Baculum
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[[Image:Raccoonpenisbone.jpg|thumb|A raccoon baculum.]]
The '''baculum''' (also '''penis bone''', '''penile bone''' or '''''os penis''''') is a [[bone]] found in the [[penis]] of most [[mammal]]s. It is absent in [[human]]s, [[equidae|equids]], [[marsupial]]s, [[lagomorph]]s, and [[hyena]]s, among others. It is used for [[Sexual intercourse|copulation]] and varies in size and shape by [[species]]. Its characteristics are sometimes used to differentiate between similar species.
The [[Baculum#Oosik|oosik]] of Native Alaskan cultures is a polished and sometimes carved baculum of various large northern carnivores such as walruses. The [[Raccoon|raccoon]] baculum is sometimes worn as a luck or fertility charm.
The word ''baculum'' originally meant "stick" or "staff" in [[Latin]]. The [[Homology (biology)|homologue]] to the baculum in female mammals is known as the '''baubellum''' or <i>'''''os clitoridis'''''</i> or <i>'''''os clitoris'''''</i>.
Clellan S. Ford and Frank A. Beach, ''Patterns of Sexual Behavior'', p. 30 says "Both gorillas and chimpanzees possess a penile bone. In the latter species the os penis is located in the lower part of the organ and measures approximately three-quarters of an inch in length."
In humans, which lack the baculum and baubellum, the rigidity of the [[erection]] is provided entirely through blood pressure in the [[corpus cavernosum]].
==Examples==
[[Image:Ospenis.jpg|thumb|320px|Penis bone (Os penis) of a dog, arrow shows the [[urethral]] [[sulcus (anatomy)|sulcus]].]]
Mammals having a penile bone (in males) and a clitoral bone (in females) include various [[eutherian]] Orders (not [[Marsupial]]s or [[Monotreme]]s):
*Order [[Primate]]s (excluding humans)
*Order [[Rodent]]ia (rodents), though not in the related order [[Lagomorpha]] (rabbits, hares etc)
*Order [[Insectivora]] (insectivores, including moles, shrews, and hedgehogs)
*Order [[Carnivora]] (including members of many well-known Families, such as [[Ursidae|Ursids]] (bears), [[Felidae|Felids]] (cats), [[Canidae|Canids]] (dogs), [[Pinniped]]s ([[Walrus]]es, Seals, Sea Lions), [[Procyonidae|Procyonids]] (Raccoons etc), and others
*Order [[Chiroptera]] (bats)
Such a wide distribution among [[eutherian|placental]] [[mammals]] [[parsimony|suggests]] that the bone evolved early in the history of these mammals, and was subsequently lost in certain groups.
===Raccoon penis bone===
A '''raccoon penis bone''' is the [[baculum]] of a [[raccoon]]. It is sometimes used as a [[charm]] for luck or fertility.<ref name= "luckymojo">{{cite web |url=http://www.luckymojo.com/raccoonpenis.html |title= Raccoon Penis Bones |accessdate=2007-04-25 |format= HTML |work= The Lucky W Amulet Archive by [[Cat Yronwode]]}}</ref>
====Popular culture====
Author [[JT LeRoy]]'s story ''[[Sarah (novel)|Sarah]]'' features raccoon penis bones,<ref name= "JT LeRoy">{{cite web |url= http://www.jtleroy.com/sarahfaq.html |title= jt leroy - sarah faq |accessdate=2007-04-25 |format= HTML}}</ref> as does [[William Gibson|William Gibson's]] novel, ''[[Count Zero]]''.
