as well as mollusks, eaten by Neander tals toward the end of their evolutionary run around 42,000 years ago (SN Online: 9/22/08). But these Neandertal caves contain no huge shell heaps that sug gest that coastal visits occurred at tidal low points, when masses of mollusks lay exposed, Marean argues.

It seems that hungry Homo sapiens patiently consulted the moon, whereas Neandertals heeded the urgency of their grumbling bellies.

New World sea cruise

Tide tracking at Pinnacle Point led to expanding numbers of people who even tually turned to sea travel to find virgin territory. These seafoodlovers may well have colonized the world.

Starting around 50,000 years ago, ocean voyagers based in Asia fanned out across the Pacific to Australia and points beyond. These mariners have sailed under the radar of many scien tists seeking the earliest settlers of the Americas, Oregon’s Erlandson asserted at the anthropology meeting.

Inland sites in North America con tain stone points and mammoth bones that have nurtured a decadesold idea: The New World was first colonized by Asian big game hunters who crossed a land bridge to Alaska around 13,000 years ago. A corridor through massive ice sheets ushered these intrepid carnivores into what’s now the United States, where they founded the Clovis culture, named after a New Mexico site that has yielded stone spear points.

It’s now an open question whether the Clovisfirst hypothesis will hold up, Erlandson says. In the March 4 Science, he and his colleagues reported that peo ple lived on California’s Channel Islands by about 12,200 years ago. A sea cruise of nine to 10 kilometers was required to reach these ocean outposts.

Three Channel Island sites — seasonal camps, most likely — yielded narrow stemmed stone points and crescent shaped implements, lying among bones of seabirds such as geese and cormo rants, seals and other sea mammals, and several types of fish. Piles of shells from

Stone tools from Channel Island sites
dating to 12,200 years ago suggest
that the first colonizers to the New
World may have come by sea.

red abalone, giant chiton, mussels and other shellfish also turned up.

Stone tools found on the Channel Islands look nothing like Clovis points. In an upcoming Quaternary International, Erlandson and Todd Braje of Humboldt State University in Arcata, Calif., argue that stemmed stone points found on the islands instead resemble those that have been found at coastal sites stretch ing from Korea, Japan and northeastern Russia to North and South America.

These finds date to bet ween 35,000 and 15,000 years ago in Asia, and to as early as 14,500 years ago in the Pacific Northwest, Erlandson said at the meeting, support ing his suspicion that initial New World colonists used canoes or other vessels to navigate along the coast from Asia to the Americas. Stemmed points found around lakes and marshes in western North America look like Channel Island finds, indicating that coastal people not only cruised the open sea but headed inland, possibly to trade for goods with Clovis people, Erlandson says.

“We have to start creating new mod els of the peopling of the Americas,” he says. “Received wisdom and a good story can inhibit research for decades, as hap pened with the Clovis hypothesis.”

Inundated evidence Encroaching oceans also inhibit inves tigations of humankind’s watertravel ing ancestors. A global sea level rise of about 120 meters between 20,000 and

6,000 years ago flooded shorelines and nearby lowlands where ancient popu lations presumably camped. “Current evidence for Stone Age coastal occupa tions represents the tip of the iceberg,” Erlandson says.

Yet the patchy evidence available for ancient tide tracking on South Africa’s coast leaves some researchers skeptical. A connection between shellfish harvest ing at Pinnacle Point and a rapid trans formation in human thinking remains questionable, argues Stanford University archaeologist Richard Klein.

Coastal caves bearing stone tools and seafood remains from more than 164,000 years ago may yet be found, he asserts. And shellfish gathering requires no special knowledge, tools or personal risk if the tide happens to be out. Coastal baboons in Africa collect and eat shell fish. Seagulls drop mussels and other tidal treats on hard ground to break open shells, leaving behind what sometimes looks like human garbage, Klein says. Also, abundant archaeological evidence of fish eating by Europeans and Africans dates to no more than 50,000 years ago, long after brain size had ballooned.

“It will take a long time to test my hypothesis about an ancient coastal adaptation in South Africa,” Marean acknowledges. Prime shoreline camps from long ago undoubtedly lie under water, “guarded by great white sharks and dangerous currents,” he says.

He and his colleagues are now explor ing more caves at Pinnacle Point and have expanded their search to caves on South Africa’s eastern coast. Some of these sites are located where the con tinental shelf drops steeply and the coast was always near, possibly giving researchers access to ancient camps that never got inundated by the ocean.