Hunting large terrestrial mammals might seem like a good subsistence strategy for Ice Age humans, but procuring small, aquatic creatures may have been more adaptive. Findings published today in the Proceedings of the National Academy of Sciences suggest that by around 28,000 years ago, anatomically modern humans had started to exploit freshwater fish and fowla dietary shift that may have given them a competitive edge over the Neandertals.

To reconstruct what early moderns ate, paleoanthropologist Erik Trinkaus of Washington University and his colleagues conducted chemical analyses of bone collagen samples from nine skeletons found in Europe and western Asia. They then compared these results with previously published findings from five European Neandertal specimens. Intriguingly, whereas the Neandertal samples indicate a diet dominated by large terrestrial herbivores, the early modern samples suggest a diet that incorporated inland freshwater fish, mollusks and birds. The data also imply that moderns were consistently exploiting small terrestrial animals, too.

This increased dietary breadth among moderns, the authors note, may have made them more resilient to natural pressures, such as seasonal and annual resource fluctuations. As such, it may well have helped the early modern human populations to expand and take over the Eurasian landscape.