Quest for Fire

The first evidence we have for the use of fire by early hominids comes from several sites, dated roughly 1 million years ago, which were likely occupied by Homo erectus. But the earliest evidence for hominids actually making fire is much younger.

Wildfire

The earliest evidence that we have for the use of fire by hominids consists of bits of burned bone and wood, presumably from a campfire. Some of them also contain flakes of flint—apparently the stones had been heat-treated in a fire to make them easier to work into tools. The two best-studied of these sites come from an excavation in Israel which has been dated to around 800,000 years ago, and the Wonderwerk Cave in South Africa which is dated to about 1 million years ago. At Wonderwerk there is an arrangement of rocks which appears to suggest a hearth. The well-studied hominid site at Koobi Fora in Kenya also has what appear to be signs of fire dating to about 1.6 million years ago. Fortunately the carbonized organic material in fires can be dated pretty reliably (though there is always the difficulty of distinguishing a hominid-tended campfire from a natural wildfire), so we are confident that hominids, probably Homo erectus, were using fire by at least a million years ago and perhaps earlier.

Paleo-anthropologists are, however, pretty sure that the habitual use of fire actually predates all these finds. When the Homo erectus species first appears over two million years ago, it already exhibits signs that the abdominal cavity has become smaller, and this is an important clue to its diet. Most earlier hominids had bulging bellies like modern-day apes and monkeys. This is because of their raw vegetarian diet. Plant food contains relatively little energy, so herbivores have to process it for a long time to extract as much as they can, and this requires a large pot-belly to hold extra-long intestines. A diet consisting largely of meat, however, provides much more energy per pound, especially if it is cooked, and predators can get by with much shorter guts and smaller slimmer bellies. So the sudden shrinking of the Homo erectus gut may indicate two important changes to their diet—they probably ate a lot of meat, and they probably cooked their food. And that required “fire”.

This does not demonstrate, however, that early hominids like Homo erectus could make fire at will. It is entirely possible that they were dependent upon finding naturally-occurring embers, from grassfires or lightning strikes, and using these to maintain their own hearth fires. If their hearth fire was extinguished for any reason, these hominids may not have been able to re-light it themselves, but may have needed to search for another source of fire. 

Anatomically-modern Stone Age humans, Homo sapiens, developed a whole series of clever methods for making fire on demand. In Asia where bamboo is common, an early fire-making device was the “fire piston”. It works in the same way that a diesel engine does: a small bit of tinder is placed inside the hollowed-out end of a stick that fits snugly into a hollow sealed tube, and then is smacked firmly to suddenly compress the air inside. This produces enough heat to set the tinder smoldering.

Many hunter-gatherer cultures in Africa, Australia and North America use fire sticks or fire drills. In this method, rapidly twisting a dry stick inside a depression made in a flat board produces enough heat by friction to form a small hot coal in a pile of tinder. Simple versions of this method produce rotation by rolling the stick between the hands. More sophisticated versions use a “fire bow”, where a bowstring is wrapped around the stick and then drawn back and forth.

None of these methods, however, leave any reliable trace in the archaeological record, since they are formed from perishable materials which rot away and are seldom preserved. So we have no way of knowing how long ago they may have appeared. They are also relatively sophisticated methods which require significant skill to make and use, and it is likely that they had been preceded by simpler technologies.

With the appearance of the Iron Age around 1500 BCE, apparently with the Hittites, another method of making fire became available. When a piece of silica-rich stone such as flint, quartz or chert is struck against a piece of iron or steel, it knocks off tiny sparks of metal that glow red-hot and which can be used to produce flames in tinder. “Flint-and-steel” became the typical method for starting fires from the time of the ancient Greeks right up to the present day–our modern cigarette and barbecue lighters are based on a version of flint-and-steel.

This led some archaeologists to speculate that perhaps early hominids were able to use their own version of flint-and-steel to make fire. They certainly had flint, and they spent a lot of time pounding on flint or quartzite nodules with various types of hammerstones to produce stone tools. And although they did not have steel or iron, they had a cruder natural version of it—iron pyrite, or “fool’s gold”. Like flint and quartz, this shiny mineral (known technically as iron sulfate) is an igneous rock formed by volcanoes, and although somewhat rare, pyrite sometimes occurs in the same deposits in which flint or obsidian are found. (A similar mineral known as “marcasite” has a higher proportion of iron.) So it is entirely possible that at some point in time an early hominid picked up a lump of pyrite or marcasite and used it to bash a nodule of flint or quartz—and found that it produced glowing-red sparks which could be used to start a fire.

Confirmation came when archaeologists began to examine the surface of Paleolithic flint hand axes made by early humans. Sure enough, under a microscope they were able to find the tell-tale parallel scratches and C-shaped marks that resulted from friction and impact. Since these were located on the flat sides of the hand axes and not on the sharpened edges, they indicated that they were not the result of cutting or chopping motions, but from intentional impacts made by another rock being bashed against the flint. It added another helpful use to the Paleolithic hand axe: it could function as part of a portable fire-making kit.

Since then, studies seem to indicate that these scratch marks are not found on hand axes made earlier than around 300,000 years ago (about the time that Homo sapiens first appeared). And they have also been found in hand axes of that time period made by Neandertals, indicating that they too were able to use pyrite-and-flint to make fire. In addition, there seems to have been a noticeable increase in the frequency of fire hearths and other indications of fire use at about this same time.

So, the evidence indicates, while early hominids were able to use and control fire at least a million years ago and perhaps as long as 2.5 million years, they were not able to make it themselves whenever they needed it, and were dependent upon finding it in the natural landscape. It wasn’t until Neandertals and modern humans appeared, about 300,000 years ago, that the technology to make fire upon demand appeared.

The ability to make fire was a crucial step in human cultural development. With fire, humans were able to extract food from a wide variety of cooked plants and animals, leading ultimately to agriculture. Fire allowed humans to produce ceramic pottery—the first artificial material—and then allowed humans to extract copper and tin to make bronze, and eventually to smelt iron ore and make steel. Without fire, there would be no human civilization today.

2 thoughts on “Quest for Fire”

  1. When I was a kid I sometimes tried the friction method to make a fire. It’s easy enough to get smoke. Fire, not so much, and I never managed the trick, which is one more reason why I have more respect for hunter-gatherers than most people nowadays. 🙂

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