Control of fire by early humans

The control of fire by early humans was a critical technology enabling the evolution of humans. Fire provided a source of warmth and lighting, protection from predators, a way to create more advanced hunting tools, and a method for cooking food. These cultural advances allowed human geographic dispersal, cultural innovations, and changes to diet and behavior. Additionally, the ability to start fires allowed human activity to continue into the darker and colder hours of the evening.
Evidence for using fire versus fire-making follow different timelines, as the earliest human fires were probably embers taken from wildfires ignited by lightning and carried back to a cave. Claims for the earliest definitive evidence of using fire by a member of Homo range from 1.7 to 2.0 million years ago. Evidence for the "microscopic traces of wood ash" as use of fire by Homo erectus, beginning roughly 1 million years ago, has scholarly support. Some of the earliest known traces of fire usage was found at the Daughters of Jacob Bridge, Israel/Golan Heights, and dated to ~790,000 years ago. At the site, archaeologists also found the oldest likely evidence for the controlled use of fire to cook food ~780,000 years ago. However, some studies suggest cooking started as early as ~1.8 million years ago.
The oldest definitive evidence for fire making, igniting a new fire, dates to about 400,000 years ago at a Neanderthal site in eastern England where burnt soil was found along with fire-cracked flint handaxes and two fragments of iron pyrite, used to strike sparks with flint. Fire was used regularly and systematically by early modern humans to heat treat silcrete stone to increase its flake-ability for the purpose of toolmaking approximately 164,000 years ago at the South African site of Pinnacle Point. Evidence of the use of controlled fire becomes far more widespread, frequent, and convincing between 300,000 and 400,000 years ago and becomes nearly as universal in its use by anatomically modern humans around 125,000 to 120,000 years ago as its use in the modern day.

Control of fire

The use and control of fire was a gradual process proceeding through more than one stage. One was a change in habitat, from dense forest where wildfires were rare but difficult to escape, to savanna where wildfires were common but easier to survive. Such a change may have occurred about 3 million years ago, when the savanna expanded in East Africa due to cooler and drier climate.
The next stage involved interaction with burned landscapes and foraging in the wake of wildfires, as observed in various wild animals. In the African savanna, animals that preferentially forage in recently burned areas include savanna chimpanzees, vervet monkeys and a variety of birds, some of which also hunt insects and small vertebrates in the wake of grass fires.
The next step would be to make some use of residual hot spots that occur in the wake of wildfires. For example, foods found in the wake of wildfires tend to be either burned or undercooked. This might have provided incentives to place undercooked foods on a hotspot or to pull food out of the fire if it was in danger of getting burned. This would require familiarity with fire and its behavior.
An early step in the control of fire would have been transporting it from burned to unburned areas and lighting them on fire, providing advantages in food acquisition. Maintaining a fire over an extended period of time, as for a season, may have led to the development of base campsites. Building a hearth or other fire enclosure such as a circle of stones would have been a later development. The ability to make fire, generally with a friction device with hardwood rubbing against softwood, was a later development.
Each of these stages could occur at different intensities, ranging from occasional or "opportunistic" to "habitual" to "obligate".

Lower Paleolithic evidence

Most of the evidence of controlled use of fire during the Lower Paleolithic is uncertain and has limited scholarly support. Some of the evidence is inconclusive because other plausible explanations, such as natural processes, exist for the findings. Findings support that the earliest known controlled use of fire took place in Wonderwerk Cave, South Africa, 1.0 Mya.

