Control of fire by early humans

File:How (and when) did humans first make fire.webm)]]

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 (mixed grass/woodland) 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.{{cite journal| last1=Pruetz| first1=Jill D.| last2=Herzog| first2=Nicole M.| s2cid=148782684| title=Savanna Chimpanzees at Fongoli, Senegal, Navigate a Fire Landscape| journal=Current Anthropology| volume=58| year=2017| page=S000| issn=0011-3204| doi=10.1086/692112}}{{cite journal| last1=Parker| first1=Christopher H.| last2=Keefe| first2=Earl R.| last3=Herzog| first3=Nicole M.| last4=O'connell| first4=James F.| last5=Hawkes| first5=Kristen| title=The pyrophilic primate hypothesis| journal=Evolutionary Anthropology: Issues, News, and Reviews| volume=25| issue=2| year=2016| pages=54–63| issn=1060-1538| doi=10.1002/evan.21475| pmid=27061034| s2cid=22744464| url=https://www.researchgate.net/publication/301252297}}

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),{{cite journal| last1=Gowlett| first1=J. A. J.| title=The discovery of fire by humans: a long and convoluted process| journal=Philosophical Transactions of the Royal Society B: Biological Sciences| volume=371| issue=1696| year=2016| pages=20150164| issn=0962-8436| doi=10.1098/rstb.2015.0164| pmid=27216521| pmc=4874402}} vervet monkeys (Cercopithecus aethiops){{cite journal| last1=Herzog| first1=Nicole M.| last2=Parker| first2=Christopher H.| last3=Keefe| first3=Earl R.| last4=Coxworth| first4=James| last5=Barrett| first5=Alan| last6=Hawkes| first6=Kristen| title=Fire and home range expansion: A behavioral response to burning among savanna dwelling vervet monkeys (Chlorocebusaethiops)| journal=American Journal of Physical Anthropology| volume=154| issue=4| year=2014| pages=554–60| issn=0002-9483| doi=10.1002/ajpa.22550| pmid=24889076}} and a variety of birds, some of which also hunt insects and small vertebrates in the wake of grass fires.{{cite book| last=Burton| first=Frances D.| title=Fire: The Spark That Ignited Human Evolution| chapter-url=https://books.google.com/books?id=z2K7_I1zKhwC&pg=PT12| access-date=19 August 2017| date=29 September 2011| publisher=UNM Press| isbn=978-0-8263-4648-3| page=12| chapter=2}}

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.{{cite journal| last1=Gowlett| first1=J. A. J.| last2=Brink| first2=J. S.| last3=Caris| first3=Adam| last4=Hoare| first4=Sally| last5=Rucina| first5=S. M.| s2cid=164509111| title=Evidence of Burning from Bushfires in Southern and East Africa and Its Relevance to Hominin Evolution| journal=Current Anthropology| volume=58| issue=S16| year=2017| pages=S206–S216| issn=0011-3204| doi=10.1086/692249}}

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.{{cite journal| last1=Chazan| first1=Michael| title=Toward a Long Prehistory of Fire| journal=Current Anthropology| volume=58| year=2017| page=S000| issn=0011-3204| doi=10.1086/691988| s2cid=149271414}} The ability to make fire, generally with a friction device with hardwood rubbing against softwood (as in a bow drill), 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).

{{Human timeline}}

Most of the evidence of controlled use of fire during the Lower Paleolithic is uncertain and has limited scholarly support.{{Cite journal|last1=Berna|first1=Francesco|last2=Goldberg|first2=Paul|last3=Horwitz|first3=Liora Kolska|last4=Brink|first4=James|last5=Holt|first5=Sharon|last6=Bamford|first6=Marion|last7=Chazan|first7=Michael|date=15 May 2012|title=Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa|journal=Proceedings of the National Academy of Sciences|language=en|volume=109|issue=20|pages=E1215–20|doi=10.1073/pnas.1117620109|issn=0027-8424|pmc=3356665|pmid=22474385|doi-access=free}} 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.{{cite journal |last1=Gowlett |first1=J. A. J. |title=The discovery of fire by humans: a long and convoluted process |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |date=23 May 2016 |volume=371 |issue=1696 |pages=20150164 |doi=10.1098/rstb.2015.0164|pmid=27216521 |pmc=4874402 }}

