Stone Age chewing gum gives insights into life of young girl An ancient form of chewing gum is providing new insights into the life of a young girl from the Stone Age. Scientists analyzed genetic material found on a 5,700-year-old piece of heated birch bark in Denmark. The girl had chewed on it before spitting it out. Her DNA was so well preserved, scientists determined she had blue eyes and dark brown hair. They could also tell her most recent meal included duck and hazelnuts.