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 an ...
females (or
hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...
s) 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 penetrat ...
.
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, ...
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 organ
An intromittent organ is any external organ of a male organism that is specialized to deliver sperm during copulation. Intromittent organs are found most often in terrestrial species, as most non-mammalian aquatic species fertilize their eggs e ...
s, but not to all. As an example, the intromittent organ of most
cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
a 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") and ...
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 squamata, squamates (snakes, lizards and amphisbaenia, worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erecti ...
.
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
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 pro ...
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 con ...
, 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 excretion, excreted from the body through the urethra.
Cel ...
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. Semen i ...
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 list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...
s) have a
cloaca
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...
(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 o ...
)
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 to ...
, 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
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...
.
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, ...
; 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 tha ...
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
The baculum (also penis bone, penile bone, or ''os penis'', ''os genitale'' or ''os priapi'') is a bone found in the penis of many placental mammals. It is absent from the human penis, but present in the penises of some primates, such as the ...
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 y ...
s.
In mammals the penis is divided into three parts:
* Roots (
crura): these begin at the
caudal
Caudal may refer to:
Anatomy
* Caudal (anatomical term) (from Latin ''cauda''; tail), used to describe how close something is to the trailing end of an organism
* Caudal artery, the portion of the dorsal aorta of a vertebrate that passes into the ...
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 o ...
: 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 an ...
, which is a collection of
blood sinusoids separated by sheets of
connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
(trabeculae). Some mammals have a lot of erectile tissue relative to connective tissue, for example horses. Because of this a
horse's penis
A stallion is a male horse that has not been gelded (castrated).
Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck ...
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 con ...
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
The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative th ...
, 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) co ...
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 huma ...
, 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 no ...
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 component ...
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 sex organ, female sex organs. The vulva includes the mons pubis (or mons veneris), labia majora, labia minora, clitoris, bulb of vestibu ...
, 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 w ...
and straightening of the
sigmoid flexure
The sigmoid colon (or pelvic colon) is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S (thus ''s ...
.
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 f ...
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
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, ...
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 wes ...
stags often have erect penises during combat.
Cetaceans
Cetaceans' reproductive organs are located inside the body. Male
cetaceans
Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...
(whales, dolphins, and porpoises) have two slits, the genital groove concealing the penis and one further behind for the
anus
The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, d ...
.
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
Right whales are three species of large baleen whales of the genus ''Eubalaena'': the North Atlantic right whale (''E. glacialis''), the North Pacific right whale (''E. japonica'') and the Southern right whale (''E. australis''). They are clas ...
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 testoster ...
, 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
Stallion
A stallion is a male horse that has not been gelded (castrated).
Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" nec ...
s (male horses)
have a vascular penis. When non-erect, it is quite flaccid and contained within the
prepuce
Prepuce , or as an adjective, preputial , refers to two homologous structures of male and female genitals:
*Clitoral hood, skin surrounding and protecting the head of the clitoris
*Foreskin, skin surrounding and protecting the head of the penis in ...
(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
Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...
(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 of ...
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 o ...
. 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 o ...
.
Domestic cats
The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of t ...
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 fertilized ...
. 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 p ...
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
Fossa may refer to:
Animals
* Fossa (animal), the common name of a carnivoran mammal of genus ''Cryptoprocta'' endemic to Madagascar
* ''Fossa'', the Latin genus name of the Malagasy civet, a related but smaller mammal endemic to Madagascar
Pla ...
has an unusually long penis and baculum
The baculum (also penis bone, penile bone, or ''os penis'', ''os genitale'' or ''os priapi'') is a bone found in the penis of many placental mammals. It is absent from the human penis, but present in the penises of some primates, such as the ...
(penis bone), reaching to between his front leg
A forelimb or front limb is one of the paired articulated appendages (limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used instead. ...
s 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 pinniped, 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 ...
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
Sheath pronounced as , may refer to:
* Scabbard, a sheath for holding a sword, knife, or other large blade, as well as guns, such as rifles.
* The outer covering of a cable
* Condom, a kind of contraception
* Debye sheath, a layer of a plasma in ...
. The baculum
The baculum (also penis bone, penile bone, or ''os penis'', ''os genitale'' or ''os priapi'') is a bone found in the penis of many placental mammals. It is absent from the human penis, but present in the penises of some primates, such as the ...
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
''Pipistrellus raceyi'', also known as Racey's pipistrelle, is a bat from Madagascar, in the genus ''Pipistrellus''. Although unidentified species of ''Pipistrellus'' had been previously reported from Madagascar since the 1990s, ''P. raceyi' ...
