Nudity, or nakedness, is the state of wearing no clothing.^[5]

The deliberate and conscious wearing of clothing is a behavioural adaptation, which among all known extant and extinct animals is a uniquely human characteristic arising from functional needs such as protection from the elements. Protection from the elements includes the sun (for depigmented human populations) and cold temperatures after the loss of body hair and the migration of humans to colder regions^[6] (around 100,000 years ago) in which they had not evolved and thus lacked the necessary physical adaptations.

According to some researchers, wearing clothes may predate early human global migrations by an additional 70,000 years.

In this case, the migrations were themselves facilitated by the innovation of clothing.^[7] It is believed that earlier species of archaic humans, including Homo neanderthalensis, Homo rhodesiensis, Homo heidelbergensis, and Homo antecessor, either were not able to create true clothing, or were not able to do it as well as Homo sapiens sapiens (anatomically modern humans). In a paper published in Journal of Anthropological Archaeology, Researchers Mark Collard, Lia Tarle, Dennis Sandgathe and Alexander AllanIt of Simon Fraser University, in British Columbia Canada suggest that their work supports (but hardly proves) the hypothesis that Homo Neanderthalensis may have only known how to make cape-like coverings and that this lack of behavioral adaptation may have contributed to their eventual extinction during ancient climate changes when they may have succumbed to hypothermia, frostbite and other cold ailments.^[8]

The amount of clothing worn depends on functional considerations, such as a need for warmth, as well as social circumstances.

In some situations, a minimum amount of clothing or none at all may be considered socially acceptable, while in others much more clothing may be expected.

Social considerations involve cultural issues of modesty, subjective decency and social norms, besides other considerations, and these may depend on the context. There may also be legal considerations.

Full nudity refers to complete nudity, while partial nudity refers to less than full nudity, with parts of the body covered in some manner. The term "partial nudity" is sometimes used to refer to exposure of skin beyond what the person using the expression considers to be within the limits of modesty. If the exposure is within the standards of modesty of a given culture and setting (e.g. wearing a bikini at a non-nude beach), terms such as nudity, partial or otherwise, are not normally used. If however, the degree of exposure exceeds the cultural norms of the setting, or if the activity or setting includes nudity as an understood part of its function, such as a nude beach, terminology relating to nudity and degrees thereof are typically used. Toplessness is regarded by most people as partial nudity.

Full frontal nudity describes a state of full nudity with the subject facing towards the viewer, with the whole front of the body exposed, including intimate parts such as a man's penis or woman's vulva. Partial frontal nudity typically only refers to the exposure of the breasts. Non-frontal nudity describes nudity where the whole back side of the body, including the buttocks, is exposed, or a side-view from any other direction.

Hair probably evolved in mammals before about 220 million years ago.

The closest living genetic relatives of humans, apes and especially chimpanzees, possess an almost complete covering of fur.

Humans are today the only naked primate in nature, that is, most of the body is not naturally covered by fur.

Reliable information on the development of nudity and the passage of time are not yet possible because hair does not fossilize.

Researchers at the University of Utah in 2004 found that human skin contains photoreceptors like those in the retina, allowing it to mount an immediate defence against damaging ultraviolet radiations.

They suspect that the protein that protects the skin from sunlight evolved following the loss of protective hair, which happened about 1.2 million years ago.^[9]

People have a variety of views on nudity, both of their own as well as those of others.

This would depend on their level of inhibition, cultural background and upbringing, as well as on context. A society's attitude to public nudity varies depending on the culture, time, location and context of an activity. There are many exceptions and particular circumstances in which nudity is tolerated, accepted or even encouraged in public spaces. Such examples would include a nude beach, within some intentional communities (such as naturist resorts or clubs) and at special events.

In general and across cultures, public indications of sexual arousal are commonly regarded as embarrassing, both to the person aroused and the onlooker, and for this reason those parts of the human body that would indicate arousal are normally covered. Arousal is most evidently indicated by the sex organs and women's breasts, which are routinely covered, even when other parts of the body may be freely uncovered. Yet the nudity taboo may have meanings deeper than the immediate possibility of sexual arousal, for example, in the cumulative weight of tradition and habit. Clothing also expresses and symbolizes authority, and more general norms and values besides those of a sexual nature.

While some European countries, such as Germany, are rather tolerant of public nudity,^[10] in many countries public nudity may meet social disapproval or even constitute a misdemeanor of indecent exposure. In 2012, the city council of San Francisco proposed a ban on public nudity in the inner city area. This was met by harsh resistance since the city is usually known for its liberal culture.^[11][12] Similarly, park rangers began filing tickets against nudists at San Onofre State Beach in 2010, also a place with long tradition of public nudity.^[13]

Some people take part in non-sexual public nude events.

These may be in a naturist resort or club or at a nude beach. Outdoor nude recreation can take place in private or rural areas, though generally limited to warm weather.

Others practice casual public nudity.

Topfree sunbathing is considered acceptable by many on the beaches of Finland, France, Spain, Italy and most of the rest of Europe (and even in some outdoor swimming pools); however, exposure of the genitals is restricted to nudist areas in most regions.

In the United States, topfree sunbathing and wearing thongs are not common in many areas, but are limited to nude beaches in various locations. It is normally acceptable for men in the U.S. to be barechested or shirtless when engaged in outdoor recreational activities.

Where the social acceptability of nudity in certain places may be well understood, the legal position is often less clear cut.

In England, for example, the law does not actually prohibit simple public nudity, but does forbid indecent exposure.

In practice, this means that successful prosecution hangs on whether there is a demonstrable intention to shock others, rather than simply a desire to be nude in a public place.

Specifically, using nudity to "harass, alarm or distress" others is an offence against the Public Order Act of 1986.

Occasional attempts to prove this point by walking naked around the country therefore often result in periods of arrest, followed by release without charge, and inconsistencies in the approach between different police jurisdictions.

Differences in the law between England and Scotland appear to make the position harder for naked ramblers once they reach Scotland.

Photography of installations of massed nude people in public places, as made repeatedly around the world by Spencer Tunick, claim artistic merit.

Nudity is at times used to draw attention to a cause, with the participants desiring to remain anonymous.

