According to the prevailing view of most paleo-anthropologists and archaeologists, about 1.5 to 2 million years ago early humans evolved into nearly hairless primates, in order to more efficiently sweat away excess body heat. According to Penn State anthropologist Nina Jablonski, humans may have later begun to decorate their skin to increase attractiveness and express group identity.
     "We find a lot of evidence of when humans began to lose hair based on molecular genetics," says Jablonski, who believes that over thousands of years, humans used their skin as canvases of self-expression in a variety ways, including permanent tattooing and branding, as well as temporary cosmetics and body painting.
     While it is difficult to know when humans began to decorate their skin, some of the earliest preserved skin shows signs of tattooing, says Jablonski.
     Decades of research in caves in Europe and South Africa, among other places, show evidence of the manufacture and use of ancient pigments, particularly for creating wall paintings. Many scientists suggest that the pigments were also used for body decoration, and the practice could go back more than 100,000 years.
     The recent discovery of a prehistoric workshop in the South African cave of Blombos, for example, revealed the manufacture of ochre where there was no evidence of any wall painting. Abalone shells were found to contain ochre, combined with fat, crushed bone, quartz and charcoal to produce a pigment compound possibly used for painting, decoration and skin protection. This was dated to about 100,000 years BP, a time when early modern humans are thought to have been on the threshold of thinking and expressing themselves in symbolic ways, laying the foundations for art and language.

Edited from Popular Archaeology (16 February 2013)