Researchers from the Goethe University and the Senckenberg Institute have gained new insights into the eating habits of early humans.
The scientists working with Wolfgang Müller and Jülide Kubat examined the teeth of humans of the species Homo erectus, who lived on the Indonesian island of Java between 1.4 million and 700,000 years ago.
They compared their findings with analyzes of the teeth of orangutans and other animals.
The researchers cut the teeth into wafer-thin slices, bombarded them with laser beams and used a mass spectrometer to determine the strontium and calcium content, among other things.
The proportion of both elements in tooth enamel reveals whether humans or animals eat more plants or meat.
Because the body gradually eliminates strontium, the strontium-calcium quotient in the food chain becomes smaller and smaller.
As omnivores, less dependent on the seasons
In early humans and orangutans, the diet changed with the seasons, the measurements showed.
However, the fluctuations were more pronounced in the monkeys.
Apparently they mainly ate fruit during the rainy season, while possibly also eating insects and eggs during the dry season.
Humans, on the other hand, were omnivores with occasional meat consumption and were less dependent on the seasonal food supply.