Public nude events are at times staged as a forum for usually unrelated messages, such as clothing-optional bike rides. At times, the cause is merely a personal justification for taking part in a nude event, which are popular in their own right. Many nude calendars are produced each year featuring naked men or women. Some of these are produced to raise money for charities or other causes. Nudity, like sexuality, is also used to draw attention for a commercial purpose, such as for promotion or advertising.

Nudity may be used as a part of artistic or erotic performance, such as in nude performance art, nude body painting (ex. Fantasy Fest), sex shows, striptease, adult entertainment conventions, and in adult-only events like Folsom Street Fair, Nudes-A-Poppin', etc.

In the privacy of their own homes, people are more casual in relation to clothing, though what each considers appropriate varies considerably.

What and how much clothing a person removes depends on a number of considerations, including the cultural background and on whether the person is alone in the privacy of their own homes.

The removal of overclothing (such as coats, hats, gloves, scarves and the like) is the norm in virtually all households.

It is also common for people to remove outdoor shoes when entering one's home and at times guests may also be expected to do the same.

It is also common to change out of work clothes (such as a suit and tie, overalls etc.) into something lighter, looser and more comfortable, and perhaps for a woman to remove her bra or stockings.

Beyond that, how much more is removed depends on personal taste, habits, circumstance and relationships of the people inside the household at a particular time.

Some people may wear only undergarments at home.

When guests or other visitors are expected to enter the household, the hosts may keep normal clothing on.

If the host/s find themselves partially dressed or undressed, they may get dressed again or put on additional clothing, such as a dressing gown.

A person's cultural background as well as their religious teachings will affect the way they view their own nudity or state of dress, alone or in the presence of others, as well as how they view the nudity of others.

Some cultures deprecate nudity even in a private context.

Another factor is the level of privacy to which a person can be assured - for example, some parts of a home may be seen from the outside or there may be a possibility of others walking in.

The expectation of privacy may be confined to the home and sometimes the backyard.

Inside the home, it may be restricted to the bedroom or just the bathroom.

If a person is not alone, their comfort in removing clothing in front of another person will generally depend on the nature of a relationship of those who jointly occupy the same private space, as well as the attitudes of others to nudity.

Besides the nature of a relationship, attitudes and incidences of nudity will also depend on the level of inhibition each person has, as well as the level of privacy to which they can be assured. Sometimes a person may unintentionally intrude on a person who is nude, which may embarrass one or both of them. The nude person may quickly cover their private parts and the clothed person may turn away, but this also depends on cultural differences and their relationship.

In the case of nudity in front of those who do not normally occupy the same private space, that will usually depend on whether the outsider is comfortable with the nudity and whether the nudity is reciprocated, as in the case of social nudism. Social nudism may take place in any private social context, such as at one's home with friends or with acquaintances at a nudist facility or event, such as a naturist club, community center, resort or other facility. To generate an atmosphere of fun at a social gathering and lighten the social atmosphere, or to heighten the sexual atmosphere and ease those present into some state of nudity, organisers of a social gathering may organise party games, which may involve some level of nudity, such as strip games, for example strip poker, which can be played by single-sex groups or by mixed groups.

A 1999 survey by the Federation of Canadian Naturists found, besides other things, that 39% of Canadians "have walked or would walk around their house nude"; that naturists tend to have above average incomes; that urban dwellers are more likely to be naturists than country dwellers; and that people under the age of 25 are the most likely to be naturists.^[14] According to a 2004 United States survey, 31% of men and 14% of women report sleeping in the nude,^[15] while a 1996 BBC survey revealed that in the UK 47% of men and 17% of women do.^[16]

Nudity in front of a sexual partner is widely accepted, but not in all cases. For example, some partners insist on nudity only at the time and place of sex, or with subdued lighting; during bathing with the partner or afterward; covered by a sheet or blanket, or while sleeping.

The invention of photography and more recently the video camera has opened the art of capturing images of people and scenes at a relatively low cost to the true amateur. A person can now capture images in both public and private situations. A feature of most private photographs and videos is that they are not intended for viewing outside of a very limited range of people, and seldom if ever by the general public. Amateur photography, which includes nude photography, which has previously been produced for personal enjoyment, is increasingly being more widely disseminated through the internet, at times without the knowledge and consent of the subject of the photograph, and to their subsequent embarrassment. Also, the use of secret photography to capture images of an unsuspecting person (undressed or not, and whether for personal use, or intended for posting on the Internet) creates additional personal privacy issues.

Some people are made anxious by being nude or being in the presence of nude people; if this begins to interfere with their well-being, the phobia is called gymnophobia.^[17]

There are differences of opinion as to whether, and if so to what extent, parents should appear naked in front of their children.

Gordon and Schroeder report that parental nudity varies considerably from family to family.^[18] They say that "there is nothing inherently wrong with bathing with children or otherwise appearing naked in front of them", noting that doing so may provide an opportunity for parents to provide important information.

They note that by ages five to six, children begin to develop a sense of modesty, and recommend to parents who wish to be sensitive to their children's wishes that they limit such activities from that age onwards.

Bonner recommends against nudity in the home if children exhibit sexual play of a type that is considered problematic.^[19]

A U.S. study by Alfred Kinsey found that 75% of the participants stated that there was never nudity in the home when they were growing up, 5% of the participants said that there was "seldom" nudity in the home, 3% said "often", and 17% said that it was "usual". The study found that there was no significant difference between what was reported by men and by women with respect to frequency of nudity in the home.^[20]

In a 1995 review of the literature, Paul Okami concluded that there was no reliable evidence linking exposure to parental nudity to any negative effect.^[21] Three years later, his team finished an 18-year longitudinal study that showed that, if anything, such exposure was associated with slight beneficial effects, particularly for boys.^[22]

Attitudes toward children seeing nude people vary substantially, depending on the child's culture, age and the context of the nudity (see also the section Home above).

Television and radio regulations in many countries require broadcasters to avoid transmitting images or language considered inappropriate for children from 5:30 am to 9 pm (the so-called "watershed"). In the United Kingdom, the Broadcasting Code states, "Nudity before the watershed must be justified by the context."^[23] In the U.S., the safe harbor rule forbids depictions of nudity between the hours of 6 am and 10 pm. Violators may be subject to civil legal action and sanctions if the Federal Communications Commission (FCC) determines the broadcaster did not meet its standards of "decency". "Material is indecent if, in context, it depicts or describes sexual or excretory organs or activities in terms patently offensive as measured by contemporary community standards for the broadcast medium."^[24]

Attitudes to nudity vary substantially throughout Europe.