Africa

Findings from Wonderwerk provide the earliest evidence for controlled use of fire. Intact sediments were analyzed using micromorphological analysis. Fourier transform infrared microspectroscopy yielded evidence, in the form of burned bones and ashed plant remains, that burning took place at the site 1.0 Mya.
East African sites, such as Chesowanja near Lake Baringo, Koobi Fora, and Olorgesailie in Kenya, show possible evidence that fire was controlled by early humans. In Chesowanja, archaeologists found red clay clasts dated to 1.4 Mya. These clasts must have been heated to to harden. However, tree stumps burned in bush fires in East Africa produce clasts, which, when broken by erosion, are like those described at Chesownja. Controlled use of fire at Chesowanja is unproven.
In Koobi Fora, sites show evidence of control of fire by Homo erectus at 1.5 Mya with findings of reddened sediment that could come from heating at. Evidence of possible human control of fire, found at Swartkrans, South Africa, includes burned bones, including ones with hominin-inflicted cut marks, along with Acheulean and bone tools. This site shows some of the earliest evidence of carnivorous behavior in H. erectus. A "hearth-like depression" that could have been used to burn bones was found in Olorgesailie, Kenya. However, it did not contain any charcoal, and no signs of fire have been observed. Some microscopic charcoal was found, but it could have resulted from a natural brush fire.
In Gadeb, Ethiopia, fragments of welded tuff that appeared to have been burned were found in Locality 8E but refiring of the rocks might have occurred due to local volcanic activity.
In the Middle Awash River Valley, cone-shaped depressions of reddish clay were found that could have been formed by temperatures of. These features, thought to have been created by burning tree stumps, were hypothesized to have been produced by early hominids lighting tree stumps so they could have fire away from their habitation site. This view is not widely accepted, though. Burned stones were found in Awash Valley, but volcanic welded tuff is found in the area, which could explain the burned stones.
Burned flints discovered near Jebel Irhoud, Morocco, dated by thermoluminescence to around 300,000 years old, were discovered in the same sedimentary layer as skulls of early Homo sapiens. Paleoanthropologist Jean-Jacques Hublin believes the flints were used as spear tips and left in fires used by the early humans for cooking food.

Asia

In Xihoudu in Shanxi Province, China, the black, blue, and grayish-green discoloration of mammalian bones found at the site illustrates evidence of burning by early hominids. In 1985, at a parallel site in China, Yuanmou in Yunnan Province, archaeologists found blackened mammal bones that date back to 1.7 Mya.

Middle East

A site at Bnot Ya'akov Bridge, Israel, has been claimed to show that H. erectus or H. ergaster controlled fires between 790,000 and 690,000 BP. An AI-powered spectroscopy helped researchers unearth evidence of the use of fire dating 800,000 and 1 million years ago. In an article published in June 2022, researchers from Weizmann Institute of Science, along with researchers at the University of Toronto and Hebrew University of Jerusalem described the use of deep learning models to analyze heat exposure of 26 flint tools that were found in 1970s at the Evron Quarry in the northwest of Israel. The results showed the tools were heated up to 600 °C.

Southeast Asia

At Trinil, Java, burned wood has been found in layers that carried H. erectus fossils dating from 830,000 to 500,000 BP. The burned wood has been claimed to indicate the use of fire by early hominids.

Middle Paleolithic evidence

Africa

The Cave of Hearths in South Africa has burn deposits, which date from 700,000 to 200,000 BP, as do various other sites such as Montagu Cave and the Klasies River Mouth.
Strong evidence comes from Kalambo Falls in Zambia, where several artifacts related to the use of fire by humans have been recovered, including charred logs, charcoal, carbonized grass stems and plants, and wooden implements, which may have been hardened by fire. The site has been dated through radiocarbon dating to 180,000 BP, through amino-acid racemization.
Fire was used for heat treatment of silcrete stones to increase their workability before they were knapped into tools by Stillbay culture in South Africa. These Stillbay sites date back from 164,000 to 72,000 years ago, with the heat treatment of stone beginning by about 164,000 years ago.

Asia

Evidence at Zhoukoudian cave in China suggests control of fire as early as 460,000 to 230,000 BP. Fire in Zhoukoudian is suggested by the presence of burned bones, burned chipped-stone artifacts, charcoal, ash, and hearths alongside H. erectus fossils in Layer 10, the earliest archaeological horizon at the site. This evidence comes from Locality 1, also known as the Peking Man site, where several bones were found to be uniformly black to grey. The bone extracts were determined to be characteristic of burned bone rather than manganese staining. These residues also showed IR spectra for oxides, and a turquoise bone was reproduced in the laboratory by heating some of the other bones found in Layer 10. The same effect might have been at the site due to natural heating, as the effect was produced on white, yellow, and black bones.
Layer 10 is ash with biologically produced silicon, aluminum, iron, and potassium, but wood ash remnants such as siliceous aggregates are missing. Among these are possible hearths "represented by finely laminated silt and clay interbedded with reddish-brown and yellow-brown fragments of organic matter, locally mixed with limestone fragments and dark brown finely laminated silt, clay, and organic matter." The site itself does not show that fires were made in Zhoukoudian, but the association of blackened bones with quartzite artifacts at least shows that humans did control fire at the time of the habitation of the Zhoukoudian cave.