What a Difference 200,000 Years Makes

Scientists re-estimate the age of a group of human ancestors, leaving them out in the cold

Homo Erectus

Wikipedia

Peking Man, a group of Homo erectus discovered in the 1920's near Beijing (then Peking), China, has been back in the spotlight over the last few days. A new estimate from American and Chinese scientists dates the fossils (and their associated population of Peking men and women) 200,000 years older than earlier measurements. The researchers reported their finding on the cover of last week's Nature.

Peking Man's new age – around 750,000 years old – results from a dating method that assesses levels of radioactive aluminum and beryllium in dirt samples and tools from the discovery site, using an extremely sensitive mass spectrometer. The researchers report that earlier estimates were achieved with a less accurate measurement of uranium levels. Considering the difficulties of accurate dating, a 200,000-year mistake is understandable. Even with this new date, researchers cage their estimate within a possible margin of 50,000 years in either direction.

None of this may seem like much of a big deal. After all, what's another 200,000 years when you're already 500,000 years old? But it's a significant change. 200,000 years, remember, is the length of time that modern humans have existed at all. The last 200,000 years have seen ice and heat, sea level rise and fall, and the extinction of giant beasts.

For Homo erectus, that difference of 200,000 years meant a major difference in climate. Living closer to 750,000 BCE, Peking man and his brethren would have had to brave the cold of a chillier age. That could mean that they used fire, though no clear evidence of this has been found. Or, it could just mean that they were even more badass than we previously thought.