WE KNOW that Homo erectus used stone tools. And now it seems likely that our ancient ancestor built shelters, too. Japanese archaeologists have discovered the remains of what is believed to be the world鈥檚 oldest artificial structure on a hillside at Chichibu, north of Tokyo.
The site has been dated to half a million years ago, a time when Homo erectus lived in the region. It consists of what seem to be 10 post holes, which form two irregular pentagons thought to be the remains of two huts. Thirty stone tools were found scattered around the site.
鈥淚t鈥檚 a nice find and it does sound important,鈥 says Chris Stringer, head of the human origins group at London鈥檚 Natural History Museum. 鈥淚f this is correctly dated and correctly interpreted, it is the first good evidence from 500 000 years ago of a hut structure made by these people.鈥 Before the discovery, the oldest remains of a structure were those at Terra Amata in France, from around 200 000 to 400 000 years ago.
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The Japanese site was discovered during the construction of a park on a flat piece of terrain with a commanding view of a river. After digging through about 2 metres of river deposits, an archaeological team organised by the local board of education found a layer of volcanic ash in which the shallow post holes appear to have been dug. The holes were filled with loose material, which was clearly distinct from the volcanic layer, says Kazutaka Shimada, curator of the Meiji University Museum in Tokyo. 鈥淭hey had well-defined edges.鈥
He says the holes form two pentagons 1.3 and 1.7 metres across. According to the board of education, which announced the find last week, the holes are roughly equidistant, but the ones on the south side are slightly farther apart, perhaps for an entrance. A total of 30 stone implements were found around the site, seven of them within the pentagons themselves. 鈥淢ost of them are crude cutting instruments made of chert and shale,鈥 says Shimada. 鈥淭hey have clearly been worked.鈥
As for dating, Shimada says the volcanic layer is between 500 000 and 600 000 years old, while the alluvial layer covering it is more than 400 000 years old, making the remains about half a million years old. Ofer Bar-Yosef, an anthropologist at Harvard University, says Japanese dating techniques using volcanic ash are usually reliable.
鈥淚f you have post holes, this is a rather exceptional situation in terms of what we know about hominid archaeology,鈥 says John Rick, an anthropologist at Stanford University. 鈥淗alf a million years ago, we don鈥檛 have any concept of what our ancestors were capable of doing at all.鈥
The remains could help explain how Homo erectus lived and hunted. 鈥淚t鈥檚 evidence that they built structures but how permanent this was we don鈥檛 know,鈥 says Stringer. 鈥淭hey were hunter-gatherers and they had to move where the resources were. Who knows whether this was a shelter they stayed in one week, or one month.鈥
Rick says that, if the find is confirmed, it will be interesting because it shows that hominids could conceive of using technology to organise things. 鈥淸They had] the idea of actually making a structure, making a cultural space; a place where you might sleep,鈥 he says. 鈥淚t represents a conceptual division between inside and outside.鈥
Bar-Yosef agrees that if the find stands up, it would add to mounting evidence that hominids living 500 000 years ago were more sophisticated than many anthropologists believe. 鈥淚t wouldn鈥檛 surprise me-the cognitive ability to predict what you鈥檒l need was already embedded in the human mind.鈥
