Scientists have found and tested an ancient human jawbone in Northern Africa that they say shows our prehistoric ancestors were much more like us than was previously thought - they had a fairly long childhood and developed slowly. The researchers, using a new x-ray technique, examined the tooth of an ancient child found in northern Africa. VOA's Jessica Berman reports.
An international team of anthropologists has unearthed an ancient tooth at a site in Morocco where archaeologists have found a number of early fossils.
Scientists, using a modern form of x-ray technology, estimate the tooth predates the earliest known homo sapien fossil by 160,000 years. Homo sapiens are man's nearest prehistoric relatives.
The team was led by Tanya Smith of the Max Planck Institute for Evolutionary Biology in Germany. Inside the tooth, Smith says, researchers discovered rings like those inside a tree trunk that offer clues as to the growth pattern.
Smith says the rings tell things like when teeth begin to grow, the age of reproduction and how slow or fast the brain grows.
"And so by being able to find these lines in the teeth and make measurements and counts, we were actually able to reconstruct the speed and the total time of development," said Tanya Smith.
Smith and colleagues compared the prehistoric tooth to those of a group of European children, and they concluded the ancient tooth probably belonged to an eight-year-old.
The results of the study were published in the journal Proceedings of the National Academy of Sciences.
There has been a debate among anthropologists about whether homo sapiens, our closest prehistoric relatives, lived short lives similar to the forebearers of the chimpanzee or whether they lived a longer age span closer to that of modern day humans.
Brian Redmond is curator of the archaeology collection at the Cleveland Museum of Natural History. He says the finding may mean that our nearest prehistoric ancestors were more like us than is commonly believed.
"It physically looks like they had extended childhoods, for example, they matured more slowly, as it seems to show, like we do today," said Brian Redmond. "Then it implies they must have had social behaviors, family groups that were much more like hunter-gatherer societies."
Tanya Smith says she would like to extend her study with other juvenile teeth, but she says they are extremely hard to find.