The fruits of migration

As chance would have it, following my recent speculative foray into the possible connection between language and crop diversity, “A Sea of Islands” an essay by the great Andrea Wulf ¹ has just appeared that tells the story of how a remarkable German naturalist used breadfruit and linguistics to work out Polynesian migration patterns long before DNA or archaeology could confirm them.

George Forster sailed with his father aboard the HMS Resolution on Cook’s second voyage (1772-1775) and encountered breadfruit across the South Pacific. He noticed that the trees were seedless and could only be propagated by root cuttings. And also that there didn’t seem to be wild breadfruit trees anywhere in the islands. That meant every tree he saw, and there were many of them, had been deliberately planted by humans.

Digging through the university library back in Göttingen, Forster later found that wild, seeded breadfruit with little flesh do exist, but in Southeast Asia. If the Pacific islands only had the improved, seedless types, he reasoned, they must have been carried there by people. That was proof both of sophisticated Polynesian plant management and of a migration route running from Southeast Asia eastward across the Pacific.

Forster combined this with careful attention to language. He deduced that most Pacific languages he encountered were dialects of a single root language, with small, systematic sound shifts. He and his father also charted how the presence of Malay loanwords decreased the farther east an island was located, which suggested that islands closer to Southeast Asia — the home of Malay — were settled earlier.

Where his fellow naturalist Joseph Banks saw the breadfruit purely as an economic resource (later lobbying to transplant it to the West Indies to feed enslaved plantation workers, hence HMS Bounty and all that), Forster saw it as historical and ethnographic evidence. That’s a strikingly different, more humanistic and — to me at least — appealing way of reading a plant.

Wulf then jumps forward to modern archaeology and genetics, which broadly confirm Forster’s reconstruction. There was an initial human population in the region of Papua New Guinea dating back 45,000 years. This was followed by a second, Austronesian-speaking wave migrating out of Taiwan and thereabouts around 3,500 years ago. They travelled by the stars in “outrigger or double-hulled canoes loaded with hogs, chickens, root vegetables, coconuts, bananas, and breadfruit seedlings.” And they mixed with the descendants of the earlier wave through Melanesia. Their own descendants eventually reached Fiji, Samoa, Tonga, and, much later, Tahiti, Hawaii, Easter Island and New Zealand.

The essay closes by tying this to Tongan historian Epeli Hau’ofa’s idea of “Oceania” — the Pacific not as scattered, isolated islands, lost in a vast ocean, but as one interconnected “sea of islands.” Exactly what Forster intuited two centuries before it became conventional wisdom.

We’ve blogged a lot about breadfruit over the years. Check out the archive. And in particular listen to the recently-retired Dr Diane Ragone describe her 40-year journey to understand this remarkable tree.