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Body hair, or androgenic hair, is the
terminal hair In humans, terminal hair is thick and long, such as what grows on the scalp, as compared with vellus hair Vellus hair is short, thin, light-colored, and barely noticeable hair Hair is a protein filament that grows from follicles foun ...
that develops on the
human body The human body is the structure of a Human, human being. It is composed of many different types of Cell (biology), cells that together create Tissue (biology), tissues and subsequently organ systems. They ensure homeostasis and the life, viabi ...

human body
during and after
puberty Puberty is the process of physical changes through which a child Biologically, a child (plural children) is a human Humans (''Homo sapiens'') are the most abundant and widespread species In biology Biology is the natur ...

puberty
. It is differentiated from the
head hair Hair is a protein filament that grows from hair follicle, follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick t ...
and less visible
vellus hair Vellus hair is short, thin, light-colored, and barely noticeable hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of g ...
, which is much finer and lighter in color. The growth of androgenic hair is related to the level of
androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone A steroid hormone is a steroid , hypothetical a steroid with 32 carbon atoms. Its core ring system (ABCD), composed of 17 c ...
s (often referred to as male
hormone A hormone (from the Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appr ...

hormone
s) and the density of androgen receptors in the dermal papillae. Both must reach a threshold for the proliferation of hair follicle cells. From childhood onward, regardless of
sex Sex is either of two divisions, typically male Male (♂) is the sex of an organism that produces the gamete known as sperm. A male gamete can fuse with a larger female gamete, or ovum, in the process of fertilization. A male cannot sexual r ...
, vellus hair covers almost the entire area of the
human body The human body is the structure of a Human, human being. It is composed of many different types of Cell (biology), cells that together create Tissue (biology), tissues and subsequently organ systems. They ensure homeostasis and the life, viabi ...

human body
. Exceptions include the lips; the backs of the ears; the palms of hands; the soles of the feet; certain external
genital A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction Sexual reproduction is a type of reproduction that involves a complex Biological life cycle, life cycle in which a gamete (such as a sp ...
areas; the
navel The navel (clinically known as the umbilicus, commonly known as the belly button) is a protruding, flat, or hollowed area on the abdomen The abdomen (colloquially called the belly, tummy, midriff or stomach) is the part of the body between th ...

navel
; and
scar A scar is an area of fibrosis, fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other Organ (anatomy), organs, and biological tissue, tissues of the b ...
tissue. The density of hair – i.e. the number of
hair follicle The hair follicle is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given org ...

hair follicle
s per unit area of skin – varies from person to person. In many cases, areas on the human body that contain vellus hair will begin to produce darker and thicker body hair, such as the first growth of
beard hair
beard hair
on a male and female adolescent's previously smooth chin; although it may appear thinner on the female. Androgenic hair follows the same growth pattern as the hair that grows on the scalp, but with a shorter
anagen phase The hair follicle is an organ Organ may refer to: Biology * Organ (biology) In biology, an organ is a collection of Tissue (biology), tissues joined in a structural unit to serve a common function. In the biological organization , hierarc ...
and longer
telogen phase The hair follicle is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given organ ...
. While the anagen phase for the hair on one's head lasts for years, the androgenic hair growth phase for body hair lasts a few months. The telogen phase for body hair lasts close to a year. This shortened growing period and extended dormant period explains why the hair on the head tends to be much longer than other hair found on the body. Differences in length seen in comparing the hair on the back of the hand and pubic hair, for example, can be explained by varied growth cycles in those two regions. The same goes for differences in body hair length seen in different people, especially when comparing
men A man is an adult 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 sexual r ...

men
and
women A woman is an adult female Female (symbol: ♀) is the sex of an organism that produces the large non-mobile ovum, ova (egg cells), the type of gamete (sex cell) that fuses with the Sperm, male gamete during sexual reproduction. A female ...

women
.


Distribution

Like much of the hair on the human body, leg, arm, chest, and back hair begin as vellus hair. As people age, the hair in these regions will often begin to grow darker and more abundantly. This will typically happen during or after puberty. Men will often have more abundant, coarser hair on the arms and back, while women tend to have a less drastic change in the hair growth in these areas but do experience a significant change in thickness of hairs. However, some women will grow darker, longer hair in one or more of these regions.


