A penis (plural ''penises'' or ''penes'' () is the primary
sexual organ
A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...
that
male
Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization.
A male organism cannot reproduce sexually without access to ...
animals use to
inseminate
Insemination is the introduction of sperm into a female’s reproductive system for the purpose of impregnating, also called fertilizing, the female for sexual reproduction. The sperm is introduced into the uterus of a mammal or the oviduct of a ...
females (or
hermaphrodites) during
copulation
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
.
Such organs occur in many animals, both
vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
and
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
, 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
homologous.
The term ''penis'' applies to many
intromittent organs, but not to all. As an example, the intromittent organ of most
cephalopoda is the
hectocotylus
A hectocotylus (plural: ''hectocotyli'') is one of the arms of male cephalopods that is specialized to store and transfer spermatophores to the female. Structurally, hectocotyli are muscular hydrostats. Depending on the species, the male may use i ...
, a specialized arm, and male spiders use their
pedipalp
Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") an ...
s. Even within the
Vertebrata
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
there are morphological variants with specific terminology, such as
hemipenes
A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamates (snakes, lizards and worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like ...
.
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
placental mammals
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...
the penis bears the
distal part of the
urethra
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra c ...
, which discharges both
urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellular ...
during
urination
Urination, also known as micturition, is the release of urine from the urinary bladder through the urethra to the outside of the body. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, ...
and
semen
Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Sem ...
during copulation.
Vertebrates
Birds
![Mallard with visible pseudo-penis (cropped)](https://upload.wikimedia.org/wikipedia/commons/a/a8/Mallard_with_visible_pseudo-penis_%28cropped%29.jpg)
Most male birds (e.g.,
rooster
The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adult m ...
s and
turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...
s) have a
cloaca (also present on the female), but not a penis. Among bird species with a penis are
paleognathes
Palaeognathae (; ) is a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contain ...
(
tinamou
Tinamous () form an order of birds called Tinamiformes (), comprising a single family called Tinamidae (), divided into two distinct subfamilies, containing 46 species found in Mexico, Central America, and South America. The word "tinamou" come ...
s and
ratites
A ratite () is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites.
The systematics ...
)
and
Anatidae
The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating ...
(ducks, geese and swans).
A bird penis is different in structure from
mammal penis
A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do no ...
es, being an erectile expansion of the cloacal wall and being erected by
lymph
Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues ...
, not blood.
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
The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating ...
) have a phallus. Most birds mate with the males balancing on top of the females and touching cloacas in a "cloacal kiss"; this makes
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.
[Brennan, P. L. R. et al. Coevolution of male and female genital morphology in waterfowl. ''PLoS ONE'' 2, e418 (2007).] 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.
![Duck Reproduction](https://upload.wikimedia.org/wikipedia/commons/b/b9/Duck_Reproduction.svg)
The
lake duck
The lake duck (''Oxyura vittata'') is a small, South American stiff-tailed duck. It is also called the Argentine blue-bill, Argentine blue-billed duck, Argentine lake duck, or Argentine ruddy duck.
Description
The lake duck grows to . Female ...
is notable for possessing, in relation to body length, the
longest penis of all
vertebrates
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
; 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. It is theorized that the remarkable size of their
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
bottle brush. The lake duck has a corkscrew shaped penis.
Male and female
emu
The emu () (''Dromaius novaehollandiae'') is the second-tallest living bird after its ratite relative the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus '' Dromaius''. The emu ...
s are similar in appearance,
[Eastman, p. 23.] although the male's penis can become visible when it defecates.
[Coddington and Cockburn, p. 366.]
The male tinamou has a corkscrew shaped penis, similar to those of the ratites and to the
hemipenis
A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamates (snakes, lizards and worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like ...
of some reptiles. Females have a small phallic organ in the cloaca which becomes larger during the breeding season.
Mammals
![Hundepenis](https://upload.wikimedia.org/wikipedia/commons/b/b5/Hundepenis.jpg)
As with any other bodily attribute, the length and girth of the penis can be highly variable between mammals of different
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
.
In many mammals, the size of a flaccid penis is smaller than its
erect size.
A bone called the
baculum or ''os penis'' is present in most mammals but absent in humans, cattle and
horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...
s.
In mammals the penis is divided into three parts:
* Roots (
crura): these begin at the
caudal border of the
pelvic ischial arch.
*
Body
Body may refer to:
In science
* Physical body, an object in physics that represents a large amount, has mass or takes up space
* Body (biology), the physical material of an organism
* Body plan, the physical features shared by a group of anima ...
: the part of the penis extending from the roots.