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 p ...
. Near the top, the penis is haired, but the base is almost naked. In the baculum
The baculum (also penis bone, penile bone, or ''os penis'', ''os genitale'' or ''os priapi'') is a bone found in the penis of many placental mammals. It is absent from the human penis, but present in the penises of some primates, such as the ...
(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
The marsh rice rat (''Oryzomys palustris'') is a semiaquatic North American rodent in the family Cricetidae. It usually occurs in wetland habitats, such as swamps and salt marshes. It is found mostly in the eastern and southern United States, fr ...
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
''Transandinomys talamancae'' is a rodent in the family Cricetidae that occurs from Costa Rica to southwestern Ecuador and northern Venezuela. Its habitat consists of lowland forests up to above sea level. With a body mass of , it is a medium-s ...
'', 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
Oryzomyini is a tribe (taxonomy), tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern List of mammals of the Uni ...
. 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 play ...
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 language, Greek roots, describe something in its standard anatomical position. Th ...
prostate
The prostate is both an Male accessory gland, 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, ...
glands and a single pair of anterior
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 ...
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 co ...
prostate glands. Part of the end of the vesicular gland
The seminal vesicles (also called vesicular glands, or seminal glands) are a pair of two convoluted tubular glands that lie behind the urinary bladder of some Sexual reproduction#Male, male mammals. They secrete fluid that partly composes the se ...
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
The baculum (also penis bone, penile bone, or ''os penis'', ''os genitale'' or ''os priapi'') is a bone found in the penis of many placental mammals. It is absent from the human penis, but present in the penises of some primates, such as the ...
(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 and ...
part of the baculum, the central digit is smaller than those at the sides.
In Drymoreomys
''Drymoreomys'' is a rodent genus in the tribe Oryzomyini that lives in the Atlantic Forest of Brazil. The single species, ''D. albimaculatus'', is known only from the states of São Paulo and Santa Catarina and was not named until 2011. I ...
, 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 s ...
'' 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 p ...
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 p ...
of a male cape ground squirrel
The Cape ground squirrel or South African ground squirrel (''Geosciurus inauris'') is found in most of the drier parts of southern Africa from South Africa, through to Botswana, and into Namibia, including Etosha National Park.
The name ''Cap ...
is large with a prominent baculum.
Unlike other squirrel species, red squirrel
The red squirrel (''Sciurus vulgaris'') is a species of tree squirrel in the genus ''Sciurus'' common throughout Europe and Asia. The red squirrel is an arboreal, primarily herbivorous rodent.
In Great Britain, Ireland, and in Italy numbers ...
s have long, thin, and narrow penises, without a prominent baculum.
Winkelmann's mouse
Winkelmann's mouse (''Peromyscus winkelmanni'') is a species of rodent in the family Cricetidae found only in Mexico, and is named for John R. Winkelmann, who collected the first specimens.
Description
Rather larger than a house mouse, an adult ...
can easily be distinguished from its close relatives by the shape of its penis, which has a partially corrugated 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 o ...
.
The foreskin of a capybara
The capybaraAlso called capivara (in Brazil), capiguara (in Bolivia), chigüire, chigüiro, or fercho (in Colombia and Venezuela), carpincho (in Argentina, Paraguay and Uruguay) and ronsoco (in Peru). or greater capybara (''Hydrochoerus hydro ...
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 selected by sperm competition
Sperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and ...
. The shape could have favored displacement of seminal fluid
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. Semen i ...
s implanted within the female reproductive tract by rival males: the thrusting action which occurs during sexual intercourse can mechanically remove seminal fluid out of the cervix
The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...
area from a previous mating.
The penile morphology of some types of strepsirrhine
Strepsirrhini or Strepsirhini (; ) is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and southeast Asia. Collec ...
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 huma ...
s has provided information about their taxonomy. Male galago
Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They ar ...
species possess very distinctive penile morphology that can be used to classify species.
The northern greater galago
The northern greater galago (''Otolemur garnettii''), also known as Garnett's greater galago, Garnett's galago, or the small-eared greater galago, is a nocturnal, arboreal primate endemic (ecology), endemic to Africa.
Subspecies
Four subspecies ...
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
The ring-tailed lemur (''Lemur catta'') is a large strepsirrhine primate and the most recognized lemur due to its long, black and white ringed tail. It belongs to Lemuridae, one of five lemur families, and is the only member of the ''Lemur'' ge ...
is nearly cylindrical in shape and is covered in small spines, as well as having two pairs of larger spines on both sides.
