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.