Many centuries ago, immigrants came to a fertile land blessed with apparently inexhaustible natural resources. It lacked a few raw materials that were important for industry, but they were readily obtained by overseas trade. For a time, the land and its neighbors prospered, and their people multiplied.
But the population of the rich land grew too large for even its abundant resources. As its forests were stripped and its soils eroded, the land could no longer nourish even its own population, let alone grow food for export. Then, as trade declined, the imported raw materials began to run short. A kaleidoscopically changing succession of local military leaders overthrew established political institutions, and civil war spread. To survive, the starving populace turned to cannibalism. The fate of their former overseas trading partners was even worse: deprived of the imports on which they had depended, they ravaged their own environments until no one was left alive.
We don’t know yet if this grim sequence of events represents our own future, but we do know that the scenario has already played itself out on three tropical Pacific islands. One of them, Pitcairn, is famous as the island to which the mutineers from hms Bounty fled in 1790. Unpeopled and very remote, Pitcairn offered a hiding place for Fletcher Christian and his mates from the vengeful British Navy. But although Pitcairn was indeed uninhabited when they landed, the mutineers found evidence that it wasn’t always so: temple platforms, petroglyphs, and stone tools gave mute testimony to Pitcairn’s former Polynesian settlers. Farther east, an even more remote island named Henderson remains uninhabited to this day, yet it too bears abundant marks of a former Polynesian population. What happened to those original Pitcairn Islanders and to their vanished cousins on Henderson?
The romance and mystery of the Bounty, retold in so many books and films, are matched by the earlier tales of these two populations and their mysterious ends. Basic information about them has only recently emerged, thanks to excavations by archeologist Marshall Weisler, who spent eight months on these lonely outposts as part of his graduate studies at the University of California at Berkeley during the early 1990s. He found that the fates of the first Pitcairners and the Henderson Islanders were linked to a slowly unfolding environmental catastrophe hundreds of miles away, on their more populous island trading partner Mangareva, where the inhabitants survived at the cost of a drastically lowered standard of living. While much mystery remains, enough is already known to warn us that these three seemingly exotic islands may carry a vivid and important lesson for our times. Just as the collapse of the Polynesian society on Easter Island warns us that environmental mismanagement can destroy those guilty of it, the fates of the people who lived on Pitcairn and Henderson warn us that societies can also be annihilated by the environmental mistakes of others.
The Polynesian expansion was the most dramatic burst of overwater exploration in human history. Until around 1500 b.c., humans from the Asian mainland, traveling through Indonesia’s islands to Australia and New Guinea, had advanced no farther east into the Pacific than the Solomon Islands. But around that time, a seafaring and farming people apparently originating in the Bismarck Archipelago northeast of New Guinea swept nearly 2,000 miles across the open oceans east of the Solomons to reach Fiji, Samoa, and Tonga and to become the ancestors of the Polynesians. While the Polynesians lacked compasses, writing, and metal tools, they were masters of navigational arts and of sailing canoe technology. Abundant archeological evidence at radiocarbon-dated sites--such as pottery and stone tools, remains of houses and temples, food debris, and human skeletons--testifies to the approximate dates and routes of their expansion. By around A.D. 1000, the Polynesians had reached every habitable scrap of land in the vast watery triangle of ocean whose apexes are Hawaii, New Zealand, and Easter Island.
Historians used to assume that all those Polynesian islands were discovered and settled by chance, when canoes full of fishermen happened to get blown off course. It is now clear, however, that both the discoveries and the settlements were meticulously planned: since much of Polynesia was settled against the prevailing winds and currents, it is unlikely that voyagers could have arrived by drifting. Furthermore, they carried with them many species of crops and livestock deemed essential to the new colonies’ survival, from taro to bananas and from pigs to chickens--a transfer that was certainly deliberate.
Among the most remote parts of Polynesia was the southeast, whose sole habitable islands are Mangareva, Pitcairn, and Henderson. Even Mangareva, the westernmost of those islands, lies about 1,000 miles from the nearest habitable islands outside southeast Polynesia, such as Tahiti and the Marquesas. By the time settlers reached the southeast, sometime between A.D. 800 and 1000, most of the rest of Polynesia, except perhaps New Zealand, had already been discovered and settled.
Of those three habitable islands, the one most abundantly endowed with natural resources important to humans, and capable of supporting the largest human population, was Mangareva. It consists of a large lagoon 15 miles in diameter, sheltered by an outer reef enclosing two dozen extinct volcanic islands and a few coral atolls, with a total land area of ten square miles. The lagoon, its reefs, and the nearby ocean teem with fish and shellfish. Especially valuable to Polynesian settlers was the black- lipped pearl oyster, of which the lagoon offered virtually inexhaustible quantities. Not only could they eat the oyster itself, but its thick shell, up to eight inches long, was an ideal raw material for carving into fishhooks, vegetable peelers and graters, and ornaments.
