This meant, Stoneking hypothesized, that clothing also dated from about 107,000 years ago. The subject was anything but frivolous: donning a garment is a complicated act. Clothing has practical uses--warming the body in cold places, shielding it from the sun in hot places--but it also transforms the appearance of the wearer, something of inescapable interest to a visually oriented species like Homo sapiens. Clothing is ornament and symbol; it separates human beings from their earlier, unself-conscious state. (Animals run, swim, and fly without clothing, but only people can be naked.) The arrival of clothing was a sign that a mental shift had occurred. The human world was becoming a realm of complex, symbolic artifacts.