Ancient Slow Growth: Fossil teeth show roots of human development
By Bruce Bower
An extended period of childhood evolved in people at least 160,000 years ago, according to a new analysis of a fossil child’s teeth. That’s the earliest evidence to date of a modern-human life history requiring intensive parental care and a wide range of early-life learning opportunities, the researchers say.
A lower jaw holding several teeth of a nearly 8-year-old early Homo sapiens child displayed tooth development comparable to that of same-age European kids today, report anthropologist Tanya M. Smith of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and her colleagues. They employed a new X-ray technique to peer inside teeth and count layers of enamel that form at regular intervals as teeth develop. Researchers previously had to cut sections out of fossil teeth to probe enamel formation.