The adult male of each vervet monkey
The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus ''Chlorocebus''. The five distinct ...
species has a pale blue scrotum
The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum cont ...
and a red penis, and male proboscis monkey
The proboscis monkey (''Nasalis larvatus'') or long-nosed monkey is an arboreal Old World monkey with an unusually large nose, a reddish-brown skin color and a long tail. It is endemic to the southeast Asian island of Borneo and is found mostly ...
s have a red penis with a black scrotum.
Male baboons
Baboons are primates comprising the genus ''Papio'', one of the 23 genera of Old World monkeys. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma ba ...
and squirrel monkeys
Squirrel monkeys are New World monkeys of the genus ''Saimiri''. ''Saimiri'' is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (''sai-mirím'' or ''çai-mbirín'', with ''sai'' meaning 'monkey' and ''mirím'' ...
sometimes gesture with an erect penis as both a warning of impending danger and a threat to predators.[ ] In male squirrel monkey
Squirrel monkeys are New World monkeys of the genus ''Saimiri''. ''Saimiri'' is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (''sai-mirím'' or ''çai-mbirín'', with ''sai'' meaning 'monkey' and ''mirím'' ...
s, 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 ...
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
s. It is a reproductive
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are als ...
, intromittent organ
An intromittent organ is any external organ of a male organism that is specialized to deliver sperm during copulation. Intromittent organs are found most often in terrestrial species, as most non-mammalian aquatic species fertilize their eggs e ...
that additionally serves as the urinal duct. The main parts are the root of the penis (radix): It is the attached part, consisting of the bulb of penis
Just before each crus of the penis meets its fellow, it presents a slight enlargement, which Georg Ludwig Kobelt named the bulb of the corpus cavernosum penis. The bulb of penis is also known as the urethral bulb.
The bulb is homologous to the v ...
in the middle and the crus of penis
For their anterior three-fourths the corpora cavernosa penis lie in intimate apposition with one another, but behind they diverge in the form of two tapering processes, known as the crura, which are firmly connected to the ischial rami.
Traced f ...
, one on either side of the bulb; the body of the penis (corpus); and the epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...
of the penis consists of the shaft skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
, the foreskin
In male human anatomy, the foreskin, also known as the prepuce, is the double-layered fold of skin, mucosal and muscular tissue at the distal end of the human penis that covers the glans and the urinary meatus. The foreskin is attached to the g ...
, and the preputial mucosa
The preputial mucosa of the penis is the epithelium of the inside of the prepuce, or foreskin. To differentiate it from the cutaneous skin of the outside of the prepuce, it is sometimes referred to as the inner mucosa. It starts at the ridged band ...
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 p ...
.
The human penis is made up of three columns of tissue: two corpora cavernosa lie next to each other on the dorsal side
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 ...
and one corpus spongiosum
The corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis. It is also called the corpus cavernosum urethrae in older texts.
Anatomy
The proximal part of the corpus spongiosum is expanded to form the uret ...
lies between them on the ventral side
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 ...
. 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 con ...
, which is the last part of the urinary tract
The urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, con ...
, traverses the corpus spongiosum, and its opening, known as the meatus
In anatomy, a meatus (, ),''OED'' 2nd edition, 1989, as . plural "meatus" or "meatuses", , 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 excretion, excreted from the body through the urethra.
Cel ...
and for the ejaculation
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 ...
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. Semen i ...
.
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 excretion, excreted from the body through the urethra.
Cel ...
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 con ...
drains the bladder through the prostate gland
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 physio ...
where it is joined by the ejaculatory duct
The ejaculatory ducts (''ductus ejaculatorii'') are paired structures in male anatomy. Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and open into the ureth ...
, and then onward to the penis.
An erection is the stiffening and rising of the penis, which occurs during sexual arousal
Sexual arousal (also known as sexual excitement) describes the physiological and psychological responses in preparation for sexual intercourse or when exposed to sexual stimuli. A number of physiological responses occur in the body and mind as ...
, 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. Semen i ...
from the penis and is usually accompanied by orgasm
Orgasm (from Greek , ; "excitement, swelling") or sexual climax is the sudden discharge of accumulated sexual excitement during the sexual response cycle, resulting in rhythmic, involuntary muscular contractions in the pelvic region charac ...
