Last January we reported that the discovery of stone hand axes on the Mediterranean island of Crete indicate that an ancient Homo species had used rafts or other seagoing vessels to cross from northern Africa to Europe via at least some of the larger islands in between. Now the debate is raging on. "I was flabbergasted," said Boston University archaeologist and stone-tool expert Curtis Runnels. "The idea of finding tools from this very early time period on Crete was about as believable as finding an iPod in King Tut's tomb." Even so, as researchers from the Directorate of Paleoanthropology and Speleology of South Greece and four U.S. universities combed the island, evidence of this unlikely journey kept mounting.
     The team lead by Providence College archaeologist Thomas Strasser found more than 30 hand axes, as well as other stone tools of similar vintage, embedded into geological deposits at nine different locations on the southwestern coast of Crete near the town of Plakias. Some artifacts had possibly eroded out from caves in the sea cliffs, becoming incorporated into ancient beach deposits. Over time, geological processes lifted these ancient beaches up and away from the shore, forming natural terraces. The team's geologists dated the youngest of the terraces associated with the hand axes to at least 45,000 years ago using radiocarbon dating, and they estimated the oldest terrace with stone tools to be at least 130,000 years ago.
     Although archaeologists had found hints of early humans on Crete, these new discoveries, says Strasser, "are the first geologically datable finds. It seems likely that future research will support this initial discovery." If ancient humans were crossing the Mediterranean, Runnels said, then they certainly could have crossed other water barriers, such as the Red Sea or the Gulf of Aden. "And that means that the assumptions that we have had-that the peopling of Eurasia was done by early hominins moving overland through the Near East, into India and down-will have to be revisited."
     Geoff Bailey, an archaeologist at York University in England and an expert on ancient coastal migrations, calls the idea of such ancient sea crossings 'plausible.' But he thinks the team needs to find and conduct excavations at sites where ancient humans were actually making and using the stone tools. "At the moment" Bailey said, "the dating is very vague." Katerina Harvati, a paleoanthropologist who has worked extensively in Greece, accepts the team's identification of the quartz artifacts as hand axes, but she wants to see other lines of evidence for the dates.
     At present, the earliest widely accepted evidence of ancient seafaring comes from Australia.To reach the southern continent from the Southeast Asian mainland some 50,000 years ago, modern humans had to cross a 600-mile-long (970-kilometer-long) band of islands and at least ten ocean straits.Other pieces of evidence, however, suggest that seafaring could go back much deeper in time. The discovery of human remains and stone tools in Spain dating to over a million years ago may indicate that some ancient hominin navigated the hazardous Straits of Gibraltar from Morocco, a journey of less than 12 miles (19 kilometers). Moreover, Michael Morwood, an archaeologist at the University of New England in Armidale, Australia, has long proposed that Homo erectus voyaged from the Indonesian island of Bali to nearby Flores, where excavations have revealed 700,000- to 800,000-year-old stone tools.
     If additional work confirms that the earliest stone tools on Crete date to more than 130,000 years ago, archaeologists may want to take a closer look at these hypotheses. One solid bet is that archaeologists will be giving more thought in years to come to the question of why early humans chose to venture out on the sea in the first place.

Source: National Geographic News (17 February 2010)