Ancient fish teeth discovered at the archaeological site of Gesher Benot Ya'aqov in Israel provide earliest evidence of our prehistoric ancestors deliberately cooking foodstuff
21 November 2022
Nutrition and the ability to prepare foodstuffs helped facilitate the evolution of the human species. Considered particularly relevant to the development of the genus Homo in this context are the processes of cooking. However, exactly when our ancestors began to intentionally cook and use heat to prepare foodstuffs was unclear until now. Thanks to fossils uncovered at the Gesher Benot Ya'aqov site in northern Israel, an international team of researchers headed by Dr. Irit Zohar of the Steinhardt Museum of Natural History of Tel Aviv University, Beit Margolin of Oranim Academic College of Education in Israel, and archaeologist Professor Naama Goren-Inbar of the Hebrew University of Jerusalem – in collaboration with paleontologist Professor Thomas Tütken of Johannes Gutenberg University Mainz (JGU) – have now come some way towards solving this question. By analyzing the chemical and mineralogical composition of discovered fish teeth, the researchers have been able to show that some 780,000 years ago prehistoric humans were already catching fish from what was once Lake Hula and cooking them on the shore. "This is the earliest evidence that has ever come to light that our very ancient ancestors used certain cooking processes to prepare their food," said Dr. Irit Zohar. Indications of such culinary practices had previously been detected in the case of early Homo sapiens and Neanderthals. The results of this recent research have now been published in Nature Ecology & Evolution.
Evidence of early human presence on the shores of Lake Hula produced by excavations being carried out at Gesher Benot Ya'aqov in the Levantine Corridor
Although we know quite a lot about the diet of Paleolithic hunter-gatherers, it is still unclear what role fish played in the nourishment of our early forebears. The team of Israeli archaeologist Dr. Irit Zohar, lead author of the published paper, and Dr. Jens Najorka of London's Natural History Museum studied the changes to the crystalline structure of the pharyngeal teeth of large freshwater barbels found at Gesher Benot Ya'aqov in the north of the Jordan Valley. The archaeological site is on what was formerly wetland on the shore of the paleo-Lake Hula. Excavations carried out here by Professor Naama Goren-Inbar since the late 1980s have produced extensive proof of human settlement in the area and of the controlled use of fire at least 780,000 years ago.
"We found clear signs of localized burning that indicate that the early hominins present around the lake had already learned how to utilize fire in the Paleolithic," emphasized Professor Nira Alperson-Afil of Bar-Ilan University in Israel. "It is possible that these early hunters, gatherers, and fisherfolk were members of the species Homo erectus," Professor Naama Goren-Inbar added. "But we have yet to find hominin skeletal remains. So far we have unearthed numerous stone tools, including hand axes."
Excavation layers with unusual fish remains
Two unexpected factors have come to light among what has been recovered at Gesher Benot Ya'aqov. In eight superimposed archaeological layers in which Professor Nira Alperson-Afil had discovered indications of the controlled use of fire, Dr. Irit Zohar and Dr. Marion Prévost of the Hebrew University of Jerusalem found that, although a large number of fish remains – more than 40,000 – were present, these belonged to a remarkably small number of different species. Predominant were those of two species of extinct giant carp-like fish, some of which could have grown to a length of more than one meter. The main species were the carp-like barbels Luciobarbus longiceps and Carasobarbus canis that were native to Lake Hula. In addition, Zohar and Prévost were surprised by the fact that despite the high numbers of fish teeth, there were almost no fish bones in these layers and yet, in contrast, they did come across the bones of land animals.
"We decided to concentrate on three main facets in order to determine whether these early ancestors of ours had in fact cooked their fish some 780,000 years ago," said Zohar. The researchers initially conducted an experiment in which they looked at the effects of cooking and exposure to high temperatures on the bodies of today's barbels. They learned that the cooking and heating processes cause the bones to soften and disintegrate while the fish teeth, with their greater mineral content, remain intact. They also found a tendency for fossil fish teeth to be accumulated near hearth sites that had been identified as such by Alperson-Afil as flint artifacts were also present that showed signs of exposure to fire. With the help of an X-ray diffraction technique, the researchers additionally observed small alterations to the crystalline structures in the fish tooth enamel. "The increase in size of the bioapatite crystals in the tooth enamel showed us that the fish were exposed to moderate temperatures only, so that they did not burn," explained Najorka of the Natural History Museum in London.
Specifically analyzed at Mainz University were the seasonal aspects of fishing at the site. The ratio of heavy to light oxygen isotopes provide information on the water temperatures at the time the fish tooth enamel was formed. "Because there are seasonal temperature variations also in Israel, we know from the oxygen isotope data that barbel were caught from the lake all year round, not just at a specific time of year," stated Professor Thomas Tütken of JGU. The freshwater fish, a source of high-quality food available during the whole year, would have represented an important element of the sustenance of the early hominins.
Cooked fish – a valuable source of food for ancient humans
"If we consider all these factors and also take into account the excellent nutritional value of the two barbel species, we gain a new and fascinating insight into the lives of the hominins of Gesher Benot Ya'aqov, who cooked their fish before eating it," emphasized Zohar. "You can eat raw fish, of course, but cooked fish contains more protein, is not a risk to health, and can be more readily digested. And if you steam or bake the fish rather than grill it, the omega-3 fatty acids DHA and EPA are also preserved."
"While it is likely that early fire-using hominins had already cooked their food, definitive evidence of this practice has only been demonstrated to date for early Homo sapiens and Neanderthals, in association with vegetal material, with the earliest date of 170,000 years ago," the authors stated in their article. Their work has thus produced the earliest and first confirmation that hominins did actually cook their fish 780,000 years ago. However, the cooking technique they used is still an enigma. No traces of any kinds of implements that might have been used for cooking have been found at the site itself or at other sites dating to the same period. One possibility is that a sort of fire pit was employed that produced temperatures of under 500 degrees Celsius, appropriate for steaming or baking the fish. "Freshwater fish were a high-quality, readily available foodstuff that the hominins of Gesher Benot Ya'aqov were happy to exploit throughout the whole year," concluded Professor Thomas Tütken in view of the findings.