Chest and abdomen

Vellus hair grows on the chest and abdomen of both sexes at all stages of development. After puberty and extending into adulthood, most males grow increasing amounts of terminal hair over the
chest The thorax or chest is a part of the anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organism In biology, an organism (from Ancient Greek, Greek: ὀργανι ...
and
abdomen The abdomen (colloquially called the belly, tummy, midriff 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 Trunk (anatomy) ...
areas. Adult women also typically can grow terminal hairs around the
areola The human areola (''areola mammae'', Entry "areola"
in


Arms

Arm hair grows on a human's
forearms The forearm is the region of the upper limb between the Elbow-joint, elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but ...
, sometimes even on the elbow area, and rarely on a human's bicep, triceps, and/or shoulders. Terminal arm hair is concentrated on the wrist end of the forearm, extending over the
hand A hand is a prehensile, multi- fingered appendage located at the end of the forearm The forearm is the region of the upper limb between the Elbow-joint, elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, ...

hand
. Terminal hair growth in adolescent males is often much more intense than that in females, particularly for individuals with dark hair. In some cultures, it is common for women to remove arm hair, though this practice is less frequent than that of leg hair removal. Terminal hair growth on
arm In human anatomy The human body is the structure of a human being Humans (''Homo sapiens'') are the most abundant and widespread species In biology, a species is the basic unit of biological classification, classification and ...

arm
s is a secondary sexual characteristic in boys and appears in the last stages of puberty. Vellus arm hair is usually concentrated on the elbow end of the forearm and often ends on the lower part of the
upper arm In human anatomy, the arm is the part of the upper limb between the glenohumeral joint (shoulder joint) and the elbow joint. In common usage, the arm extends through the hand. It can be divided into the upper arm, which extends from the shoulder ...
. This type of intense arm vellus hair growth sometimes occurs in girls and children of both sexes until puberty. Even though this causes the arms to appear hairy, it is not caused solely by testosterone. The hair is softer and different from men's arm hair, in texture.


Feet

Visible hair appearing on the top surfaces of the feet and
toes Toes are the Digit (anatomy), digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being ''digitigrade''. Humans, and other animals that walk on the soles of their feet, are described a ...

toes
generally begins with the onset of puberty. Terminal hair growth on the feet is typically more intense in adult and adolescent males than in females.


Legs

Leg hair sometimes appears at the onset of adulthood, with the legs of men more often hairier than those of women. For a variety of reasons, people may shave their leg hair, including cultural practice or individual needs. Around the world, women generally shave their leg hair more regularly than men, to conform with the social norms of many cultures, many of which perceive smooth skin as a sign of youth, beauty, and in some cultures, hygiene. However, athletes of both sexes –
swimmers Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust whic ...
,
runners Sneakers (also called trainers, athletic shoes, tennis shoes, gym shoes, kicks, sport shoes, flats, running shoes, skate shoes, or runners) are shoes primarily designed for sports or other forms of physical exercise but that are now also wide ...
,
cyclists Cycling, also called bicycling or biking, is the use of bicycles for transport, recreation, Physical exercise, exercise or sport. People engaged in cycling are referred to as "cyclists", "bicyclists", or "bikers". Apart from two-wheeled bic ...
and
bodybuilders Bodybuilding is the use of Weight training, progressive resistance exercise to control and develop one's Muscle, musculature (muscle building) by muscle hypertrophy for aesthetic purposes. It is distinct from similar activities such as powerl ...

bodybuilders
in particular – may shave their androgenic hair to reduce friction, highlight muscular development or to make it easier to get into and out of skin-tight clothing.


Pubic

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 ...

Pubic hair
is a collection of coarse hair found in the pubic region. It will often also grow on the thighs and abdomen. Zoologist
Desmond Morris Desmond John Morris FLS ''hon. caus.'' (born 24 January 1928) is an English zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Anim ...
disputes theories that it developed to signal sexual maturity or protect the skin from chafing during copulation, and prefers the explanation that pubic hair acts as a scent trap. Also, both sexes having thick pubic hairs act as a partial cushion during intercourse. The
genital A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction Sexual reproduction is a type of reproduction that involves a complex Biological life cycle, life cycle in which a gamete (such as a sp ...
area of males and females are first inhabited by shorter, lighter vellus hairs that are next to invisible and only begin to develop into darker, thicker pubic hair at
puberty Puberty is the process of physical changes through which a child Biologically, a child (plural children) is a human Humans (''Homo sapiens'') are the most abundant and widespread species In biology Biology is the natur ...

puberty
. At this time, the
pituitary gland In vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Hetero ...

pituitary gland
secretes
gonadotropin Gonadotropins are glycoprotein Glycoproteins are protein Proteins are large s and s that comprise one or more long chains of . Proteins perform a vast array of functions within organisms, including , , , providing and , and from one ...
hormones which trigger the production of testosterone in the testicles and ovaries, promoting pubic hair growth. The average ages pubic hair begins to grow in males and females are 12 and 11, respectively. However, in some females, pubic hair has been known to start growing as early as age 7. Just as individual people differ in scalp hair color, they can also differ in pubic hair color. Differences in thickness, growth rate, and length are also evident.


