=Windmill |first3=James F. C. |bibcode=2011PLoSO...621089S |doi-access=free }}</ref>
 
In 2010, entomologist Charles Linehard described ''[[Neotrogla]]'', a new genus of [[Psocoptera|barkflies]]. Species of this genus have sex-reversed genitalia. Females have penis-like organs called gynosomes that are inserted into vagina-like openings of males during mating.<ref name="Lienhard2010">{{cite journal|first1=Charles|last1=Lienhard|first2=Thais|last2=Oliveira do Carmo|first3=Rodrigo|last3=Lopes Ferreira|year=2010|url=http://biostor.org/reference/134593|title=A new genus of Sensitibillini from Brazilian caves (Psocodea: 'Psocoptera': Prionoglarididae)|journal=Revue Suisse de Zoologie|volume=117|issue=4|pages=611–635|issn=0035-418X|url-status=live|archive-url=https://web.archive.org/web/20141103042552/http://biostor.org/reference/134593|archive-date=2014-11-03|doi=10.5962/bhl.part.117600}}</ref>  In 2014, a detailed study of the insects reproductive habits led by Kazunori Yoshizawae confirmed that the organ functions similar to a penis – for example, it swells during sexual intercourse – and is used to extract sperm from the male.<ref>{{cite journal|author=Kazunori Yoshizawae |author2=Rodrigo L. Ferreira |author3=Yoshitaka Kamimura |author4=Charles Lienhard |title=Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect|journal=Current Biology|date=17 April 2014|doi=10.1016/j.cub.2014.03.022 |volume=24 |issue=9 |pages=1006–1010 |pmid=24746797|doi-access=free}}</ref><ref>{{cite news|title=In sex-reversed cave insects, females have the penises.|url=https://www.sciencedaily.com/releases/2014/04/140417101146.htm|access-date=27 April 2014|newspaper=Science Daily|date=17 April 2014|author=Cell Press|url-status=live|archive-url=https://web.archive.org/web/20140426233436/http://www.sciencedaily.com/releases/2014/04/140417101146.htm|archive-date=26 April 2014}}</ref>
 
=== Mollusks ===
The penis in most male [[Coleoidea|Coleoid]] [[cephalopods]] is a long and muscular end of the gonoduct used to transfer spermatophores to a modified arm called a [[hectocotylus]]. That, in turn, is used to transfer the spermatophores to the female. In species where the hectocotylus is missing, the penis is long and able to extend beyond the mantle cavity and transfers the spermatophores directly to the female. Deepwater squid have the [[Squid#Reproductive system|greatest known penis length relative to body size]] of all mobile animals, second in the entire animal kingdom only to certain sessile [[barnacle]]s Penis elongation in ''[[Onykia ingens]]'' may result in a penis that is as long as the mantle, head and arms combined.<ref name=penis /><ref>Walker, M. 2010. [http://news.bbc.co.uk/earth/hi/earth_news/newsid_8792000/8792008.stm Super squid sex organ discovered] {{webarchive|url=https://web.archive.org/web/20100707185137/http://news.bbc.co.uk/earth/hi/earth_news/newsid_8792000/8792008.stm |date=2010-07-07 }}. ''BBC Earth News'', July 7, 2010.</ref> [[Giant squid]] of the genus ''[[Architeuthis]]'' are unusual in that they possess both a large penis and modified arm tips, although it is uncertain whether the latter are used for spermatophore transfer.<ref name=penis>{{cite journal | last1 = Arkhipkin | first1 = A.I. | last2 = Laptikhovsky | first2 = V.V. | year = 2010 | title = Observation of penis elongation in ''Onykia ingens'': implications for spermatophore transfer in deep-water squid | journal = Journal of Molluscan Studies | volume =  76| issue = 3| pages =  299–300| doi = 10.1093/mollus/eyq019 | doi-access = free }}</ref>
 
