The control of fire by early humans was a critical technology enabling the
evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
of
humans" \n\n\n\n\nThe robots exclusion standard, also known as the robots exclusion protocol or simply robots.txt, is a standard used by websites to indicate to visiting web crawlers and other web robots which portions of the site they are allowed to visi ...
.
Fire
Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.
At a certain point in the combustion reaction, called the ignition point, flames ...
lighting
Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing dayl ...
, protection from predators (especially at night), a way to create more advanced
hunting
Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...
tools, and a method for cooking food. These cultural advances allowed human geographic dispersal, cultural innovations, and changes to diet and behavior. Additionally, creating fire allowed human activity to continue into the dark and colder hours of the evening.
Claims for the earliest definitive evidence of control of fire by a member of ''
Homo
''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely rela ...
'' range from 1.7 to 2.0 million years ago ( Mya). Evidence for the "microscopic traces of wood ash" as controlled use of fire by ''
Homo erectus
''Homo erectus'' (; meaning "upright man") is an extinct species of archaic human from the Pleistocene, with its earliest occurrence about 2 million years ago. Several human species, such as '' H. heidelbergensis'' and '' H. antecessor ...
'', beginning roughly 1 million years ago, has wide scholarly support. Some of the earliest known traces of controlled fire were found at the
Daughters of Jacob Bridge
Daughters of Jacob Bridge ( he, גשר בנות יעקב, ''Gesher Bnot Ya'akov''; ar, جسر بنات يعقوب, ''Jisr Benat Ya'kub''). is a bridge that spans the last natural ford of the Jordan at the southern end of the Hula Basin between ...
,
Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
, and dated to 790,000 years ago.
Flint blades burned in fires roughly 300,000 years ago were found near fossils of early but not entirely modern ''
Homo sapiens
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture ...
'' in
Morocco
Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to A ...
. 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 widespread control of fire by anatomically modern humans dates to approximately 125,000 years ago.
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 common, to
savanna
A savanna or savannah is a mixed woodland- grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground ...
(mixed grass/woodland) where wildfires were of higher intensity. Such a change may have occurred about 3 million years ago, when the savanna expanded in
East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa:
Due to the historica ...
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 (a variety of ''
Pan troglodytes verus
The western chimpanzee, or West African chimpanzee, (''Pan troglodytes verus'') is a Critically Endangered subspecies of the common chimpanzee. It inhabits western Africa, specifically Côte d'Ivoire, Guinea, Liberia, Mali, Senegal, Ghana, Gu ...
''),vervet monkeys (''Cercopithecus aethiops'') 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 were 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 (such as the dry 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 (as in a
bow drill
A bow drill is a simple hand-operated type of tool, consisting of a rod (the ''spindle'' or ''drill shaft'') that is set in rapid rotary motion by means of a cord wrapped around it, kept taut by a bow which is pushed back and forth with one ha ...
), was a later development.
Each of these stages could occur at different intensities, ranging from occasional or " opportunistic" to "habitual" to "obligate" (unable to survive without it).
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 exist, such as natural processes, for the findings. Recent findings support that the earliest known controlled use of fire took place in Wonderwerk Cave,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...
, 1.0 Mya.
Africa
Findings from the Wonderwerk Cave site, in the Northern Cape province of South Africa, provide the earliest evidence for controlled use of fire. Intact sediments were analyzed using micromorphological analysis and Fourier transform infrared microspectroscopy (mFTIR) and 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
Olorgesailie is a geological formation in East Africa, on the floor of the Eastern Rift Valley in southern Kenya, southwest of Nairobi along the road to Lake Magadi. It contains a group of Lower Paleolithic archaeological sites. Olorgesailie ...
in
Kenya
)
, national_anthem = " Ee Mungu Nguvu Yetu"()
, image_map =
, map_caption =
, image_map2 =
, capital = Nairobi
, coordinates =
, largest_city = Nairobi
, ...