. A series of muscular contractions delivers semen, containing male gametes
A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce t ...
known as sperm cells or spermatozoa
A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, ...
, from the penis.
The most common form of genital alteration is circumcision
Circumcision is a surgical procedure, procedure that removes the foreskin from the human penis. In the most common form of the operation, the foreskin is extended with forceps, then a circumcision device may be placed, after which the foreskin ...
, 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
A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...
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 mole
Marsupial moles, the Notoryctidae , are highly specialized marsupial mammals, known from two species found at the Australian interior.
* ''Notoryctes typhlops'' (southern marsupial mole, known as the ''itjaritjari'' by the Pitjantjatjara and Yan ...
s (assuming the latter are true marsupials), have a bifurcated penis, separated into two columns, so that the penis has two ends corresponding to the females' two vaginas.
Monotremes
Monotreme
Monotremes () are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria), and marsupials (Metatheria). Monotremes are typified by structural differences in their brain ...
s and marsupial mole
Marsupial moles, the Notoryctidae , are highly specialized marsupial mammals, known from two species found at the Australian interior.
* ''Notoryctes typhlops'' (southern marsupial mole, known as the ''itjaritjari'' by the Pitjantjatjara and Yan ...
s are the only mammals in which the penis is located inside the cloaca.
Male echidna
Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the ...
s 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 o ...
. The penis is nearly a quarter of his body length when erect.
Others
The penis of the bush hyrax
The yellow-spotted rock hyrax or bush hyrax (''Heterohyrax brucei'') is a species of mammal in the family Procaviidae. It is found in Angola, Botswana, Burundi, the Democratic Republic of the Congo, southern Egypt, Eritrea, Ethiopia, Kenya, Ma ...
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 orifice
An orifice is any opening, mouth, hole or vent, as in a pipe, a plate, or a body
* Body orifice, any opening in the body of a human or animal
*Orifice plate, a restriction used to measure flow or to control pressure or flow, sometimes given specia ...
. During musth
Musth or must (from Persian, )''The Oxford Dictionary and Thesaurus: American edition'', published 1996 by Oxford University Press; p. 984 is a periodic condition in bull (male) elephants characterized by aggressive behavior and accompanied by ...
, a male elephant may urinate with his penis still in the sheath
Sheath pronounced as , may refer to:
* Scabbard, a sheath for holding a sword, knife, or other large blade, as well as guns, such as rifles.
* The outer covering of a cable
* Condom, a kind of contraception
* Debye sheath, a layer of a plasma in ...
, which causes the urine to spray on the hind legs
A hindlimb or back limb is one of the paired articulated appendages (limbs) attached on the caudal ( posterior) end of a terrestrial tetrapod vertebrate's torso.http://www.merriam-webster.com/medical/hind%20limb, Merriam Webster Dictionary-Hindl ...
.[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 mounting another elephant.
In giant anteaters
The giant anteater (''Myrmecophaga tridactyla'') is an Insectivore, insectivorous mammal native to Central America, Central and South America. It is one of four living species of anteaters, of which it is the largest member. The only extant memb ...
, the (retracted) penis and testes are located internally between the rectum and urinary bladder
The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...
.
When the male armadillo ''Chaetophractus villosus
The big (or large) hairy armadillo (''Chaetophractus villosus'') is one of the largest and most numerous armadillos in South America. It lives from sea level to altitudes of up to 1,300 meters across the southern portion of South America, and c ...
'' is sexually aroused
Sexual arousal (also known as sexual excitement) describes the physiological and psychological responses in preparation for sexual intercourse or when exposed to sexual stimuli. A number of physiological responses occur in the body and mind ...
, 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 rostral
Rostral may refer to:
Anatomy
* Rostral (anatomical term), situated toward the oral or nasal region
* Rostral bone, in ceratopsian dinosaurs
* Rostral organ, of certain fish
* Rostral scale, in snakes and scaled reptiles
Other uses
* Rostral colu ...
direction.
Fish and reptiles
Male turtle
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...
s and crocodile
Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...
s have a penis, while male specimens of the reptile order Squamata
Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, ...
have two paired organs called hemipenes
A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamata, squamates (snakes, lizards and amphisbaenia, worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erecti ...
. Tuatara
Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and m ...
s must use their cloacae for reproduction. Due to evolutionary convergence
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
, turtle and mammal penises have a similar structure.
In some fish, the gonopodium
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
, andropodium
Fins are distinctive anatomical features composed of bony spine (zoology), spines or Ray (fish fin anatomy), rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bon ...