*
Glans
The glans (, plural "glandes" ; from the Latin word for "acorn") is a vascular structure located at the tip of the penis in male mammals or a homologous genital structure of the clitoris in female mammals.
Structure
The exterior structure ...
: the free end of the penis.
The internal structures of the penis consist mainly of cavernous,
erectile tissue Erectile tissue is tissue in the body with numerous vascular spaces, or cavernous tissue, that may become engorged with blood. However, tissue that is devoid of or otherwise lacking erectile tissue (such as the labia minora, the vestibule/vagina and ...
, which is a collection of
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
A bull is an intact (i.e., not castrated) adult male of the species ''Bos taurus'' (cattle). More muscular and aggressive than the females of the same species (i.e., cows), bulls have long been an important symbol in many religions,
includ ...
. The
urethra
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra c ...
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 specieseven between closely related ones. For example, an adult
gorilla
Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
's erect penis is about in length; an adult
chimpanzee, significantly smaller (in body size) than a gorilla, has a penis size about double that of the gorilla. In comparison, the
human penis
The human penis is an external male intromittent organ that additionally serves as the urinary duct. The main parts are the root (radix); the body (corpus); and the epithelium of the penis including the shaft skin and the foreskin (prepuce) c ...
is larger than that of any other
primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...
, both in proportion to body size and in absolute terms.
Artiodactyls
The penises of even-toed ungulates are curved in an S-shape when not erect. In
bull
A bull is an intact (i.e., not castrated) adult male of the species ''Bos taurus'' (cattle). More muscular and aggressive than the females of the same species (i.e., cows), bulls have long been an important symbol in many religions,
includin ...
s,
rams
In engineering, RAMS (reliability, availability, maintainability and safety)boar
The wild boar (''Sus scrofa''), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species is ...
s, the sigmoid flexure of the penis straightens out during erection.
When mating, the tip of a male
pronghorn
The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American a ...
's penis is often the first part to touch the female pronghorn. The pronghorn's penis is about long, and is shaped like an ice pick. The front of a pronghorn's glans penis is relatively flat, while the back is relatively thick. The male pronghorn usually
ejaculates
Ejaculation is the discharge of semen (the ''ejaculate''; normally containing sperm) from the male reproductory tract as a result of an orgasm. It is the final stage and natural objective of male sexual stimulation, and an essential componen ...
immediately after intromission.
The penis of a
dromedary
The dromedary (''Camelus dromedarius'' or ;), also known as the dromedary camel, Arabian camel, or one-humped camel, is a large even-toed ungulate, of the genus ''Camelus'', with one hump on its back.
It is the tallest of the three species of ...
camel is covered by a triangular penile sheath opening backwards,
and is about long.
The camelmen often aid the male to enter his penis into the female's
vulva
The vulva (plural: vulvas or vulvae; derived from Latin for wrapper or covering) consists of the external female sex organs. The vulva includes the mons pubis (or mons veneris), labia majora, labia minora, clitoris, vestibular bulbs, vulv ...
, though the male is considered able to do it on his own. Copulation time ranges from 7 to 35 minutes, averaging 11–15 minutes.
Bulls
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
In some animals the male penis possesses a muscle enabling retraction into the prepuce.
In particular animals
The retractor penis muscle occurs in marsupials and carnivorans, but it is absent in humans. A stag's penis forms an S-shaped curve ...
and straightening of the
sigmoid flexure.
The male genitalia of
mouse deer
Chevrotains, or mouse-deer, are small even-toed ungulates that make up the family Tragulidae, the only extant members of the infraorder Tragulina. The 10 extant species are placed in three genera, but several species also are known only ...
are similar to those of pigs. A boar's penis, which rotates rhythmically during copulation,
is about long, and ejaculates about a pint of semen.
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.
[Heptner, V. G.; Nasimovich, A. A.; Bannikov, A. G.; Hoffman, R. S. (1988]
''Mammals of the Soviet Union''
Volume I, Washington, D.C. : Smithsonian Institution Libraries and National Science Foundation, pp. 19-82
=Deer
=
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. Some deer species
spray urine on their bodies by urinating from an erect penis.
One type of scent-marking behavior in elk is known as "thrash-urination,
which typically involves palpitation of the erect penis.
A male elk's urethra points upward so that urine is sprayed almost at a right angle to the penis.
A
sambar stag will mark himself by
spraying urine directly in the face with a highly mobile penis, which is often
erect during its
rutting activities.
[''Deer of the world: their evolution, behaviour, and ecology.'' Valerius Geist. Stackpole Books. 1998. Pg. 73-77.] Red deer
The red deer (''Cervus elaphus'') is one of the largest deer species. A male red deer is called a stag or hart, and a female is called a hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Iran, and parts of we ...
stags often have erect penises during combat.
