One theory about how modern human brains became so large is that nutrients from seafood and shellfish permitted our ancestors to grow energetically expensive brains. A new study from this year shows that Neanderthals were also exploiting marine resources: crabs. At Gruta de Figueira Brava, a cave site in coastal Portugal, Neanderthals were cooking and eating brown crabs as early as 90,000 years ago. Black burn marks on some of the crab carapaces and pincers indicate that they were subjected to temperatures up to 300-500 degrees Celsius (~600-900 Fahrenheit), indicative of being roasted on coals. The type of fracture on the crab pincers support this interpretation, and it appears that the Neanderthals there particularly went after larger crabs. Consumption of marine foods by Neanderthals casts doubt on the hypothesis that eating shellfish led to modern humans in sub-Saharan Africa evolving uniquely large brains. Gathering of marine resources also implies swimming and/or knowledge of the tides.

These findings were presented in the journal Frontiers in Environmental Archaeology on February 7th, 2023, by Mariana Nabais and colleagues.