Findings from Wonderwerk provide the earliest evidence for controlled use of fire. Intact sediments were analyzed using micromorphological analysis. Fourier transform infrared microspectroscopy ({{not a typo|mFTIR}}) 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 {{convert|400|C|round=25}} 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 {{convert|200|-|400|C|F|abbr=on|round=25}}. Evidence of possible human control of fire, found at Swartkrans, South Africa,Renfrew and Bahn (2004). Archaeology: Theories, Methods and Practice (Fourth Edition). Thames and Hudson, p. 341 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 {{convert|200|C|abbr=on|round=25}}. 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.

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.

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.{{cite news|first=Paul|last=Rincon|url=http://news.bbc.co.uk/2/hi/science/nature/3670017.stm | title=Early human fire skills revealed|work=BBC News | date=29 April 2004|access-date=12 November 2007}} An AI-powered spectroscopy helped researchers unearth evidence of the use of fire dating 800,000 and 1 million years ago.{{Cite web |title=The heat is on: Traces of fire uncovered dating back at least 800,000 years: Using advanced AI techniques, researchers discover one of the earliest pieces of evidence for the use of fire |url=https://www.sciencedaily.com/releases/2022/06/220627100154.htm |access-date=2022-07-08 |website=ScienceDaily |language=en}} In an article published in June 2022,{{Cite journal |last1=Stepka |first1=Zane |last2=Azuri |first2=Ido |last3=Horwitz |first3=Liora Kolska |last4=Chazan |first4=Michael |last5=Natalio |first5=Filipe |date=2022-06-21 |title=Hidden signatures of early fire at Evron Quarry (1.0 to 0.8 Mya) |journal=Proceedings of the National Academy of Sciences |language=en |volume=119 |issue=25 |pages=e2123439119 |doi=10.1073/pnas.2123439119 |doi-access=free |issn=0027-8424 |pmc=9231470 |pmid=35696581|bibcode=2022PNAS..11923439S }} 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.

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

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, 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.{{cite journal | last1 = Brown | first1 = KS | last2 = Marean | first2 = CW | last3 = Herries | first3 = AI | last4 = Jacobs | first4 = Z | last5 = Tribolo | first5 = C | last6 = Braun | first6 = D | last7 = Roberts | first7 = DL | last8 = Meyer | first8 = MC | last9 = Bernatchez | first9 = J | s2cid = 43916405 | year = 2009 | title = Fire As an Engineering Tool of Early Modern Humans | journal = Science | volume = 325 | issue = 5942| pages = 859–62 | doi = 10.1126/science.1175028 | pmid=19679810| bibcode = 2009Sci...325..859B | hdl = 11422/11102 | hdl-access = free }}{{cite journal | last1 = Webb | first1 = J. Domanski M. | year = 2009 | title = Fire and Stone | journal = Science | volume = 325 | issue = 5942| pages = 820–21 | doi = 10.1126/science.1178014 | pmid = 19679799 | bibcode = 2009Sci...325..820W | s2cid = 206521911 }}Callaway. E. (13 August 2009) [https://www.newscientist.com/article/dn17604-earliest-fired-knives-improved-stone-age-tool-kit.html Earliest fired knives improved stone age tool kit] New Scientist, online 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.

File:Zhoukoudian Caves July2004.jpg Caves, a World Heritage Site and an early site of human use of fire in China]]

Evidence at Zhoukoudian cave in China suggests control of fire as early as 460,000 to 230,000 BP.{{cite web|url=http://www.beyondveg.com/nicholson-w/hb/hb-interview2c.shtml|title=First Control of Fire by Human Beings – How Early?|access-date=12 November 2007}} 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.{{cite journal|last=Weiner|first=S.|year=1998|title=Evidence for the Use of Fire at Zhoukoudian, China|journal=Science|volume=281|issue=5374|pages=251–53|doi=10.1126/science.281.5374.251|pmid=9657718|author2=Q. Xu|author3=P. Goldberg|author4=J. Liu|author5=O. Bar-Yosef|bibcode=1998Sci...281..251W}} 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.{{Citation needed|date=June 2024}}