===Oosik===
'''Oosik''' is a term used in [[Alaska]] to describe the [[baculum]] ([[penis|penile]] bone) of [[walrus]]es, [[Phocidae|seals]], [[sea lion]]s, and [[polar bear]]s. Sometimes as long as 60 cm (2 ft), it can be polished and used as a handle for [[knife|knives]] and other tools. It is also frequently sold as a souvenir to tourists by [[Alaska Natives]], the only people permitted to hunt the walrus today. In [[2007]] a 4.5 foot long [[fossil]]ized penis bone from an extinct species of walrus, believed by the seller to be the largest in existence, sold for $8000.<ref name= "4.5foot">{{cite web |url=http://sfgate.com/cgi-bin/article.cgi?f=/n/a/2007/08/26/state/n154935D40.DTL |title= Walrus penis sells for $8,000 at Beverly Hills action |accessdate=2007-08-30 |format= HTML |work= AP}}</ref>
[[Image:WalrusOosik.jpg|frame|center|Walrus baculum, approximately 22 inches (56 centimetres) long]]
==Absence in humans==
Humans, unlike other primates, lack an os penis / os clitoris. However, this bone is much reduced among the [[great ape]]s: in many species it is a relatively insignificant 10-20 mm structure. There are reported cases of human penis ossification following trauma,<ref>{{cite journal |last=Sarma |first=Deba |authorlink= |coauthors=Thomas Weilbaecher |year=1990 |month= |title=Human os penis |journal=Urology |volume=35 |issue= |pages=349–350 |id= |url= |accessdate= 2008-02-05 |quote=|doi=10.1016/0090-4295(90)80163-H }}</ref> and one reported case of a congenital os penis surgically removed from a 5 year old boy, who also had other developmental abnormalities, including a cleft scrotum.<ref>{{cite journal |last=Champion |first=RH |authorlink= |coauthors=J Wegrzyn |year=1964 |month= |title=Congenital os penis |journal=Journal of Urology |volume=91 |issue= |pages=663 |id= |url= |accessdate= 2008-02-05 |quote= }}</ref>
The zoologist [[Richard Dawkins]] speculated in 2006, that the loss of the bone in humans, when it is present in our nearest related species the [[chimpanzee]], is probably a result of [[sexual selection]] by females looking for signs of good health in prospective mates. The reliance of the human penis solely on [[hydraulic]] means to achieve a rigid state makes it particularly vulnerable to blood pressure variation. Poor erectile function betrays not only physical states such as diabetes and neurological disorders but mental states such as stress and depression.<ref>{{cite book |last=Dawkins |first=Richard |authorlink=Richard Dawkins |coauthors= |editor= |others= |title=[[The Selfish Gene]] |origdate= |origyear=1978 |origmonth= |url= |format= |accessdate= |accessyear=2006 |accessmonth= |edition=30th anniversary edition |series= |date=2006 |year= |month= |publisher= |location=Endnote to 30th anniversary edition |language= |isbn=0199291144 |oclc= |doi= |id= |pages=p158 endnote |chapter= |chapterurl= |quote=It is not implausible that, with natural selection refining their diagnostic skills, females could glean all sorts of clues about a male’s health, and robustness of his ability to cope with stress, from the tone and bearing of his penis.}}</ref>
==References==
===Notes===
<references/>
===General references===
*Gilbert, Scott F. and Ziony Zevit. 2001. Congenital human baculum deficiency: The generative bone of Genesis 2:21–23. American Journal of Medical Genetics 101(3): 284–285.
*Clellan S. And Frank A. Beach 1951 ''Patterns of Sexual Behavior'' Publisher: N.Y., Harper, and Paul B. Hoeber, Inc. Medical Books (ISBN 0313223556)
==External links==
*Beresford WA, Burkart S. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=604330&dopt=Abstract The penile bone and anterior process of the rat in scanning electron microscopy.] ''J Anat.'' 1977 Dec;124(3):589–97.
*The San Diego Zoo's Conservation and research for endangered species projects. [http://cres.sandiegozoo.org/projects/pd_significance_baculum.html 'What is the significance of the baculum in animals?']
*[http://www.geocities.com/abaccola/oosik.html Ode to an Oosik] – poem and picture of an Oosik
[[Category:Animal anatomy]]
[[Category:Andrology]]
[[Category:Penis]]
[[Category:Luck]]
[[ar:عظمة القضيب]]
[[de:Penisknochen]]
[[es:Báculo (hueso peneano)]]
[[fr:Baculum]]
[[hr:Penisna kost]]
[[it:Osso penico]]
[[nl:Penisbot]]
[[ja:陰茎骨]]
[[pl:Kość prącia]]
[[ru:Бакулюм]]
[[sl:Bakulum]]
[[sv:Penisben]]