Almost from the start, it seems, humans headed for the shore to get away from the cares at home. But this was no holiday for them. More than likely, it was a matter of survival at a perilous time of climate change throughout Africa 164,000 years ago.

By then, Homo sapiens had developed a taste for shellfish, out of necessity and much earlier than previously thought, while adapting to life in caves on the craggy coast of southern Africa, scientists report in Thursday's issue of the journal Nature.

Exploring a cave in a steep cliff overlooking the ocean, an international team of scientists found deposits of shellfish remains, hearths, small stone blades and fragments of hematite, some of which had been ground apparently for use as the coloring agent red ocher, which sometimes had symbolic meaning.

"The shellfish," the researchers concluded, "may have been crucial to the survival of these early humans as they expanded their home ranges" in response to the cooler and drier conditions that had prevailed for thousands of years in the interior of Africa.