A new study in the Proceedings of the National Academy of Sciences presents dental evidence that Neanderthals matured more rapidly than modern humans. The researchers examined 11 teeth from Neanderthals and other early hominids using synchrotron micro-computed tomography. The technique is a high resolution version of the x-ray CT scans used in medical settings. X-ray images are recorded from different directions to model the internal structure of a sample. The x-rays source is charged particles that are acclerated around a curved path or ring until synchrotron radiation is emitted.
     Professor Tanya Smith from Harvard University and her collegues used this specialized tomography to count 'growth rings' in the sample teeth and very accurately determine time of death. This was compared to the age of death that was estimated from the physical development of the individuals. In one case of a Neanderthal child, the age was determined to be only 3 years rather than the 4-5 years previously estimated.
     It is known that our primate ancestors mature much more rapidly, reproduce earlier and die younger than humans. This new evidence about Neanderthals indicates that the long childhood characteristic of modern humans is a relatively recent evolutionary development. "These new methods present a unique opportunity to assess the origins of a fundamentally human condition: the costly yet advantageous shift from a primitive 'live fast and die young' strategy to the 'live slow and grow old' strategy that has helped to make humans one of the most successful organisms on the planet," Smith says. Humans' extended maturation may have facilitated additional learning and complex cognition, possibly giving early Homo sapiens an advantage over their Neanderthal cousins.

Edited from ScienceDaily, Discovery News (15 November 2010)