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Did the ancestors of modern humans beings spend a lot of time by the seaside?

Latest Mind and Matter column in the Wall Street Journal:


Photo: Jon Erlandson


Last week archaeologists working on the Channel Islands of California announced that they had found delicate stone tools of remarkable antiquity-possibly as old as 13,000 years. These are among the oldest artifacts ever discovered in North America. To judge by the types of tool and bone, there was a people living there who relied heavily on abalone, seals, cormorants, ducks and fish for food.

This discovery fits a pattern. From the stone age to ancient Greece to the Maya to modern Japan, the most technologically advanced and economically successful human beings have often been seafarers and fish-eaters-and they still are, as the latest tsunami reminds us. Indeed, it may not be going too far to describe our species as a maritime ape.

The oldest human site with evidence of symbolic culture and sophisticated tools is a cave overlooking the sea at Pinnacle Point in South Africa; it dates from 170,000 years ago. Piles of mussel shells testify to the denizens’ taste for seafood. Around 100,000 years later, another flowering of technology and culture occurred at the Blombos caves further west.

African people subsequently expanded into Asia, and anthropologists now think they did so at first primarily along the shores of the Indian Ocean. The evidence for this “beachcomber express” is chiefly genetic. Genes show that people reached the Andaman islands, Melanesia and Australia, all of which required sea crossings, within a few thousand years-whereas it took them tens of thousands of years even to begin to oust our Neanderthal rivals from Europe and inland Asia.

Further hints of maritime habits abound throughout the prehistoric record, with rich old-stone-age cultures around the Mediterranean, the Red Sea and in parts of Asia. The oldest known Briton of a recognizably modern-human kind-29,000 years old-is the skeleton of a man found in a cave overlooking the sea at Paviland in Wales.

But there is a problem: Sea level is more than 200 feet higher today than it was 15,000 years ago, having risen steadily once the ice age loosened its grip on the continents. So the bulk of the evidence of ancient coastal settlements must be buried beneath the waves. What finds we have are fortuitous: At Pinnacle Point, Blombos and Paviland, hospitable caves a steep climb up from the sea must have tempted people to make a base higher than usual above sea level.

For our ancestors, the shoreline provided a far richer source of calories and protein than the interior of continents-once they had acquired the skills and tools to exploit it. The richest and most socially stratified cultures of hunter-gatherers in recent times were consequently marine ones: the coastal tribes of Peru, California, Oregon, British Columbia and some Pacific islands being prime examples.

Supposing maritime human settlements usually achieved high densities and high birth rates, then it would have been they who gave rise to inland tribes rather than vice versa. Hence many of us-however landlocked our more recent ancestors were-may ultimately be descended from people who once lived off seafood and knew the sea shore.

Does this explain our love of eating seafood, or the high nutritional value that our bodies put on omega-3 fatty acids? Does it explain our obsession with heading for the beach when on vacation?

Back in the 1960s, in order to understand our hairless bodies, upright stance and subcutaneous fat, a British marine biologist named Alister Hardy first floated the idea of an ancestral human species having gone through a wholly aquatic phase. That probably goes too far-the dates are wrong-but there could yet be a germ of truth in it if some modern human traits were honed, more recently, at least partly by life on the ocean shore.

By Matt Ridley | Tagged:  wall-street-journal