"the team identified two dozen behaviors that fall into three of the four categories of cultural elements: labels, signals and skills (The fourth category is symbols, which only humans employ). (C.P.) Van Schaik notes that the group found 'the biggest behavioral repertoires within sites that showed the most social contact, thus giving the animals the greatest opportunity to learn from one another.' Examples of culturally-based behaviors that the scientists distinguished include using leaves as napkins, using leafy branches to ward off attacking insects and riding 'snag' (dead trees that are falling toward the ground) for sport." S. Graham, "The Cultured Orangutan." Scientific American, January 03, 2003.