Armpits

Underarm hair normally starts to appear at the
beginning Beginning may refer to: *Beginning (song), "Beginning" (song), by Kotipelto *Beginning (album), ''Beginning'' (album), by Pakho Chau *Beginning (play), ''Beginning'' (play), a 2017 play by David Eldridge *Beginning (film), ''Beginning'' (film), a G ...
of
puberty Puberty is the process of physical changes through which a child Biologically, a child (plural children) is a human Humans (''Homo sapiens'') are the most abundant and widespread species In biology Biology is the natur ...

puberty
, with growth usually completed by the end of the teenage years. Today in much of the world, it is common for women to regularly their underarm hair. The prevalence of this practice varies widely, though. The practice became popular for cosmetic reasons around 1915 in the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

United States
and
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,Usage is mixed. The Guardian' and Telegraph' use Britain as a synonym for the United Kingdom. Some prefer to use Britain as shorth ...

United Kingdom
, when one or more magazines showed a woman in a dress with shaved underarms. Regular shaving became feasible with the introduction of the
safety razor A safety razor is a shaving implement with a protective device positioned between the edge of the blade A blade is the portion of a tool, weapon, or machine with an edge that is designed to wikt:puncture, puncture, wikt:chop, chop, Cutting, sl ...

safety razor
at the beginning of the 20th century. While underarm shaving was quickly adopted in some
English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, which has eventually become the World language, leading lan ...

English
speaking countries, especially in the US and
Canada Canada is a country in the northern part of North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, ...

Canada
, it did not become widespread in
Europe Europe is a continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of scienc ...

Europe
until well after
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a global war A world war is "a war War is an intense armed conflict between states State may refer to: Arts, entertainment, and media Literatur ...
. Since then the practice has spread worldwide, some men also choose to shave their armpits.


Facial

Facial hair Facial hair is hair Hair is a protein filament In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molec ...
grows primarily on or around one's face. Both men and women experience facial hair growth. Like pubic hair, non-vellus facial hair will begin to grow in around puberty.
Moustache A moustache (; en-US, mustache, ) is a strip of facial hair grown above the upper lip. Moustaches have been worn in various styles throughout history. Etymology The word "moustache" is French language, French, and is derived from the Itali ...

Moustache
s in young men usually begin to grow in at around the age of puberty, although some men may not grow a moustache until they reach late teens or at all. In some cases facial hair development may take longer to mature than the late teens, and some men experience no facial hair development even at an older age. It is common for many women to develop a few facial hairs under or around the chin, along the sides of the face (in the area of sideburns), or on the upper lip. These may appear at any age after puberty but are often seen in women after
menopause Menopause, also known as the climacteric, is the time in women's lives when menstrual periods stop permanently, and they are no longer able to bear children. Menopause usually occurs between the age of 48 and 52. Medical professionals often ...
due to decreased levels of estrogen. A darkening of the vellus hair of the upper lip in women is not considered true facial hair, though it is often referred to as a "moustache"; the appearance of these dark vellus hairs may be lessened by bleaching. A relatively small number of women are able to grow enough facial hair to have a distinct beard. In some cases, female beard growth is the result of a hormonal imbalance (usually
androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone A steroid hormone is a steroid , hypothetical a steroid with 32 carbon atoms. Its core ring system (ABCD), composed of 17 c ...
excess), or a rare genetic disorder known as
hypertrichosis Hypertrichosis is an abnormal amount of hair growth The growth of human hair occurs everywhere on the body except for the soles of the feet, the inside of the mouth, the lips, the backs of the ears, the palms of the hands, some external genita ...
. Sometimes it is caused by use of
anabolic steroid Anabolic steroids, also known more properly as anabolic–androgenic steroids (AAS), are steroid A steroid is a biologically active organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability t ...
s. Cultural pressure leads most women to remove facial hair, as it may be viewed as a
social stigma Social stigma is the disapproval of, or discrimination Discrimination is the act of making unjustified distinctions between people based on the groups, classes, or other categories to which they belong or are perceived to belong. People ma ...
.