Male and female nudity in Scandinavia is not uncommon. The region has a very open attitude about nudity, although it strictly prohibits children's access to pornography.^[25]

Another issue has been the nudity of children in front of other children.

In many countries, including the U.S., the U.K., Australia and some of the English-speaking majority of Canada, students at public schools have historically been required to shower communally with classmates of the same sex after physical education classes. In the U.S., public objections and the threat of lawsuits have resulted in a number of school districts in recent years changing policy to make showers optional. Private boarding schools and military academies in the U.S. often have communal showers, since the focus there is on 24-hours-a-day education and rooming, rather than just acting as day schools. Students in these establishments need places to clean themselves daily.^[26] A court case in Colorado noted that students have a reduced expectation of personal privacy in regards to "communal undress" while showering after physical education classes.^[27] According to an interview with a middle school principal, most objections to showering at school that he had heard were actually from the students' parents rather than from the students.^[28]

Children who are within a naturist home will usually also be naked, together with their family, and may see and be seen by non-family members in the nude. They may also be taken to naturist venues and events where they, their families and others would also generally be nude.

In many cultures, different standards have applied and continue to apply for males and females with regard to communal nudity in the presence of the same sex.

Particularly in English-speaking countries, males have historically been more likely to be expected to engage in practices such as nude swimming in swimming pools, or to be mandated to have communal showers with no privacy in schools,^[29] based on the cultural beliefs that women need more privacy.^[30] Communal male nudity in the United States and other Western countries was not a taboo for much of the 20th century. Social attitudes maintained that it was healthy and normal for men and boys to be nude around each other and schools, gymnasia, and other such organizations typically required nude male swimming in part for sanitary reasons due to the use of wool swimsuits. There was less tolerance for female nudity and the same schools and gyms that insisted on wool swimwear being unsanitary for males did not make an exception when women were concerned. Nonetheless, some schools did allow girls to swim nude if they wished. By the 1970s, most schools and gyms in the United States had become mixed-sex, which put an end to nude swimming.^[31]

Nudity in film has, since the development of the medium, been somewhat controversial, though there was no defined censorship, especially of nudity, in the early years of Hollywood, until the Hays Code of the 1930s. Under present-day guidelines, most nude scenes in films have had to be justified as being part of the story, in the concept of "artistically justifiable nudity". In some cases nudity is itself the object of a film or is used in the development of the character of the subject. There are film scenes where nudity, in routine and non-sexual situations, such as mixed shower scenes, has been used to emphasize gender equality in the future.^[32][33][34]

In some cases, nudity has been criticized as "superfluous" or "gratuitous" to the plot, and some film producers have been accused of including nudity in a film to appeal to audiences.

Many actors and actresses have appeared nude, or exposing parts of their bodies or dressed in ways considered provocative by contemporary standards at some point in their careers.

Erotic films usually contain nudity, and nudity in a sexual context is common in pornographic films. A film on naturism, or about people for whom nudity is common, for example, many societies and people who live in hot climates, or films set in times such as the 1960s or 1970s era of liberation, may contain non-sexual nudity, and many non-pornographic films contain nude scenes.

Mainstream art generally reflects – with some exceptions – social standards of aesthetics and morality of a society at various periods of time. Beyond mainstream standards, artistic expression may be merely tolerated, or be considered as fringe. Since prehistoric time, humans, both male and female, have been depicted in all states of dress, including all states of undress. Nudity in all styles has been and continues to be found in art. Nudity is also a subject of many literary works and in film. All professionally produced works of art use stylised compositions to depict the nude body. This also applies to cinema, where even nude scenes are staged and rehearsed.

The erotic aspect of nudity in the arts has been an important factor in its attraction, and has come to be associated with certain states and emotions, such as innocence, playfulness, vulnerability, etc. Pornography does not necessarily involve a naked person, but it involves sexualized scenes, and usually it does not claim to have any artistic merit.

The visual arts were at times the only means available to the general public to view a nude body.

Today, the opportunities available for the viewing of the nude body are very wide, and these include magazines, television, films, and the Internet.

Depictions of child nudity or children with nude adults appear in works of art in various cultures and historical periods. These attitudes have changed over time and have become increasingly frowned upon particularly in recent years,^[35] especially in the case of photography. In recent years, there have been a few incidents in which snapshots taken by parents of their infant or toddler children bathing or otherwise naked were challenged as child pornography.^[36]

In May 2008, police in Sydney, Australia, raided an exhibition by the photographer Bill Henson featuring images of naked children on allegations of child pornography.^[37][1] Comparable artworks by Henson had been exhibited without incident since 1975, perhaps indicating that this sensitivity has heightened in recent years.

In June 2008, it was reported in The Age that police would have no basis to prosecute Henson over his photographs of naked teenagers, after they were declared "mild and justified" and given a PG rating by the Australian Classification Board, suggesting viewing by children under the age of 16 is suitable with parental guidance.^[38] Out of protest, the Art Monthly Australia magazine published an image of the 6-year-old Olympia Nelson taken by her mother, Polixeni Papapetrou. According to the then-11-year-old Olympia, she did not believe the photograph amounted to abuse and was upset with Prime Minister Kevin Rudd's remark that he hated it. Olympia's father, art critic Professor Robert Nelson, defended it, saying: "It has nothing to do with pedophilia. The connection between artistic pictures and pedophilia cannot be made and there is no evidence for it."^[39][2]

A full-body scanner is a device that creates an image of a person's nude body through their clothing to look for hidden objects without physically removing their clothes or making physical contact.

They are increasingly being deployed at airports and train stations in many countries.

One technology used under the name "full-body scanner" is the millimeter wave scanner, the active form of which reflects extremely high frequency radio waves off the body to make an image on which one can see some types of objects hidden under the clothes. Passive millimeter wave screening devices rely on only the raw energy that is naturally emitted from the human body or objects concealed on the body; passive devices do not transmit millimeter waves.^[41][42] Another technology in use is the backscatter X-ray.

