Anthropology / Researchers disagree on which of the human ancestors discovered fire, when and on which continent
Artists in prehistoric times paint by the light of oil lamps in a cave. Work by Charles R. Knight, 1920
Almost all cultures of the world have myths, telling how some rogue - a wise man or a sympathetic god - brought the fire to the people, and changed their lives. The fire made cooking possible and provided protection from madmen and a source. She lit up the night and paved the way for music, art and poetry.
Few anthropologists disagree with this view, but there is a debate among them on the question of when our ancestors received the control of fire and what this means for their way of life and their evolutionary development. "There is no consensus even regarding the question of which hominid tamed fire," said Ofer Bar-Yosef, professor of anthropology at Harvard University.
At one end of the spectrum are the anthropologists who claim that Homo erectus, generally regarded as the first successful human ancestor, evolved with the help of fire in East Africa about 1.8 million years ago. Armed with fire and stone tools and weapons, these ancestors soon began to spread throughout Europe and Asia, even reaching Indonesia.
However, the prevailing opinion among anthropologists for a long time is that the archaeological evidence from East Africa for the early discovery of fire is controversial at best, and that Homo erectus actually lived without fire successfully as a hunter and scavenger for more than a million years. Homo erectus, and perhaps other human ancestor species, the theory goes, began to control fire only out of necessity, when they moved to more northern latitudes and had to make do with frozen meat and deal with freezing cold.
Until recently, the earliest accepted evidence of fire being used by man was from Zukodian Cave in China, where "Peking Man" was found; About 500 years old, said Richard Klein, professor of anthropology at Stanford University. There are also a site or two in Europe that contain evidence of the use of fire about 400 years ago, Dr. Klein added.
"But if you are interested in solid evidence of fire, such as examples of stone hearths and clay ovens, you are in the last 250 years," he said. This is the period of early Homo sapiens in Europe and late Homo erectus in Asia.
However, in the last two years, several groups of researchers published a series of articles, which deepened the controversy. They cast doubt on the evidence for man-made fire at Zukodian and again supported the argument that fire control was achieved much earlier.
Dr. Bar-Yosef's team found that the ash in Zodokian, which archaeologists long believed was created by man-made fire 500 years ago, was washed in from the outside and may have been created by natural causes. The charred bones and stone tools still suggest the existence of fire, but there is no direct evidence that humans produced it, said Dr. Paul Goldberg, a member of the research team.
At the same time, two separate groups of anthropologists theorized that the tubers and boiled roots played an important role in human evolution. Cooking makes the tubers more edible and increases their nutritional value as it softens them, and in many cases frees them of toxic substances, said Richard Wrangham, a professor of anthropology at Harvard, who leads a group of researchers from Harvard and the University of Minnesota.
Dr. Wrangham and his colleagues believe that Australopithecines, the ape-like ancestors of Homo erectus, mastered fire and began cooking tubers and roots in East Africa 1.9 million years ago. Within a few hundred generations - a short period in evolutionary terms - the Australopithecines evolved into Homo erectus. "Evolution is driven by a cultural event: the conquest of fire," Wrangham said.
Homo erectus differed in its physiological and neurological structure from its australopithecine ancestors: its brain was much larger, its teeth were smaller and it walked upright. The females also began to form separate mating relationships with the males within the large social groups, Dr. Wrangham believes, mainly to prevent other males from stealing food they had gathered and prepared around the campfire.
Dr. James O'Connell and Dr. Christine Hawks, anthropologists at the University of Utah, along with Dr. Nicholas Blarton Jones of the University of California, Los Angeles, also link the boiled tubers directly to evolution, population growth, and the migration of Homo erectus.
Dr. O'Connell and his colleagues speculate that in response to a drier, colder climate, which reduced the availability of traditional foods such as fruit, women in some groups turned to gathering and cooking tubers and other roots. These customs, the anthropologists believe, allowed women after childbearing age to participate in feeding their families. The combination of better food and a greater contribution to feeding the family helped reduce the adult mortality rate, Dr. O'Connell said, and improved the nutrition of children and mothers.
The "boiled tuber" theories have caused considerable disagreement, in large part because they assume that the control of fire was central to early human evolution, and that eating meat was less important than believed. Some anthropologists claim that eating meat was central to the development - especially to the formation of the larger brain - of Homo erectus and modern humans.
"The conventional wisdom holds that the hunting and gathering of carrion meat by the males are responsible for the changes we see in Homo erectus," said Dr. O'Connell. "But if you do the calculations, it is impossible to find the nutritional resources needed for this in meat alone."
The suggestions have prompted some researchers to look again at the evidence for the early existence of fire in East Africa. The sites at Gadeb in Ethiopia, Kobi Pora and Cheswanja in Kenya, and the Oldubai Gorge in Tanzania yielded evidence such as heat-altered stone tools and circles of burnt clay 1.5 to 1.7 million years old. Burnt bones from about 1.5 million years ago were found in Swartcrans Cave in South Africa.
The material at least hints at the possibility of man-made fire, said John Harris, a professor of anthropology at Rutgers University. He studied many of the sites in the 70s and 80s and thinks the new theories about cooking reinforce this approach.
Other researchers aren't so sure that the kind of definitive evidence that many archaeologists demand will ever be found. Dr. O'Connell said, that "most archaeologists do not understand what character may be small fires in the bush (bushes and low woodland). They are small and leave very few traces." The coal and ash left behind quickly disappear.
In the absence of physical evidence, said Dr. Klein, it is possible that the only way to answer the question would be to examine the reasons for the formation of the large brain in Homo erectus. "About 1.8 million years ago, the brain grew dramatically, and a high-energy food source was needed for this. It may require fire to break down the muscles and plant fibers for digestion," said Dr. Klein.
However, Klein added, until the theory is proven, "the question will continue to lead to speculation and disagreements."
(Originally published on 16.1)
{Appeared in Haaretz newspaper, 22/1/2001}
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