The human ancestor Homo erectus may have been pushed out by the evolution of Homo sapiens, neanderthals and other, more modern hominids. As new species began taking their place, the ancient ancestors went extinct.
Or maybe, they were just lazy.
A new study is showing that part of the reasons Homo erectus died out is that the species may have been out-competed by better tool users among modern humans and neanderthals.
Researchers from Australian National University studying the older hominid species’ stone tools said that they were poorly made and used materials that were nearby. In contrast, H. sapiens and neanderthals went far out of their way to find better materials, transporting stones over long distances so that they could make better tools.
While Homo erectus was the first hominid species known to have left Africa, they don’t seem to have done so with a sense of real purpose, the researchers said.
“They really don’t seem to have been pushing themselves,” lead researcher Dr. Ceri Shipton told the Daily Mail. “I don’t get the sense they were explorers looking over the horizon. They didn’t have that same sense of wonder that we have.”
Homo erectus evolved about 1.9 million years ago in Africa. They migrated into Eurasia, with evidence they spread as far as Georgia in the Caucasus region, China and Indonesia.
But the species faded away about 140,000 years ago as Homo sapiens and related human species were on the rise.
Although Homo erectus made stone tools and had the ability to use fire, the ANU researchers think they grew lazy, unwilling or unable to keep learning, innovating and creating. They point to the tools as evidence.
“To make their stone tools they would use whatever rocks they could ind lying around their camp, which were mostly of comparatively low quality to what later stone tool makers used,” Shipton said.
Researchers have found no evidence of stone quarrying at Homo erectus living places, even when good stone sites were nearby. Instead, they just used what they found lying around.
That disinterest in learning, plus their inability to adapt with a changing climate, may have led the species to its end.
“Not only were they lazy, but they were also very conservative,” Shipton said. “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.”
The study has been published in the journal PLoS One.
By Kyla Cathey, Earth.com staff writer