In some situations, nudity is imposed on a person.

For example, imposed nudity (full or partial) can be part of a corporal punishment or as humiliation, especially when administered in public. In fact, torture manuals have distinguished between the male and female psychological aversion to self-exposure versus being disrobed.

Nazis used forced nudity to attempt to humiliate inmates in concentration camps. This was depicted in the film Schindler's List.^[43]

In 2003, Abu Ghraib prison in Baghdad (Iraq) gained international notoriety for accounts of torture and abuses by members of the United States Army Reserve during the post-invasion period. Photographic images were circulated that exposed the posing of prisoners naked, sometimes bound, and being intimidated and otherwise humiliated, resulting in widespread condemnation of the abuse.

Nudity is used in strip searches to ensure that subjects are not hiding any items beneath clothing or in body cavities.

In 2014 it was reported that more than 4,600 children had been strip-searched by the Metropolitan Police in the preceding five years, with the youngest being ten years old. This was out of a total of 134,000 strip-searched. A charity described the number of younger children searched in this way as being "disturbing".^[44]

Functional nudity for a short time, such as when changing clothes on a beach, is sometimes acceptable, while staying nude on the beach generally is not nor is it legal in some jurisdictions.

On designated nude beaches, it is acceptable and legal to be nude.

Breastfeeding in public is forbidden in some jurisdictions, not legislated for in others, and a legal right in public and the workplace in yet others. Where it is a legal right, some mothers may be reluctant to breastfeed,^[45][46] and some people may object to the practice.^[47]

In some cultures, toplessness is regarded as partial nudity, and the exposure of breasts or nipples may be regarded as indecent exposure. However, in many western societies and in appropriate settings, such as while suntanning, toplessness is not, of itself, normally regarded as indecent. In the United States, however, exposure of female nipples is a criminal offense in many states and not usually allowed in public (see indecent exposure), while in the United Kingdom, nudity may not be used to "harass, alarm or distress" according to the Public Order Act of 1986.^[48] Different standards apply to art, with one example being the dome of the US Capitol featuring a fresco depicting goddesses with their breasts exposed.

Prosecution of cases has given rise to a movement advocating "topfreedom", promoting equal rights for women to have no clothing above the waist, on the same basis that would apply to men in the same circumstances. The term topfree rather than topless is advocated to avoid the latter term's perceived sexual connotations.

Naturism (or nudism) is a cultural and political movement practising, advocating and defending private and public nudity. It is also a lifestyle based on personal, family and/or social preference.

Naturists reject contemporary standards of modesty, which discourage personal, family and social nudity. They instead seek to create a social environment where individuals feel comfortable in the company of nude people, and being seen nude, either just by other naturists, or also by the general public.

The trend in some European countries (for instance Germany, Finland and the Netherlands) is to allow both genders to bathe together naked. Many German spas allow mixed nude bathing. For example, the Friedrichsbad in Baden-Baden has designated times when mixed nude bathing is permitted. Most German (not to mention French, Spanish and Greek) beaches and swimming pools offer FKK (clothing-optional) areas. In general, continental Europeans have a more relaxed attitude about nudity than is seen in the British-influenced world. Some have attributed this difference to the influence of Queen Victoria's husband Albert, who was raised in a very restricting religious sect (see Victorian morality).

The sauna, originating from Finland, is attended nude in its source country^[49] as well as in most Scandinavian and in the German-speaking countries of Europe.^[40] This is true even when a swimsuit must be worn in the swimming pool area of the same complex.^[49] Saunas are very common in modern Finland, where there is one sauna for every three people^[51] and became very popular in the remainder of Europe in recent decades. German soldiers had got to know the Finnish saunas during their fight against the Soviet Union in the Continuation War, where Germany and Finland fought on the same side. Finnish hygiene depended so exclusively on saunas, that they had built saunas not only in mobile tents but even in bunkers.^[40] After the war, the German soldiers brought the habit back to Germany and Austria, where it became popular in the second half of the 20th century.^[40] The German sauna culture also became popular in neighbouring countries such as Switzerland, Belgium, the Netherlands and Luxemburg.^[3] In contrast to Scandinavia, public sauna facilities in these countries commonly do not segregate genders while still keeping the rule of general nudity.^[4][40]

In Russia, public banyas are also attended nude, however, they are always segregated by gender, either by having separate sections, or by days of the week. Shared areas (such as swimming pools), if present, can only be attended in bathing suits.

Attitudes in Western cultures are not all the same as explained above, and likewise attitudes in non-Western cultures are many and variant. In almost all cultures, acceptability of nudity depends on the situation.

Cultural and/or religious traditions usually dictate what is proper and what is not socially acceptable.

Many non-Western cultures allow women to breastfeed in public, while some have very strict laws about showing any bare skin.

In Africa, women have used stripping naked on purpose as a curse, both historically, and in modern times.

The idea is that women give life and they can take it away.

The curse initiates an extreme form of ostracism, which anthropologist Terisa Turner has likened to "social execution". The curse extends to foreign men as well, and is believed to cause impotence, madness or other similar harm.^[53] The threat has been used successfully in mass protests against the petroleum industry in Nigeria,^[54] by Leymah Gbowee during the Second Liberian Civil War,^[55] and against President Laurent Gbagbo of the Ivory Coast.^[56]

Different traditions exist among, for example, sub-Saharan Africans, partly persisting in the post-colonial era. Whereas it is the norm among some ethnic and family groups including some Burkinabese and Nilo-Saharan (e.g. Nuba and Surma people) in daily life or on particular occasions not to wear any clothes or without any covering below the waist – for example, at highly attended stick-fighting tournaments well-exposed young men use the occasion to catch the eye of a prospective bride.

In modern Liberia, soldiers under General "Butt Naked" Joshua Blahyi fought naked in order to terrorize their opponents.^[57] Nude except for lace-up leather shoes and a gun, the general led his fierce Butt Naked Battalion into battle on behalf of the warlord Roosevelt Johnson, who hired the unclothed warriors for their fearlessness and fighting skills.

