Was there someone before human existence who had the same or may be higher intelligence level? A study conducted by scientists in the deserts of north western Kenya tries to answer this question after they found tools that dated back at least 700,000 years.
The tools, whose makers may or may not have been some sort of human ancestor, poses a challenge to the notion that our own most direct ancestors were the first to bang two rocks together to create new technology.
The discovery is the first evidence of an even earlier group of proto-humans who may have had the thinking abilities needed to figure out how to make sharp-edged tools.
Geologist Chris Lepre said the whole site was surprising; "it just rewrites the book on a lot of things that we thought were true."
Author Sonia Harmand added that the tools shed light on an unexpected and previously unknown period of hominin behavior, and could tell a lot about cognitive development in human ancestors that they couldn't understand from fossils alone.
Hominins are a group of species that include modern humans, Homo Sapiens, and our closest evolutionary ancestors. It was thought that Homo Sapiens were the first one to do the discovery, but researchers have been uncovering tantalizing clues that some other, possibly earlier species of hominin might have figured it out.
One line of thinking is that hominins started knapping - banging one rock against another to make sharp-edged stones so that they could cut the meat off of animal carcasses. But, the size and markings of the newly discovered tools suggests that they were doing something different as well.
The researchers think the tools could have been used for breaking open nuts or tubers, bashing open dead logs to get at insects inside.
Ancient stone artifacts from East Africa were first uncovered at the Olduvai Gorge in Tanzania in the mid-20th century, and those tools, were later associated with fossil discoveries in the 1960s of the early human ancestor Homo Habilis. That species has been dated to 2.1 million to 1.5 million years ago.
The researchers tried knapping stones themselves to better understand how the tools they found might have been made. They concluded that the techniques used could represent a technological stage between a hypothetical pounding-oriented stone tool used by an earlier hominin and the flaking-oriented knapping behavior of tool makers.
Chimpanzees and other primates are known to use a stone to hammer open nuts atop another stone. But using a stone for multiple purposes, and using one to crack apart another into a sharper tool, is more advanced behavior. The research is published in a scientific journal Nature