March 11, 2009

“˜Peking Man’ Could Be Older Than Scientists Thought

Chinese researchers say a new and more accurate dating method shows that Peking Man may be 200,000 years older than what experts previously thought, The Associated Press reported.

The bones of the so-called Peking Man "” a batch of Homo erectus fossils found in the 1920s during cave excavations near Beijing "” were originally believed to have been some 550,000 years old.

Researchers have now developed a new method that examines the radioactive decay of aluminum and beryllium in quartz grains, which enabled them to get a more precise age for the fossils.

The experiments, led by Guanjun Shen of China's Nanjing Normal University, wrote in an article in Nature that the analysis dated the finds to around 750,000 years old, some 200,000 years older than previous estimates.

The researchers wrote: "The finding indicates a hominin presence in the area through glacial and interglacial cycles. The results should help to build a more reliable chronology of human evolution in East Asia."

The study's co-author Darryl Granger, an atmospheric scientist at Purdue University, suggests he was probably the oldest cold weather inhabitant in human ancestry.

The average yearly temperature at the time in that part of China hovered around the freezing mark, but it was too dry for an ice sheet, he told AP.

"Think of living in a dry windy cold much like winters in Calgary, Canada, without warm close-fitting clothes and well-made buildings to keep you warm," he said. "And these inhabitants may not have even been able to warm up with a fire whenever they wanted either."

Rick Potts, a Smithsonian Institution human origins expert who wasn't part of the research, said it also demonstrates just how "wimpy" modern humans are.

Potts said there were likely three possibilities that show how Peking Man survived such extreme weather:

  • Fire. Early findings showed signs of a fire in Peking Man's cave. But there has been debate about whether the fire was accidental or controlled, and evidence doesn't point conclusively either way.
  • Fur. There is no evidence that this human ancestor used crude tools to make more form-fitting clothes. Loosely worn animal fur is more likely.
  • Homo erectus had evolved to handle the cold.

Potts said just like the more modern Neanderthal, Peking Man may have had physiological changes that allowed more blood to flow to his extremities.


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