Forum für Wissenschaft, Industrie und Wirtschaft

Home Fachgebiete Studien Analysen Nachricht

Ancestor’s diet changed seasonally

nächste Meldung

The study appearing in the November issue of the journal Science shows that the eating habits of an early human relative called Paranthropus robustus varied between seasons and even years.

The massive facial and dental “architecture” of Paranthropus lead scientists to believe that they were vegetarians specialising in extremely hard plant foods that required a lot of crushing. Not so, say the team of scientists.

Co-author of the study, Julia Lee-Thorp, Professor of Archaeological Sciences at the University of Bradford, said: “Previously we had only a very averaged view about the diet of Paranthropus robustus. Our earlier carbon isotope work hinted that they were not specialist vegetarians, but gave no details. Now, by analysing tiny increments of fossil enamel, we can demonstrate that what they ate changed during the year.”

The study includes researchers from the University of Colorado at Boulder, Texas A&M University, Ohio State University and the University of Bradford.

The study analysed four fossil teeth of Paranthropus from Swartkrans, South Africa. Researchers used a laser to vapourise tiny samples of enamel, which were analysed in a mass spectrometer to determine the ratio of carbon – 13 to carbon – 12 isotopes.

The “laser ablation method” was fine-tuned at the University of Utah, where the analyses were carried out, so that it was able to handle human-sized teeth.

If the sample has a relatively high ratio of carbon – 13 to carbon -12, it means the early human relative ate a diet rich in C4 plants, such as seeds and roots from grasses. Importantly, they may also have eaten animals that ate the C4 plants.

Alternatively if the sample has a lower ratio of carbon – 13 to carbon -12, it means that the Paranthropus was eating C3 foods that included leaves and fruits of trees and shrubs.

African savannas have both C3 (trees and herbs) and C4 plants (tropical grasses), while forests have only C3 plants.

Analyses of the fossil Paranthropus teeth revealed that their diets varied in the proportion of C3 - and C4 – derived carbon both seasonally and from year to year. The year to year variation in Paranthropus’ diet “might reflect yearly differences in rainfall-related food availability,” the study’s authors write. “Another possible explanation is that these individuals were migrating between more wooded habitats and more open savannas.”

The researchers noted that Paranthropus has often been portrayed as a specialist that lacked a varied diet, and that has been used to explain why Paranthropus became extinct as Africa became drier, while tool-wielding Homo – with a highly varied diet – survived and became more successful.

The new study casts doubt on that theory by showing that Paranthropus, like Homo, also consumed a variety of foods. It shows that they were able to change their food-collecting strategies in response to changing conditions. “This implies that they were very adaptable and flexible.” says Professor Lee-Thorp.

The researchers conclude: “Thus, other biological, social or cultural differences may be needed to explain the different fates of Homo and Paranthropus.”

Emma Banks | Quelle: alphagalileo
Weitere Informationen: www.bradford.ac.uk/corpcomms/pressreleases

nächste Meldung