When we first learned to cook food is one of the most important evolutionary moments of our species. It’s what transformed us into modern humans.
"Around 1 to 2 million years ago, early humans developed taller bodies and bigger brains. The thinking is that calorie-rich diets, and cooking in particular, drove this change," said David Braun, professor of anthropology at Columbian College of Arts and Sciences in Washington, D.C.
A new study, published in Nature Ecology and Evolution, suggests that early humans first cooked food around 780,000 years ago. Before now, the earliest evidence of cooked food was around 170,000 years ago, with early Homo sapiens and Neanderthals using fire to cook vegetables and meat.
First cooking fires predate Homo sapiens
The new study shows that Homo erectus, an ancestor of modern humans, was cooking food much further back in history.
"Setting this date back by more than 600,000 years has implications for reconstructing the evolutionary history of ancient humans," study co-author Jens Najorka from The Natural History Museum, London, told DW.
The study team found their evidence in an archaeological site located in the northern Jordan Valley, in modern-day Israel. The site, called Gesher Benot Ya’aqov, is known to date back to around 780,000 years ago.
It is believed that Homo erectus communities of the so-called Acheulian culture lived in the region. The communities had a varied diet, including large game, fruit and vegetables, and freshwater fish from the nearby paleo-Lake Hula. But until now, experts didn’t know if they ate their food raw or cooked.
Burnt fish teeth reveal ancient cooking practices
The study team analyzed the remains of fish teeth (from carp and barbel) found in the proximity of fireplaces at Gesher Benot Ya’aqov.
By analyzing the crystal structure of the teeth, the team found that they had been cooked under 500 degrees Celsius (932 degrees Fahrenheit).
"This suggested that the fish had been cooked at a controlled temperature rather than just burned," study co-author Irit Zohar from Tel Aviv University, Israel, told DW. "Until now, no one could prove that Homo erectus cooked food. This is the first evidence that erectus had the cognitive ability to control fire and cook food."
Why it matters when humans started cooking
The development of cooking was a huge moment in human evolution.
"People think that the evolution from Homo erectus to Homo sapiens must have been associated with a change in diet and the use of fire to cook food. There are changes in the jaw and skull anatomy that suggest this," Zohar said.
Cooking makes meat, fish, and vegetables easier to digest, enabling body and brain growth much more efficiently than eating raw food. It also makes food much safer to eat as it kills off pathogens.
"From the cooking hypothesis, we were expecting early humans to cook food this far back, but we never had the evidence. Now we do, and it confirms our hypotheses about the importance of cooking for early humans," said Braun, who was not part of the study.
Did humans follow the fish out of Africa?
According to Zohar, early humans migrated out of Africa via freshwater lakes and rivers. Sites of settlements and early human activity are always found near freshwater.
"Of course they are a source of water, but I think what’s overlooked is the importance of fish as a stable food source [for early humans]," Zohar said.
Fish are a rich source of protein and nutrients and, unlike game animals, are available to eat all year round.
"Some people think that early humans only ate fish when nothing else was available. Our study suggests this isn’t true ― we found that the fish were cooked at all times of the year, suggesting they were an important component of the diet," Zohar said.
How did Homo erectus catch fish?
For Braun, one of the open questions is how Homo erectus were catching fish.
"There's no evidence of fishing technology back then. The authors found 5,000 teeth at the site — that’s a serious amount of fish cooking in a small community," Braun said.
According to the authors, the water in the wetlands was very shallow, so people don’t necessarily need technology like nets or rods to catch the fish.
"We think they used their hands, like people still do with river fish today," Zohar said.
Shore fishing with tools like spears and nets is believed to be a relatively recent development in human history. The oldest fishhook dates back 42,000 years, meaning humans grappled with fish for hundreds of thousands of years before more reliable methods than "grab it with your hands" were invented.
Edited by: Carla Bleiker