The early humans also appear to have created black (manganese), brown, green, and white pigments, and perforated a piece of ochre on opposite sides in order to possibly wear or carry the colorful rock. By 77,000–80,000 years ago, there is evidence that humans were wearing beads with ochre on them. Neanderthals also appear to have used red ochre pigments by at least 250,000 years ago.
Early humans could have applied color to signify their social networks. Potts pointed out that this still occurs today with flags, tattoos, hats, university t-shirts, and other visual signs of affiliation.
"Placing color on skin, hair, and other parts of the body can be a symbolic behavior," Potts explained. "It can communicate, 'I'm part of a group that you know and you like us.'"
Conflicts occur among hunter-gatherers, but since smaller populations were spread over vast distances in Africa, the researchers believe that warfare during these earlier periods of human history would have been inherently kept in check.
This is not to say that the different hunter-gatherer groups did not have arguments. Spoken language cannot be preserved in the fossil record, save for evidence that a hominid possessed anatomy capable of speech. The researchers, however, suspect that the emergence of more complex social networks over longer distances and resulting symbolic behaviors would have advanced language evolution.
Humans in Africa probably did not talk much about killing large animals for sustenance. With many big animal species
extinct and replaced by smaller taxa, people appear to have relied more on small game.
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Brooks and her team found remains for antelopes, bat-eared foxes, springhares (a type of rodent), root rats, hoofed mammals such as pigs, and more. Brooks has studied hunter-gatherers in Africa for nearly two decades, and such groups today often consume such smaller game. It is therefore possible that the hunter-gatherer diet in Africa has not changed much over thousands of years.
"Even to catch smaller animals you need snares, hooks, and other technologies," Brooks said, adding that some of these tools, such as rope, tend not to preserve well over the millennia.
The third study, led by Alan Deino of the Berkeley Geochronology Center, provides detailed dating of sites within the Olorgesailie Basin. The work, based on argon and uranium dating methods, helps to elucidate the critical transition between the Acheulean period and the Middle Stone Age.
Yet another related study is now in the works. Potts told Seeker that he and his team have drilled a large sediment core from a flat piece of ground in East Africa.
"It provides a beautiful environmental record," he said.
"This is an evolutionary story,” he added. “It's not that one day there was Homo heidelbergensis and the next day there was Homo sapiens. The changes happened over tens of thousands of years, and we can see this evolution occurring in East Africa."