In Brazil, the Yawalapiti, an indigenous Xingu tribe in the Amazon Basin, practice a funeral ritual known as Quarup, to celebrate life, death and rebirth, and also involves the presentation of all young girls who have begun menstruating since the last Quarup and whose time has come to choose a partner.

In Japan, public baths are very common.

Bathing nude with family members or friends in public bath houses, saunas, or natural hot springs (Onsen) is popular.

In Korea, public baths (Jjimjilbang) are widespread and communal nude bathing is normal, although nudity is not permitted in unisex areas.

Nudity is considered shameful in the conservative society of India, although nude beaches can be found in Goa and nude saints like those of the Digambara sect of Jainism and Hindu Sadhus are respected and worshipped.

In many Muslim countries, public nudity is illegal.

Nudity, or nakedness, is the state of wearing no clothing.

The deliberate and conscious wearing of clothing is a behavioural adaptation, which among all known extant and extinct animals is a uniquely human characteristic arising from functional needs such as protection from the elements. Protection from the elements includes the sun (for depigmented human populations) and cold temperatures after the loss of body hair and the migration of humans to colder regions (around 100,000 years ago) in which they had not evolved and thus lacked the necessary physical adaptations.

According to some researchers, wearing clothes may predate early human global migrations by an additional 70,000 years.

In this case, the migrations were themselves facilitated by the innovation of clothing.

It is believed that earlier species of archaic humans, including Homo neanderthalensis, Homo rhodesiensis, Homo heidelbergensis, and Homo antecessor, either were not able to create true clothing, or were not able to do it as well as Homo sapiens sapiens (anatomically modern humans). At most, as in the case of Homo neanderthalensis, they are believed to have worn only capes, if any coverings at all. This lack of behavioral adaptation, in turn, may have contributed to their eventual extinction during ancient climate changes when they may have succumbed to hypothermia, frostbite and other cold ailments.

The amount of clothing worn depends on functional considerations, such as a need for warmth, as well as social circumstances.

In some situations, a minimum amount of clothing or none at all may be considered socially acceptable, while in others much more clothing may be expected.

Social considerations involve cultural issues of modesty, subjective decency and social norms, besides other considerations, and these may depend on the context. There may also be legal considerations.

Full nudity refers to complete nudity, while partial nudity refers to less than full nudity, with parts of the body covered in some manner. The term "partial nudity" is sometimes used to refer to exposure of skin beyond what the person using the expression considers to be within the limits of modesty. If the exposure is within the standards of modesty of a given culture and setting (e.g. wearing a bikini at a non-nude beach), terms such as nudity, partial or otherwise, are not normally used. If however, the degree of exposure exceeds the cultural norms of the setting, or if the activity or setting includes nudity as an understood part of its function, such as a nude beach, terminology relating to nudity and degrees thereof are typically used. Toplessness is regarded by most people as partial nudity.

Full frontal nudity describes a state of full nudity with the subject facing towards the viewer, with the whole front of the body exposed, including intimate parts such as a man's penis or woman's vulva. Partial frontal nudity typically only refers to the exposure of the breasts. Non-frontal nudity describes nudity where the whole back side of the body, including the buttocks, is exposed, or a side-view from any other direction.

Hair probably evolved in mammals before about 220 million years ago.

The closest living genetic relatives of humans, apes and especially chimpanzees, possess an almost complete covering of fur.

Humans are today the only naked primate in nature, that is, most of the body is not naturally covered by fur.

Reliable information on the development of nudity and the passage of time are not yet possible because hair does not fossilize.

Researchers at the University of Utah in 2004 found that human skin contains photoreceptors like those in the retina, allowing it to mount an immediate defence against damaging ultraviolet radiations.

They suspect that the protein that protects the skin from sunlight evolved following the loss of protective hair, which happened about 1.2 million years ago.

People have a variety of views on nudity, both of their own as well as those of others.

This would depend on their level of inhibition, cultural background and upbringing, as well as on context. A society's attitude to public nudity varies depending on the culture, time, location and context of an activity. There are many exceptions and particular circumstances in which nudity is tolerated, accepted or even encouraged in public spaces. Such examples would include a nude beach, within some intentional communities (such as naturist resorts or clubs) and at special events.

In general and across cultures, public indications of sexual arousal are commonly regarded as embarrassing, both to the person aroused and the onlooker, and for this reason those parts of the human body that would indicate arousal are normally covered. Arousal is most evidently indicated by the sex organs and women's breasts, which are routinely covered, even when other parts of the body may be freely uncovered. Yet the nudity taboo may have meanings deeper than the immediate possibility of sexual arousal, for example, in the cumulative weight of tradition and habit. Clothing also expresses and symbolizes authority, and more general norms and values besides those of a sexual nature.

While some European countries, such as Germany, are rather tolerant of public nudity, in many countries public nudity may meet social disapproval or even constitute a misdemeanor of indecent exposure. In 2012, the city council of San Francisco proposed a ban on public nudity in the inner city area. This was met by harsh resistance since the city is usually known for its liberal culture. Similarly, park rangers began filing tickets against nudists at San Onofre State Beach in 2010, also a place with long tradition of public nudity.

Some people take part in non-sexual public nude events.

These may be in a naturist resort or club or at a nude beach. Outdoor nude recreation can take place in private or rural areas, though generally limited to warm weather.

Others practice casual public nudity.

Topfree sunbathing is considered acceptable by many on the beaches of Finland, France, Spain, Italy and most of the rest of Europe (and even in some outdoor swimming pools); however, exposure of the genitals is restricted to nudist areas in most regions.

In the United States, topfree sunbathing and wearing thongs are not common in many areas, but are limited to nude beaches in various locations. It is normally acceptable for men in the U.S. to be barechested or shirtless when engaged in outdoor recreational activities.

Where the social acceptability of nudity in certain places may be well understood, the legal position is often less clear cut.

In England, for example, the law does not actually prohibit simple public nudity, but does forbid indecent exposure.

In practice, this means that successful prosecution hangs on whether there is a demonstrable intention to shock others, rather than simply a desire to be nude in a public place.

Specifically, using nudity to "harass, alarm or distress" others is an offence against the Public Order Act of 1986.

Occasional attempts to prove this point by walking naked around the country therefore often result in periods of arrest, followed by release without charge, and inconsistencies in the approach between different police jurisdictions.

