The essential roles of fire in human evolution and in humanity’s technological mastery of the natural world are disproportional to our
understanding of its earliest domestication. Archaeologists researching relatively recent occurrences of fire, only after ~0.4 Ma and mostly in
Europe, are particularly critical of earlier archaeological claims of fire from African sites older than 1.0 million years old.
1 The problem is that the initial harnessing of fire was such an extraordinary accomplishment that any claim of that achievement requires extraordinary
evidence for its acceptance. Unfortunately, ancient fire lacks the tangibility of prehistoric stone tools, the oldest of which are 2.6 million years
old2 but that are also still readily accessible to us by sight and by touch. Fire – even when employed in the
most evolutionarily important of ways (e.g. to cook food, provide nocturnal illumination and ward off carnivores) – is ephemeral; it burns
itself out. Thus, the occurrence of fire in the deep past left only trace evidence, if any at all.
So instead of being based on easily identifiable, well-developed hearths, the very earliest claims of hominin-controlled fire from Africa are
based on more dubious evidence, like patches of heated sediment or burned clumps of clay found in association with simple stone tools at some
archaeological sites in Kenya which are 1.5-1.4 million years old.3,4 Sceptics want to know if
wildfires, rather than hominins, actually created these prehistoric indications of burning, and if their associations with bona fide archaeological
remains are coincidental instead of behavioural. Even the ballyhooed reports of charred plants and heated flint from the ~0.8-million-year-old
Gesher Benot Ya’aqov site (Israel)5,6 encounter some resistance, as the site was formed in
the open and thus may have been susceptible to burning by wildfires.
Using micromorphological and Fourier transform infrared microspectroscopy techniques to analyse intact sediments from the South African cave site
of Wonderwerk, Francesco Berna and his colleagues have just demonstrated the presence of in situ fire in the cave’s
1.0-million-year-old Acheulean stratum 10; in doing so, they have also shown what newly applied rigor in archaeological recovery adds to the quest
for the world’s earliest controlled fire.7 Berna et al.’s7 analyses
revealed that the stratum 10 sediment contains inclusions of ashed plants and burned bone fragments. The plant remains are well preserved and the
bone fragments are still sharp-edged, indicating that both were burned at the locus of recovery, and not blown or washed in from outside the cave.
Additionally, the cave entrance is ~30 m from the excavation area, and was even further away 1.0 Ma, when the archaeological evidence
accumulated. By noting the absence of bat guano in the Acheulean level, Berna et al.7 neutralise anticipated
criticisms that self-ignition of that fuel caused the burning in stratum 10. Putting a point on their thesis, the authors also describe larger
pieces of charred and calcined bones, as well as banded ironstone tools and manuports (i.e. non-worked, non-local stones transported to the cave
by hominins) with heat-generated pot-lid fractures. In sum, the research at Wonderwerk was exacting, the data are powerful and the conclusions
Even so, the notion of hominin control of fire by 1.0 Ma does not surprise me, having directed research at Swartkrans Cave (South Africa) for the
last several years. One of the most important discoveries at Swartkrans by my predecessor, Bob Brain, was the presence of 270 burned bone fragments
in Member 3, a depositional unit of the Swartkrans Formation that dates~1.5 Ma – 1.0 Ma.8
Like the Wonderwerk sediments and bones,7 most of the Swartkrans bones were burned in fires reaching temperatures around or in excess of
400 °C – 500 °C.9,10 Within a fire, temperatures vary at different
heights, but small campfires rarely exceed 700 °C and have an average overall temperature of ~400 °C, whereas wildfire
temperatures can near 800 °C aboveground, but are dramatically cooler at the ground subsurface.
Thus, determining the origin of a fire based on proxy indications of its heat is tricky; for example, a bone burned at low temperatures for a long
time can assume heat-altered chemistry and histology similar to that of one burned
at high temperatures for a short time.
Complicating matters, the Swartkrans burned bones, unlike those from Wonderwerk, were probably transported short distances from their loci of
combustion. To sceptics this means that wildfires probably ignited flammable detritus, including bones, which was lying jumbled on the floor of the
cave mouth, and was then eventually washed deeper into the gully in which the Member 3 deposit formed. In contrast,
Brain13 contends that hominins regularly tended fires in the mouth of the gully, with bony debris from those fires,
as well as other cultural materials, washing deeper into the cave over time.
The strength of Brain’s interpretation is contextual. Firstly, only two other burned bone fragments have been found in the entire Swartkrans
Formation, which includes four other early Pleistocene depositional units, each yielding thousands to tens of thousands of macrovertebrate fossils;
so why would wildfires not have affected each assemblage similarly? Secondly, burned bones were excavated from much of the entire 6-m thickness of
Member 3, suggesting that fires were maintained repeatedly over the thousands of years that it took the deposit to accumulate. Lastly, four of the
burned bones are also scarred by defleshing butchery marks,13 so the sample is linked functionally to a spatially
of Early Acheulean stone cutting tools.14 The possibility exists, of course, that uncooked bones were defleshed by
dropped in or near the cave entrance, burned in a wildfire and then washed deeper into the Member 3 gully. It is, however, just as likely that
uncooked butchered bones were dropped into fires tended by hominins for purposes other than cooking meat; Brain13,
for one, believes
that hominins employed fires initially to fend off carnivores.
