A new study which appears in the journal Nature details archeological discoveries in a sea cave on the tip of South Africa. The finds point out that people were already living near the coast some 165,000 years ago and relying heavily on a diet of shellfish, some 40,000 years before it was previously thought. The Pinnacle Point cave site, on the south coast of South Africa, is located somewhere near Mossel Bay.

The team of researchers, led by paleoanthropologist Curtis Marean of Arizona State University, found a bowl's worth of edible shellfish, as well as small stone blades and reddish rocks tossed in with the shells. This means that not only the inhabitants of the cave consumed seafood, but they also prepared a pigment called ochre, perhaps for painting their bodies, caves, or other objects. The stone blades could be used at the tip of a spear.

"It is likely that shellfish was a critical food resource for the survival of this population during this long dry time period, when terrestrial food resources were likely less productive," Marean said.

The most interesting find is probably that these humans used pigments, which may indicate the development of symbolic thought. The team found some 57 pieces of iron-rich hematite rock with flattened sides bearing parallel grooves. This particular shape indicates that the South African seafood eaters scraped the rocks to make powder, which in turn yields a reddish or pinkish paint when mixed with a binder.

"One could argue that we had cognitively modern humans around for a long time," he says. "Then you get this harsh environment that provides a context where all of a sudden their abilities to 'symbol' [or symbolize] are tapped. I think that's very likely."

There is an ongoing debate whether the cognitive functions appeared at once or gradually over tens of thousands of years. There is evidence going both ways.

Marean also told AP that it appears the women gathered the mussels, clams and snails two to three miles away from the cave and brought them back to the cave. Afterwards, they put the shellfish over hot rocks to cook. When the food was done, the shells popped open by themselves similarly to modern-day mussel-steaming, but without the steam pot. Essentially, they cooked them the same, the only difference was that the South African tribe obtained dryer food because the moisture inside evaporated.