==Etymology==
The word "penis" is taken from the [[Latin]] word for "[[Latin profanity#Synonyms and metaphors|tail]]". Some derive that from [[Proto-Indo-European language|Indo-European]] ''*pesnis'', and the Greek word πέος = "penis" from Indo-European ''*pesos''. Prior to the adoption of the Latin word in English the penis was referred to as a "yard". The [[Oxford English Dictionary]] cites an example of the word ''yard'' used in this sense from 1379,<ref name="oed-yard">{{cite book |last1=Basu |first1=S. C. |title=Male Reproductive Dysfunction |date=2011 |publisher=JP Medical Ltd |isbn=9789350252208 |page=101 |url=https://books.google.com/books?id=BoL2I7yg67cC&q=Simpson,+John;+Weiner,+Edmund,+eds.+(1989).+%22yard,+n.2%22.+Oxford+English+Dictionary&pg=PA101 |language=en}}</ref> and notes that in his ''Physical Dictionary'' of 1684, [[Steven Blankaart]] defined the word ''penis'' as "the Yard, made up of two nervous Bodies, the Channel, Nut, Skin, and Fore-skin, etc."<ref name="oed-penis">{{Cite book|title=Oxford English Dictionary|contribution=penis, ''n''.|contribution-url=http://dictionary.oed.com/cgi/entry/50174565|publisher=[[Oxford University Press]]|editor-last=Simpson|editor-first=John|editor-link=John Simpson (lexicographer)|isbn=978-0-19-861186-8<!--|edition=Draft revision September 2005|year=2005-->|year=1989|edition=second|title-link=Oxford English Dictionary}}{{Dead link|date=June 2013}}</ref> According to [https://en.wiktionary.org/wiki/%C8%9Derde#Middle_English-bar Wiktionary], this term meant (among other senses) "rod" or "bar".
 
As with nearly any aspect of the body involved in sexual or [[excretory]] functions, the penis is the subject of many [[slang]] words and [[euphemism]]s for it, a particularly common and enduring one being "cock". See [[Wiktionary:WikiSaurus:penis|WikiSaurus:penis]] for a list of alternative words for penis.
 
The Latin word ''"[[phallus]]"'' (from [[Greek language|Greek]] φαλλος) is sometimes used to describe the penis, although "phallus" originally was used to describe ''representations'', pictorial or carved, of the penis.<ref>{{cite web |url=http://www.etymonline.com/index.php?search=penis&searchmode=none |title=Online Etymology Dictionary |publisher=Etymonline.com |access-date=2011-05-28 |url-status=live |archive-url=https://web.archive.org/web/20110606085622/http://www.etymonline.com/index.php?search=penis&searchmode=none |archive-date=2011-06-06 }}</ref>
 
==Heraldry==
{{Main|Pizzle}}
Pizzles are represented in [[heraldry]], where the adjective ''pizzled'' (or ''vilené''<ref name="rietstap-1884">{{Cite journal |last=Rietstap |first=J. B. |title=Armorial général; précédé d'un Dictionnaire des termes du blason |year=1884 |page=XXXI |publisher=G. B. van Goor zonen |quote=Vilené: se dit un animal qui a la marque du sexe d'un autre émail que le corps |url= https://archive.org/details/armorialgnralpr00rollgoog }}</ref>) indicates that part of an animate [[Charge (heraldry)|charge]]'s anatomy, especially if coloured differently.
 