, and clasper
In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating.
Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's c ...
s 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
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...
. 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
Traumatic insemination, also known as hypodermic insemination, is the mating practice in some species of invertebrates in which the male pierces the female's abdomen with his aedeagus and injects his sperm through the wound into her abdominal c ...
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
Bed bugs are insects from the genus ''Cimex'' that feed on blood, usually at night. Their bites can result in a number of health impacts including skin rashes, psychological effects, and allergic symptoms. Bed bug bites may lead to skin changes ...
s.
Some millipede
Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a resu ...
s have penises. In these species, the penis is simply one or two projections on underneath the third body segment
Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, an ...
that produce a spermatophore
A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores ...
or sperm packet. The act of insemination, however, occurs through specialized legs called gonopods
Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and milli ...
which collect the spermatophore and insert it into the female.
Insects
In male insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s, the structure analogous to a penis is known as aedeagus
An aedeagus (plural aedeagi) is a reproductive organ of male arthropods through which they secrete sperm from the testes during copulation with a female. It can be thought of as the insect equivalent of a mammal's penis, though the comparison ...
. The male copulatory organ of various lower invertebrate animals is often called the ''cirrus''.
The lesser water boatman
The lesser waterboatman or lesser water boatman (''Corixa punctata'') is a water-dwelling insect of the order Hemiptera.
Adults normally range in size from 5 to 15 mm long, and are found in ponds, lakes and sometimes even swimming pools. ...
's mating call
A mating call is the auditory signal used by animals to attract mates. It can occur in males or females, but literature is abundantly favored toward researching mating calls in females. In addition, mating calls are often the subject of mate choic ...
, generated by rubbing the penis against the abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...
, is the loudest sound, relative to body size, in the animal kingdom.
In 2010, entomologist Charles Linehard described ''Neotrogla
''Neotrogla'' is a genus of barklice noted for its reversed sex roles and organs, traits shared by all species of the genus.
Habitat
''Neotrogla'' are found in dry cave systems throughout Brazil. They feed primarily on bat guano.
Description
...
'', a new genus of 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 Coleoid
Subclass (biology), Subclass Coleoidea,
or Dibranchiata, is the grouping of cephalopods containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e., octopuses, squid and cuttlefish). Unlike its extant sister group, ...
cephalopods
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, an ...
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 greatest known penis length relative to body size of all mobile animals, second in the entire animal kingdom only to certain sessile barnacle
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...
s Penis elongation in ''Onykia ingens
''Onykia ingens'', the greater hooked squid, is a species of squid in the family Onychoteuthidae. It occurs worldwide in subantarctic oceans.
Although ''O. ingens'' was long attributed to the genus ''Moroteuthis'', several authors have recently ...
'' may result in a penis that is as long as the mantle, head and arms combined. Giant squid
The giant squid (''Architeuthis dux'') is a species of deep-ocean dwelling squid in the family Architeuthidae. It can grow to a tremendous size, offering an example of abyssal gigantism: recent estimates put the maximum size at around Trace ...
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
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
word for "tail
The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...
". Some derive that from Indo-European
The Indo-European languages are a language family native to the overwhelming majority of Europe, the Iranian plateau, and the northern Indian subcontinent. Some European languages of this family, English, French, Portuguese, Russian, Dutch ...
''*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
The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a com ...
cites an example of the word ''yard'' used in this sense from 1379, and notes that in his ''Physical Dictionary'' of 1684, Steven Blankaart
Steven Blankaart (24 October 1650, Middelburg, Zeeland, Middelburg – 23 February 1704, Amsterdam) was a Dutch physician, iatrochemist, and Entomology, entomologist, who worked on the same field as Jan Swammerdam. Blankaart proved the exist ...
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
Excretion is a process in which metabolic waste
is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after l ...
functions, the penis is the subject of many slang
Slang is vocabulary (words, phrases, and linguistic usages) of an informal register, common in spoken conversation but avoided in formal writing. It also sometimes refers to the language generally exclusive to the members of particular in-gro ...
words and euphemism
A euphemism () is an innocuous word or expression used in place of one that is deemed offensive or suggests something unpleasant. Some euphemisms are intended to amuse, while others use bland, inoffensive terms for concepts that the user wishes ...
s for it, a particularly common and enduring one being "cock". See WikiSaurus:penis for a list of alternative words for penis.
The Latin word ''"phallus
A phallus is a penis (especially when erect), an object that resembles a penis, or a mimetic image of an erect penis. In art history a figure with an erect penis is described as ithyphallic.
