The biology of being oily. Something old and something new
I think our skin oils have a higher purpose and that is to give our uniquely individual scent. In non-mammalian primates, such as gerbils, rats and mice for example, sebaceous gland secretions are the means of communicating individual identification and sexual attraction. Most likely early humans identify each other by their scent. Perhaps, the sense of smell was more heightened as a means of communication before language was invented. It still persists in our modern world only in some aboriginal cultures. In the Desana tribe of the Amazon and the Batek Negrito of the Malay Peninsula, tribal membership is based on similarity of body odor and marriage is allowed only to a person from another tribal group with a different odor. The Ongee of Andaman Islands, the Bororo of Brazil and the Serer Ndut of Senegal all recognize personal identity by the individual’s smell.