Behavioral inferences from the high levels of dental chipping in Homo naledi.

Results indicate that the teeth of H. naledi were exposed to acute trauma on a regular basis. Because interproximal areas are more affected than buccal and posterior teeth more than anterior, it is unlikely that nonmasticatory cultural behavior was the cause. A diet containing hard and resistant food, or contaminants such as grit, is more likely. The small chip size, and steep occlusal wear and cupped dentine on some molars are supportive of the latter possibility. This pattern of chipping suggests that H. naledi differed considerably-in terms of diet, environment, and/or specialized masticatory processing-relative to other African fossil hominins.