==See also==
{{Div col|colwidth=15em}}
*[[Buried penis]]
*[[Castration anxiety]]
*[[Dildo]]
*[[Diphallia]]
*[[Erogenous zone]]
*[[Fascinus]]
*[[Koteka]]
*[[Micropenis]]
*[[Penis enlargement]]
*[[Penis envy]]
*[[Penis removal]]
*[[Phallic architecture]]
*[[Preputioplasty]]
*[[Pubic hair]]
*[[Stamen]]
*[[Stunt cock]]
*[[Testicle]]
{{Div col end}}
 
==References==
=== Citations ===
{{reflist|colwidth=30em}}
 
=== General and cited references ===
====Horses====
{{refbegin|2}}
*{{cite book|first1=Donald F.|last1=Walker|first2=John T.|last2=Vaughan|title=Bovine and equine urogenital surgery|url=https://books.google.com/books?id=dpo1VZBIORUC|access-date=23 July 2013|date=1 June 1980|publisher=[[Lea & Febiger]]|isbn=978-0-8121-0284-0}}
*{{cite web|title=The Stallion: Breeding Soundness Examination & Reproductive Anatomy|publisher=University of Wisconsin-Madison|url=http://www.wisc.edu/ansci_repro/101equinelab/reproduction/stallion_exam.html|access-date=7 July 2007|archive-url=https://web.archive.org/web/20070716140038/http://www.wisc.edu/ansci_repro/101equinelab/reproduction/stallion_exam.html|archive-date=2007-07-16}}
*{{cite book|last1=Munroe|first1=Graham|last2=Weese|first2=Scott|title=Equine Clinical Medicine, Surgery and Reproduction|url=https://books.google.com/books?id=Cu-XUjVS85QC|access-date=18 February 2014|date=15 March 2011|publisher=Manson Publishing|isbn=978-1-84076-608-0}}
*{{cite book|first1=Klaus Dieter|last1=Budras|first12=W. O.|last2=Sack|title=Anatomy of the Horse|url=https://books.google.com/books?id=2FjNASBMUqgC|access-date=1 July 2013|date=1 March 2012|publisher=Manson Publishing|isbn=978-3-8426-8368-6}}
*{{cite book|last=England|first=Gary|title=Fertility and Obstetrics in the Horse|url=https://books.google.com/books?id=A-R2ZhT_oHQC|access-date=18 February 2014|date=15 April 2008|publisher=John Wiley & Sons|isbn=978-0-470-75041-4}}
*{{cite book|author=Equine Research|title=Horse Conformation: Structure, Soundness, and Performance|url=https://books.google.com/books?id=krD1bAEqypcC|archive-url=https://web.archive.org/web/20140707070110/http://books.google.com/books?id=krD1bAEqypcC|url-status=dead|archive-date=7 July 2014|access-date=23 July 2013|year=2004|publisher=Lyons Press|isbn=978-1-59228-487-0}}
*{{cite book|first=James Warren|last=Evans|title=The Horse|url=https://archive.org/details/isbn_9780716718116|url-access=registration|access-date=23 July 2013|date=15 February 1990|publisher=W. H. Freeman|isbn=978-0-7167-1811-6}}
*{{cite book|first1=M. Horace|last1=Hayes|first2=Peter D.|last2=Rossdale|title=Veterinary Notes for Horse Owners: An Illustrated Manual of Horse Medicine and Surgery|url=https://books.google.com/books?id=LHlwaJnOVCEC&q=penis|access-date=1 July 2013|date=March 1988|publisher=Simon & Schuster|isbn=978-0-671-76561-3}}
*{{cite book|last=McBane|first=Susan|title=Modern Horse Breeding: A Guide for Owners|url=https://books.google.com/books?id=BBoMV-CIHpYC|archive-url=https://web.archive.org/web/20140707073433/http://books.google.com/books?id=BBoMV-CIHpYC|url-status=dead|archive-date=7 July 2014|access-date=18 February 2014|year=2001|publisher=Globe Pequot Press|isbn=978-1-58574-389-6}}
{{refend}}
 