, show some 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
''Homo erectus'' (; meaning "upright man") is an extinct species of archaic human from the Pleistocene, with its earliest occurrence about 2 million years ago. Several human species, such as '' H. heidelbergensis'' and '' H. antecessor ...
'' 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 several burned bones, including ones with hominin-inflicted cut marks, along with Acheulean and bone tools. This site also 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 at a site in Olorgesailie, Kenya. However, it did not contain any
charcoal
Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, ...
, 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
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...
, fragments of
welded tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...
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 are also found in Awash Valley, but volcanic welded tuff is also found in the area, which could explain the burned stones.
Burned flints discovered near
Jebel Irhoud
Jebel Irhoud or Adrar n Ighoud ( zgh, ⴰⴷⵔⴰⵔ ⵏ ⵉⵖⵓⴷ, Adrar n Iɣud; ar, جبل إيغود, žbəl iġud), is an archaeological site located just north of the locality known as Tlet Ighoud, approximately south-east of the cit ...
, 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
Jean-Jacques Hublin (born 30 November 1953) is a French paleoanthropologist. He is a professor at the Max Planck Society, Leiden University and the University of Leipzig and the founder and director of the Department of Human Evolution at the ...
believes the flints were used as spear tips and left in fires used by the early humans for cooking food.
Asia
In
Xihoudu
Xihoudu () is an archeological site located in the Shanxi Province of China. The site dates to the Paleolithic Age. In total 32 stone implements were found at the site. Discovery
In 1929, Chinese prehistoric archaeologist and paleontologist Profes ...
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
, the black, blue, and grayish-green discoloration of mammalian bones found at the site illustrates the evidence of burning by early hominids. In 1985, at a parallel site in China, Yuanmou in
Yunnan Province
Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the ...
, archaeologists found blackened mammal bones that date back to 1.7 Mya.
Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
, has been claimed to show that '' H. erectus'' or ''
H. ergaster
''Homo ergaster'' is an extinct species or subspecies of archaic humans who lived in Africa in the Early Pleistocene. Whether ''H. ergaster'' constitutes a species of its own or should be subsumed into ''H. erectus'' is an ongoing and unresolv ...
'' controlled fires between 790,000 and 690,000 BP. An AI powered spectroscopy in archaeology has helped researchers unearth hidden evidence of the use of fire by humans dating 800,000 and 1 million years ago. In an article published in June 2022, researchers from Weizmann Institute of Science, who pioneered the AI application, along with researchers at 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 that the tools were heated up to 600°C.
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
, burned wood has been found in layers that carried ''H. erectus'' (
Java Man
Java Man (''Homo erectus erectus'', formerly also ''Anthropopithecus erectus'', ''Pithecanthropus erectus'') is an early human fossil discovered in 1891 and 1892 on the island of Java (Dutch East Indies, now part of Indonesia). Estimated to be b ...
) 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 (200,000 to 58,000 BP) and the Klasies River Mouth (130,000 to 120,000 BP).
Strong evidence comes from Kalambo Falls in
Zambia
Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are t ...
, 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
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
The method was de ...
Stillbay
The Stillbay (also Still bay) industry is the name given by archaeologists A. J. H. Goodwin and C. van Riet Lowe in 1929 to a Middle Stone Age stone tool manufacturing style after the site of Stilbaai (also called Still Bay) in South Africa where ...
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
Zhoukoudian Area () is a town and an area located on the east Fangshan District, Beijing, China. It borders Nanjiao and Fozizhuang Townships to its north, Xiangyang, Chengguan and Yingfeng Subdistricts to its east, Shilou and Hangcunhe Towns t ...
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 extracts from the bones were determined to be characteristic of burned bone rather than manganese staining. These residues also showed IR spectra for oxides, and a bone that was turquoise was reproduced in the laboratory by heating some of the other bones found in Layer 10. At the site, the same effect might have been due to natural heating, as the effect was produced on white, yellow, and black bones.