Development

Hair follicles are to varying degrees sensitive to androgen, primarily
testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testes and prostate, as well as promoting secondar ...
and its derivatives, particularly
dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous Endogenous substances and processes are those that originate from within a system such as an organism, Tissue (biology), tissue, or Cell ...
, with different areas on the body having different sensitivity. As androgen levels increase, the rate of hair growth and the weight of the hairs increase. Genetic factors determine both individual levels of androgen and the hair follicle's sensitivity to androgen, as well as other characteristics such as hair colour, type of hair and hair retention. Rising levels of androgen during puberty cause vellus hair to transform into terminal hair over many areas of the body. The sequence of appearance of terminal hair reflects the level of androgen sensitivity, with
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 ...

pubic hair
being the first to appear due to the area's special sensitivity to androgen. The appearance of pubic hair in both sexes is usually seen as an indication of the start of a person's puberty. There is a
sexual differentiation Sexual differentiation is the process of development of the sex Sex is either of two divisions, typically male Male (♂) is the sex of an organism that produces the gamete known as sperm. A male gamete can fuse with a larger female gamete ...
in the amount and distribution of androgenic hair, with men tending to have more terminal hair in more areas. This includes
facial hair Facial hair is hair Hair is a protein filament In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molec ...
,
chest hair Chest hair is hair that grows on the chest of a male in the region between the neck and the Human abdomen, abdomen. Chest hair develops during and after puberty along with other types of androgenic hair. Development and growth Although vellus ...
,
abdominal hair Abdominal hair is the hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which ...
,
leg hair Leg hair is hair that grows on the legs of humans, generally appearing after the onset of puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initia ...

leg hair
, arm hair, and foot hair. Women retain more of the less visible vellus hair, although leg, arm, and foot hair can be noticeable on women. It is not unusual for women to have a few terminal hairs around their nipples as well. In the later decades of life, especially after the 5th decade, there begins a noticeable reduction in body hair especially in the legs. The reason for this is not known but it could be due to poorer circulation, lower free circulating hormone amounts or other reasons.


Function

Androgenic hair provides tactile sensory input by transferring hair movement and vibration via the shaft to sensory nerves within the skin. Follicular nerves detect displacement of hair shafts and other nerve endings in the surrounding skin detect vibration and distortions of the skin around the follicles. Androgenic hair extends the sense of touch beyond the surface of the skin into the air and space surrounding it, detecting air movements as well as hair displacement from contact by insects or objects.


Evolution

Determining the evolutionary function of androgenic hair must take into account both
human evolution Human evolution is the evolution Evolution is change in the heritable Heredity, also called inheritance or biological inheritance, is the passing on of Phenotypic trait, traits from parents to their offspring; either through asexual ...

human evolution
and the thermal properties of hair itself. The thermodynamic properties of hair are based on the properties of the
keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin Alpha-keratin, or α-keratin, is a type of keratin Keratin () is one of a family of fibrous structural proteins known as Scleroprot ...

keratin
strands and
amino acids Amino acids are organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of organic compounds are known. The study of the properties, reactions, a ...

amino acids
that combine into a 'coiled' structure. This structure lends to many of the properties of hair, such as its ability to stretch and return to its original length. This coiled structure does not predispose curly or frizzy hair, both of which are defined by oval or triangular hair follicle cross-sections.


Evolution of less body hair

Hair is a very good thermal conductor and aids heat transfer both into and out of the body. When
goose bumps Goose bumps, goosebumps or goose-pimples are the bumps on a person's skin at the base of body hairs which may involuntarily develop when a person is tickled, cold , a common physiological response to cold, aiming to reduce the loss of bo ...

goose bumps
are observed, small muscles (
arrector pili muscle The arrector pili muscles, also knows as hair erector muscles, are small muscles attached to hair follicles The hair follicle is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with si ...
) contract to raise the hairs both to provide insulation, by reducing cooling by air convection of the skin, as well as in response to central nervous stimulus, similar to the feeling of 'hairs standing up on the back of your neck'. This phenomenon also occurs when static charge is built up and stored in the hair. Keratin however can easily be damaged by excessive heat and dryness, suggesting that extreme sun exposure, perhaps due to a lack of clothing, would result in perpetual hair destruction, eventually resulting in the genes being bred out in favor of high skin
pigmentation A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes 300px, Yarn drying after being dyed in the early American tradition, at living_history_museum.html"_;"title="Conner_Prairie_living_history_muse ...
. It is also true that parasites can live on and in hair thus peoples who preserved their body hair would have required greater general hygiene to prevent diseases. Markus J. Rantala of the Department of Biological and Environmental Science, University of Jyväskylä,
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the west, Russia to the east, Norway to the north, and is defined by the Gulf of B ...