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.{{cite journal |vauthors=Karkanas P, Shahack-Gross R, Ayalon A |title=Evidence for habitual use of fire at the end of the Lower Paleolithic: site-formation processes at Qesem Cave, Israel |journal=J. Hum. Evol. |volume=53 |issue=2 |pages=197–212 |date=August 2007 |pmid=17572475 |doi=10.1016/j.jhevol.2007.04.002 |bibcode=2007JHumE..53..197K |url=http://www.tau.ac.il/humanities/archaeology/info/ran_barkai/HabitualUseofFireJHE2007.pdf|display-authors=etal}} In addition, hominins living in Qesem cave managed to heat their flint to varying temperatures before knapping it into different tools.{{cite journal |last1=Agam |first1=Aviad |last2=Azuri |first2=Ido |last3=Pinkas |first3=Iddo |last4=Gopher |first4=Avi |last5=Natalio |first5=Filipe |url=https://files.springernature.com/getResource/Full%20text%3A%2041562_2020_Article_955.pdf?token=IULUvIufpS8AXE43riPpExKrcZMUcwpHIO0w4yhOno61RnG9Vz6%2Fr7GCrI5AcBi92o1n3tikPjKFkiYotkHNpNM75Zwrwg1JnULfD6ql3lbB4%2B2k4SPGekWdBGLFLq2puCh%2FZ3DLB4IVSRfpmhKqIEBM6VRi4TYfMGfmPXWr3JRHuW%2Fj5Wod1fsOibZcggI%2B6R1Se4bGQnT7HNP7lnlhp40M0VnqSPp7kwO%2Fuk2bUqy4COccDRtTVCPDgs7U4YSWRA6eUNeoCaxT6qM4JD785x3MLr9Sg3IyUT768TYA36RHaIKwhpKR5msxE9Z7qNrUmSnxANKxcm2QxaNEzOo9fA%3D%3D |title=Estimating temperatures of heated Lower Palaeolithic flint artefacts |journal=Nature Human Behaviour |year=2020 |volume=5 |issue=2 |pages=221–228 |doi=10.1038/s41562-020-00955-z |pmid=33020589 |s2cid=222160202 }}{{Dead link|date=May 2024 |bot=InternetArchiveBot |fix-attempted=yes }}

The earliest evidence for controlled fire use by humans on the Indian subcontinent, dating to between 50,000 and 55,000 years ago, comes from the Main Belan archaeological site, located in the Belan River valley in Uttar Pradesh, India.{{cite journal |last1=Jha |first1=Deepak Kumar |last2=Samrat |first2=Rahul |last3=Sanyal |first3=Prasanta |date=15 January 2021 |title=The first evidence of controlled use of fire by prehistoric humans during the Middle Paleolithic phase from the Indian subcontinent |url=https://www.sciencedirect.com/science/article/abs/pii/S003101822030599X |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=562 |page=110151 |doi=10.1016/j.palaeo.2020.110151 |bibcode=2021PPP...56210151J |s2cid=229392002 |access-date=5 November 2022}}

Multiple sites in Europe, such as Torralba and Ambrona, Spain, and St. Esteve-Janson, France, have also shown evidence of the use of fire by later versions of H. erectus. The oldest has been found in England at the site of Beeches Pit, Suffolk; uranium series dating and thermoluminescence dating place the use of fire at 415,000 BP.{{cite journal|last=Preece|first=R. C.|year=2006|title=Humans in the Hoxnian: habitat, context and fire use at Beeches Pit, West Stow, Suffolk, UK|journal=Journal of Quaternary Science|volume=21|issue=5|pages=485–96|doi=10.1002/jqs.1043|bibcode=2006JQS....21..485P|doi-access=free}} At Vértesszőlős, Hungary, while no charcoal has been found, burned bones have been discovered dating from c. 350,000 years ago. At Torralba and Ambrona, Spain, objects such as Acheulean stone tools, remains of large mammals such as extinct elephants, charcoal, and wood were discovered. At Terra Amata in France, there is a fireplace with ashes (dated between 380,000 BP and 230,000 BP). At Saint-Estève-Janson in France, 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 hand axes from France exhibiting use-wear traces suggesting these tools were struck with the mineral pyrite to produce sparks around 50,000 years ago.{{Cite journal|last1=Sorensen|first1=A. C.|last2=Claud|first2=E.|last3=Soressi|first3=M.|date=2018-07-19|title=Neandertal fire-making technology inferred from microwear analysis|journal=Scientific Reports|language=en|volume=8|issue=1|page=10065|doi=10.1038/s41598-018-28342-9|pmid=30026576|issn=2045-2322|pmc=6053370|bibcode=2018NatSR...810065S}}