Layer 10 itself is described as 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
Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...
artifacts at least shows that humans did control fire at the time of the habitation of the Zhoukoudian cave.
Middle East
At the Amudian site of Qesem Cave, near the city of Kfar Qasim, Israel, evidence exists of the regular use of fire from before 382,000 BP to around 200,000 BP, at the end of Lower Pleistocene. Large quantities of burned bone and moderately heated soil lumps were found, and the cut marks found on the bones suggest that butchering and prey-defleshing took place near fireplaces. In addition, hominins living in Qesem cave managed to heat their flint to varying temperatures before knapping it into different tools.
Indian Subcontinent
The earliest evidence for controlled fire use by humans on the
Indian subcontinent
The Indian subcontinent is a physiographical region in Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian Ocean from the Himalayas. Geopolitically, it includes the countries of Bangladesh, Bhutan, In ...
, dating to between 50,000 and 55,000 years ago, comes from the Main Belan archaeological site, located in the
Belan River
Belan river (बेलन नदी) is a river in Indian state of Uttar Pradesh.it Originates from Western part of Sonbhadra district Uttar Pradesh.It is famous for prehistoric sites on its banks.
Origination
It originates from western part of S ...
valley in
Uttar Pradesh
Uttar Pradesh (; , 'Northern Province') is a state in northern India. With over 200 million inhabitants, it is the most populated state in India as well as the most populous country subdivision in the world. It was established in 195 ...
,
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...
.
Europe
Multiple sites in Europe, such as Torralba and Ambrona, Spain, and St. Esteve-Janson, France, have also shown evidence of use of fire by later versions of ''H. erectus''. The oldest has been found in
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...
at the site of Beeches Pit,
Suffolk
Suffolk () is a ceremonial county of England in East Anglia. It borders Norfolk to the north, Cambridgeshire to the west and Essex to the south; the North Sea lies to the east. The county town is Ipswich; other important towns include ...
; uranium series dating and
thermoluminescence dating
Thermoluminescence dating (TL) is the determination, by means of measuring the accumulated radiation dose, of the time elapsed since material containing crystalline minerals was either heated ( lava, ceramics) or exposed to sunlight ( sed ...
place the use of fire at 415,000 BP. At
Vértesszőlős
Vértesszőlős is a village in Komárom-Esztergom county, Hungary. It is most known for the archaeological site where a Middle Pleistocene human fossil, known as " Samu", was found.
History Prehistory
Vértesszőlős sits at the foot of the ...
,
Hungary
Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Cr ...
, while no charcoal has been found, burned bones have been discovered dating from c. 350,000 years ago. At Torralba and
Ambrona
Torralba and Ambrona (Province of Soria, Castile and León, Spain) are two paleontological and archaeological sites that correspond to various fossiliferous levels with Acheulean lithic industry (Lower Paleolithic) associated, at least about 350 ...
,
Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = '' Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, ...
, objects such as Acheulean stone tools, remains of large mammals such as extinct elephants, charcoal, and wood were discovered. At Terra Amata in
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, there is a fireplace with ashes (dated between 380,000 BP and 230,000 BP). At Saint-Estève-Janson in
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, there is evidence of five hearths and reddened earth in the Escale Cave; these hearths have been dated to 200,000 BP. Evidence for fire making dates to at least the Middle Paleolithic, with dozens of
Neanderthal
Neanderthals (, also ''Homo neanderthalensis'' and erroneously ''Homo sapiens neanderthalensis''), also written as Neandertals, are an Extinction, extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ag ...
hand axe
A hand axe (or handaxe or Acheulean hand axe) is a prehistoric stone tool with two faces that is the longest-used tool in human history, yet there is no academic consensus on what they were used for. It is made from stone, usually flint or ...
s from France exhibiting use-wear traces suggesting these tools were struck with the mineral
pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic Luster (mineralogy), lust ...
to produce sparks around 50,000 years ago.
