Watching teeth grow
For more than two decades, scientists have relied on studies linking tooth development in juvenile primates with their weaning as a rough proxy for understanding similar landmarks in the evolution of early humans. New research from Harvard, however, challenges that thinking by showing that tooth development and weaning aren’t as closely related as previously thought. A team of researchers led by three members of Harvard’s Department of Human Evolutionary Biology — professors Tanya Smith and Richard Wrangham and postdoctoral fellow Zarin Machanda — used high-resolution digital photographs of chimps in the wild to show that after the eruption of their first molar, many juvenile chimps continue to nurse as much as, if not more than, they had in the past. The study is described in a Jan. 28 paper in the Proceedings of the National Academy of Sciences. “When these earlier studies were published about 20 years ago, they found a very...