The discovery of fire provided various uses for early hominids. Its warmth kept them alive during low nighttime temperatures in colder environments, allowing geographic expansion from tropical and subtropical climates to temperate areas. Its blaze warded off predatory animals, especially in the dark.{{Cite news|url=http://discovermagazine.com/2013/may/09-archaeologists-find-earliest-evidence-of-humans-cooking-with-fire|title=Archaeologists Find Earliest Evidence of Humans Cooking With Fire {{!}} DiscoverMagazine.com|newspaper=Discover Magazine|access-date=13 November 2016}}

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 be dried and smoked by fire, preserving it for lean seasons.{{Cite web|last=McKenna|first=Ryan|url=http://fubini.swarthmore.edu/~ENVS2/S2007/rmckenn1/FirstEssay.htm|title=Fire and {{sic|I|t's|nolink=y}} Value to Early Man|website=fubini.Swarthmore.edu|access-date=23 November 2017}} Fire was even used in manufacturing tools for hunting and butchering.{{Cite news|url=http://www.ibtimes.com/when-did-man-discover-fire-ancestors-modern-humans-used-fire-350000-years-ago-new-1758607|title=When Did Man Discover Fire? Ancestors of Modern Humans Used Fire 350,000 Years Ago, New Study Suggests|date=15 December 2014|newspaper=International Business Times|access-date=13 November 2016}} Hominids also learned that starting bushfires to burn large areas could increase land fertility and clear terrain to make hunting easier.{{Cite journal |last=Bellomo |first=Randy V. |date=1 July 1994 |title=Methods of determining early hominid behavioral activities associated with the controlled use of fire at FxJj 20 Main, Koobi Fora, Kenva |journal=Journal of Human Evolution |volume=27 |issue=1 |pages=173–195 |doi=10.1006/jhev.1994.1041|bibcode=1994JHumE..27..173B }} Evidence shows that early hominids were able to corral and trap prey animals using fire.{{citation needed|date=March 2020}} Fire was used to clear out caves before living in them, helping to begin the use of shelter.{{Cite book |last=Washburn |first=S. L. |url=https://books.google.com/books?id=aTNUAQAAQBAJ&q=early%20human%20hunting%20with%20fire&pg=PA176 |title=Social Life of Early Man |date=11 October 2013 |publisher=Routledge |isbn=978-1-136-54361-6 |language=en}} The many uses of fire may have led to specialized social roles, such as the separation of cooking from hunting.{{Cite news|url=https://www.nytimes.com/2016/08/09/science/fire-smoke-evolution-tuberculosis.html|title=Smoke, Fire and Human Evolution|last=Yin|first=Steph|date=5 August 2016|newspaper=The New York Times|issn=0362-4331|access-date=13 November 2016}}

The control of fire enabled important changes in human behavior, health, energy expenditure, and geographic expansion. After the loss of body hair, hominids could move into much colder regions that would have previously been uninhabitable. Evidence of more complex management to change biomes can be found as far back as 200,000 to 100,000 years ago, at minimum.