Impact on human evolution
Cultural innovation
Uses of fire by early humans
The discovery of fire came to provide a wide variety of uses for early hominids. Its warmth kept them alive during low nighttime temperatures in colder environments, allowing geographic expansion from
tropic
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
al and subtropical climates to temperate areas. Its blaze warded off predatory animals, especially in the dark.
Fire also played a major role in changing food habits. Cooking allowed a significant increase in meat consumption and calorie intake. It was soon discovered that meat could also be dried and smoked by fire, preserving it for lean seasons. Fire was even used in manufacturing
tool
A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many animals use simple tools, only human beings, whose use of stone tools dates b ...
s for hunting and butchering. Hominids also learned that starting brush fires to burn large areas could increase land fertility and clear terrain to make hunting easier. Evidence shows that early hominids were able to corral and trap prey animals by means of fire. Fire was used to clear out caves prior to living in them, helping to begin the use of shelter. The many uses of fire may have led to specialized social roles, such as the separation of cooking from hunting.
The control of fire enabled important changes in human behavior, health, energy expenditure, and geographic expansion. They could move into much colder regions that would have previously been uninhabitable after the loss of body hair. Evidence of more complex management to change
biome
A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader ...
s can be found as far back as 200,000 to 100,000 years ago at a minimum.
Tool and weapon making
Fire also allowed major innovations in tool and weapon manufacture. In an archeological dig that dates to around 400,000 years ago, researchers excavating in the 'Spear Horizon' in
Schöningen
Schöningen is a town of about 11,000 inhabitants in the district of Helmstedt, in Lower Saxony, Germany.
Geography
The town is located on the southeastern rim of the Elm hill range, near the border with the state of Saxony-Anhalt. In its cur ...
, Germany, unearthed eight wooden
spear
A spear is a pole weapon consisting of a shaft, usually of wood, with a pointed head. The head may be simply the sharpened end of the shaft itself, as is the case with fire hardened spears, or it may be made of a more durable material fastene ...
s among a trove of preserved artifacts. The spears were found along with stone tools and horse remains, one of which still had a spear through its pelvis. At another dig site located in Lehringen, Germany, a fire-hardened lance was found thrust into the rib cage of a '
straight-tusked elephant
The straight-tusked elephant (''Palaeoloxodon antiquus'') is an extinct species of elephant that inhabited Europe and Western Asia during the Middle and Late Pleistocene (781,000–30,000 years before present). Recovered individuals have re ...
'. These archeological digs provide evidence that the spears were deliberately fire-hardened, allowing early humans to use the spears as thrusting rather than throwing weapons. Researchers further uncovered environmental evidence that these early hunters may have hidden in ambush.
More recent evidence dating to roughly 164,000 years ago indicates that early humans in
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...
during the Middle Stone Age used fire to alter the mechanical properties of tool materials applying heat treatment to a fine-grained rock called silcrete. The heated rocks were then tempered into crescent-shaped blades or arrowhead for hunting and butchering prey. This may have been the first time that
bow and arrow
The bow and arrow is a ranged weapon system consisting of an elastic launching device (bow) and long-shafted projectiles (arrows). Humans used bows and arrows for hunting and aggression long before recorded history, and the practice was common ...
were used for hunting, with far-ranging impact.
Art and ceramics
Fire was also used in the creation of art. Archaeologists have discovered several 1- to 10-inch Venus figurine statues in Europe dating to the
Paleolithic
The Paleolithic or Palaeolithic (), also called the Old Stone Age (from Greek: παλαιός '' palaios'', "old" and λίθος ''lithos'', "stone"), is a period in human prehistory that is distinguished by the original development of stone too ...
, several carved from stone and ivory, others shaped from
clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4).
Clays develop plasticity when wet, due to a molecular film of water surrounding the clay pa ...
and then fired. These are some of the earliest examples of ceramics. Fire was also commonly used to create
pottery
Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and ...