Cetaceans
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.
Cetaceans have fibroelastic penises, similar to those of
Artiodactyla
The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poster ...
.
The tapering tip of the cetacean penis is called the ''pars intrapraeputialis'' or ''terminal cone''.
The
blue whale
The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known to have ever existed. The blue whale's long and slender body can ...
has the
largest penis of any organism on the planet, typically measuring .
Accurate measurements are difficult to take because its erect length can only be observed during mating,
which occurs underwater. The penis on a
right whale can be up to – the
testes
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...
, at up to in length, in diameter, and weighing up to , are also by far the largest of any animal on Earth.
On at least one occasion, a dolphin towed bathers through the water by hooking his erect penis around them.
Between male bottlenose dolphins,
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
A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...
and sometimes anus.
Perissodactyls
Stallions (male horses)
have a vascular penis. When non-erect, it is quite flaccid and contained within the
prepuce (foreskin, or sheath).
Tapirs
Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a pig, with a short, prehensile nose trunk. Tapirs inhabit jungle and forest regions of South and Central America, with one species inhabit ...
have exceptionally long penises relative to their body size.
The glans of the Malayan tapir resembles a mushroom, and is similar to the glans of the horse. The penis of the
Sumatran rhinoceros
The Sumatran rhinoceros (''Dicerorhinus sumatrensis''), also known as the Sumatran rhino, hairy rhinoceros or Asian two-horned rhinoceros, is a rare member of the family Rhinocerotidae and one of five extant species of rhinoceros. It is the o ...
contains two lateral lobes and a structure called the ''processus glandis''.
Carnivores
![Image_from_page_91_of_](https://upload.wikimedia.org/wikipedia/commons/f/fb/Image_from_page_91_of_%22Bulletin%22_%281918%29_%2820241179329%29.jpg)
All members of
Carnivora (except
hyenas
Hyenas, or hyaenas (from Ancient Greek , ), are feliform carnivoran mammals of the family Hyaenidae . With only four extant species (each in its own genus), it is the fifth-smallest family in the Carnivora and one of the smallest in the cla ...
) have a baculum.
Canine penis
Canine reproduction is the process of sexual reproduction in domestic dogs, wolves, coyotes and other canine species.
Canine sexual anatomy and development Male reproductive system Erectile tissue
As with all mammals, a dog's penis is made up o ...
es have a structure at the base called the
bulbus glandis
The bulbus glandis (also called a bulb or knot) is an erectile tissue structure on the penis of canid mammals. During mating, immediately before ejaculation the tissues swell up to lock ('' tie'') the male's penis inside the female. The locking i ...
.
[
During copulation, the spotted hyena inserts his penis through the female's pseudo-penis instead of directly through the ]vagina
In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
, 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. 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
The glans (, plural "glandes" ; from the Latin word for "acorn") is a vascular structure located at the tip of the penis in male mammals or a homologous genital structure of the clitoris in female mammals.
Structure
The exterior structure ...
. In male spotted hyenas, as well as females, the base of the glans is covered with penile spines
Many mammalian species have developed keratinized penile spines along the glans and/or shaft, which may be involved in sexual selection. These spines have been described as being simple, single-pointed structures (macaques) or complex with two ...
.
Domestic cats have barbed penises, with about 120–150 one millimeter long backwards-pointing spines. Upon withdrawal of the penis, the spines rake the walls of the female's vagina, which is a trigger for ovulation
Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilize ...
. Lions also have barbed penises. Male felids urinate backwards by curving the tip of the glans penis
In male human anatomy, the glans penis, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and their primary anatomical source of sexual pl ...
backward. When 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.
The male fossa has an unusually long penis and baculum (penis bone), reaching to between his front legs when erect with backwards-pointing spines along most of its length. The male fossa has scent glands near the penis, with the penile glands emitting a strong odor.
The beech marten
The beech marten (''Martes foina''), also known as the stone marten, house marten or white breasted marten, is a species of marten native to much of Europe and Central Asia, though it has established a feral population in North America. It is li ...
's penis is larger than the pine marten's, with the bacula
Bacula is an open-source, enterprise-level computer backup system for heterogeneous networks. It is designed to automate backup tasks that had often required intervention from a systems administrator or computer operator.
Bacula supports Lin ...
of young beech martens often outsizing those of old pine martens.
Raccoon
The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...
s have penis bones which bend at a 90 degree angle at the tip. The extrusibility of a raccoon's penis can be used to distinguish mature males from immature males.
