COLUMBUS, Ohio - The bands of ancient Neanderthals that struggled throughout Europe during the last Ice Age faced challenges no tougher than those confronted by the modern Inuit, or Eskimos.
That's the conclusion of a new study intended to test a long-standing belief among anthropologists that the life of the Neanderthals was too tough for their line to coexist with Homo sapiens.
And the evidence discounting that theory lies with tiny grooves that mar the teeth of these ancient people.
Neanderthals, Homo neanderthalensis, were the dominant hominid inhabiting most of what is now Europe and western Asia. Remains have been found as far south as Iraq and as far north as Great Britain. Fossil skulls reveal the distinctively prominent brows and missing chins that set them apart from later humans.
They thrived from about 200,000 to 30,000 years ago until their lineage failed for as-yet unknown reasons. Most researchers have argued that their life in extremely harsh, Ice Age-like environments, coupled with their limited technological skills, ultimately led to their demise. Homo sapiens arrived in Europe about 40,000 years ago and survived using more advanced technology. But the short lifespans of Neanderthals and evidence of arthritis in their skeletons suggests that their lives were extremely difficult.
That's where Debbie Guatelli-Steinberg's work comes in. An assistant professor of anthropology at Ohio State University, she published a recent study in the Journal of Human Evolution that changes our view of the Neanderthals' unbearable lives.
Guatelli-Steinberg has spent the last decade investigating tiny defects -- linear enamel hypoplasia -- in tooth enamel from primates, modern and early humans. These defects serve as markers of periods during early childhood when food was scarce and nutrition was low.
These tiny horizontal lines and grooves in tooth enamel form when the body faces either a systemic illness or a severely deficient diet. In essence, they are reminders of times when the body's normal process of forming tooth enamel during childhood simply shut down for a period of time.
"Looking at these fossilized teeth, you can easily see these defects that showed Neanderthals periodically struggled nutritionally," she said. "But I wanted to know if that struggle was any harder than that of more modern humans."
To find that answer, she turned to two collections of skeletal remains: One was a collection of Neanderthal skulls at least 40,000 years old from various sites across Europe; the other was a set of remains of Inuit Eskimos from Point Hope, Alaska. The Inuit remains, some 2,500 years old, are maintained by the American Museum of Natural History in New York.
She microscopically examined teeth from the Neanderthal skulls for signs of linear enamel hypoplasia, as well as other normal growth increments in teeth called perikymata, and compared their prevalence with those from the Inuit skulls.
"The evidence shows that Neanderthals were no worse off than the Inuit who lived in equally harsh environmental conditions," she said, despite the fact that the Inuit use more advanced technology.
"It is somewhat startling that Neanderthals weren't suffering as badly as people had thought, relative to a modern human group (the Inuits)."
Guatelli-Steinberg's examination of perikymata offered snapshots of Neanderthal survival. Smaller than the linear enamel hypoplasia, perikymata are even tinier horizontal lines on the teeth surface. Each one represents about eight days of enamel growth so by counting their number, researchers can gauge the speed of tooth development - more perikymata mean slower growth of the tooth surface.
Guatelli-Steinberg counted perikymata within linear enamel hypoplasias, and was able to gauge how long these episodes of physiological stress lasted. The perikymata showed that periods of up to three months of starvation for both the Neanderthals and the Inuit were not uncommon. In fact, Guatelli-Steinberg found that Inuit teeth showed significantly more perikymata than did the Neanderthals, suggesting that the Inuit experienced stress episodes that lasted slightly longer than did those of the Neanderthals.
She is looking ahead to do a similar comparison of tooth defects among the European Cro-Magnon who thrived after the Neanderthals disappeared. Coupled with the results of this project, and that of earlier work with non-human primates, she hopes to improve researchers' understanding of just what information these tooth defects might reveal.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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