A sophisticated new examination of teeth from 11 Neanderthal and early human fossils shows that modern humans are slower than our ancestors to reach full maturity.
These finding suggests 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.
Tanya M Smith, assistant professor of human evolutionary biology at Harvard, says: ‘Teeth are remarkable time recorders, capturing each day of growth much like rings in trees reveal yearly progress.
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.’
Compared to even early humans, other primates have shorter gestation, faster childhood maturation, younger age at first reproduction, and a shorter overall lifespan. It’s been unclear exactly when, in the six to seven million years since our evolutionary split from non-human primates, the life course shifted.
Dr Smith and her colleagues found that young Neanderthals’ teeth growth 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.