Pacific Island cultures are useful for testing theories of nature and nurture, as Jared Diamond emphasized in Guns, Germs, and Steel:
Moriori and Maori constitutes a brief, small-scale natural experiment that tests how environments affect human societies. Before you read a whole book examining environmental effects on a very large scale— effects on human societies around the world for the last 13,000 years—you might reasonably want assurance, from smaller tests, that such effects really are significant. If you were a laboratory scientist studying rats, you might perform such a test by taking one rat colony, distributing groups of those ancestral rats among many cages with differing environments, and coming back many rat generations later to see what had happened. Of course, such purposeful experiments cannot be carried out on human societies. Instead, scientists must look for “natural experiments,” in which something similar befell humans in the past. Such an experiment unfolded during the settlement of Polynesia. Scattered over the Pacific Ocean beyond New Guinea and Melanesia are thousands of islands differing greatly in area, isolation, elevation, climate, productivity, and geological and biological resources. For most of human history those islands lay far beyond the reach of watercraft.
Diamond begins with the story of how in 1835, the teeming masses warlike Maoris of New Zealand invaded and conquered their pacifist hunter-gatherer cousins, the Moriori of the remote and chilly Chatham Islands. Polynesian crops wouldn’t grow on the Chatham Islands, so the settlers had centuries before become foragers. If the old stories are true, the Moriori may have been one of the few pacifist cultures in human history.
The origins of the Moriori of Rekohu (the native moniker for the Chathams) remain a mystery to this day. Mr. Evans evinces the belief they are descended from the Jews expelled from Spain, citing their hooked noses and sneering lips. Mr. D’Arnoq’s preferred theorem, that the Moriori were once Maori whose canoes were wrecked upon these remotest of isles, is founded on similarities of tongue & mythology & thereby possess a higher carat of logic. What is certain is that, after centuries or millennia of living in isolation, the Moriori lived as primitive a life as their woebegone cousins of Van Diemen’s Land. Arts of boatbuilding (beyond crude woven rafts used to cross the channels betwixt islands) & navigation fell into disuse. That the terraqueous globe held other lands, trod by other feet, the Moriori dreamt not. Indeed their language lacks a word for “race” & “Moriori” means, simply, “People.” … In their virgin state, the Moriori were foragers, picking up paua shellfish, diving for crayfish, plundering bird eggs, spearing seals, gather kelp & digging for grubs & roots.
… Old Rekohu’s claim to singularity, however, lay in its unique pacific creed. Since time immemorial, the Moriori’s priestly caste dictated that whosoever spilt a man’s blood killed his own mana – his honor, his worth, his standing & his soul. No Moriori would shelter, feed, converse with, or even see the persona non grata. If the ostracized murderer survived his first winter, the desperation of solitude usually drove him to a blowhole on Cape Young, where he took his life.
Consider this, Mr. D’Arnoq urged us. Two thousand savages (Mr. Evans’s best guess) enshrine “Thou Shalt Not Kill” in word & in deed & frame an oral “Magna Carta” to create a harmony unknown elsewhere for the sixty centuries since Adam first tasted the fruit of the Tree of Knowledge. War was as alien a concept to the Moriori as the telescope is to the Pygmy. …
All those misfortunes the Moriori might have endured, however, were it not for reports arriving in New Zealand depicting the Chathams as a veritable Canaan of eel-stuffed lagoons, shellfish-carpeted coves & inhabitants who understand neither combat nor weapons. To the ears of the Ngati Tama & Ngati Mutunga, two clans of the Taranaki Te Ati Awa Maori …, these rumors promised compensation for the tracts of their ancestral estates lost during the recent “Musket Wars.” … The tattooed Maori conquistadores found their single-barked armada in Captain Harewood of the brig Rodney, who in the dying months of 1835, agreed to transport nine hundred Maori & seven war canoes in two voyages, in guerno for seed potatoes, firearms, pigs, a great supply of scraped flax & a cannon. (Mr. D’Arnoq encountered Harewood five years ago, penurious in a Bay of Islands tavern. He at first denied being the Rodney’s Harewood, then swore he had been coerced into conveying the Blacks, but was unclear how this coercion had been worked upon him.) …
… Fourteen years ago, the Moriori men held on that sacred ground a parliament. Three days it lasted, its object to settle this question: Would the spillage of Maori blood also destroy one’s mana? Younger men argued the creed of Peace did not encompass foreign cannibals of whom their ancestors knew nothing. The Moriori must kill or be killed. Elders urged appeasement, for as long as the Moriori preserved their mana with their land, their gods & ancestors would deliver the race from harm. “Embrace your enemy,” the elders urged, “to prevent him from striking you.” (“Embrace your enemy,” Henry quipped, “to feel his dagger tickle your kidneys.”)
The elders won the day, but it mattered little. “When lacking numerical superiority,” Mr. D’Arnoq told us, “the Maori seize an advantage by striking first & hardest, has many hapless British & French can testify from their graves.” … On Waitangi Beach fifty Moriori were beheaded, filleted, wrapped in flax leaves, then baked in a giant earth oven with yams & sweet potatoes. Not half those Moriori who had seen Old Rekohu’s last sunset were alive to see the Maori sun rise.