The Use of Fire

Homo erectus or 'upright man', who lived from about 1.5 million years ago in Africa, was the first creature to stand fully upright. By about 500,000 years ago, these early humans had spread to southern Asia and Europe. They were probably the first to use fire. This was useful for cooking food, keeping warm, and scaring animals away from shelters. http://www.gridclub.com/fact_gadget/1001/human_world/prehistoric_people/639.html

We think that Homo erectus built campfires and may have made simple ovens with hot stones

Use of fire for cooking can be definitely traced back at least to 60,000 years ago, and some archaeological discoveries suggest the use of fire for cooking as far back as 400,000 years ago. Use of fire for the making of ceramics, bonding, and metallurgic purposes dates to at least 10,000 years ago. And the 30,000-year-old paintings of animals in caves would certainly suggest that the painters needed fire, lamps, or lanterns in order to see to paint in the dark caves.

http://www.beyondveg.com/nicholson-w/hb/hb-interview2c.shtml#fire,%20first%20control

• Evidence for very early control of fire is sparse and ambiguous. The earliest evidence for control of fire by humans, in the form of fires at Swartkrans, South Africa and at Chesowanja, in Kenya, suggests that it may possibly have been in use there as early as about 1.4 or 1.5 million years ago.[100] However, the interpretation of the physical evidence at these early sites has been under question in the archaeological community for some years now, with critics saying these fires could have been wildfires instead of human- made fires. They suggest the evidence for human control of fire might be a misreading of other factors, such as magnesium- staining of soils, which can mimic the results of fire if not specifically accounted for. For indisputable evidence of fire intentionally set and controlled by humans, the presence of a hearth or circle of scorched stones is often demanded as conclusive proof,[101] and at these early sites, the evidence tying the fires to human control is based on other factors.
• Earliest dates for control of fire accepted by skeptical critics. At the other end of the timescale, these same critics who are only willing to consider the most unequivocal evidence will still admit that at least by 230,000 years ago[102] there is enough good evidence at at least one site to establish fire was under control at this time by humans. At this site, called Terra Amata, an ancient beach location on the French Riviera, stone hearths are found at the center of what may have been huts; and more recent sources may put the site's age at possibly 300,000 years old rather than 230,000.[103]

  Somewhat further back-- from around 300,000 to 500,000 years ago-- more evidence has been accumulating recently at sites in Spain and France[104] that looks as if it may force the ultraconservative paleontologists to concede their 230,000-year-ago date is too stingy, but we'll see.

• And then there is Zhoukoudian cave in China, one of the most famous sites connected with Homo erectus, where claims that fire may have been used as early as 500,000 to 1.5 million years ago have now largely been discredited due to the complex and overlapping nature of the evidence left by not just humans, but hyenas and owls who also inhabited the cave. (Owl droppings could conceivably have caught fire and caused many of the fires.) Even after discounting the most extreme claims, however, it does seem likely that at least by 230,000 to 460,000 years ago humans were using fire in the cave[105], and given scorching patterns around the teeth and skulls of some animal remains, it does appear the hominids may have done this to cook the brains (not an uncommon practice among hunting- gathering peoples today).[106]
• The most recent excavation with evidence for early use of fire has been within just the last couple of years in France at the Menez- Dregan site, where a hearth and evidence of fire has been preliminarily dated to approximately 380,000 to 465,000 years. If early interpretations of the evidence withstand criticism and further analysis, the fact that a hearth composed of stone blocks inside a small cave was found with burnt rhinoceros bones close by has provoked speculation that the rhino may have been cooked at the site.[107]

Sequence of stages in control: fire for warmth vs. fire for cooking. One thing we can say about the widespread use of fire probable by 125,000 years ago, however, is that it would almost certainly have included the use of fire for cooking.* Why can this be assumed? It has to do with the sequence for the progressive stages of control over fire that would have had to have taken place prior to fire usage becoming commonplace. And the most interesting of these is that fire for cooking would almost inevitably have been one of the first uses it was put to by humans, rather than some later- stage use.*

The first fires on earth occurred approximately 350 million years ago-- the geological evidence for fire in remains of forest vegetation being as old as the forests themselves.[110] It is usual to focus only on fire's immediately destructive effects to plants and wildlife, but there are also benefits. In response to occasional periodic wildfires, for example, certain plants and trees have evolved known as "pyrophytes," for whose existence periodic wildfires are essential. Fire revitalizes them by destroying their parasites and competitors, and such plants include grasses eaten by herbivores as well as trees that provide shelter and food for animals.[111]

Opportunistic exploitation of animal kills by predators after wildfires. Fires also provide other unintended benefits to animals as well. Even at the time a wildfire is still burning, birds of prey (such as falcons and kites)-- the first types of predators to appear at fires-- are attracted to the flames to hunt fleeing animals and insects. Later, land- animal predators appear when the ashes are smoldering and dying out to pick out the burnt victims for consumption. Others, such as deer and bovine animals appear after that to lick the ashes for their salt content. Notable as well is that most mammals appear to enjoy the heat radiated at night at sites of recently burned- out fires.[112]

It would have been inconceivable, therefore, that human beings, being similarly observant and opportunistic creatures, would not also have partaken of the dietary windfall provided by wildfires they came across. And thus, even before humans had learned to control fire purposefully-- and without here getting into the later stages of control over fire-- their early passive exposures to it would have already introduced them, like the other animals, to the role fire could play in obtaining edible food and providing warmth.

