Nudity is a state of being in which a human is not wearing clothing or specifically is not covering the genitals. In some societies, partial nudity is defined as not covering other parts of the body that are deemed to be sexual. Nakedness, or the loss of body fur, was one of the physical characteristics that marked the evolution of modern humans from their hominini ancestors. For many thousands of years, humans wore no clothing. Worldwide, current social norms vary from banning nudity except in complete privacy to the acceptance of public nudity as a natural human state. It is generally accepted that the widespread adoption of clothing occurred as people migrated to other climates which required protection from the elements. In addition, as societies developed from being hunter-gatherers to being agrarian, clothing became part of cultural evolution as individuals and groups became differentiated by status and class. In early civilizations such as Egypt; slaves, children, and others with lower status often continued to be naked. The modern understanding of nudity is culturally complex due to different meanings given various states of undress in differing social situations. In any particular society, nudity is defined in relation to being properly dressed, not in relation to the specific body parts being exposed. For humans, nakedness and clothing are connected to many cultural categories such as identity, privacy, social status and moral behavior. Synonyms and euphemisms for nudity abound, including "birthday suit", "in the altogether" and "in the buff". "In a state of nature" is also used by philosophers to refer to the state of humans before the existence of organized societies. In Western societies, there are two cultural traditions relating to nudity in various contexts. The first tradition comes from the ancient Greeks, who saw the naked body as the natural state and as essentially positive. The second is based upon the Abrahamic religions—Judaism, Christianity, and Islam—which have viewed being naked as shameful and essentially negative. The interaction between these traditions has resulted in Western ambivalence toward nudity. While public nudity remains limited in most situations, in America nudity is more likely to be seen sexually, while in much of Europe, there is more openness to non-sexual nudity in recreation and daily life. In Africa, there is a sharp contrast between the attitude toward nudity in Islamic countries and the attitude toward nudity in certain sub-Saharan countries that never abandoned, or are reasserting, precolonial norms. In Asia, the norms regarding public nudity are in keeping with the cultural values of social propriety and human dignity. Rather than being perceived as immoral or shameful, nakedness is perceived as a breach of etiquette. Societies use clothing (or the lack thereof) as a marker of social status. Generally, social norms regarding nudity are different for men than they are for women. It was not until the 17th century in Europe that the female breast became a part of the body that must be covered in public. It is only in the modern era that the nudity of children represented anything but innocence. Individuals may intentionally violate norms regarding nudity; those without power may use nudity as a form of protest, and those with power may impose nakedness on others as a form of punishment.