Differences in the law between England and Scotland appear to make the position harder for naked ramblers once they reach Scotland.

Photography of installations of massed nude people in public places, as made repeatedly around the world by Spencer Tunick, claim artistic merit.

Nudity is at times used to draw attention to a cause, with the participants desiring to remain anonymous.

Public nude events are at times staged as a forum for usually unrelated messages, such as clothing-optional bike rides. At times, the cause is merely a personal justification for taking part in a nude event, which are popular in their own right. Many nude calendars are produced each year featuring naked men or women. Some of these are produced to raise money for charities or other causes. Nudity, like sexuality, is also used to draw attention for a commercial purpose, such as for promotion or advertising.

Nudity may be used as a part of artistic or erotic performance, such as in nude performance art, nude body painting (ex. Fantasy Fest), sex shows, striptease, adult entertainment conventions, and in adult-only events like Folsom Street Fair, Nudes-A-Poppin', etc.

In the privacy of their own homes, people are more casual in relation to clothing, though what each considers appropriate varies considerably.

What and how much clothing a person removes depends on a number of considerations, including the cultural background and on whether the person is alone in the privacy of their own homes.

The removal of overclothing, such as coats, hats, gloves, scarves and the like, is the norm in virtually all households.

It is also common for people to remove outdoor shoes when entering one's home and at times guests may also be expected to do the same.

It is also common to change out of work clothes (such as a suit and tie, overalls etc.) into something lighter, looser and more comfortable, and perhaps for a woman to remove her bra or stockings.

Beyond that, how much more is removed depends on personal taste, habits, circumstance and relationships of the people inside the household at a particular time.

A person's cultural background as well as their religious teachings will affect the way they view their own nudity or state of dress, alone or in the presence of others, as well as how they view the nudity of others.

Some cultures deprecate nudity even in a private context.

Another factor is the level of privacy to which a person can be assured - for example, some parts of a home may be seen from the outside or there may be a possibility of others walking in.

The expectation of privacy may be confined to the home and sometimes the backyard.

Inside the home, it may be restricted to the bedroom or just the bathroom.

If a person is not alone, their comfort in removing clothing in front of another person will generally depend on the nature of a relationship of those who jointly occupy the same private space, as well as the attitudes of others to nudity.

Besides the nature of a relationship, attitudes and incidences of nudity will also depend on the level of inhibition that each person has, as well as the level of privacy to which that they can be assured. Sometimes a person may unintentionally intrude on a person who is in the nude, which may lead to embarrassment of one or both of the people. The nude person may seek to quickly cover their private parts, while the clothed person may turn away, but this also depends on cultural differences and the relationship of the people.

In the case of nudity in front of those who do not normally occupy the same private space, that will usually depend on whether the outsider is comfortable with the nudity and whether the nudity is reciprocated, as in the case of social nudism. Social nudism may take place in any private social context, such as at one's home with friends or with acquaintances at a nudist facility or event, such as a naturist club, community center, resort or other facility. To generate an atmosphere of fun at a social gathering and lighten the social atmosphere, or to heighten the sexual atmosphere and ease those present into some state of nudity, organisers of a social gathering may organise party games, which may involve some level of nudity, such as strip games, for example strip poker, which can be played by single-sex groups or by mixed groups.

A 1999 survey by the Federation of Canadian Naturists found, besides other things, that 39% of Canadians "have walked or would walk around their house nude"; that naturists tend to have above average incomes; that urban dwellers are more likely to be naturists than country dwellers; and that people under the age of 25 are the most likely to be naturists. According to a 2004 United States survey, 31% of men and 14% of women report sleeping in the nude, while a 1996 BBC survey revealed that in the UK 47% of men and 17% of women do.

Nudity in front of a sexual partner is widely accepted, but not in all cases. For example, some partners insist on nudity only at the time and place of sex, or with subdued lighting; during bathing with the partner or afterward; covered by a sheet or blanket, or while sleeping.

The invention of photography and more recently the video camera has opened the art of capturing images of people and scenes at a relatively low cost to the true amateur. A person can now capture images in both public and private situations. A feature of most private photographs and videos is that they are not intended for viewing outside of a very limited range of people, and seldom if ever by the general public. Amateur photography, which includes nude photography, which has previously been produced for personal enjoyment, is increasingly being more widely disseminated through the internet, at times without the knowledge and consent of the subject of the photograph, and to their subsequent embarrassment. Also, the use of secret photography to capture images of an unsuspecting person (undressed or not, and whether for personal use, or intended for posting on the Internet) creates additional personal privacy issues.

Some people are made anxious by being nude or being in the presence of nude people; if this begins to interfere with their well-being, the phobia is called gymnophobia.

There are differences of opinion as to whether, and if so to what extent, parents should appear naked in front of their children.

Gordon and Schroeder report that parental nudity varies considerably from family to family.

They say that "there is nothing inherently wrong with bathing with children or otherwise appearing naked in front of them", noting that doing so may provide an opportunity for parents to provide important information.

They note that by ages five to six, children begin to develop a sense of modesty, and recommend to parents who wish to be sensitive to their children's wishes that they limit such activities from that age onwards.

Bonner recommends against nudity in the home if children exhibit sexual play of a type that is considered problematic.

A U.S. study by Alfred Kinsey found that 75% of the participants stated that there was never nudity in the home when they were growing up, 5% of the participants said that there was "seldom" nudity in the home, 3% said "often", and 17% said that it was "usual". The study found that there was no significant difference between what was reported by men and by women with respect to frequency of nudity in the home.

In a 1995 review of the literature, Paul Okami concluded that there was no reliable evidence linking exposure to parental nudity to any negative effect.

Three years later, his team finished an 18-year longitudinal study that showed that, if anything, such exposure was associated with slight beneficial effects, particularly for boys.

Attitudes toward children seeing nude people vary substantially, depending on the child's culture, age and the context of the nudity (see also the section Home above).

Television and radio regulations in many countries require broadcasters to avoid transmitting images or language considered inappropriate for children from 5:30 am to 9 pm (the so-called "watershed"). In the United Kingdom, the Broadcasting Code states, "Nudity before the watershed must be justified by the context." In the U.S., the safe harbor rule forbids depictions of nudity between the hours of 6 am and 10 pm. Violators may be subject to civil legal action and sanctions if the Federal Communications Commission (FCC) determines the broadcaster did not meet its standards of "decency". "Material is indecent if, in context, it depicts or describes sexual or excretory organs or activities in terms patently offensive as measured by contemporary community standards for the broadcast medium."

