Scientists have discovered the earliest evidence of humans eating snails, according to a new paper published in the journal Quaternary Science Reviews.
In a southern African cave, paleontologists uncovered pieces of shells from large land snails that date to 70,000 to 170,000 years ago. From past research, scientists had evidence of humans eating snails around 49,000 years ago in Africa and about 36,000 years ago in Europe. But these older shells showed signs of having been heated, perhaps in cooking, leading researchers to conclude that humans ate snails much longer ago than thought.
The findings are strong evidence that people who used the cave at the time methodically dined on snails, Bernd Schöne, who studies mollusk shells at Johannes Gutenberg University Mainz in Germany and wasn’t involved in the study, tells New Scientist’s Carolyn Wilke.
Snail meat is pretty nutritious—it’s rich in protein, iron, potassium, calcium and omega-3 fatty acids, according to the paper. And the prehistoric snail shell fragments are thought to be from relatives of modern behemoths that can grow to the size of a human hand and weigh more than two pounds. In other words, they could have provided a lot of meat. People today eat snails all over the world, including in the Mediterranean, Southeast Asia, northeastern India, Nepal and South America.
Prior to this study, archaeologists thought that humans didn’t rely on eating snails and other small animals until the end of the last Ice Age, first author Marine Wojcieszak, a chemist at the Royal Institute for Cultural Heritage in Belgium, tells Science News’ Bruce Bower. But this paper provides new evidence to challenge that view.
The team examined snail shells found in Border Cave, a rock-shelter on a cliff some 2,000 feet above sea level near the boundary between South Africa and Eswatini. Numerous past archaeological excavations have occurred in the cave. The ancient shell pieces came in colors from beige to brown and gray—and since heat can change a shell’s color, the range of hues suggested the fragments might have been exposed to fire.
To test this theory, the researchers warmed modern pieces of giant land snail shells to between 392 and 1022 degrees Fahrenheit for various periods ranging from five minutes to 36 hours. They observed the shells’ color change, weight loss, breakage and shifts in the chemical makeup of the pieces.
The heating caused the new shells to change color to white or gray, like some of the prehistoric fragments, and the process created tiny cracks also seen in the older shells, writes New Scientist.
This new evidence, as well as remains of edible plants found in Border Cave during other research, suggests the cave may have been used as a home base where people ate together, the authors write in the paper.
“The easy-to-eat, fatty protein of snails would have been an important food for the elderly and small children, who are less able to chew hard foods,” Wojcieszak tells Science News. “Food sharing [at Border Cave] shows that cooperative social behavior was in place from the dawn of our species.”
While it’s possible the shells were accidentally heated by a fireplace, archaeologists did find other remains of items possibly used for food nearby, including charred seeds and animal bones, Wojcieszak tells New Scientist.