Primal Kitchens

http://www.harvard-magazine.com/archive/00nd/nd00_rn_1.html

The most dramatic moment in human evolution took place about 1.9 million years ago, with the emergence of homo erectus. "Something radical happened," says professor of anthropology Richard Wrangham. "The change happened almost too quickly for the fossil record to record its intermediate stages."

The australopithecine creatures who inhabited the African woodlands before that time looked and acted more like chimpanzees than humans. They were short and short-legged; females weighed only about 60 pounds, males about twice as much. They had large faces, mouths, teeth, and guts, and arms and shoulders that were well adapted--like those of chimps--to hanging for hours in trees, where they could both forage for food and sleep. Then a markedly different creature suddenly emerged from one of the australopithecine populations, and within 100,000 years had spread from Africa to Europe and probably Asia. Homo erectus looked so much like modern humans, Wrangham says, that "if you dressed one in clothes, put a hat on her, and walked her down a Manhattan street, she wouldn't draw too many stares."

In a Current Anthropology article published last December, Wrangham and coauthors James Holland Jones, assistant senior tutor in Mather House, Greg Laden of the University of Minnesota, Ford professor of the social sciences David Pilbeam, and research assistant Nancylou Conklin-Brittain advance a new theory to account for the sudden change. They suggest that the discovery of fire and its corollary, cooking, occurred much earlier in prehistory than generally believed--and furthermore, that the innovation of cooking fundamentally reshaped the body. "All humans cook, and cooking has such big effects on what you can digest that it would necessarily have major impact on any species that adopts it," Wrangham explains. "Things like the shape and size of teeth, for example, are closely adapted to what you eat. But until now, no one has suggested any time [frame for] when cooking evolved that coincides with big changes in the morphology of the body."

The cooking hypothesis is bold because scholars routinely link the origin of cooking to archaeological indications of fire--and there is scant evidence for human control of fire earlier than 300,000 to 400,000 years ago. "But," says Wrangham, "fire doesn't leave much behind in the archaeological record." Furthermore, recent thermal and paleomagnetic data obtained from reddened patches of rock in Kenya suggest the existence of hearths as old as 1.6 million years. "We know that the environment was getting drier [1.9 million years ago]," Wrangham says, "so lightning, for example, would start natural fires. One can imagine a root being cooked by chance, then found and eaten by an australopithecine who liked it."

"Most foraging peoples live under nutritional stress," Pilbeam notes, and cooking expands the range of edible food and improves its overall quality. Wrangham explains, "Cooking breaks down indigestible molecules and makes them digestible. Starch in uncooked roots, for example, is often in a crystalline form. Until it's heated, our digestive systems can't use it." That means our ancestors could obtain as much nutrition from one roasted tuber as they could from several raw ones, and therefore needed to eat less. Consequently, over time, they might have developed smaller, flatter guts and the inward-tilting ribs seen in homo erectus. Cooking also softens food, diminishing the need for big teeth that can shear and pulverize. Indeed, with the emergence of homo erectus, "You see a greater reduction in the size of teeth than at any other point in our ancestry," Wrangham says. Smaller teeth also mean smaller faces, as well as much smaller mouths. And controlled fire would also help defend against night predators, a necessity for creatures who were now sleeping not in trees, but on the ground.

Where foraging apes usually pop food immediately into their mouths, the advent of cooking--a time-consuming activity--meant that hominids had to wait while the foods that they had collected were readied for eating. (The first "homes" were probably pantries at hearthsides.) But with waiting comes the possibility of theft. "The female suddenly becomes vulnerable to a new problem--she can easily lose her food to the much larger, dominant Australopithecus males who might steal it, profiting from her hours of foraging effort," Wrangham says. Pilbeam adds, "She would have an incentive to attach herself to a male defender who could guard the food supply. This could be the point at which human monogamy first occurred."

Under these conditions, females would compete with each other for the best male protectors, in terms of both their strength and agility and their ability to summon allies. The researchers speculate that to attract such males to their hearths, these early women became "sexier," evolving an extended period of sexual desirability, including the concealed ovulatory pattern of human females, and copulating throughout the menstrual cycle. "The theft hypothesis portrays the human family as originating in a swirl of sexual and domestic politics around a kitchen hearth," writes Wrangham, who later adds a classical allusion: "Prometheus is said to have created humans by quickening clay figures with fire. If the foraging and mating systems of humans were indeed shaped powerfully by cooking, the ancient Greek myth may have been close to the truth."