. Although pottery was formerly thought to have begun with the Neolithic around 10,000 years ago, scientists in
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
discovered pottery fragments in the
Xianrendong
The Xianren Cave (, ''Xiānréndòng''), together with the nearby Diaotonghuan (, ''Diàotǒnghuán'') rock shelter, is an archaeological site in Dayuan Township (), Wannian County in the Jiangxi province, China and a location of historically imp ...
Cave that were about 20,000 years old. During the
Neolithic Age
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several pa ...
and agricultural revolution about 10,000 years ago, pottery became far more common and widespread, often carved and painted with simple linear designs and geometric shapes.
Social development and nighttime activity
Fire was an important factor in expanding and developing societies of early hominids. One impact fire might have had was
social stratification
Social stratification refers to a society's categorization of its people into groups based on socioeconomic factors like wealth, income, race, education, ethnicity, gender, occupation, social status, or derived power (social and politi ...
. The power to make and wield fire may have conferred prestige and social position. Fire also led to a lengthening of daytime activities, and allowed more nighttime activities. Evidence of large hearths indicate that the majority of nighttime was spent around the fire. The increased social interaction from gathering around the fire may have fostered the development of language.
Another effect of fire use on hominid societies was that it required larger groups to work together to maintain the fire, finding fuel, portioning it onto the fire, and re-igniting it when necessary. These larger groups might have included older individuals such as grandparents, who helped to care for children. Ultimately, fire had a significant influence on the size and social interactions of early hominid communities.
Exposure to artificial light during later hours of the day changed humans'
circadian rhythm
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., endogenous) and responds to ...
s, contributing to a longer waking day. The modern human's waking day is 16 hours, while many mammals are only awake for half as many hours. Additionally, humans are most awake during the early evening hours, while other primates' days begin at dawn and end at sundown. Many of these behavioral changes can be attributed to the control of fire and its impact on daylight extension.
The cooking hypothesis
The cooking hypothesis proposes the idea that the ability to cook allowed for the brain size of hominids to increase over time. This idea was first presented by
Friedrich Engels
Friedrich Engels ( ,"Engels" '' The Part Played by Labour in the Transition from Ape to Man" and later recapitulated in the book '' Catching Fire: How Cooking Made Us Human'' by Richard Wrangham and then in a book by Suzana Herculano-Houzel. Critics of the hypothesis argue that cooking with controlled fire was insufficient to start the increasing brain size trend.
The cooking hypothesis gains support by comparing the nutrients in raw food to the much more easily digested nutrients in cooked food, as in an examination of protein ingestion from raw vs. cooked egg. Scientists have found that among several primates, the restriction of feeding to raw foods during daylight hours limits the metabolic energy available. Genus ''
Homo
''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely rela ...
'' was able to break through the limit by cooking food to shorten their feeding times and be able to absorb more nutrients to accommodate the increasing need for energy. In addition, scientists argue that the ''Homo'' species was also able to obtain nutrients like docosahexaenoic acid from algae that were especially beneficial and critical for brain evolution, and the detoxification of food by the cooking process enabled early humans to access these resources.
Besides the brain, other human organs also demand a high
metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run ...
. During human evolution, the body-mass proportion of different organs changed to allow brain expansion.
Changes to diet
Before the advent of fire, the hominid diet was limited to mostly plant parts composed of simple sugars and
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may o ...
s such as seeds, flowers, and fleshy fruits. Parts of the plant such as stems, mature leaves, enlarged roots, and tubers would have been inaccessible as a food source due to the indigestibility of raw
cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
and
starch
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human die ...
. Cooking, however, made starchy and fibrous foods edible and greatly increased the diversity of other foods available to early humans. Toxin-containing foods including seeds and similar carbohydrate sources, such as cyanogenic glycosides found in linseed and
cassava
''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated ...