The higher islands of Mangareva’s lagoon receive enough rain to have springs and intermittent streams, and they were originally forested. Polynesian colonists built their settlements in the narrow band of flat land around the coasts. On the slopes behind the villages they grew crops such as sweet potato and yams; on terraced slopes and flats below the springs they planted taro, which they irrigated with springwater; and on higher elevations they grew tree crops, such as breadfruit and bananas. Mangareva would have been able to support a human population of several thousand, more than ten times the likely combined populations of Pitcairn and Henderson in Polynesian times.
From a Polynesian perspective, Mangareva’s most significant drawback was its lack of high-quality stone for making adzes and other tools. (That’s as if the United States contained every important natural resource except high-grade iron deposits.) The coral atolls in the lagoon had no good stone at all, and even the volcanic islands offered only relatively coarse-grained basalt, which was adequate for building houses and garden walls, for using as oven stones, and for fashioning into canoe anchors and crude tools but which yielded only inferior adzes.
Fortunately, that deficiency was spectacularly remedied on Pitcairn, the much smaller (less than two square miles) and steeper extinct volcanic island lying 250 miles southeast of Mangareva. Imagine the excitement when the first canoeload of Mangarevans discovered Pitcairn: after several days’ travel on open ocean, they spied the island, landed at its only feasible beach, scrambled up the steep slopes, and came upon Down Rope Quarry, southeast Polynesia’s sole usable lode of volcanic glass, whose flakes could serve as sharp tools for fine cutting tasks--the Polynesian equivalent of scissors and scalpels. Their excitement would have turned to ecstasy when, barely a mile farther west along the coast, they discovered the Tautama lode of fine-grained basalt, which became southeast Polynesia’s biggest quarry for making adzes.
In other respects, Pitcairn offered much more limited opportunities than Mangareva. It did have intermittent streams, and in its forests grew trees large enough to fashion into the hulls of outrigger canoes. But Pitcairn was too small and steep to afford much land suitable for agriculture. Furthermore, because Pitcairn’s coastline lacks a reef, and the surrounding sea bottom falls off steeply, fishing and searching for shellfish are much less rewarding than on Mangareva; in particular, Pitcairn has no black-lipped pearl oysters. Hence the total population of Pitcairn in Polynesian times was probably not much greater than a hundred people. The descendants of the original 27 Bounty mutineers and their Polynesian companions living on Pitcairn today number only 52. When their number climbed to 194 in the year 1856, that population overtaxed Pitcairn’s agricultural potential, and many people had to be evacuated by the British government to a distant island.
The remaining habitable island of southeast Polynesia, Henderson, is the largest (14 square miles) but also the most remote (70 miles northeast of Pitcairn; 300 miles east of Mangareva) and the most marginal for human existence. Unlike Mangareva or Pitcairn, Henderson is not volcanic--it’s a coral reef that geologic processes thrust up 100 feet above sea level and is therefore devoid of basalt or other volcanic rocks suitable for toolmaking. That’s an awful limitation for a society of makers of stone tools. To make matters worse, because the island consists of porous limestone, Henderson has no streams or reliable freshwater. At best, water drips from the roofs of caves and puddles on the ground for a few days after the unpredictable arrival of rain. During Marshall Weisler’s months on Henderson, he found it a constant effort to obtain drinking water, even with modern tarpaulins to catch the rain.
Henderson’s tallest trees are only about 40 feet high, not big enough to fashion into canoe hulls. Its beaches are narrow and confined to the north and east end, and the south coast consists of vertical cliffs where it is impossible to land a boat. There, alternating rows of razor- sharp limestone ridges and fissures are capable of cutting your hands to shreds if you fall. Europeans have reached the south end only three times, including Weisler’s trip. It took Weisler, wearing hiking boots, five hours to cover the five miles from Henderson’s north coast to its south coast-- where he discovered a rock shelter formerly occupied by barefoot Polynesians.
Offsetting these fearsome disadvantages, Henderson does have attractions. In the reef and shallow waters nearby live lobsters, crabs, octopuses, and a limited variety of fish and shellfish, unfortunately not including the black-lipped pearl oyster. Each year, green turtles come ashore to lay eggs on the beaches. Henderson used to support at least 17 species of breeding seabirds, including petrel colonies possibly as large as millions of birds, whose adults and chicks would have been easy to catch on the nest. There were enough birds for a hundred people to eat one apiece, every day of the year, without endangering the colonies’ survival. The island was also home to nine species of resident land birds, several of them flightless or weak fliers, including three species of pigeons that must have been especially delectable.
All these features would have made Henderson a great place for an afternoon picnic ashore, or for a short vacation to glut yourself on seafood and birds and turtles--but a risky and marginal home in which to try to eke out a permanent existence. Weisler’s excavations nevertheless showed, to the surprise of anyone who has seen or heard of Henderson, that the island did evidently support a permanent tiny population of perhaps a few dozen people. A huge buried midden--an accumulation of shells and of bird and fish bones and other garbage left behind from generations of people feasting--runs 300 yards along the beach. Every cave and rock shelter near the coast with a flat floor and accessible opening--even small recesses only two by three yards wide, barely large enough for two people to sit there protected from the sun--contained human debris testifying to former habitation. Charcoal, piles of stones, and relict stands of crop plants showed that the northeast part of the island had been burned and laboriously converted to garden patches where crops could be planted in pockets of soil. Among the crops and useful plants that the settlers must have introduced intentionally, Weisler found, were coconuts and bananas, several species of timber trees, candlenut trees whose nut husks are burned for illumination, hibiscus trees yielding fiber for making rope, and the ti shrub. The latter’s sugary roots serve only as an emergency food supply elsewhere in Polynesia but were evidently a staple vegetable food on Henderson. Ti leaves could be used to make clothing, house thatching, and food wrappings.
