Skip to comments.Drifters Could Explain Sweet-Potato Travel
Posted on 05/20/2007 4:28:04 PM PDT by blam
Drifters could explain sweet-potato travel
An unsteered ship may have delivered crop to Polynesia.
Where did these come from?
How did the South American sweet potato wind up in Polynesia? New research suggests that the crop could have simply floated there on a ship.
The origin of the sweet potato in the South Pacific has long been a mystery. The food crop undisputedly has its roots in the Andes. It was once thought to have been spread by Spanish and Portuguese sailors in the sixteenth century, but archaeological evidence indicates that Polynesians were cultivating the orange-fleshed tuber much earlier than that, by at least AD 1000. However, there's no hard evidence of people travelling between South America and the South Pacific so early in history. Most Polynesian crops have their origins in Asia, where the people are thought to have migrated from.
Some scientists have suggested that sweet-potato seeds were carried in the stomachs of itinerant birds. Others suggested that Polynesians once voyaged to the Ecuadorian coast, and foregoing such South American staples such as maize and Phaseolus beans they brought back a root that reminded them of Asian yams. Still others proposed that the sweet potato floated 8,000 kilometres across open ocean, either in its spherical seed pod or in a drifting vessel.
An unlikely journey
This last theory was dismissed in the 1970s, when a group of researchers ran what was then a state-of-the-art ocean-circulation simulation and concluded that the vessels would be extremely unlikely to drift into Polynesia by accident1. But Álvaro Montenegro, an oceanographer at the University of Victoria, British Columbia, says that this old model has "outlived its usefulness". Researchers now know, for instance, that the equatorial ocean currents travel much faster than previously thought; projections of drift have changed.
Montenegro and his team used data from the Estimating the Circulation and Climate of the Ocean (ECCO) experiment, which combines a circulation model with 12 years of oceanographic measurements. This approach gives a glimpse of circulation patterns with a spatial resolution of about 50 square kilometres, and allowed Montenegro to consider 160 launch sites along the South and Central American coast compared with the earlier team's six.
In the simulation, sweet-potato seed pods that started off in these American waters could reasonably hit seven different island groups, and had the best chance of landing on the Marquesas. "Among the three most likely targets that get hit, two are within the area where people believe the crop was introduced," says Montenegro. But the trip took at least four months. Even coconuts can't survive in salt water that long.
More likely, says the team, a loaded vessel was blown out to sea and landed on the islands which could take as little as 90 days, they report in an upcoming issue of the Journal of Archaeological Science2. Montenegro notes that seed pods are transported by currents alone, but a drifting vessel gains momentum from the wind.
Rooted in fact?
With 2,000 years between sweet-potato domestication in South America and its arrival in Polynesia, there have probably been numerous such drift events. But did people survive the trip, along with the crops?
Montenegro says linguistic similarities between the Quechua word for the tuber, cumal, and the Polynesian one, kumala, suggest that humans must have been along for the ride. Patrick Kirch, an archaeologist at the University of California, Berkeley, who has worked on the issue, thinks that more extensive and deliberate contact must have taken place. "In my view, the most probable mechanism of transport was Polynesians sailing to South America," he says.
The simulations, Montenegro says, simply demonstrate the feasibility of the drift theory, but a final verdict will depend on future archaeological findings. This approach may also help us understand how other plants, such as the bottle gourd, have drifted to the distant islands. And vessel drift is not just a thing of the past either. Montenegro points out that in 2005-2006, a fishing boat from Mexico was swept to the Marshall Islands just as his model predicts.
Another recent potato story:
Hey, someone was going to...
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In NZ these “sweet potato” are called kumara. They have three colors: gold, white, and red. Much nicer than what you Yanks would call “yams”: you can prepare them exactly like you would a potato. Very, very nice: deep-fried they are a delicious change from Freedom Fries. (Serve with sour cream rather than ketchup, perfect for soaking up excess beer urrrp!). Very nice mashed, or roasted with other root vegetables around the Sunday roast.
Did they arrive here from the Andes? I doubt it. Maori have been cultivating kumara ever since they arrived here in NZ, it is a hi-value hi-energy carbohydrate that would be just perfect for hooning around the South Pacific in dugout canoes. Just as likely a roving band of Maori dropped some kumara off in the Andes during one of their South Pacific cannibalizing jaunts.
The longer I live in NZ, the more convinced I am that the Maori and the Pacific Islanders were alot more clever and mobile than history has given them credit for. The mere facts that they never discovered the wheel, or metals, or a written language is quite deceiving.
Nope: I’m going to put a stake in the ground and state confidently that the Maori brought Kumara to South America, and not the other way around.
I’m just glad they got here.
> Drifters could explain sweet-potato travel
> An unsteered ship may have delivered crop to Polynesia.
I used to be of the opinion that Maori shipwrecked ashore in New Zealand and that they did not navigate their way here, contrary to their oral traditions.
I have changed my mind, having become immersed in their culture.
They were very, very clever with their dugout ocean-going canoes, filled with fghting-fit warrior cannibals, each of them rowing under the direction of a single Navigator. They could beyond doubt navigate by stars, and they could use ocean currents like we use Interstate Hiways.
Something like stone-age Vikings, except with fewer clothes.
Beyond doubt they had regular exchange with Tahitians and Cook Islanders (the languages and physical characteristics are virtually identical) and definitely the Hawaiians (a nine hour flite from Auckland: still, the languages are strikingly similar).
The jolly “kumara” sweet potatoes would never have gotten here by drifting. If brought to NZ from South America, it would have been delivered by war canoe by a marauding raiding party of hungry Maori cannibals, who would have noticed that kumara made a nice condiment to be served with Incas, both roasted slowly in their clay hangi pits.
More likely in my view, the Maori brought kumara to South America.
I would think that this had already been settled back in the 40’s by Thor Heyerdahl.
What "primitive people" but the Maori were able to fight the Europeans to a standstill?
I thought you’d be interested...
Thor Heyerdahl's main theory turned out to be wrong, as genetic evidence makes it obvious that current Polynesians are from Southeast Asia, not the Americas.
> Thor Heyerdahl’s main theory turned out to be wrong, as genetic evidence makes it obvious that current Polynesians are from Southeast Asia, not the Americas.
Perhaps the Southeast Asians are from Polynesia?
This is all just rumor and innuendo. My forebears were not “drifters” at all. Rather, I come from a long line of rogues, charming and rakishly handsome all, and we shall not abide this calumny!
DNA studies show that there was no gene flow from South America out into the Pacific.
Nah. The potato, all 2,000 varieties, are native to South America...no one questions that. The question is how they got to the Pacific Islands.
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