====Marsupials====
{{refbegin|2}}
*{{cite book|last=Parker|first=Rick|title=Equine Science|url=https://books.google.com/books?id=cCt9EKwu9r0C|access-date=18 February 2014|edition=4|date=13 January 2012|publisher=Cengage Learning|isbn=978-1-111-13877-6}}
*{{cite book|last=Flannery|first=Tim|title=Chasing Kangaroos: A Continent, a Scientist, and a Search for the World's Most Extraordinary Creature|url=https://books.google.com/books?id=ep-PUlwyxDMC|access-date=5 May 2013|year=2008|publisher=Grove/Atlantic, Incorporated|isbn=9780802143716|pages=60–}}
*{{cite book|last=Hunsaker|first=Don II|title=The Biology of Marsupials|url=https://books.google.com/books?id=cESCLrRJGm0C|access-date=18 February 2014|date=2 December 2012|publisher=Elsevier Science|isbn=978-0-323-14620-3}}
*{{cite book|last1=Jones|first1=Menna E.|last2=Dickman|first2=Chris R.|last3=Archer|first3=Mike|first4=Michael|last4=Archer|title=Predators With Pouches: The Biology of Carnivorous Marsupials|url=https://books.google.com/books?id=3YQSDiWHfD0C|access-date=5 May 2013|year=2003|publisher=Csiro Publishing|isbn=9780643066342}}
*{{cite web|url=http://www.biology.iastate.edu/InternationalTrips/1Australia/Australia%20papers/Discoveries%20about%20Marsupial%20Rep |publisher=Iowa State University Biology Dept. |title=Discoveries about Marsupial Reproduction |first=Anna |last=King |year=2001 |access-date=2012-11-22 |url-status=dead |archive-url=https://web.archive.org/web/20120905123347/http://www.biology.iastate.edu/InternationalTrips/1Australia/Australia%20papers/Discoveries%20about%20Marsupial%20Rep |archive-date=September 5, 2012 }}
*{{cite book|first1=Bernard|last1=Stonehouse|first2=Desmond|last2=Gilmore|title=The Biology of marsupials|url=https://books.google.com/books?id=l63wAAAAMAAJ&q=penis|access-date=25 July 2013|year=1977|publisher=University Park Press|isbn=978-0-8391-0852-8}}
*{{cite book|last=Tyndale-Biscoe|first=C. Hugh|title=Life of Marsupials|url=https://books.google.com/books?id=KqtlPZJ9y8EC|access-date=18 February 2014|year=2005|publisher=Csiro Publishing|isbn=978-0-643-06257-3}}
{{refend}}
 
