National Geographic : 2000 Dec
any climate finally began to occupy Earth's last temperate landscape. Of course this is all speculation. There's ab solutely no solid evidence that the first human beings to come to the Americas passed any where near this coast line. But today the study of who the first Americans were, where they came from, and when they arrived -always a contentious business-is in tur moil. In this atmosphere even scientists have loosened the reins on that restless racehorse called speculation and let imagination run. This is a bad time if you want certainty about the first Americans but a good time if you like informed mystery. Discoveries in the past decade have cast old concepts in doubt, while others haven't fully developed to take their place. Just enough new information has come to light to enchant the mind with alter native theories, but it's not solid enough to eliminate the old ones. We have entered a period of widespread questioning. Ten years ago most experts would have agreed that the first Americans arrived about 14,000 years ago by walking across a land bridge connecting Siberia and Alaska, then traveled south through an inland corridor between continental ice sheets. Today scientists who are researching the story of the first Americans-archaeologists, physical anthropologists, DNA experts, linguists-disagree on some fundamental parts of that story. Instead of an arrival 14,000 years ago, some scientists now place humans in the Americas 15,000, 20,000, or even 30,000 NATIONAL GEOGRAPHIC, DECEMBER 2000 SOCIETY GRANT Research Committee projects are supported by your Society membership.