We may take them for granted, but a sophisticated new examination of teeth from 11 Neanderthal and early human fossils show how slow-growing more modern humans had the edge over their ancestors.
The finding suggests that our characteristically slow development and long childhood are recent and unique to our own species, and may have given early humans an evolutionary advantage over Neanderthals.
The research, led by scientists at Harvard University, the Max Planck Institute for Evolutionary Biology (MPI-EVA), and the European Synchrotron Radiation Facility (ESRF), is detailed in the Proceedings of the National Academy of Sciences.
“Teeth are remarkable time recorders, capturing each day of growth much like rings in trees reveal yearly progress,” says Tanya M. Smith, assistant professor of human evolutionary biology at Harvard. “Even more impressive is the fact that our first molars contain a tiny ‘birth certificate,’ and finding this birth line allows scientists to calculate exactly how old a juvenile was when it died.”
Professor Smith and her colleagues found that teeth growth in a young Neanderthal – an indicator of overall development – was significantly faster than in our own species, including some of the earliest groups of modern humans to leave Africa some 90,000 to 100,000 years ago.
The current study involves some of the most famous Neanderthal children ever discovered, including the first hominin fossil, discovered in Belgium in the winter of 1829-30. This individual was previously thought, based on comparisons with modern humans, to have been four to five years old at the time of death. Now, powerful synchrotron X-rays and biological rhythms inside teeth have revealed the child was only three years old.
So next time you look in the mirror, remember that early humans may have taken longer to grow up than their ancestors, but this gave them longer to learn and think about life, possibly giving early Homo sapiens an advantage over their Neanderthal cousins.