, were incorporated into their diets as cooking rendered them nontoxic.
Cooking could also kill parasites, reduce the amount of energy required for chewing and digestion, and release more nutrients from plants and meat. Due to the difficulty of chewing raw meat and digesting tough proteins (e.g. collagen) and carbohydrates, the development of cooking served as an effective mechanism to efficiently process meat and allow for its consumption in larger quantities. With its high caloric density and content of important nutrients, meat thus became a staple in the diet of early humans. By increasing digestibility, cooking allowed hominids to maximize the energy gained from consuming foods. Studies show that caloric intake from cooking starches improves 12-35% and 45-78% for protein. As a result of the increases in net energy gain from food consumption, survival and reproductive rates in hominids increased. Through lowering food toxicity and increasing nutritive yield, cooking allowed for an earlier weaning age, permitting females to have more children. In this way, too, it facilitated population growth.
It has been proposed that the use of fire for cooking caused environmental toxins to accumulate in the placenta, which led to a species-wide taboo on
human placentophagy
Human placentophagy, or consumption of the placenta, is defined as "the ingestion of a human placenta postpartum, at any time, by any person, either in raw or altered (e.g., cooked, dried, steeped in liquid) form". While there are several anecdotes ...
around the time of the mastery of fire. Placentophagy is common in other primates.
Biological changes
Before their use of fire, the hominid species had large premolars, which were used to chew harder foods, such as large seeds. In addition, due to the shape of the molar cusps, the diet is inferred to have been more leaf- or fruit-based. Probably in response to consuming cooked foods, the molar teeth of ''H. erectus'' gradually shrank, suggesting that their diet had changed from tougher foods such as crisp root vegetables to softer cooked foods such as meat. Cooked foods further selected for the differentiation of their teeth and eventually led to a decreased jaw volume with a variety of smaller teeth in hominids. Today, a smaller jaw volume and teeth size of humans is seen in comparison to other primates.
Due to the increased digestibility of many cooked foods, less digestion was needed to procure the necessary nutrients. As a result, the gastrointestinal tract and organs in the digestive system decreased in size. This is in contrast to other primates, where a larger digestive tract is needed for fermentation of long carbohydrate chains. Thus, humans evolved from the large colons and tracts that are seen in other primates to smaller ones.
According to Wrangham, control of fire allowed hominids to sleep on the ground and in caves instead of trees and led to more time being spent on the ground. This may have contributed to the evolution of bipedalism, as such an ability became increasingly necessary for human activity.
Criticism
Critics of the hypothesis argue that while a linear increase in brain volume of the genus ''Homo'' is seen over time, adding fire control and cooking does not add anything meaningful to the data. Species such as ''H. ergaster'' existed with large brain volumes during time periods with little to no evidence of fire for cooking. Little variation exists in the brain sizes of ''H. erectus'' dated from periods of weak and strong evidence for cooking. An experiment involving mice fed raw versus cooked meat found that cooking meat did not increase the amount of calories taken up by mice, leading to the study's conclusion that the energetic gain is the same, if not greater, in raw meat diets than cooked meats. Studies such as this and others have led to criticisms of the hypothesis that state that the increases in human brain-size occurred well before the advent of cooking due to a shift away from the consumption of nuts and berries to the consumption of meat. Other anthropologists argue that the evidence suggests that cooking fires began in earnest only 250,000 BP, when ancient hearths, earth ovens, burned animal bones, and flint appear across Europe and the Middle East.
See also
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Hunting hypothesis
In paleoanthropology, the hunting hypothesis is the hypothesis that human evolution was primarily influenced by the activity of hunting for relatively large and fast animals, and that the activity of hunting distinguished human ancestors from ot ...
National Museum of Natural History
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7. ...
Fire
Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.
At a certain point in the combustion reaction, called the ignition point, flames ...
Fire
Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.
At a certain point in the combustion reaction, called the ignition point, flames ...