Humans Sped to U.K. After Ice Age, Study Says
Posted: Monday, November 3, 2003
James Owen in England
for National Geographic News
November 3, 2003
Humans hotfooted it to Britain after the last ice age, scientists say. The new research, which challenges previous studies, suggests these early settlers advanced rapidly as the glaciers melted away.
A team of European scientists estimated the speed and timing of human resettlement in late glacial Britain by comparing radiocarbon dated remains with ice-core climate records. Their findings, now published in the Journal of Quaternary Science, suggest a wave of migration coincided with a sudden rise in temperature and the northwards spread of herd animals such as wild horse and deer.
Previously, scientists thought repopulation had been a drawn-out affair, preceded by centuries of sporadic forays from mainland Europe.
"The big question has always been how quickly, and in what number, did people return once the glaciers had retreated," said research team leader Nick Barton, from the anthropology department of Oxford Brookes University, Oxford, England. "Now with the benefit of larger numbers of radiocarbon dates corrected against a highly accurate record of global climatic change from the Greenland ice record, it seems reoccupation was an almost instantaneous event across northern and central Europe."
Early modern humans reached Britain by around 30,000 years ago, but within 3,000 years they were driven out by the advance of the last ice age.
The archaeologists looked for evidence of their return in ancient caves in western and northern England. The team radiocarbon dated bits of butchered bone from animals the settlers hunted such as red deer, and wild horse and cattle. The data reveal repopulation began as far back as 16,000 years ago.
Roger Jacobi, from the paleontology department of the Natural History Museum, London, said: "When you compare the pattern of radiocarbon dating against the Greenland ice core, humans get back when the ice cores are showing quite a sharp temperature rise."
Jacobi says the oldest bones came from a cave at Cheddar Gorge, Somerset. He added: "They were a group of neck vertebrae from wild horses that had been butchered and were therefore covered in cut marks. It's very clear humans had been instrumental in dismembering them."
The bones are only slightly younger than earliest dated human-modified remains from countries such as Belgium and Germany, suggesting a rapid advance from mainland Europe. Their progress was helped by the fact Britain was a peninsula, not an island.
"Most of the English Channel and southern North Sea would have been dry land," added Jacobi. "So Britain would have been joined eastwards to the northern tip of Denmark. It was a huge land connection."
Jacobi and his colleagues suggest it was the movement of animals across this same land connection that triggered the wave of human migration.
"It seems clear that people were following herds of large animals, like horse, which expanded to occupy the continent," said co-researcher Martin Street, from the Römisch-Germanisches Zentralmuseum, Neuwied, Germany. "Humans can be seen as part of that pulse."
They brought with them a tool kit of projectile points and knives used to kill and dismember their prey. Analysis of flint tools specific to the late glacial period shows these early settlers were highly mobile and covered large distances.
"For instance, we know from flint evidence at Cheddar Gorge that hunters were moving at least 70 kilometers (43 miles) on a regular basis," Jacobi added.
One of the strongest patterns to emerge from the study is the correlation between the location of early settlement sites and the edges of upland areas. Jacobi says this again highlights the importance of prey animals as a catalyst for human repopulation.
"It looks as if there was a whole range of micro-environments at the interface between uplands and lowlands," said Jacobi. "The joy of living on an upland edge is that you are able to exploit a whole range of environments and with it a more diverse fauna. The typography of places like Cheddar Gorge also make them ideal for trapping game against rock walls."
Remains found at Creswell Crags in Derbyshire suggest these early Britons were also partial to Arctic hare. "As well as its meat, they were probably going for the white winter pelts which were thick and look so attractive," Jacobi added.
The recent discovery at Creswell Crags of the world's northernmost ice age cave art lends weight to the study's findings. Though no match for the artistry of examples from caves in France and Spain, one of the animals depicted hints at the speed at which migrants spread from mainland Europe.
Archaeologists made out the outline of an ibex, an animal which is thought to have been absent from Britain.
"It's possible evidence that these people came from an area like Belgium, as ibexes certainly occurred in places like the Ardennes," said Jacobi. "Some researchers have interpreted this as indicating that groups had seen ibex on the continent and were drawing them from memory."
Yet these early colonizers secured only a temporary foothold in Britain, as Jacobi explains. "Interestingly, radiocarbon dating seems to show that humans, having resettled Britain in the late glacial period, then go away again for several hundred years, when it gets very cold again."
So it appears humans were cleaned out of Britain one last time, around 12,000 years ago. But they soon returned, hot on the heels of those deer and wild horses. And this time they were there to stay.
Reproduced from: news.nationalgeographic.com
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