====Other animals====
{{refbegin|2}}
*{{cite book|first1=Colin Russell|last1=Austin|first2=Roger Valentine|last2=Short|title=Reproduction in Mammals: Volume 4, Reproductive Fitness|url=https://books.google.com/books?id=P5Al0X60UAIC|access-date=22 July 2013|date=21 March 1985|publisher=Cambridge University Press|isbn=978-0-521-31984-3}}
*{{cite book|last1=Bassert|first1=Joanna M.|last2=McCurnin|first2=Dennis M.|title=McCurnin's Clinical Textbook for Veterinary Technicians|url=https://books.google.com/books?id=i-YhIvDgfJoC|access-date=18 February 2014|date=1 April 2013|publisher=Elsevier Health Sciences|isbn=978-1-4557-2884-8}}
* {{cite journal |last1=Bates |first1=Paul J. J. |last2=Ratrimomanarivo |first2=Fanja H. |last3=Harrison |first3=David L. |last4=Goodman |first4=Steven M. |title=A description of a new species of Pipistrellus (Chiroptera: Vespertilionidae) from Madagascar with a review of related Vespertilioninae from the island |journal=Acta Chiropterologica |date=December 2006 |volume=8 |issue=2 |pages=299–324 |doi=10.3161/1733-5329(2006)8[299:ADOANS]2.0.CO;2|s2cid=85825521 }}
*{{cite book|first1=Benjamin B.|last1=Beck|first2=Christen M.|last2=Wemmer|title=The Biology and management of an extinct species: Père David's deer|url=https://books.google.com/books?id=g2W1AAAAIAAJ|access-date=5 July 2013|year=1983|publisher=Noyes Publications|isbn=978-0-8155-0938-7}}
*{{cite book|first=Eugene|last=Burns|title=The sex life of wild animals: a North American study|url=https://books.google.com/books?id=2mFBAAAAYAAJ|access-date=23 July 2013|year=1953|publisher=Rinehart}}
*{{cite book|first=Trevor|last=Carnaby|title=Beat About the Bush: Mammals|url=https://books.google.com/books?id=4u-VroUwC6QC|access-date=19 July 2013|date=22 January 2007|publisher=Jacana Media|isbn=978-1-77009-240-2}}
*{{Cite journal|last=Brehm|first=Alfred Edmund|url=https://archive.org/details/brehmslifeofanim00breh|title=Brehm's Life of Animals|publisher=Chicago: A. N. Marquis & Company|year=1895|access-date=2013-11-08}}
*{{cite book|first1=Lawrence Mark|last1=Elbroch|first2=Michael Raymond|last2=Kresky|first3=Jonah Wy|last3=Evans|title=Field Guide to Animal Tracks and Scat of California|url=https://books.google.com/books?id=XwFDoJhezwAC|access-date=5 July 2013|date=7 April 2012|publisher=University of California Press|isbn=978-0-520-95164-8}}
*{{cite book|first=Stewart Keith|last=Eltringham|title=The ecology and conservation of large African mammals|url=https://books.google.com/books?ei=yAHrUe-DNtOkyAGQkIGQDw|access-date=20 July 2013|year=1979|publisher=Macmillan|isbn=978-0-333-23580-5}}
* {{Cite book|last=Estes|first=Richard|title=The safari companion: a guide to watching African mammals, including hoofed mammals, carnivores, and primates|publisher=Chelsea Green Publishing|year=1998|isbn=978-1-890132-44-6|url=https://archive.org/details/safaricompaniong00este_0}}
*{{cite book|first1=Rowen D.|last1=Frandson|first2=W. Lee|last2=Wilke|first3=Anna Dee|last3=Fails|title=Anatomy and Physiology of Farm Animals|url=https://books.google.com/books?id=I9ZZkwnFLN0C|access-date=1 July 2013|date=30 June 2009|publisher=John Wiley & Sons|isbn=978-0-8138-1394-3}}
*{{cite book|first=Valerius|last=Geist|title=Elk Country|url=https://books.google.com/books?id=b0K9OG6znDgC|access-date=5 July 2013|year=1993|publisher=T&N Children's Publishing|isbn=978-1-55971-208-8}}
*{{cite book|first1=Virginia Douglass|last1=Hayssen|first2=Ari Van|last2=Tienhoven|title=Asdell's Patterns of Mammalian Reproduction: A Compendium of Species-Specific Data|url=https://archive.org/details/asdellspatternso00hays|url-access=registration|access-date=23 July 2013|year=1993|publisher=Cornell University Press|isbn=978-0-8014-1753-5}}
*{{Cite book|last1=Heptner|first1=V. G.|last2=Sludskii|first2=A. A.|url=https://archive.org/details/mammalsofsov212001gept|title=Mammals of the Soviet Union. Vol. II, part 1b, Carnivores (Mustelidae and Procyonidae)|publisher=Washington, D.C. : Smithsonian Institution Libraries and National Science Foundation|year=2002|isbn=978-90-04-08876-4|access-date=2013-11-08}}
*{{cite book|first=Donald F.|last=Hoffmeister|title=Mammals of Illinois|url=https://books.google.com/books?id=IH4iv6MrrW4C|access-date=22 July 2013|year=2002|publisher=University of Illinois Press|isbn=978-0-252-07083-9}}
