The Impact of Fire on Human Evolution — How It Changed Our Lives Forever
Last month, my friend and I went on a hiking-camping excursion in the foothills of the Himalayas. Although it was an adventure, the negative temperature gave our bodies a fight to go to sleep at night. If we hadn’t started the fire, which protected us from the stinging cold as well as the wild animals, we would not have been able to endure those nights for even a single second. Fire gave us comfort and the assurance we needed to go to sleep.
One evening, after coming back home, I pondered what a boon fire would have been to the early humans who had to survive each day in the wild without the camping gear we had. The subject of when humans originally used fire is hotly contested, although research indicates that the first indications of habitual fire use in Europe date between 300,000 and 400,000 years ago, following human migration to northern latitudes.
Fire has been a source of awe and wonder since time immemorial, with humans perceiving it as a blessing from the Gods. But, little do we know that our association with fire goes beyond edible delights — its effects on human evolution are far-reaching and profound. Charles Darwin himself considered fire and language to be the two most significant achievements of humanity.
Fire gave us the brains we got
Despite sharing 99.6% of our DNA with chimpanzees (specifically the chimp and bonobos species), which are the closest living relatives of humans, their brains are nevertheless considerably smaller than ours. It is interesting to note that domesticating fire had a key role in forming our brains and setting us apart from other animals. Many researchers and scientists believe that the power of cooking paved the way for a dramatic expansion of the human brain. To develop larger brains, our early ancestors needed more energy required for the functioning and development of larger brains.
Three possible solutions to feed the extra calories required by larger brains:
1) Eating more
2) Eating high-calorie food
3) Powering bigger brains by sacrificing energy from other organs or physical parts.
Primal humans spent most of their time gathering, foraging, and eating (so it was quite difficult that they could have earned more calories by eating more). The second solution of eating high-caloric food, like meat and marrow, could be a good option to satisfy the energy requirement of the bigger and more ravenous brain. However, as meat could not be consumed uncooked, the fire gave a gateway to humans to cook their meat and gain more calories in the same time spent eating low-quality plant diet.
Consuming a higher quality diet and less bulky plant fiber not only provided the additional energy for a larger brain, but also allowed humans to have smaller guts. Hence, using fire to cook meat also fulfills the third solution of reducing the calorie requirement of the digestive system by shortening the guts and predigesting the meat.
Cooking is the latest theory to explain how humans can feed their voracious brains enough calories to survive. Paleoanthropologist Leslie Aiello, then of University College, London, and physiologist Peter Wheeler of Liverpool John Moores University discovered the tradeoff in guts and brains in 18 species of primates. They found that our gastrointestinal tract is only 60% of the size expected for a primate of similar size (Science, 29 May 1998, p. 1345).
Fire had a major contribution to the formation of civilizations
When early humans learned the art to control fire, they saw it as a great tool to clear away the forest vegetation and eliminate pest species, providing them with barren land which they could use to grow crops. They could light up the ground in a controlled manner, saving time and effort by not manually removing growth in the forest land. Evidence of widespread control of fire by anatomically modern humans dates to approximately 125,000 years ago.
Hominids (Bipedal apes, which include us, Homo sapiens, and other members of our genus) also learned that starting bushfires to burn large areas could increase land fertility and clear terrain to make hunting easier. Cleared terrain made it possible for wheat and other grasses to monopolize sunlight, water, and nutrients, which gradually provided nomadic humans the ability to settle down and cultivate food. There are still communities and farmers that use Slash-and-burn agriculture to grow crops.
Agricultural communities were created as a result of human settlement and the domestication of plants and animals. Cities and civilizations emerged from agriculture, and since it was now possible to raise crops and animals to meet demand, the world’s population exploded — from about five million people 10,000 years ago to more than eight billion now.
Fire even provided tools melted and forged out of metal used for various agricultural and military purposes, which further helped in the rise of multiple civilizations. The production of implements made of bronze and iron contributed to the efficiency and ease of agricultural work. Harder soils could be worked by peasants, allowing for the cultivation and growth of new plant species. More effective ways of doing work helped to free up time. With greater time, people could now pursue careers outside of farming, such as selling or exchanging their produce.
Note: As farming emerged, nomadic hunter-gatherers gradually were pushed off prime farmland, and eventually they became limited to the forests of the Amazon, the arid grasslands of Africa, the remote islands of Southeast Asia, and the tundra of the Arctic. Today, only a few scattered tribes of hunter-gatherers remain on the planet.
Socializing effect of fire
Have you ever had an experience when you are looking at the burning flames while it holds an attraction to your eye, and you stare at the flames continuously? I always have this experience with it, while looking at the fire my mind switches itself into a meditative mode. We have a deep and enduring affinity for fire and are pulled towards it. When we are near it, our brains experience a sense of security. Still to this date, people gather around the fire while camping, during traditional festivities, or just to express their awe to Gods.
For early humans, fire provided a center around which social life moved and, for the first time, large groups of early humans gathered around a communal cooking place after the day’s hunting got over. They had stories to tell each other about the animals they chased, the plants they gathered, and the new landscape they discovered. To this date, fire holds the utmost importance in various sections of our society. Some festivals see fire as its core element. The festival of “Lohri” is one of the well-known fire-themed celebrations in my community that belongs to the region of Punjab and is mostly celebrated in the northern part of India. On this day foods like til (black sesame seeds), gajak, gur (jaggery), peanuts, and popcorn are fed to the fire as part of the harvest ritual. Offering food to the God of Fire on this day is thought to help remove all negativity from life and bring prosperity.
The control of fire enabled essential changes in human behavior, health, energy expenditure, and geographic expansion. Since childhood, I had never underestimated the power of fire, but since that night I have truly understood its importance and have more respect for it.
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