Finland
, said humans evolved by "natural selection" to be hairless when the trade off of "having fewer parasites" became more important than having a "warming, furry coat". P.E. Wheeler of the Department of Biology at Liverpool Polytechnic said
quadrupedal Quadrupedalism is a form of terrestrial locomotion where a tetrapod animal uses all four limb (anatomy), limbs (legs) to weight-bearing, bear weight, walking, walk, and running, run. An animal or machine that usually maintains a four-legged po ...
savannah A savanna or savannah is a mixed woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats ...

savannah
mammal Mammals (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be i ...
s of similar volume to humans have body hair to keep warm while only larger quadrupedal savannah mammals lack body hair, because their body volume itself is enough to keep them warm. Therefore, Wheeler said humans who should have body hair based on predictions of body volume alone for savannah mammals evolved no body hair after evolving
bipedalism Bipedalism is a form of terrestrial locomotion Terrestrial locomotion has evolved Evolution is change in the heritable Heredity, also called inheritance or biological inheritance, is the passing on of Phenotypic trait, traits from ...

bipedalism
which he said reduced the amount of body area exposed to the sun by 40%, reducing the solar warming effect on the human body. Loss of fur occurred at least 2 million years ago, but possibly as early as 3.3 million years ago judging from the divergence of head and pubic lice, and aided
persistence hunting Persistence hunting (sometimes called endurance hunting) is a hunting technique A hunting strategy, or hunting method, is a tactic that is used to target, pursue, and kill a targeted animal. The hunting strategy that a hunter uses depends on the s ...
(the ability to catch prey in very long distance chases) in the warm savannas where hominins first evolved. The two main advantages are felt to be bipedal locomotion and greater thermal load dissipation capacity due to better sweating and less hair.


Sexual selection

Markus J. Rantala of the Department of Biological and Environmental Science, University of Jyväskylä,
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the west, Russia to the east, Norway to the north, and is defined by the Gulf of B ...

Finland
, said the existence of
androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone A steroid hormone is a steroid , hypothetical a steroid with 32 carbon atoms. Its core ring system (ABCD), composed of 17 c ...
dependent hair on men could be explained by
sexual attraction Sexual attraction is attraction Attraction may refer to: * Attractiveness ** Interpersonal attraction, the attraction between people which leads to friendships and platonic and romantic relationships ** Physical attractiveness, attraction on t ...
whereby hair on the genitals would trap
pheromones A pheromone (from Ancient Greek ' "to bear" and hormone) is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the s ...
and hair on the chin would make the chin appear more massive.Rantala, M.J. (1999). Human nakedness: adaptation against ectoparasites? International Journal for Parasitology 29 1987±1989


Across populations

In 1876,
Oscar Peschel Oscar Ferdinand Peschel (17 March 1826, Dresden Dresden (, ; wen, label=Sorbian languages, Upper and Lower Sorbian, Drježdźany) is the capital city of the Germany, German States of Germany, state of Saxony and its second most populous city, ...
wrote that North Asiatic Mongols, Native Americans, Malays, Hottentots and Bushmen have little to no body hair, while Semitics, Indo-Europeans, and Southern Europeans (especially the Portuguese and Spanish) have extensive body hair. Anthropologist
Joseph Deniker Joseph Deniker (russian: Иосиф Егорович Деникер, ''Yosif Yegorovich Deniker''; 6 March 1852, in Astrakhan Astrakhan ( rus, Астрахань, p=ˈastrəxənʲ), is the largest city and administrative centreAn administrative ...