Fire allowed major innovations in tool and weapon manufacture. Evidence dating to roughly 164,000 years ago indicates that early humans in South Africa 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.{{Cite journal|last1=Delagnes|first1=Anne|last2=Schmidt|first2=Patrick|last3=Douze|first3=Katja|last4=Wurz|first4=Sarah|last5=Bellot-Gurlet|first5=Ludovic|last6=Conard|first6=Nicholas J.|last7=Nickel|first7=Klaus G.|last8=Niekerk|first8=Karen L. van|last9=Henshilwood|first9=Christopher S.|date=19 October 2016|title=Early Evidence for the Extensive Heat Treatment of Silcrete in the Howiesons Poort at Klipdrift Shelter (Layer PBD, 65 ka), South Africa|journal=PLOS ONE|volume=11|issue=10|pages=e0163874|doi=10.1371/journal.pone.0163874|issn=1932-6203|pmc=5070848|pmid=27760210|bibcode=2016PLoSO..1163874D|doi-access=free}} The heated rocks were then tempered into crescent-shaped blades or arrowheads for hunting and butchering prey. This may have been the first time that bow and arrow were used for hunting, with far-ranging impact.{{Cite web|url=http://www.uib.no/en/news/101760/early-humans-used-innovative-heating-techniques|title=Humans used fire earlier than previously known {{!}} University of Bergen|website=www.uib.no|access-date=13 November 2016}}

Fire was used in the creation of art. Archaeologists have discovered several 1- to 10-inch Venus figurine statues in Europe dating to the Paleolithic, several carved from stone and ivory, others shaped from clay and then fired. These are some of the earliest examples of ceramics.{{cite web|url=https://digital.library.txstate.edu/bitstream/handle/10877/3202/fulltext.pdf|title=Female Figurines of the Upper Paleolithic|website=TxState.Edu|publisher=Texas State University, San Marcos|last1=Jennett|first1=Karen|access-date=13 November 2016}} Fire was also commonly used to create pottery. Although pottery was formerly thought to have begun with the Neolithic around 10,000 years ago, scientists in China discovered pottery fragments in the Xianrendong Cave that were about 20,000 years old.{{cite web|url=http://popular-archaeology.com/issue/june-2012/article/the-earliest-known-pottery|title=The Earliest Known Pottery|publisher=Popular Archaeology|access-date=13 November 2016|archive-url=https://web.archive.org/web/20161108111906/http://popular-archaeology.com/issue/june-2012/article/the-earliest-known-pottery|archive-date=8 November 2016|url-status=dead}} During the Neolithic Age 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.{{cite web|url=http://www.sourcinginnovation.com/archaeology/Arch05.htm|title=What we know of early human society & behavior|website=Sourcing Innovation|last1=Lamoureux|first1=Michael|access-date=13 November 2016}}

Fire was an important factor in expanding and developing societies of early hominids. One impact fire might have had was social stratification. 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.{{Cite book|url=https://books.google.com/books?id=VEakAgAAQBAJ&pg=PA277|title=Lucy to Language: The Benchmark Papers|last1=Dunbar|first1=R. I. M.|last2=Gamble|first2=Clive|last3=Gowlett|first3=J. A. J.|date=13 November 2016|publisher=OUP Oxford|isbn=978-0-19-965259-4|language=en}} Evidence of large hearths indicate that the majority of nighttime was spent around the fire.{{Cite journal|last=Gowlett|first=J. a. J.|date=5 June 2016|title=The discovery of fire by humans: a long and convoluted process|journal=Phil. Trans. R. Soc. B|language=en|volume=371|issue=1696|pages=20150164|doi=10.1098/rstb.2015.0164|issn=0962-8436|pmc=4874402|pmid=27216521}} 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 significantly influenced the size and social interactions of early hominid communities.