Male walrus
The walrus (''Odobenus rosmarus'') is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the fami ...
es possess the largest penis bones of any land mammal, both in absolute size and relative to body size.
The adult male American mink
The American mink (''Neogale vison'') is a semiaquatic species of mustelid native to North America, though human intervention has expanded its range to many parts of Europe, Asia and South America. Because of range expansion, the American mink i ...
's penis is long, and is covered by a sheath. The baculum is well-developed, being triangular in cross section
Cross section may refer to:
* Cross section (geometry)
** Cross-sectional views in architecture & engineering 3D
*Cross section (geology)
* Cross section (electronics)
* Radar cross section, measure of detectability
* Cross section (physics)
**Abs ...
and curved at the tip.
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
In male human anatomy, the glans penis, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and their primary anatomical source of sexual pl ...
. 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. The length of the penis and baculum distinguish ''P. raceyi'' from all comparably sized African and Malagasy vespertilionids. In males, penis length is and baculum length is .
Copulation by male greater short-nosed fruit bat
The greater short-nosed fruit bat (''Cynopterus sphinx''), or short-nosed Indian fruit bat, is a species of megabat in the family Pteropodidae found in South and Southeast Asia.
Description
These bats have a relatively long snout. Their upper pa ...
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.
Rodents
The glans penis of the marsh rice rat is long and robust, averaging long and broad, and the baculum (penis bone) is long. As is characteristic of Sigmodontinae
The rodent subfamily Sigmodontinae includes New World rats and mice, with at least 376 species. Many authorities include the Neotominae and Tylomyinae as part of a larger definition of Sigmodontinae. When those genera are included, the specie ...
, the marsh rice rat has a complex penis, with the distal (far) end of the baculum ending in three digits. The central digit is notably larger than those at the sides.[ The outer surface of the penis is mostly 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
''Oligoryzomys'' is a genus of rodents in the tribe Oryzomyini of family Cricetidae. Many species are known as pygmy rice rats or colilargos.Musser and Carleton, 2005 The genus is found from Mexico to Tierra del Fuego and includes approximately 1 ...
'' and ''Oryzomys couesi'' among oryzomyines examined. On the urethral process, located in the crater at the end of the penis, a fleshy process (the subapical lobule) is present; it is absent in all other oryzomyines with studied penes except ''O. couesi'' and ''Holochilus brasiliensis
''Holochilus brasiliensis'', also known as the Brazilian marsh ratMusser, G.G. and Carleton, M.D. 2005. Superfamily Muroidea. Pp. 894–1531 in Wilson, D.E. and Reeder, D.M. (eds.)Mammal Species of the World: a taxonomic and geographic refer ...
''. The baculum is deeper than it is wide.[
In '' Transandinomys talamancae'', the outer surface of the penis is mostly covered by small spines, but there is a broad band of nonspinous tissue.
Some features of the accessory glands in the male genital region vary among oryzomyines. In ''Transandinomys talamancae'', a single pair of ]preputial gland Preputial glands are exocrine glands that are located in the folds of skin front of the genitals of some mammals. They occur in several species, including mice, ferrets, rhinoceroses, and even-toed ungulates and produce pheromones. The glands pla ...
s is present at the penis. As is usual for sigmodontines, there are two pairs of ventral
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
prostate
The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and phys ...
glands and a single pair of anterior and dorsal
Dorsal (from Latin ''dorsum'' ‘back’) may refer to:
* Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism
* Dorsal, positioned on top of an aircraft's fuselage
* Dorsal c ...
prostate glands. Part of the end of the vesicular gland is irregularly folded, not smooth as in most oryzomyines.
In Pseudoryzomys
''Pseudoryzomys simplex'', also known as the Brazilian false rice rat or false oryzomys, is a species of rodent in the family Cricetidae from south-central South America. It is found in lowland palm savanna and thorn scrub habitats. It is a me ...
, the baculum (penis bone) displays large protuberances at the sides. In the cartilaginous
Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck a ...
part of the baculum, the central digit is smaller than those at the sides.
In Drymoreomys, there are three digits at the tip of the penis, of which the central one is the largest.
In ''Thomasomys ucucha
''Thomasomys ucucha'', also known as the ucucha thomasomys, is a rodent in the genus ''Thomasomys'' of the family Cricetidae. It is known only from high altitude forest and grassland habitats in the Cordillera Oriental of Ecuador. Seven other ...
'' the glans penis
In male human anatomy, the glans penis, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and their primary anatomical source of sexual pl ...
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.
The glans penis
In male human anatomy, the glans penis, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and their primary anatomical source of sexual pl ...
of a male cape ground squirrel is large with a prominent baculum.