Joseph Deniker
said in 1901 that the very hirsute peoples are the
Ainu Ainu or Aynu may refer to: *Ainu people, an East Asian ethnic group of Japan and Russian Far East *Ainu languages, a family of languages **Ainu language of Hokkaido **Kuril Ainu language, extinct language of the Kuril Islands **Sakhalin Ainu languag ...
s,
Iranian Iranian may refer to: * Iran Iran ( fa, ایران ), also called Persia, and officially the Islamic Republic of Iran, is a country in Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion A subreg ...
s,
Australian aborigine Aboriginal Australians are the various Indigenous peoples Indigenous peoples, also referred to as first peoples, first nations, aboriginal peoples, native peoples (with these terms often capitalized when referred to relating to specific ...
s (
Arnhem Land Arnhem Land is a historical region of the Northern Territory The Northern Territory (NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern region ...
being less hairy), Toda,
Dravidian Dravidian, Dravidan, or Dravida may refer to: Language and culture *Dravidian languages, a family of languages spoken mainly in South India and northeastern Sri Lanka *Proto-Dravidian language, a model of the common ancestor of the Dravidian langu ...

Dravidian
s and
Melanesian Melanesian is the adjectival form of Melanesia Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from the island of New Guinea in the west to Tonga in the east, and includes the Arafura Sea. The region in ...
s, while the most glabrous peoples are the American Indians, , and
East Asian East Asia is the eastern region In geography, regions are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and the environment ( ...
s, who include
Chinese Chinese can refer to: * Something related to China China (), officially the People's Republic of China (PRC; ), is a country in . It is the world's , with a of more than 1.4 billion. China spans five geographical and 14 different count ...

Chinese
,
Mongol The Mongols ( mn, Монголчууд, , ''Mongolchuud'', ; russian: Монголы, ) are an East Asian East Asia is the eastern region In geography Geography (from Greek: , ''geographia'', literally "earth description") ...

Mongol
s, and
Malay Malay may refer to: Languages * Malay language or Bahasa Melayu, a major Austronesian language spoken in Indonesia, Malaysia, Brunei and Singapore ** History of the Malay language#Old Malay, the Malay language from the 4th to the 14th century ** ...
s. Deniker said that hirsute peoples tend to have thicker beards, eyelashes, and eyebrows but fewer hairs on their scalp. C.H. Danforth and Mildred Trotter of the Department of Anatomy at
Washington University Washington University in St. Louis (WashU, or WUSTL) is a private Private or privates may refer to: Music * "In Private "In Private" was the third single in a row to be a charting success for United Kingdom, British singer Dusty Springfiel ...
conducted a study using army soldiers of European origin in 1922 where they concluded that dark-haired
white White is the lightest color Color (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the Unite ...
men are generally more hairy than fair-haired white men. H. Harris, publishing in the ''British Journal of Dermatology'' in 1947, wrote American Indians have the least body hair,
Chinese Chinese can refer to: * Something related to China China (), officially the People's Republic of China (PRC; ), is a country in . It is the world's , with a of more than 1.4 billion. China spans five geographical and 14 different count ...

Chinese
and
Black people Black people is a racialized In sociology Sociology is the study of society, human social behaviour, patterns of social relationships, social interaction, and culture that surrounds everyday life. It is a social science that uses vario ...
have little body hair,
white people White is a Race (human categorization), racialized classification of people and a Human skin color, skin color specifier, generally used for people of Ethnic groups in Europe, European origin; although the definition can vary depending on cont ...
have more body hair than Black people and
Ainu Ainu or Aynu may refer to: *Ainu people, an East Asian ethnic group of Japan and Russian Far East *Ainu languages, a family of languages **Ainu language of Hokkaido **Kuril Ainu language, extinct language of the Kuril Islands **Sakhalin Ainu languag ...
have the most body hair. Anthropologist , in 1970, described the
Ainu Ainu or Aynu may refer to: *Ainu people, an East Asian ethnic group of Japan and Russian Far East *Ainu languages, a family of languages **Ainu language of Hokkaido **Kuril Ainu language, extinct language of the Kuril Islands **Sakhalin Ainu languag ...
as having hairy bodies. Stewart W. Hindley and Albert Damon of the Department of Anthropology at
Stanford University Stanford University, officially Leland Stanford Junior University, is a private Private or privates may refer to: Music * "In Private "In Private" was the third single in a row to be a charting success for United Kingdom, British singer Du ...

