Neanderthals lived fast, died young, study shows
Neanderthal tots grew up much more quickly than modern human children, a new international study shows. The researchers believe Neanderthal kids matured faster because they contended with high-risk survival activities whereas their closest cousins matured more slowly but enjoyed a longer life. The finding is presented in the journal Proceedings of the National Academy of Sciences (PNAS). Led by researchers at Harvard University in the US, the Max Planck Institute for Evolutionary Anthropology in Germany, and the France-based European Synchrotron Radiation Facility (ESRF), the team used sophisticated tools, namely a new 'supermicroscrope' and an advanced X-ray technique, to examine the teeth from 11 Neanderthal and early human fossils, including the first hominin fossil, discovered in Belgium in 1829-30. The sophisticated testing revealed that this individual was only three years old at the time of her death, and not four or five years old as initially thought. The findings of this latest study suggest that our characteristically slow development and long childhood are fresh events that are unique to our species. The researchers note that this difference may have given early humans an evolutionary edge over Neanderthals who became extinct some 28,000 years ago. '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,' explains Harvard's Professor Tanya Smith from the Department of Human Evolutionary Biology and lead author of the study. By developing and maturing slowly, the modern human likely secured more learning and complex cognition skills. This probably gave Homo sapiens an advantage over the Neanderthals. Commenting that teeth provide insight into overall development, Professor Smith, says: 'Teeth are remarkable time recorders, capturing each day of growth much like rings in trees reveal yearly progress.' Counting lines in teeth may not be a new method, but doing it 'virtually' via synchrotron micro-computed tomography is, she notes. '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 comments, adding that Neanderthal children appeared to exhibit a great deal of stress. The finding also shows that other primates mature more quickly, have shorter gestation, are younger at first reproduction, and have a shorter lifespan than the modern human. A case in point is ape females: chimpanzees on average bear their first offspring at age 13 versus 19 in humans. 'It doesn't make any sense to lengthen your childhood if there is no guarantee you are going to make it to a ripe old age,' Professor Smith remarks. Researchers have yet to determine when the life course shifted following our evolutionary split from non-human primates some 7 million years ago. The team found that Neanderthal tots' teeth growth was much more rapid compared to our own species, including some of the earliest groups of modern humans that left Africa almost 100,000 years ago. It should be noted that this is just one of many studies that shed light on the existing, yet subtle, developmental differences between us and our Neanderthal cousins. Furthermore, the recent sequencing of the Neanderthal genome offers key genetic clues about the differences in cranial and skeletal development between us and the Neanderthals. Experts from other German and US institutions, as well as institutions from Belgium, Croatia, France and the UK contributed to this study.
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Belgium, Germany, France, Croatia, United Kingdom, United States