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Jülide Kubat and Wolfgang Müller load the LA-ICPMS with a thin section of tooth for analysis. Photo Credit: Jülide Kubat |
An interdisciplinary team of scientists, led by Goethe University Frankfurt and the Senckenberg Research Institute and Natural History Museum Frankfurt, has discovered – by analyzing their teeth – what our ancestors of the species Homo erectus ate hundreds of thousands of years ago on the island of Java in Southeast Asia: over the course of a year, these early humans switched from a plant-based diet to a mixed one, but were far less dependent on seasonal food supply than, for example, orangutans, which also inhabited the island.
If you take a magnifying glass and a torch and look at your teeth very carefully in the mirror, in places you can spot a pattern of fine, parallel lines running across your teeth. These correspond to the striae of Retzius that mark the growth of our tooth enamel. Enamel starts forming in the womb and continues to mineralize until adolescence, when the last milk teeth fall out and are replaced by permanent ones. Like in all land-dwelling vertebrates, tooth enamel mineralizes gradually in microscopically thin layers in humans too, represented by the striae of Retzius. The speed with which a human develops can be read from these Retzius lines. Physiological changes, such as birth, weaning or illness, for example, leave distinctive traces. The striae of Retzius also form the chronological framework for the chemical composition of tooth enamel, which in turn reflects changes in the diet of that individual.