Any object that symbolically—or, more precisel ...
"'' (from Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
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
Heraldry is a discipline relating to the design, display and study of armorial bearings (known as armory), as well as related disciplines, such as vexillology, together with the study of ceremony, rank and pedigree. Armory, the best-known branch ...
, where the adjective ''pizzled'' (or ''vilené'') indicates that part of an animate charge
Charge or charged may refer to:
Arts, entertainment, and media Films
* ''Charge, Zero Emissions/Maximum Speed'', a 2011 documentary
Music
* ''Charge'' (David Ford album)
* ''Charge'' (Machel Montano album)
* ''Charge!!'', an album by The Aqua ...
's anatomy, especially if coloured differently.
See also
*Buried penis
Buried penis (also known as hidden penis or retractile penis) is a congenital or acquired condition in which the penis is partially or completely hidden below the surface of the skin. A buried penis can lead to urinary difficulties, poor hygiene ...
*Castration anxiety
Castration anxiety is the fear of emasculation in both the literal and metaphorical sense. Castration anxiety is an overwhelming fear of damage to, or loss of, the penis—one of Sigmund Freud's earliest psychoanalytic theories. Although Freud ...
*Dildo
A dildo is a sex toy, often explicitly phallic in appearance, intended for sexual penetration or other sexual activity during masturbation or with sex partners. Dildos can be made from a number of materials and shaped like an erect human penis ...
*Diphallia
Diphallia, penile duplication (PD), diphallic terata, or diphallasparatus, is an extremely rare developmental abnormality in which a male is born with two penises. The first reported case was by Johannes Jacob Wecker in 1609. Its occurrence is 1 ...
*Erogenous zone
An erogenous zone (from Greek , ''érōs'' "love"; and English ''-genous'' "producing", from Greek , ''-genḗs'' "born") is an area of the human body that has heightened sensitivity, the stimulation of which may generate a sexual response, su ...
*Fascinus
In ancient Roman religion and magic, the ''fascinus'' or ''fascinum'' was the embodiment of the divine phallus. The word can refer to phallus effigies and amulets, and to the spells used to invoke his divine protection. Pliny calls it a ''medi ...
*Koteka
The koteka, also referred to as a horim or penis gourd, is a penis sheath traditionally worn by native male inhabitants of some (mainly highland) ethnic groups in New Guinea, Indonesia to cover their penises. The koteka is normally made from a ...
*Micropenis
Micropenis is an unusually small penis. A common criterion is a dorsal (measured on top) penile length of at least 2.5 standard deviations smaller than the mean human penis size (stretched penile length less than 9.3 cm (3.67 in) in adults). ...
*Penis enlargement
Penis enlargement, or male enhancement, is any technique aimed to increase the size of a human penis. Some methods aim to increase total length, others the shaft's girth, and yet others the glans size. Techniques include surgery, supplements, o ...
*Penis envy
Penis envy (german: Penisneid) is a stage theorized by Sigmund Freud regarding female psychosexual development, in which young girls experience anxiety upon realization that they do not have a penis. Freud considered this realization a defining m ...
*Penis removal
In ancient civilizations, the removal of the human penis was sometimes used to demonstrate superiority or dominance over an enemy. Armies were sometimes known to sever the penises of their enemies to count the dead, as well as for trophies. The ...
*Phallic architecture
Phallic architecture consciously or unconsciously creates a symbolic representation of the human penis. Buildings intentionally or unintentionally resembling the human penis are a source of amusement to locals and tourists in various places around ...
*Preputioplasty
Preputioplasty or prepuce plasty, also known as "limited dorsal slit with transverse closure", is a plastic surgical operation on the prepuce or foreskin of the penis, to widen a narrow non-retractile foreskin which cannot comfortably be drawn ba ...
*Pubic hair
Pubic hair is terminal body hair that is found in the genital area of adolescent and adult humans. The hair is located on and around the sex organs and sometimes at the top of the inside of the thighs. In the pubic region around the pubis bon ...
*Stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
*Stunt cock A stunt cock is the term for a substitute (sometimes prosthetic) penis that is used during the shooting of pornographic films.
The stunt cock is used in an extreme close up so as not to identify its bearer, the goal being to deceive the viewer into ...
*Testicle
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 testostero ...
References
Citations
General and cited references
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External links
Kinsey Institute on the penis
{{Authority control
Animal male reproductive system
Articles containing video clips
Sex organs