Scientists hot on trail of flames' first taming

SUN JOURNAL

Archaeology: A dig in northern Israel indicates perhaps man's earliest controlled use of fire.

May 02, 2004|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

Call it the great-granddaddy of every candle, furnace and backyard grill ever invented.

Archaeologists digging on the banks of the Jordan River in northern Israel say they have found the earliest evidence outside Africa of the controlled use of fire by our ancestors - and perhaps the strongest such evidence anywhere.

Their discoveries, in lake sediments laid down as long as 790,000 years ago, included tool-making debris - flint chips - that were crazed and cracked by fire, as well as charred fruits and grains, and pieces of Syrian ash and wild olive evidently used as firewood.

The burned material was found in clusters, surrounded by other, unburned evidence of tool making and food preparation.

"We suggest that the clustering of the burned micro-artifacts indicates the location of Acheulean [early Stone Age] hearths," the scientists report in a study published in the current issue of the journal Science.

Mastery of fire was a quintessentially human achievement that "surely led to dramatic changes in behavior connected with diet, defense and social interaction," the researchers write.

In a sense, it presaged everything from Fourth of July barbecues to firebombs.

Hearths, or fire pits, offered heat, light and a measure of protection against enemies and wild animals. They were also centers of social interaction, where generations passed down their accumulated knowledge and cultural heritage.

Roasting destroyed toxins, cracked the hardest nuts, softened food and released nutrients not otherwise available to our forebears. It made foods easier for the youngest and oldest to consume.

Some scientists say the advent of cooking explains why our ancestors' teeth and jaws began to get smaller 1.5 million years ago - even as the rest of their bodies got bigger. Cooking would have reduced the need for powerful jaw muscles and large teeth that could crack and grind. A number of researchers even argue that lighter jaw muscles freed the brain to expand, although that theory remains controversial.

The Jordan River dig, at a place called Gesher Benot Ya'aqov, was led by Naama Goren-Inbar of the Hebrew University in Jerusalem. A member of her team, Nira Alperson, says many questions remain about the people who used the hearths they found.

"We cannot answer the question of whether they carried fire with them, whether they ignited it themselves or took it from natural burning," she says.

The scientists can't even say whether these early humans were archaic forms of our species, Homo sapiens, or an earlier, ancestral species such as Homo erectus or Homo ergaster.

But "surely this is the earliest [evidence for the use of fire] outside of Africa, and we feel that our evidence is perhaps stronger" than that of the African finds, Alperson says.

Alison S. Brooks, chair of the anthropology department at George Washington University, who has no ties to the Israeli dig, says that until recently the oldest acknowledged hearths - with fire-cracked rocks and deep accumulations of black ash and wood - were no older than 40,000 years.

More recent discoveries in France, Israel and Zambia pushed the dates for controlled fire back to 130,000 years ago.

Many older claims, dating as far back as 1.7 million years ago, have been discredited, she says. For example, new chemical and physical tests showed that "ashes" associated with a 400,000-year-old Peking Man site in China weren't ash but a natural alteration of the soil. Patches of red soil once attributed to campfires have been disputed as the remains of termite mounds.

Better accepted, scientists say, is evidence published in 1988 describing hartebeest bones burned at high temperatures associated with hearth fires. Found at Swartkrans Cave in South Africa, they were more than 1 million years old, and perhaps the work of Australopithecus or our direct ancestor, Homo erectus.

The deposits at Gesher Benot Ya'aqov (GBY) have been known since the 1930s. The site lies on what was once the shore of a lake, now called paleo-Lake Hula. Waterlogged sediments there are 111 feet deep and rich in paleolithic artifacts.

The two layers excavated by Goren-Inbar's team spanned occupations lasting tens of thousands of years, sometime between 690,000 and 790,000 years ago.

The layers were littered with flint chips from tool making. But the archaeologists found that a small number of them were cracked and crazed in ways that showed they had been heated to temperatures of 660 to 930 degrees Fahrenheit - consistent with campfires but not a transient wildfire.

Because this burned flint was found in small clusters, the team concluded that the clusters marked hearth sites.

They also found tens of thousands of pieces of wood and bark preserved by the wet sediments. There were burned bits of Syrian ash, wild grape and olive trees, mesquite and other trees that still grow in the region. There were also burned foods - fruit parts and grains of bedstraw, wild barley and goatgrass.

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