The true stone age diet
Microscopic wear marks on fossil teeth reveal what early humans ate. At the same time, they convey an impression of how climate change influenced our evolution.
Late one evening in 1990 I was sitting in my hut on the banks of the Alas River at the Ketambe Research Station in Indonesia's Gunung Leuser National Park. By the light of a kerosene lamp, I wrote my notes neatly. For my doctoral thesis, I wanted to find out here what and how the small apes and great apes in the region eat. The idea behind this was that such observations should match the size, shape and wear marks of the teeth: cynomolgus monkeys have a set of teeth with large incisors and flat molars, which according to traditional belief is built for eating fruit. But the monkeys I've seen over the past four days seem to only eat young leaves. It was then that I realized that the relationship between the form and function of teeth is more complicated than what textbooks say-teeth don't necessarily tell you what an animal is eating. This may sound absurd, but this finding has a significant impact on our understanding of the evolution of animals, including us humans.
As a paleontologist, I make a living reconstructing the behavior of extinct species from their fossil remains. I am particularly interested in how animals used to get their food and how environmental changes affected them. The year in Ketambe shaped my thinking about primates and their communities. I recognized the biosphere of our planet as a richly laid table. The animals stand at the buffet with their plates in their hands, so to speak, and choose from what is available at the time. Choice defines each species' place in nature.
Teeth play a key role in food selection - after all, you need the right tools…