There is now voluminous data on pre-Columbian trans-oceanic contacts with America. Alice Kehoe cites such examples as the unusual sewn-plank canoes shared by the Polynesians and the Chumash and Kumivit of southern California; the sweet potato, which is native to South America and spread through the Pacific about a thousand years ago: “There is no way sweet potatoes spread through the Pacific except by being carried in boats, and sharing the same word for the plant [kumara] implies peaceful trading contact”.
She makes a compelling case for inter-societal contacts across vast major bodies of water: paper-making, royal purple dye, wheeled figurines; fighting cocks fitted with Asian-style spurs; distilling liquor through Asian-style pot stills; Mesoamericans “valuing jade highly and placing a jade bead painted red with cinnabar in the mouths of corpses; building tiered pyramids symbolising the seven or nine or thirteen heavens; formal body and hand positions (called mudra in India) seen in Mesoamerican art. and the ruler seated on his throne with one leg tucked under, the other hanging. Other customs, like calendar astrology…are widespread in Eurasia, including the Tree of Life with a great bird on top, a lion or jaguar on earth, and a serpent among its roots.. Peanuts and other American crops continue to turn up in Eurasian and Oceanic excavations, substantiating references in pre-Columbian Chinese and Indian texts on cultivated plants. Taken together, there is strong evidence for multiple transoceanic contacts and borrowings before 1492, and at the same time, absolute evidence that American civilizations developed independently of any attempts at colonization by Eurasian or African nations. What the evidence shows is that America’s indigenous nations were part of global connections for several thousands of years before Columbus kicked off the historic invasions”[Controversies in Archaeology, chapter 7].