Stanford University
studied, in 1973, the frequency of hair on the middle finger joint (mid- hair) of Solomon Islanders, as a part of a series of
anthropometric Anthropometry (from Ancient Greek, Greek ''anthropos'', 'human', and ''metron'', 'measure') refers to the measurement of the human individual. An early tool of biological anthropology, physical anthropology, it has been used for identification ...
studies of these populations. They summarize other studies on prevalence of this trait as reporting, in general, that
Caucasoid The Caucasian race (also Caucasoid or Europid, Europoid) is an Historical race concepts, obsolete racial classification of human beings based on a now-disproven theory of biological race. The ''Caucasian race'' was historically regarded as a b ...
s are more likely to have hair on the middle finger joint than
Negroid Negroid (less commonly called Congoid) is an obsolete racial grouping of various people indigenous to Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11 ...
s and
Mongoloid Mongoloid () is an Historical race concepts, obsolete racial grouping of various people indigenous to large parts of Asia, the Americas, and some regions in Oceania. The term is derived from a now-disproven theory of biological race. In the past, ...
s, and collect the following frequencies from previously published literature:
Andamanese The Andamanese are the various indigenous peoples Indigenous peoples, also referred to as first peoples, first nations, aboriginal peoples, native peoples (with these terms often capitalized when referred to relating to specific countrie ...
0%,
Eskimo Eskimo ( ) or Eskimos is a term used to refer to two closely related Indigenous peoples: The Inuit (including the Alaskan Iñupiat, the Greenlandic Inuit, and the Canadian Inuit) and the Yupik peoples, Yupik (or Siberian Yupik, Yuit) of eastern S ...

Eskimo
1%, African American 16% or 28%,
Ethiopians Ethiopians are the native inhabitants of Ethiopia, as well as the global diaspora of Ethiopia. Ethiopians constitute Ethiopians#Component Ethnicities, several component ethnic groups, many of which are closely related to ethnic groups in neighbo ...
25.6%,
Mexicans Mexicans ( es, mexicanos) are the citizens Citizenship is a relationship between an individual and a state to which the individual owes allegiance and in turn is entitled to its protection. Each state determines the conditions under which ...
of the 20.9%,
Penobscot The Penobscot (''Panawahpskek'') are an Indigenous people in North America from the Northeastern Woodlands region. They are organized as a federally recognized tribe This is a list of federally recognized tribes in the contiguous United Stat ...
and Shinnecock 22.7%,
Gurkha The Gurkhas or Gorkhas (), with endonym An endonym (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Eu ...

Gurkha
33.6%,
Japanese Japanese may refer to: * Something from or related to Japan Japan ( ja, 日本, or , and formally ) is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or ...
44.6%, various
Hindu Hindus (; ) are persons who regard themselves as culturally, ethnically, or religiously adhering to aspects of Hinduism Hinduism () is an Indian religion Indian religions, sometimes also termed Dharmic religions or Indic re ...

Hindu
s 40–50%,
Egyptians Egyptians ( arz, المصريين, ; cop, ⲣⲉⲙⲛ̀ⲭⲏⲙⲓ, remenkhēmi) are an ethnic group of people originating from the country of Egypt Egypt ( ar, مِصر, Miṣr), officially the Arab Republic of Egypt, is a spanning t ...
52.3%,
Near Eastern The Near East ( ar, الشرق الأدنى, al-Sharq al-'Adnā, he, המזרח הקרוב, arc, ܕܢܚܐ ܩܪܒ, fa, خاور نزدیک, Xāvar-e nazdik, tr, Yakın Doğu) is a geographical term which roughly encompasses a transcontinental ...
peoples 62–71%, various Europeans 60–80%. However, they never completed an Androgenic hair map. According to anthropologist and professor
Ashley Montagu Montague Francis Ashley-Montagu (19051999) — born Israel Ehrenberg — was a British-American anthropologist who popularized the study of topics such as Race (classification of human beings), race and gender and their relation to politics and de ...
in 1989,
Asian people Asian people (or Asiatic people)United States National Library of Medicine. Medical Subject Headings. 2004. November 17, 200Nlm.nih.gov: ''Asian Continental Ancestry Group'' is also used for categorical purposes. are the people A peopl ...
and
black people Black people is a racialized In sociology Sociology is the study of society, human social behaviour, patterns of social relationships, social interaction, and culture that surrounds everyday life. It is a social science that uses vario ...
such as the
San people The San peoples (also Saan), or Bushmen, are members of various Khoe Maharishi International University (MIU), formerly Maharishi University of Management, is a private university in Fairfield, Iowa. It was founded in 1973 by Maharishi Mahesh ...

