What Else Makes Us Human?
Fire

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Over the last few months I’ve been discussing the characteristics that make us human, and which of the classic ‘uniquely human’ traits, really are ours and ours alone. But one aspect of human behaviour which I have not discussed so far is our use of fire. No other animal has learned to harness and control fire as humans have.

A recent discovery of wood ash along with animal bones and stone tools in a cave in South Africa suggests that humans may have used fire as early as 1 million years ago. This is around 300,000 years earlier than previously thought, and may indicate that earlier hominid species such as Homo erectus were using fire. Other tentative support for fire use by early hominids such as H.erectus and A.robustus have been found in South Africa and Kenya, possibly as early as 1.5 million years ago. Further evidence from Northern Israel in the form of burnt flint tools and plant remains indicates that H. erectusmay have been controlling fire around 800,000 years ago.

These finds are not undisputed, however, and many scientists believe these burnt artefacts simply represent opportunistic use of natural fire, as opposed to evidence of direct control of fire by early humans. Less controversial evidence for the control of fire by humans is much more recent, with sites in China, Israel and South Africa showing evidence for fire use from around 400,000 years ago. The construction of stone hearths is clear evidence of deliberate fire use, and the appearance of these has been dated to between 200,000 and 400,000 years ago.

Harnessing fire offered early humans a huge number of benefits: extending activity beyond daylight hours and providing a controlled source of heat; improved nutritional value of food, the opportunity to produce more varied tools using heat-treated stone and clay, and a deterrent against many wild animals and biting insects. Cooking meat increased its nutritional value, and cooking plant matter allowed greater access to complex carbohydrates which are difficult to digest in their uncooked form. Some have even suggested that cooking enabled humans to increase their calorie intake and thereby facilitated further brain expansion. Fire may also have played an important social role for early humans; socialising around a campfire is surely a uniquely human trait? And although it is not clear whether humans had control of fire when they began to leave warm African climates for cooler Northern ones, it would have certainly proved useful in surviving long winters in Europe.

There is no evidence for controlled fire use in non-human animals. Some animals and plants do take advantage of fire when it occurs naturally, but none have yet harnessed it for themselves. Many plants found in fire-prone environments have seeds which can only germinate following contact with fire – this enables them to germinate into a freshly cleared environment where their chances of survival are greater. Furthermore, animals such as the Australian fire hawk also take advantage of natural fire, snatching trapped prey animals. One bonobo chimpanzee, named Kanzi, was taught some human language, and also learned how to build a fire, light a match and cook food. However, this is not a natural behaviour and it has never been observed in wild Chimpanzee populations.

The deliberate use of fire for warmth, light, cooking and other uses is a uniquely human trait. This may be because the forethought required to use fire (a very destructive force, if not properly controlled) is simply too cognitively complex for non-human animals. Humans are unique in the extent of their ability to plan for the future and imagine and understand the consequences of their actions. This ability has enabled us to take tool use to far greater levels than any other animal, and may explain why we alone have harnessed fire. It may be little surprise, therefore, that the earliest undisputed evidence of human control of fire coincides closely with the appearance of complex Mousterian tools around 250,000 years ago. These tools required a number of steps to construct, and initial steps did not obviously progress the object towards its goal. Fire may be similar in this respect; the act of creating a fire does not obviously result in benefits such as cooked food. This may go some way to explaining why fire truly represents one of the few uniquely human traits.

Articles in this Series:

  1. Intro: What Makes Us Human?
  2. Part One: A Brief History
  3. Part Two: Intelligence and Language
  4. Part Three: Anatomical Adaptations
  5. Part Four: Culture and Faith

Want to Know More?

  • Berna et al (2012) Microstratigraphic evience of in situ fire in the Acheulean strata of Wonerwerk Cave, Northern Cap Province, South Africa. Proceedings of the National Academy of Sciences
  • Karkanas et al (2004) The earliest evidence for clay hearths: Aurignacian features in Klisoura cave 1, southern Greece. Antiquity 78(301)
  • Brian and Sillent (1988) Evidence from the Swartkrans cave for the earliest use of fire. Nature 336: 464 – 466
  • Gowlett et al (1981) Early archaeological sites, hominid remains and traces of fire from Chesowanja, Kenya. Nature 294: 125 – 129
  • Roebroeks and Villa (2011) On the earliest evidence for habitual use of fire in Europe. Proceedings of the National Academy of Sciences

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