* {{cite journal |last1=Hooper |first1=E.T. |last2=Musser |first2=G.G. |year=1964 |url=http://hdl.handle.net/2027.42/56367 |title=The glans penis in Neotropical cricetines (Family Muridae) with comments on classification of muroid rodents |journal=Miscellaneous Publications of the University of Michigan Museum of Zoology |volume=123 |pages=1–57|hdl=2027.42/56367 }}
*{{cite book|first1=Barbara N.|last1=Horowitz|first2=Kathryn|last2=Bowers|title=Zoobiquity: What Animals Can Teach Us About Being Human|url=https://books.google.com/books?id=sQraNhrbX2IC|access-date=25 July 2013|date=12 June 2012|publisher=Doubleday Canada|isbn=978-0-385-67061-6}}
*{{cite book|first=Robert H.|last=Horwich|title=The ontogeny of social behavior in the gray squirrel (Sciurus carolinensis)|url=https://books.google.com/books?id=-nMeAQAAMAAJ|access-date=23 July 2013|date=June 1972|publisher=P. Parey|isbn=978-3-489-68036-9}}
*{{cite book|first1=Hartley H.|last1=Jackson|title=Mammals of Wisconsin|url=https://books.google.com/books?id=qQfigtpJ11gC|access-date=22 July 2013|date=January 1961|publisher=Univ of Wisconsin Press|isbn=978-0-299-02150-4}}
*{{cite book|title=Journal of the Mammalogical Society of Japan|url=https://books.google.com/books?id=w91KAAAAYAAJ|access-date=5 July 2013|year=1986|publisher=The Society}}
*{{cite book|first1=Dev Raj|last1=Khanna|first2=P. R.|last2=Yadav|title=Biology Of Mammals|url=https://books.google.com/books?id=4snvlKZpPecC|access-date=20 July 2013|date=1 January 2005|publisher=Discovery Publishing House|isbn=978-81-7141-934-0}}
*{{cite book|first=Jonathan|last=Kingdon|title=East African Mammals: An Atlas of Evolution in Africa. Vol. I|url=https://books.google.com/books?id=x75kYjINSqUC|access-date=22 July 2013|date=January 1984|publisher=University of Chicago Press|isbn=978-0-226-43718-7}}
*{{cite book |last1=Kingdon |first1=Jonathan |title=East African Mammals: An Atlas of Evolution in Africa |date=1984 |publisher=University of Chicago Press |isbn=9780226437187 |url=https://books.google.com/books?id=x75kYjINSqUC |language=en}}
*{{cite book|first1=Horst Erich|last1=König|first2=Hans-Georg|last2=Liebich|title=Veterinary Anatomy of Domestic Mammals: Textbook and Atlas|url=https://books.google.com/books?id=QoXiBjSp368C|access-date=23 July 2013|year=2007|publisher=Schattauer Verlag|isbn=978-3-7945-2485-3}}
*{{cite book|first=R. L.|last=Kotpal|title=Modern Text Book Of Zoology Vertebrates|url=https://books.google.com/books?id=U7N1j-8LMsEC|access-date=23 July 2013|year=2010|publisher=Rastogi Publications|isbn=978-81-7133-891-7}}
*{{cite book|first=William J.|last=Krause|title=An Atlas of Opossum Organogenesis|url=https://books.google.com/books?id=fMpj9XNCss8C|access-date=20 July 2013|date=1 March 2008|publisher=Universal-Publishers|isbn=978-1-58112-969-4}}
*{{cite book|first=Donald W.|last=Linzey|title=Vertebrate Biology|url=https://books.google.com/books?id=qpQ9y-vXovoC|access-date=20 July 2013|date=28 December 2011|publisher=JHU Press|isbn=978-1-4214-0040-2}}
*{{cite book|first1=Steven D.|last1=Lukefahr|first2=Peter R.|last2=Cheeke|first3=Nephi M.|last3=Patton|title=Rabbit Production|url=https://books.google.com/books?id=ZY-8F9MwBWsC|access-date=20 July 2013|year=2013|publisher=CABI|isbn=978-1-78064-012-9}}
*{{cite book|title=Natural History Bulletin of the Siam Society|url=https://books.google.com/books?id=iWRMAQAAIAAJ|access-date=5 July 2013|year=1975}}
* {{Cite journal | doi = 10.1111/j.1096-3642.2010.00643.x | last1 = Percequillo | first1 = A.R. | last2 = Weksler | first2 = M. | last3 = Costa | first3 = L.P. | title = A new genus and species of rodent from the Brazilian Atlantic Forest (Rodentia: Cricetidae: Sigmodontinae: Oryzomyini), with comments on oryzomyine biogeography | journal = Zoological Journal of the Linnean Society | volume = 161 | issue = 2 | pages = 357–390 | year = 2011| doi-access = free }}
*{{cite book|first1=Kenneth D.|last1=Rose|first2=J. David|last2=Archibald|title=The Rise of Placental Mammals: Origins and Relationships of the Major Extant Clades|url=https://books.google.com/books?id=DhchVG_rbQ8C|access-date=22 July 2013|date=22 February 2005|publisher=JHU Press|isbn=978-0-8018-8022-3}}