Attitudes to nudity vary substantially throughout Europe.

Male and female nudity in Scandinavia is not uncommon. The region has a very open attitude about nudity, although it strictly prohibits children's access to pornography.

Another issue has been the nudity of children in front of other children.

In many countries, including the U.S., the U.K., Australia and some of the English-speaking majority of Canada, students at public schools have historically been required to shower communally with classmates of the same sex after physical education classes. In the U.S., public objections and the threat of lawsuits have resulted in a number of school districts in recent years changing policy to make showers optional. Private boarding schools and military academies in the U.S. often have communal showers, since the focus there is on 24-hours-a-day education and rooming, rather than just acting as day schools. Students in these establishments need places to clean themselves daily. A court case in Colorado noted that students have a reduced expectation of personal privacy in regards to "communal undress" while showering after physical education classes. According to an interview with a middle school principal, most objections to showering at school that he had heard were actually from the students' parents rather than from the students.

Children who are within a naturist home will usually also be naked, together with their family, and may see and be seen by non-family members in the nude. They may also be taken to naturist venues and events where they, their families and others would also generally be nude.

In many cultures, different standards have applied and continue to apply for males and females with regard to communal nudity in the presence of the same sex.

Particularly in English-speaking countries, males have historically been more likely to be expected to engage in practices such as nude swimming in swimming pools, or to be mandated to have communal showers with no privacy in schools, based on the cultural beliefs that women need more privacy.

Communal male nudity in the United States and other Western countries was not a taboo for much of the 20th century.

Social attitudes maintained that it was healthy and normal for men and boys to be nude around each other and schools, gymnasia, and other such organizations typically required nude male swimming in part for sanitary reasons due to the use of wool swimsuits.

There was less tolerance for female nudity and the same schools and gyms that insisted on wool swimwear being unsanitary for males did not make an exception when women were concerned.

Nonetheless, some schools did allow girls to swim nude if they wished.

By the 1970s, most schools and gyms in the United States had become mixed-sex, which put an end to nude swimming.

Nudity in film has, since the development of the medium, been somewhat controversial, though there was no defined censorship, especially of nudity, in the early years of Hollywood, until the Hays Code of the 1930s. Under present-day guidelines, most nude scenes in films have had to be justified as being part of the story, in the concept of "artistically justifiable nudity". In some cases nudity is itself the object of a film or is used in the development of the character of the subject. There are film scenes where nudity, in routine and non-sexual situations, such as mixed shower scenes, has been used to emphasize gender equality in the future.

In some cases, nudity has been criticized as "superfluous" or "gratuitous" to the plot, and some film producers have been accused of including nudity in a film to appeal to audiences.

Many actors and actresses have appeared nude, or exposing parts of their bodies or dressed in ways considered provocative by contemporary standards at some point in their careers.

Erotic films usually contain nudity, and nudity in a sexual context is common in pornographic films. A film on naturism, or about people for whom nudity is common, for example, many societies and people who live in hot climates, or films set in times such as the 1960s or 1970s era of liberation, may contain non-sexual nudity, and many non-pornographic films contain nude scenes.

Mainstream art generally reflects – with some exceptions – social standards of aesthetics and morality of a society at various periods of time. Beyond mainstream standards, artistic expression may be merely tolerated, or be considered as fringe. Since prehistoric time, humans, both male and female, have been depicted in all states of dress, including all states of undress. Nudity in all styles has been and continues to be found in art. Nudity is also a subject of many literary works and in film. All professionally produced works of art use stylised compositions to depict the nude body. This also applies to cinema, where even nude scenes are staged and rehearsed.

The erotic aspect of nudity in the arts has been an important factor in its attraction, and has come to be associated with certain states and emotions, such as innocence, playfulness, vulnerability, etc. Pornography does not necessarily involve a naked person, but it involves sexualized scenes, and usually it does not claim to have any artistic merit.

The visual arts were at times the only means available to the general public to view a nude body.

Today, the opportunities available for the viewing of the nude body are very wide, and these include magazines, television, films, and the Internet.

Depictions of child nudity or children with nude adults appear in works of art in various cultures and historical periods. These attitudes have changed over time and have become increasingly frowned upon particularly in recent years, especially in the case of photography. In recent years, there have been a few incidents in which snapshots taken by parents of their infant or toddler children bathing or otherwise naked were challenged as child pornography.

In May 2008, police in Sydney, Australia, raided an exhibition by the photographer Bill Henson featuring images of naked children on allegations of child pornography. Comparable artworks by Henson had been exhibited without incident since 1975, perhaps indicating that this sensitivity has heightened in recent years.

In June 2008, it was reported in The Age that police would have no basis to prosecute Henson over his photographs of naked teenagers, after they were declared "mild and justified" and given a PG rating by the Australian Classification Board, suggesting viewing by children under the age of 16 is suitable with parental guidance. Out of protest, the Art Monthly Australia magazine published an image of the 6-year-old Olympia Nelson taken by her mother, Polixeni Papapetrou. According to the then-11-year-old Olympia, she did not believe the photograph amounted to abuse and was upset with Prime Minister Kevin Rudd's remark that he hated it. Olympia's father, art critic Professor Robert Nelson, defended it, saying: "It has nothing to do with pedophilia. The connection between artistic pictures and pedophilia cannot be made and there is no evidence for it."

A full-body scanner is a device that creates an image of a person's nude body through their clothing to look for hidden objects without physically removing their clothes or making physical contact.

They are increasingly being deployed at airports and train stations in many countries.

One technology used under the name "full-body scanner" is the millimeter wave scanner, the active form of which reflects extremely high frequency radio waves off the body to make an image on which one can see some types of objects hidden under the clothes. Passive millimeter wave screening devices rely on only the raw energy that is naturally emitted from the human body or objects concealed on the body; passive devices do not transmit millimeter waves. Another technology in use is the backscatter X-ray.

In some situations, nudity is imposed on a person.