Exposure to artificial light during later hours of the day changed humans' circadian rhythms, contributing to a longer waking day.{{Cite journal|last=Wiessner|first=Polly W.|date=30 September 2014|title=Embers of society: Firelight talk among the Ju/'hoansi Bushmen|journal=Proceedings of the National Academy of Sciences|language=en|volume=111|issue=39|pages=14027–14035|doi=10.1073/pnas.1404212111|issn=0027-8424|pmc=4191796|pmid=25246574|doi-access=free}} 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 proposes that the ability to cook allowed for the brain size of hominids to increase over time. This idea was first presented by Friedrich Engels in the article "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.{{Cite book|title=Human AdvantageA New Understanding of How Our Brain Became Remarkable – MIT Press Scholarship|last=Herculano-Houzel|first=Suzana|doi=10.7551/mitpress/9780262034258.001.0001|year = 2016|isbn = 978-0-262-03425-8}} 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.{{Cite journal|last1=Evenepoel|first1=Pieter|last2=Geypens|first2=Benny|last3=Luypaerts|first3=Anja|last4=Hiele|first4=Martin|last5=Ghoos|first5=Yvo|last6=Rutgeerts|first6=Paul|date=1 October 1998|title=Digestibility of Cooked and Raw Egg Protein in Humans as Assessed by Stable Isotope Techniques|journal=The Journal of Nutrition|language=en|volume=128|issue=10|pages=1716–1722|issn=0022-3166|pmid=9772141|doi=10.1093/jn/128.10.1716|doi-access=free}} Scientists have found that among several primates, the restriction of feeding to raw foods during daylight hours limits the metabolic energy available.{{Cite journal|last1=Fonseca-Azevedo|first1=Karina|last2=Herculano-Houzel|first2=Suzana|date=6 November 2012|title=Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution|journal=Proceedings of the National Academy of Sciences|language=en|volume=109|issue=45|pages=18571–18576|doi=10.1073/pnas.1206390109|issn=0027-8424|pmc=3494886|pmid=23090991|bibcode=2012PNAS..10918571F|doi-access=free}} Genus Homo 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.{{Cite journal |last1=Aiello |first1=Leslie C. |last2=Wheeler |first2=Peter |date=1 January 1995 |title=The Expensive-Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution |journal=Current Anthropology |volume=36 |issue=2 |pages=199–221 |doi=10.1086/204350 |jstor=2744104 |s2cid=144317407}} 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. The detoxification of food by the cooking process enabled early humans to access these resources.{{Cite journal|last=Bradbury|first=Joanne|date=10 May 2011|title=Docosahexaenoic Acid (DHA): An Ancient Nutrient for the Modern Human Brain|journal=Nutrients|language=en|volume=3|issue=5|pages=529–554|doi=10.3390/nu3050529|pmc=3257695|pmid=22254110|doi-access=free}}

Besides the brain, other human organs also demand a high metabolism. During human evolution, the body-mass proportion of different organs changed to allow brain expansion.

Before the advent of fire, the hominid diet was limited to mostly plant parts composed of simple sugars and carbohydrates 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 and starch. 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, were incorporated into their diets as cooking rendered them nontoxic.{{cite journal|last=Stahl|first=Ann Brower|author-link=Ann B. Stahl|date=April 1984|title=Hominid Dietary Selection Before Fire|journal=Current Anthropology|volume=25|issue=2|pages=151–168|doi=10.1086/203106|s2cid=84337150}}

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 process meat efficiently 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.Luca, F., G.H. Perry, and A. Di Rienzo. "Evolutionary Adaptations to Dietary Changes." Annual Review of Nutrition. U.S. National Library of Medicine, 21 August 2010. Weborn 14 November 2016. 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.{{cite journal | last1 = Wrangham | first1 = Richard W. | last2 = Carmody | first2 = Rachel Naomi | year = 2010 | title = Human adaptation to the control of fire | url = https://dash.harvard.edu/bitstream/handle/1/8944723/human_adaptation_to_the_control.pdf?sequence=1| journal = Evolutionary Anthropology | volume = 19 | issue = 5| pages = 187–199 | doi=10.1002/evan.20275| s2cid = 34878981 }} Through lowering food toxicity and increasing nutritive yield, cooking allowed for an earlier weaning age, permitting females to have more children.Daniel Lieberman, L'histoire du corps humain, JC Lattès, 2015, p. 99 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 around the time of the mastery of fire. Placentophagy is common in other primates.{{cite journal |last1=Young |first1=Sharon M. |last2=Benyshek |first2=Daniel C. |last3=Lienard |first3=Pierre |title=The Conspicuous Absence of Placenta Consumption in Human Postpartum Females: The Fire Hypothesis |journal=Ecology of Food and Nutrition |date=May 2012 |volume=51 |issue=3 |pages=198–217 |doi=10.1080/03670244.2012.661349|pmid=22632060 |bibcode=2012EcoFN..51..198Y |s2cid=1279726 }}