*{{cite book|first=Uldis|last=Roze|title=The North American Porcupine|url=https://books.google.com/books?id=A3HuW_DMglQC|access-date=25 July 2013|year=2009|publisher=Cornell University Press|isbn=978-0-8014-4646-7}}
*{{cite book|first=Amita|last=Sarkar|title=Sexual Behaviour In Animals|url=https://books.google.com/books?id=bsCiWUiPY5UC|access-date=20 July 2013|date=1 January 2003|publisher=Discovery Publishing House|isbn=978-81-7141-746-9}}
*{{cite book|first1=Heide|last1=Schatten|first2=Gheorghe M.|last2=Constantinescu|title=Comparative Reproductive Biology|url=https://books.google.com/books?id=6iNdSk7gPf4C|access-date=23 July 2013|date=21 March 2008|publisher=John Wiley & Sons|isbn=978-0-470-39025-2}}
*{{cite book|first=Meredith F.|last=Small|title=Female Choices: Sexual Behavior of Female Primates|url=https://archive.org/details/femalechoicessex0000smal|url-access=registration|access-date=23 July 2013|year=1993|publisher=Cornell University Press|isbn=978-0-8014-8305-9}}
*{{cite book|first1=J. D. |last1=Skinner|first2=Christian T.|last2=Chimimba|title=The Mammals of the Southern African Sub-region|url=https://books.google.com/books?id=iqwEYkTDZf4C|access-date=19 July 2013|date=15 November 2005|publisher=Cambridge University Press|isbn=978-0-521-84418-5}}
*{{cite book|first=Lynda|last=Staker|title=The Complete Guide to the Care of Macropods: A Comprehensive Guide to the Handrearing, Rehabilitation and Captive Management of Kangaroo Species|url=https://books.google.com/books?id=9P0COKdYFcMC|access-date=19 July 2013|year=2006|isbn=978-0-9775751-0-7}}
*{{cite book|first1=Shirley C.|last1=Strum|first2=Linda Marie|last2=Fedigan|title=Primate Encounters: Models of Science, Gender, and Society|url=https://books.google.com/books?id=SIl0-eDu8DMC|access-date=22 July 2013|date=15 August 2000|publisher=University of Chicago Press|isbn=978-0-226-77754-2}}
*{{cite book|first1=Robin|last1=Sturtz|first2=Lori|last2=Asprea|title=Anatomy and Physiology for Veterinary Technicians and Nurses: A Clinical Approach|url=https://books.google.com/books?id=KHg_QqV8jC4C|access-date=22 July 2013|date=30 July 2012|publisher=John Wiley & Sons|isbn=978-1-118-40585-7}}
*{{cite book|author1=Peter J Chenoweth|author2=Steven Lorton|title=Animal Andrology: Theories and Applications|url=https://books.google.com/books?id=hv6dAwAAQBAJ|date=30 April 2014|publisher=CABI|isbn=978-1-78064-316-8}}
*{{cite book|first1=B. J.|last1=Verts|first2=Leslie N.|last2=Carraway|title=Land Mammals of Oregon|url=https://books.google.com/books?id=8KI1AmzIDnwC&pg=PA41|access-date=20 July 2013|year=1998|publisher=University of California Press|isbn=978-0-520-21199-5|page=41}}
*{{cite journal |last1=Voss |first1=R.S. |last2=Linzey |first2=A.V. |year=1981 |url=http://hdl.handle.net/2027.42/56403 |title=Comparative gross morphology of male accessory glands among Neotropical Muridae (Mammalia: Rodentia) with comments on systematic implications |journal=Miscellaneous Publications of the University of Michigan Museum of Zoology |volume=159 |pages=1–41|hdl=2027.42/56403 }}
*{{cite journal|last1=Voss|first1= R.S|date= 2003|title= A new species of ''Thomasomys'' (Rodentia: Muridae) from eastern Ecuador, with remarks on mammalian diversity and biogeography in the Cordillera Oriental|journal= [[American Museum Novitates]]|issue= 3421|pages=1–47|doi=10.1206/0003-0082(2003)421<0001:ansotr>2.0.co;2 |hdl= 2246/2850|s2cid= 62795333|url= https://zenodo.org/record/4734917|hdl-access= free}}
*{{cite journal |last=Weksler |first=M. |year=2006 |url=http://hdl.handle.net/2246/5777 |title=Phylogenetic relationships of oryzomyine rodents (Muroidea: Sigmodontinae): separate and combined analyses of morphological and molecular data |journal=Bulletin of the American Museum of Natural History |volume=296 |pages=1–149|doi=10.1206/0003-0090(2006)296[0001:PROORM]2.0.CO;2 |hdl=2246/5777 |s2cid=86057173 }}
*{{cite book|first1=Don E.|last1=Wilson|first2=DeeAnn M.|last2=Reeder|title=Mammal Species of the World: A Taxonomic and Geographic Reference|url=https://books.google.com/books?id=JgAMbNSt8ikC|access-date=20 July 2013|date=16 November 2005|publisher=JHU Press|isbn=978-0801882210}}
{{refend}}
 