San people
are less hairy than
white people White is a Race (human categorization), racialized classification of people and a Human skin color, skin color specifier, generally used for people of Ethnic groups in Europe, European origin; although the definition can vary depending on cont ...
. Montagu said that the hairless feature is a trait.Montagu, Ashley. Growing Young. Published by Greenwood Publishing Group, 1989 Eike-Meinrad Winkler and Kerrin Christiansen of the Institut für Humanbiologie studied, in 1993, Kavango people and !Kung people of body hair and hormone levels to investigate the reason
black Africans Black people is a Racialization, racialized classification of people, usually a Politics, political and Human skin color, skin color-based category for specific populations with a mid to dark brown complexion. Not all people considered "black" ...
did not have bodies as hairy as
Europeans Europeans are the focus of European ethnology, the field of anthropology related to the various indigenous groups that reside in the List of sovereign states and dependent territories in Europe, nations of Europe. Groups may be defined by commo ...

Europeans
. Winkler and Christiansen concluded the difference in hairiness between black Africans and Europeans had to do with differences in
androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone A steroid hormone is a steroid , hypothetical a steroid with 32 carbon atoms. Its core ring system (ABCD), composed of 17 c ...
or
estradiol Estradiol (E2), also spelled oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous cycle, estrous and menstrual cycle, menstrual female reproductive cycles. Estradiol is resp ...

estradiol
production, in androgen
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life Life is a characteristic that distinguishes physical entities A bubble of exhaled gas in water In common usage and classical mechanics, a phys ...

metabolism
, and in
sex hormone Sex hormones, also known as sex steroids, gonadocorticoids and gonadal steroids, are steroid hormone A steroid hormone is a steroid , hypothetical a steroid with 32 carbon atoms. Its core ring system (ABCD), composed of 17 carbon atoms, is ...
action in the target cells. Valerie Anne Randall of the Department of Biomedical Sciences,
University of Bradford The University of Bradford is a public research university located in the city of Bradford, West Yorkshire, England. A plate glass university, it received its royal charter in 1966, making it the 40th university to be created in Britain, but ...

University of Bradford
, said in 1994 beard growth in Caucasian men increases until the mid-thirties due to a delay caused by growth cycles changing from
vellus hair Vellus hair is short, thin, light-colored, and barely noticeable hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of g ...
to
terminal hair In humans, terminal hair is thick and long, such as what grows on the scalp, as compared with vellus hair Vellus hair is short, thin, light-colored, and barely noticeable hair Hair is a protein filament that grows from follicles foun ...
. Randall said white men and women are hairier than Japanese men and women even with the same total plasma
androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone A steroid hormone is a steroid , hypothetical a steroid with 32 carbon atoms. Its core ring system (ABCD), composed of 17 c ...
levels. Randall says that the reason for some people being hairy and some people not being hairy is unclear, but that it probably is related to differing sensitivity of
hair follicle The hair follicle is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given org ...

hair follicle
s to 5α-reductase. Rodney P.R. Dawber of the Oxford Hair Foundation said in 1997 that East Asian males have little or no facial or body hair and Dawber also said that
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...
males are covered with an exuberant pelage. Milkica Nešić and her colleagues from the Department of Physiology at the
University of Niš The University of Niš ( sr, Универзитет у Нишу, Univerzitet u Nišu) is a List of universities in Serbia, public university in Serbia. It was founded in 1965 and consists of 13 faculties with 1,492 academic staff and around 20,500 ...
, Serbia, cited prior studies in a 2010 publication as indicating that the frequency of hair on the middle finger joint (mid- hair) in whites is significantly higher than in Black people, Black populations.


Androgenic hair as biometric

It has been shown that individuals can be uniquely identified by their androgenic hair patterns. For example, even when one's particular distinguishing features such as face and tattoos are obscured, persons can still be identified by their hair on other parts of their body.Huynh, N. Q., Xu, X., Kong, A. W. K., & Subbiah, S. (2014, December). A preliminary report on a full-body imaging system for effectively collecting and processing biometric traits of prisoners. In Computational Intelligence in Biometrics and Identity Management (CIBIM), 2014 IEEE Symposium on (pp. 167–174). IEEE.


See also

* Alopecia * Hair removal * Hirsutism * Human hair color * Trichotillomania


References

{{DEFAULTSORT:Androgenic Hair Hair anatomy Human development Human hair