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 more challenging foods such as crisp root vegetables to softer cooked foods such as meat.{{cite news|url=http://www.abc.net.au/science/articles/2005/11/22/1514032.htm|title= Homo erectus ate crunchy food|work = News in Science | publisher = abc.net.au | access-date = 12 November 2007 | last = Viegas | first = Jennifer|date=22 November 2005}}{{cite web|url=http://anthro.palomar.edu/homo/homo_2.htm|title=Early Human Evolution: Homo ergaster and erectus|access-date=12 November 2007|archive-date=19 December 2007|archive-url=https://web.archive.org/web/20071219092405/http://anthro.palomar.edu/homo/homo_2.htm|url-status=dead}} 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.{{cite web|url=https://www.newscientist.com/article/dn7035-human-dental-chaos-linked-to-evolution-of-cooking.html |title=Human 'dental chaos' linked to evolution of cooking |last=Pickrell|first=John|date=19 February 2005|access-date=7 October 2011}}

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 the fermentation of long carbohydrate chains. Thus, humans evolved from the large colons and tracts that are seen in other primates to smaller ones.{{cite journal|title=Food for Thought|last=Gibbons|first=Ann|date=15 June 2007|journal=Science|doi=10.1126/science.316.5831.1558|volume=316|pages=1558–60|pmid=17569838|issue=5831|s2cid=9071168}}

According to Wrangham, fire control allowed hominids to sleep on the ground and in caves instead of trees and led to more time spent on the ground. This may have contributed to the evolution of bipedalism, as such an ability became increasingly necessary for human activity.{{Cite news|url=http://www.smithsonianmag.com/science-nature/why-fire-makes-us-human-72989884/?no-ist|title=Why Fire Makes Us Human|last=Adler|first=Jerry|newspaper=Smithsonian|access-date=13 November 2016}}

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 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.{{cite journal | last1 = Cornélio | first1 = Alianda | display-authors = etal | year = 2016 | title = Human Brain Expansion during Evolution Is Independent of Fire Control and Cooking | journal = Frontiers in Neuroscience | volume = 10 | page = 167 | doi = 10.3389/fnins.2016.00167 | pmid = 27199631 | pmc = 4842772 | doi-access = free }} 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.{{cite web|url=http://berkeley.edu/news/media/releases/99legacy/6-14-1999a.html|title=Meat-eating was essential for human evolution, says UC Berkeley anthropologist specializing in diet|date=14 June 1999|access-date=6 December 2010}}{{cite journal|last=Mann|first=Neil|date=15 August 2007|title=Meat in the human diet: An anthropological perspective|journal=Nutrition & Dietetics|volume=64|issue=Supplement s4|pages=102–107|doi=10.1111/j.1747-0080.2007.00194.x|doi-access=}} 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.{{cite journal|last=Pennisi|first=Elizabeth|author-link=Elizabeth Pennisi|date=26 March 1999|title=Human evolution: Did Cooked Tubers Spur the Evolution of Big Brains?|url=http://cogweb.ucla.edu/Abstracts/Pennisi_99.html|journal=Science | volume=283|issue=5410|pages=2004–2005|doi=10.1126/science.283.5410.2004|pmid=10206901|s2cid=39775701}}

{{Portal|Evolutionary biology|Science}}

• Hunting hypothesis
• Savannah hypothesis
• Theft of fire

{{Reflist}}

• "[http://aeon.co/magazine/science/how-our-pact-with-fire-made-us-what-we-are/ How our pact with fire made us what we are]" {{Webarchive|url=https://web.archive.org/web/20150906012250/http://aeon.co/magazine/science/how-our-pact-with-fire-made-us-what-we-are/ |date=6 September 2015 }}—Article by Stephen J Pyne
• [http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive Human Timeline (Interactive)] – National Museum of Natural History, Smithsonian (August 2016).

{{Fire}}

{{Firelighting}}

{{Prehistoric technology|state=expanded}}

{{Human Evolution}}

Category:Fire

Category:History of inventions

Fire

Fire