Ancient tools found in Britain show that humans lived in northern Europe 200,000 years earlier than previously thought, at a time when the climate was warm enough for lions, elephants and saber-toothed tigers to also roam what is now England.
Scientists said Wednesday that 32 black flint artifacts, found in river sediments in Pakefield in eastern England, date back 700,000 years and represent the earliest unequivocal evidence of human presence north of the Alps.
Scientists had long held that humans had not migrated north from the relatively warm climates of the Mediterranean region until half a million years ago.
"The discovery that early humans could have existed this far north this long ago was startling," said Prof. Chris Stringer, a paleontologist at the Natural History Museum, one of four British scientists involved in the study who announced the finding at a news conference in London. Their discovery is detailed in the scientific journal Nature.
Roebroeks, who was not involved in the study, said it showed that "early humans were evidently roaming the banks of these rivers ... much earlier than hitherto thought for this part of Europe."
But another outside expert called for caution.
"One always has to be skeptical, given that previous claims of early human presence in northern Europe have had problems with the date or authenticity of the artifacts found. If indeed subsequent findings support this discovery, it would be very exciting and would change our ideas about the adaptability of early humans," Alison Brooks, an anthropologist at George Washington University in Washington, D.C., said in an interview.
Stringer said now scientists can search for human remains, and perhaps find humans arrived in the region even earlier than 700,000 years ago.
"We have a whole new area of research opening up to us," he said.
Prof. Jim Rose of the University of London, another researcher involved in the study, said that 700,000 years ago, England was still connected the European mainland and enjoyed relatively short periods of balmy weather between the time that massive glaciers swept through the area, freezing and reforming the landscapes.
During such thaws, he said, early humans would have been able to migrate to England from the Mediterranean and enjoy mild winters, flat landscapes and major rivers.
Rhinoceroses, elephants, saber-toothed tigers, lions, hippopotamuses and bears lived in the area at the time. The scientists said they don't know whether the humans used the discovered sharp-edged tools to kill animals for food, or merely to scavenge from carcasses that predators left behind.
The artifacts suggest that the early humans did not colonize northern areas of Europe, but merely expanded their migratory patterns there when the weather permitted, the scientists said.
Pakefield, a coastal village 120 miles northeast of London, is one of the few areas where glaciers preserved, rather than destroyed, the sediment that contained ancient artifacts, Rose said. Coastal erosion is now opening up cliffs around Pakefield, exposing fossils and artifacts.
Before that discovery the earliest unambiguous traces of human beings in Europe north of the Alps were dated to about 500,000 years ago, and included flint artifacts, bones of mammals and even some human remains that were discovered in Bosgrove on the southern coast of England.
The earliest traces of human presence in southern Europe are at least 800,000 years old and include materials that were discovered in Atapuerca, Spain.