Unlike other squirrel species, red squirrels have long, thin, and narrow penises, without a prominent baculum.
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.
The foreskin of a capybara is attached to the anus in an unusual way, forming an anogenital invagination.
Primates
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 fluids 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.
The penile morphology of some types of Strepsirrhini, strepsirrhine primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...
s has provided information about their taxonomy. Male galago species possess very distinctive penile morphology that can be used to classify species.
The northern greater galago penis is on average in length, with doubled headed or even tridentate spines pointing towards the body. They are less densely packed than in ''Otolemur crassicaudatus''. 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.
The adult male of each vervet monkey species has a pale blue scrotum and a red penis, and male proboscis monkeys have a red penis with a black scrotum.
Male baboons and squirrel monkeys sometimes gesture with an erect penis as both a warning of impending danger and a threat to predators.[ ] In male common squirrel monkey, squirrel monkeys, this gesture is used for social communication.
=Humans
=
The human penis is an external sex organ of male
Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization.
A male organism cannot reproduce sexually without access to ...
humans. 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
In male human anatomy, the glans penis, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and their primary anatomical source of sexual pl ...
.
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
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra c ...
, which is the last part of the urinary tract, traverses the corpus spongiosum, and its opening, known as the External urethral orifice (male), meatus , lies on the tip of the glans penis. It is a passage both for urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellular ...
and for the ejaculation of semen
Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Sem ...
.
In males, the expulsion of urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellular ...
from the body is done through the penis. The urethra
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra c ...
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
Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Sem ...
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.
, a systematic review of 15,521 men, who were measured by health professionals rather than themselves, concluded that the average length of an erect human penis is 13.12 cm (5.17 inches) long, while the average circumference of an erect human penis is 11.66 cm (4.59 inches).
Marsupials
Most marsupials, except for the two largest species of kangaroos and marsupial moles (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.
Monotremes
Monotremes and marsupial moles are the only mammals in which the penis is located inside the cloaca.
Male echidnas have a bilaterally symmetrical, rosette-like, four-headed penis. 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.[Augee, Gooden and Musser, p. 81.] When not in use, the penis is retracted inside a preputial sac in the cloaca. The male echidna's penis is long when erect, and its shaft is covered with penile spines
Many mammalian species have developed keratinized penile spines along the glans and/or shaft, which may be involved in sexual selection. These spines have been described as being simple, single-pointed structures (macaques) or complex with two ...
. The penis is nearly a quarter of his body length when erect.
Others
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 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.
An adult elephant has the largest penis of any land animal. An elephant's penis can reach a length of and a diameter of at the base. It is S-shaped when fully erect and has a Y-shaped External urethral orifice (male), orifice. 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.[Sukumar, pp. 100–08.] An elephant's penis is very mobile, being able to move independently of the male's pelvis, and the penis curves forward and upward prior to Mating elephants, mounting another elephant.
In giant anteaters, the (retracted) penis and testes are located internally between the rectum and urinary bladder.
When the male armadillo ''Chaetophractus villosus'' is sexually aroused, species determination is easier. Its penis can be as long as , and usually remains completely withdrawn inside a skin receptacle. 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.
Fish and reptiles
Male turtles and crocodiles have a penis, while male specimens of the reptile order Squamata have two paired organs called hemipenis, hemipenes. Tuataras must use their cloacae for reproduction. Due to evolutionary convergence, turtle and mammal penises have a similar structure.
In some fish, the gonopodium, andropodium, and claspers are intromittent organs (to introduce sperm into the female) developed from modified fins.
Invertebrates
Arthropods
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 bugs.
Some millipedes 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
In male insects, the structure analogous to a penis is known as aedeagus. The male copulatory organ of various lower invertebrate animals is often called the ''cirrus''.
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.
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. 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.
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
A hectocotylus (plural: ''hectocotyli'') is one of the arms of male cephalopods that is specialized to store and transfer spermatophores to the female. Structurally, hectocotyli are muscular hydrostats. Depending on the species, the male may use i ...
. 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 barnacles Penis elongation in ''Onykia ingens'' may result in a penis that is as long as the mantle, head and arms combined. 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.
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, 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." According t
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 euphemisms 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.
Heraldry
Pizzles are represented in heraldry, where the adjective ''pizzled'' (or ''vilené'') indicates that part of an animate Charge (heraldry), charge's anatomy, especially if coloured differently.
See also
*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
References
Citations
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External links
Kinsey Institute on the penis
{{Authority control
Penis,
Animal male reproductive system
Articles containing video clips
Sex organs