Laziness May Have Doomed This Human Ancestor

The reconstructed skull of a Homo erectus specimen at the Smithsonian Natural History Museum. David H. Koch Hall of Human Origins (CC By-SA 2.0)

We've all had that friend who just can't seem to get it together. A friend like this is just bad at taking care of themselves: They loaf around on your couch in a desultory way, watching other people play video games, asking if you have anything to drink besides water. Sometimes you think it's a pity they're too old to be sent off to camp.

About 20 human species have roamed this planet over the past 7 million years or so, and all but one — here's looking at you! — went extinct for one reason or another. But new research published in the journal PloS One suggests that at least one species of ancient human died out because they collectively weren't showing very much initiative. As a species, Homo erectus might have gone extinct because it simply couldn't get its act together.

This is not to say H. erectus made a poor showing during its time on this planet: It hung out here for more than a million years, after all, and it was the first cosmopolitan hominin, meaning it was the first human species spread out to more than just one continent. It also had a larger body and bigger brain than its predecessors, it stood upright (its name literally means "upright human") and was also an early adopter of rudimentary stone tools, like axes for butchering animals.

However, the researchers from the Australian National University (ANU) suggest H. erectus probably could have made more of an effort to keep its whole existence thing going. Based on evidence found during an excavation in an artifact-dense area of the Arabian Peninsula, H. erectus was clever, but not particularly driven, which began to become a problem when the climate started to change.

"They really don't seem to have been pushing themselves," said lead author Ceri Shipton of the ANU School of Culture, History and Language, in a press release.

According to Shipton, the sheer laziness of Homo erectus can be observed in the manner in which they made their tools. Where later species of humans were very selective about their materials, H. erectus seems to have just picked up whatever stone was lying within reach.

"At the site we looked at there was a big rocky outcrop of quality stone just a short distance away up a small hill," said Shipton. "But rather than walk up the hill they would just use whatever bits had rolled down and were lying at the bottom. When we looked at the rocky outcrop there were no signs of any activity, no artefacts and no quarrying of the stone. They knew it was there, but because they had enough adequate resources they seem to have thought, 'why bother?'"

This probably worked out for them for a time — they called this planet home for much longer than Neanderthals (400,000 years) and even us fancy-pants modern humans (200,000). However, when the climate in central-Saudi Arabia began to dry out, they didn't innovate.

"Not only were they lazy, but they were also very conservative," said Shipton. "The sediment samples showed the environment around them was changing, but they were doing the exact same things with their tools. There was no progression at all, and their tools are never very far from these now dry river beds. I think in the end the environment just got too dry for them."

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