The mystery of when humans first used fire to cook food has been partially answered by archaeologists and biologists.
Cooking food is considered crucial, with some researchers suggesting that this practice helped our ancestors absorb more energy and nutrients, thereby contributing to the development of the brain.
No one knows exactly when this began, but evidence indicates that humans have been cooking for at least 50,000 years and possibly for as long as 2 million years. Evidence comes from both archaeology and biology. One archaeological piece of evidence for cooking is the discovery of cooked starch grains in the dental calculus of human teeth from 50,000 years ago. However, it is unclear whether humans were cooking food even earlier.
In general, scientists often look for evidence of humans controlling fire, but this evidence does not necessarily confirm cooking, as people could have used fire for warmth or for making tools. Professor Bethan Linscott of Oxford University, an expert in archaeological geochemistry, said that while there is much evidence of fire in archaeological sites, the challenge is determining whether the fire was intentionally set by humans or caused by natural wildfires.
It is possible that an early hominid picked up a smoldering branch from a wildfire and used it to start a fire for cooking or tool-making. A key aspect of searching for evidence of fire control is finding a man-made fire structure.
For example, stones arranged in a circle with little ash in the middle could be the remains of a hearth or might just be siliceous structures formed from long-dead plants, along with burnt tools and utensils.
Researchers have found these types of tools at many habitation sites of Homo erectus, indicating that earlier humans may have used fire.
One research team discovered evidence of a 300,000-year-old hearth near piles of butchered animal bones in Qesem Cave in Israel, and a 400,000-year-old hearth in Suffolk, England, containing charred bones and flint tools.
Going further back in time, charred ash found deep inside Wonderwerk Cave in South Africa may be evidence of cooking from around 1 million years ago. Since the cave is located 30 meters deep, it is unlikely that the fire occurred naturally, suggesting that early humans may have been able to start fires.
Similarly, 1.6-million-year-old evidence has been found in Kenya.
At the Gesher Benot Ya’aqov archaeological site in Israel, researchers also found stone circles resembling fireplaces, along with fish bones showing signs of being heated, dating back 780,000 years.
In addition to archaeological evidence, biological evidence suggests when humans began eating cooked food through sudden evolutionary changes in the body.
Humans are unique among animals on Earth in that our bodies are adapted to eating cooked food. For example, a study of people who eat only raw food found that they tend to lose weight, and one-third of the women in the study stopped menstruating. So the question arises: when did humans begin using fire? The answer is likely before modern humans appeared. Homo erectus was the first human species to have fewer primate-like features and more characteristics of modern humans. Some of these characteristics suggest that Homo erectus may have been the first human species to cook food.
A key difference between humans and related primates is the size of the intestines. Since cooked food requires less digestion, our intestines are smaller than those of our primate relatives. Additionally, our stomachs are smaller, which is why our bellies are flatter rather than distended, especially after eating, as is the case with other primates.
To accommodate a larger gut, non-human primates have broad pelvises and expanded, flaring rib cages. Our human ancestors lost these features about 2 million years ago.
Another biological trait is the evolution of the human jaw. Human jaws are not as large as those of other primates, which corresponds with a sudden change in the diet—specifically, food becoming easier to chew because it was softer.
This change occurred about 1.8 million years ago, which aligns with the timing of skeletal evolution.
In summary, the story here is that cooking began around 1.9 million years ago in species closely resembling us during the evolutionary process, specifically Homo erectus.
Scientists believe that the use of cooked food and the ability to control fire were key factors in the evolutionary advancement of Homo erectus. However, without evidence of controlled fire—meaning the ability to start a fire rather than merely using wildfires—this conclusion remains controversial.
Professor Linscott said, “Researchers will continue to investigate this issue for a long time, and I am not sure if they will ever be able to determine the exact time.”