For example, imposed nudity (full or partial) can be part of a corporal punishment or as humiliation, especially when administered in public. In fact, torture manuals have distinguished between the male and female psychological aversion to self-exposure versus being disrobed.

Nazis used forced nudity to attempt to humiliate inmates in concentration camps. This was depicted in the film Schindler's List .

In 2003, Abu Ghraib prison in Baghdad (Iraq) gained international notoriety for accounts of torture and abuses by members of the United States Army Reserve during the post-invasion period. Photographic images were circulated that exposed the posing of prisoners naked, sometimes bound, and being intimidated and otherwise humiliated, resulting in widespread condemnation of the abuse.

Functional nudity for a short time, such as when changing clothes on a beach, is sometimes acceptable, while staying nude on the beach generally is not nor is it legal in some jurisdictions.

On designated nude beaches, it is acceptable and legal to be nude.

Breastfeeding in public is forbidden in some jurisdictions, not legislated for in others, and a legal right in public and the workplace in yet others. Where it is a legal right, some mothers may be reluctant to breastfeed, and some people may object to the practice.

In some cultures, toplessness is regarded as partial nudity, and the exposure of breasts or nipples may be regarded as indecent exposure. However, in many western societies and in appropriate settings, such as while suntanning, toplessness is not, of itself, normally regarded as indecent. In the United States, however, exposure of female nipples is a criminal offense in many states and not usually allowed in public (see indecent exposure), while in the United Kingdom, nudity may not be used to "harass, alarm or distress" according to the Public Order Act of 1986. Different standards apply to art, with one example being the dome of the US Capitol featuring a fresco depicting goddesses with their breasts exposed.

Prosecution of cases has given rise to a movement advocating "topfreedom", promoting equal rights for women to have no clothing above the waist, on the same basis that would apply to men in the same circumstances. The term topfree rather than topless is advocated to avoid the latter term's perceived sexual connotations.

Naturism (or nudism) is a cultural and political movement practising, advocating and defending private and public nudity. It is also a lifestyle based on personal, family and/or social preference.

Naturists reject contemporary standards of modesty, which discourage personal, family and social nudity. They instead seek to create a social environment where individuals feel comfortable in the company of nude people, and being seen nude, either just by other naturists, or also by the general public.

The trend in some European countries (for instance Germany, Finland and the Netherlands) is to allow both genders to bathe together naked. Many German spas allow mixed nude bathing. For example, the Friedrichsbad in Baden-Baden has designated times when mixed nude bathing is permitted. Most German (not to mention French, Spanish and Greek) beaches and swimming pools offer FKK (clothing-optional) areas. In general, continental Europeans have a more relaxed attitude about nudity than is seen in the British-influenced world. Some have attributed this difference to the influence of Queen Victoria's husband Albert, who was raised in a very restricting religious sect (see Victorian morality).

The sauna, originating from Finland, is attended nude in its source country as well as in most Scandinavian and in the German-speaking countries of Europe. This is true even when a swimsuit must be worn in the swimming pool area of the same complex. Saunas are very common in modern Finland, where there is one sauna for every three people and became very popular in the remainder of Europe in recent decades. German soldiers had got to know the Finnish saunas during their fight against the Soviet Union in the Continuation War, where Germany and Finland fought on the same side. Finnish hygiene depended so exclusively on saunas, that they had built saunas not only in mobile tents but even in bunkers.. After the war, the German soldiers brought the habit back to Germany and Austria, where it became popular in the second half of the 20th century. The German sauna culture also became popular in neighbouring countries such as Switzerland, Belgium, the Netherlands and Luxemburg. In contrast to Scandinavia, public sauna facilities in these countries commonly do not seggregate genders while still keeping the rule of general nudity.

In Russia, public banyas are also attended nude, however, they are always segregated by gender, either by having separate sections, or by days of the week. Shared areas (such as swimming pools), if present, can only be attended in bathing suits.

Attitudes in Western cultures are not all the same as explained above, and likewise attitudes in non-Western cultures are many and variant. In almost all cultures, acceptability of nudity depends on the situation.

Cultural and/or religious traditions usually dictate what is proper and what is not socially acceptable.

Many non-Western cultures allow women to breastfeed in public, while some have very strict laws about showing any bare skin.

In Africa, women have used stripping naked on purpose as a curse, both historically, and in modern times.

The idea is that women give life and they can take it away.

The curse initiates an extreme form of ostracism, which anthropologist Terisa Turner has likened to "social execution". The curse extends to foreign men as well, and is believed to cause impotence, madness or other similar harm. The threat has been used successfully in mass protests against the petroleum industry in Nigeria, by Leymah Gbowee during the Second Liberian Civil War, and against President Laurent Gbagbo of the Ivory Coast.

Different traditions exist among, for example, sub-Saharan Africans, partly persisting in the post-colonial era. Whereas it is the norm among some ethnic and family groups including some Burkinabese and Nilo-Saharan (e.g. Nuba and Surma people) in daily life or on particular occasions not to wear any clothes or without any covering below the waist – for example, at highly attended stick-fighting tournaments well-exposed young men use the occasion to catch the eye of a prospective bride.

In modern Liberia, soldiers under General "Butt Naked" Joshua Blahyi fought naked in order to terrorize their opponents. Nude except for lace-up leather shoes and a gun, the general led his fierce Butt Naked Battalion into battle on behalf of the warlord Roosevelt Johnson, who hired the unclothed warriors for their fearlessness and fighting skills.

In Brazil, the Yawalapiti, an indigenous Xingu tribe in the Amazon Basin, practice a funeral ritual known as Quarup, to celebrate life, death and rebirth, and also involves the presentation of all young girls who have begun menstruating since the last Quarup and whose time has come to choose a partner.

In Japan, public baths are very common.

Bathing nude with family members or friends in public bath houses, saunas, or natural hot springs (Onsen) is popular.

In Korea, public baths (Jjimjilbang) are widespread and communal nude bathing is normal, although nudity is not permitted in unisex areas.

Nudity is considered shameful in the conservative society of India, although nude beaches can be found in Goa and nude saints like those of the Digambara sect of Jainism and Hindu Sadhus are respected and worshipped.

In many Muslim countries, public nudity is illegal.