More evidence that humans roamed North America before the Clovis culture 13,000 years ago has emerged from analysis of a bone-tip spear embedded in a mastodon bone, scientists said Thursday. The rib bone was found embedded with the tip of an ancient weapon in the 1970s, but a new analysis using DNA and radiocarbon dating shows it is actually 13,800 years old, placing it almost a millennia earlier than the Clovis people. The research, led by Michael Waters of Texas A&M University and Eske Willerslev from the University of Copenhagen, appears in the journal Science. \"I am sure that especially the Native Americans are pleased with the results of the study. It is further proof that humans have been present in North America for longer than previously believed,\" said Willerslev, director of the Centre for GeoGenetics at the Natural History Museum of Denmark. \"The \'Clovis First\' theory, which many scientists swore to just a few years back, has finally been buried with the conclusions of this study.\" The mastodon bones and spear-tip, which was also carved from a mastodon bone, were found at the Manis Mastodon site in the western state of Washington\'s Olympic Peninsula. Mastodons, now extinct, were mammals that resembled elephants and had very long tusks. The finding that humans were hunting mastodons before the Clovis people helps discount the theory of a \"Clovis blitzkrieg,\" or heavy hunting over a short term that eradicated the giant beasts. \"The Manis site provides further evidence of a human presence in the New World 800 years before Clovis and shows that people were hunting with mastodon bone weapons made from earlier kills,\" said the study. Previously, it was widely believed that the hunt for mastodons in North America began with the Clovis culture, \"a type of common culture ancestral for all Native American tribes in North America,\" it said. Willerslev and colleagues published a study three years ago that found the first traces of humans in North America are approximately 14,340 years old, based on Carbon-14 dating and DNA analysis of human remains in caves in the western state of Oregon, suggesting that American Indians are descendants of migrants who came from Asia.