Indeed, even though much is made of Richard Wrangham’s15,16 hypothesis that early
Homo was biologically adapted to eating
cooked food, the vast majority of butchered bones in Swartkrans Member 3,17 in addition to all of them at other
early Pleistocene African
sites, are not burned.18 Further work on the taphonomy of the Wonderwerk fauna might, in the future, elucidate the
issue of meat cooking.
And, our own work at Swartkrans is now focused on this question.
As it now stands, the new evidence of fire at Wonderwerk also does nothing to resolve the question of whether early African Homo cooked
plant foods. The burned plant matter is only identified to broad taxonomic categories, and the statement that ‘data suggest that the fuel
used in Wonderwerk was composed mainly of ‘light’ plant materials such as grasses, brushes and
leaves’7 could indicate
that Wonderwerk hominins used those plants primarily for fuel rather than for food.
None of this parsing of the data is meant to impugn the revelations from Wonderwerk, but is instead to demonstrate the importance of considering
the new evidence in the broadest reasonable context. We ought to resist the temptation to simply cast aside previous claims of early hominin fire
management in the wake of newer, fancier analytical techniques. Combining all scientifically sound observations of ancient archaeological fire
provides a much richer picture of the possibilities of its domestication and uses, and will also allow us to build more comprehensive hypotheses to
be tested against the next new claim.
1. Roebroeks W, Villa P. On the earliest evidence for habitual use of fire in Europe. Proc Natl Acad Sci USA. 2010;108:5209–5214.
2. Semaw S, Harris JWK, Feibel CS, Bernor RL, Fesseha N, Mowbray K. 2.5 million-year-old stone tools from Gona, Ethiopia. Nature.
3.Bellomo R. Methods of determining early hominid behavioral activities associated with the controlled use of fire at FxJj 20 Main, Koobi Fora,
Kenya. J Hum Evol. 1994;27:173–195.
4. Gowlett JAJ, Harris JWK, Walton D, Wood BA. Early archaeological sites, hominid remains, and traces of fire from Chesowanja, Kenya. Nature.
5. Goren-Inbar N, Alperson N, Kislev ME, et al. Evidence of hominin control of fire at Gesher Benot Ya’aqov. Science. 2004;304:725–727.
6. Alperson N, Goren-Inbar N. The Acheulian site of Gesher Benot Ya’aqov, Vol 2: Ancient flames and controlled use of fire. New York:
7. Berna F, Goldberg P, Horwitz LK, et al. Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape
Province, South Africa. Proc Natl Acad Sci USA. In press.
8. Brain CK, Sillen A. Evidence from Swartkrans Cave for the earliest use of fire. Nature. 1988;336:464–466.
9.Brain CK. The occurrence of burnt bones at Swartkrans and their implications for the control of fire by early hominids. In: Brain CK, editor.
Swartkrans: A cave’s chronicle of early man. Pretoria: Transvaal Museum, 1993; p. 229–242.
11.Sillen A, Hoering T. Chemical characterization of burnt bones from Swartkrans. In: Brain CK, editor. Swartkrans: A cave’s chronicle of
early man. Pretoria: Transvaal Museum, 1993; p. 243–249.
11. Tylecote RF. Metallurgy in archaeology. London: Arnold; 1962.
12. Wright H, Bailey PW. Fire ecology: United States and Southern Canada. New York: John Wiley and Sons; 1982.
13. Brain CK. A taphonomic overview of the Swartkrans fossil assemblages. In: Brain CK, editor. Swartkrans: A cave’s chronicle of early man.
Pretoria: Transvaal Museum, 1993; p. 257–264.
14. Field AS. An analytical and comparative study of the earlier Stone Age archaeology of the Sterkfontein Valley. PhD thesis, Johannesburg,
University of the Witwatersrand, 1999.
15. Wrangham RW. Catching fire: How cooking made us human. New York: Basic Books; 2009.
16. Organ C, Nunn CL, Machanda Z, Wrangham RW. Phylogenetic rate shifts in feeding time during the evolution of Homo.
Proc Natl Acad Sci USA. 2011;108:14555–14559.
17. Pickering TR, Domínguez-Rodrigo M, Egeland CP, Brain CK. Carcass foraging by early hominids at Swartkrans Cave (South Africa): A new
investigation of the zooarchaeology and taphonomy of Member 3. In: Pickering TR, Schick K, Toth N, editors. Breathing life into fossils: Taphonomic
studies in honor of C.K. (Bob) Brain. Bloomington, IN: Stone Age Institute Press, 2007; p. 233–253.
18. Pickering TR, Bunn HT. Another take on meat-foraging by Pleistocene African hominins: Tracking behavioral evolution beyond baseline inferences
of early access to carcasses. In: Domínguez-Rodrigo M, editor. Stone tools and fossil bones: Debates in the archaeology of human origins.
Cambridge: Cambridge University Press, 2012; p. 152–173.