==External links==
{{Wiktionary|penis}}
{{Commons|Penis}}
{{Commons category|Male genitalia in heraldry}}
* [http://www.kinseyinstitute.org/resources/bib-penis.html Kinsey Institute on the penis]
 
{{Male reproductive system}}
{{Authority control}}
 
[[Category:Penis| ]]
[[Category:Animal male reproductive system]]
[[Category:Articles containing video clips]]
[[Category:Sex organs]]

Revision as of 06:36, 31 October 2022

Basics

  • Open-source project
  • A drivechain is an alternative to the sidechain vision outlined in the original whitepaper. The Drivechain protocol is an alternative to the sidechain concept because it enables multiple blockchain compatibilities but the system utilizes the same 21 million bitcoins. Sztorc’s Drivechain system claims to allow permissionless innovation without diluting the value of the main cryptocurrency. Because a Drivechain is aligned with Nakamoto consensus it offers the security of the network but with an expanded set of services like smart contracts.

Sztorc has been working on the Drivechain project for quite some time now, and last December we reported on the two Drivechain BIP proposals Sztorc submitted for review and feedback. This week Sztorc explains he is pleased to announce the first Drivechain version called Testdrive and notes that the release is in two parts.  

  • In a drivechain, miners signal the current state of a sidechain. In other words, the miners are essentially the custodian of funds, and they’re able to unfreeze funds for users who wish to move their coins back to the main chain.
  • One of the key tenets of drivechains is that miners are the least problematic custodians of funds being used on a sidechain from a game theory perspective. According to Sztorc, drivechains can be structured in a way in which any theft of coins frozen on the mainchain would obviously be orchestrated by miners.
  • Sideshift is one application among others created for the open-source project Drivechain 

Team, investors, etc.

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