Thus, southeast Polynesia presented colonists with only a few potentially habitable islands, each with more or less serious drawbacks. But as Weisler’s excavations show, they managed. He uncovered extensive evidence of trade among all three islands, whereby each island’s surpluses filled the other islands’ deficiencies. Trade objects, even stone ones lacking organic carbon suitable for radiocarbon dating, can be dated from radiocarbon measurements on charcoal excavated from the same archeological layer. In that way, Weisler established that trade began by A.D. 1000, probably simultaneously with the first settlement by humans, and continued for many centuries. Numerous objects excavated at Weisler’s sites on Henderson could immediately be identified as imports because they were made from materials foreign to Henderson: oyster-shell fishhooks, volcanic-glass cutting tools, and basalt adzes and oven stones.
Where did those imports come from? A reasonable guess, of course, is that oyster shell for fishhooks came from Mangareva--other islands with oyster beds are much more distant. A few oyster-shell artifacts have also been found on Pitcairn and are similarly presumed to have come from Mangareva. But it is a much more difficult problem to identify sources of the volcanic-stone artifacts found on Henderson, because both Mangareva and Pitcairn, as well as many other distant Polynesian islands, have volcanic- stone sources.
Hence Weisler developed or adapted techniques for discriminating among volcanic stones from different sources. Volcanoes spew out many different types of lava, of which basalt (the category of volcanic stone occurring on Mangareva and Pitcairn) is defined by its chemical composition and color. However, basalts from different islands, and often even from different quarries on the same island, differ from each other in finer details of chemical composition, such as their relative contents of sodium, potassium, niobium, and strontium. An even finer discriminating detail is that lead occurs naturally in several forms, or isotopes, whose proportions also differ from one basalt source to another. To a geologist, these details of composition constitute a fingerprint identifying the source of a stone.
Weisler arranged for analyses of chemical composition and lead- isotope ratios in dozens of stone tools and fragments that he had excavated from dated layers of archeological sites on Henderson. For comparison, he analyzed volcanic rocks from quarries and other potential sources of useful rocks on Mangareva and Pitcairn. Just to be sure, he also analyzed volcanic rocks from more distant Polynesian islands, including Hawaii, Easter, the Marquesas, and Samoa.
The conclusions that emerged from these analyses were unequivocal. All analyzed pieces of volcanic glass found on Henderson originated at the Down Rope quarry on Pitcairn. Most of Henderson’s basalt adzes also originated on Pitcairn, but some came from Mangareva. On Mangareva itself, although far fewer searches have been made for stone artifacts there than on Henderson, some adzes were also evidently made from Pitcairn’s high-quality basalt. Conversely, of the vesicular basalt stones excavated on Henderson, most came from Mangareva, but a minority were from Pitcairn. Such stones were regularly used throughout Polynesia as oven stones, to be heated in a fire for cooking, much like the charcoal bricks used in modern barbecues. Those putative oven stones on Henderson showed signs of having been heated, confirming their surmised function.
In short, archeological studies have now documented a former flourishing trade in raw materials and possibly also in finished tools: in pearl shell, from Mangareva to Pitcairn and Henderson; in volcanic glass, from Pitcairn to Henderson; and in basalt, from Pitcairn to Mangareva and Henderson, and from Mangareva to Henderson. In addition, Polynesia’s pigs and its bananas, taro, and other main crops are species that did not occur on Polynesian islands before humans arrived. If Mangareva was settled before Pitcairn and Henderson, as seems likely because Mangareva is the closest of the three to other Polynesian islands, then trade from Mangareva probably also brought the indispensable crops and pigs to Pitcairn and Henderson. Especially at the time when Mangareva’s colonies on Pitcairn and Henderson were being founded, the canoes bringing imports from Mangareva represented an umbilical cord essential for populating and stocking the new colonies.
As for what products Henderson exported to Pitcairn and Mangareva in return, we can only guess. They must have been perishable items unlikely to survive in Pitcairn and Mangareva archeological sites, since Henderson lacks stones or shells worth exporting. One plausible candidate is live sea turtles, which today breed in southeast Polynesia only on Henderson, and which throughout Polynesia were prized as a prestigious luxury food consumed mainly by chiefs--like truffles and caviar nowadays. A second candidate is red feathers from Henderson’s parrot, fruit dove, and red- tailed tropic bird, red feathers being another luxury item used for ornaments and feather cloaks in Polynesia, analogous to gold and sable.
Then as now, however, exchanges of raw materials, manufactured items, and luxuries would not have been the sole motive for transoceanic trade and travel. Even after Pitcairn’s and Henderson’s populations had grown to their maximum possible size, their numbers--about a hundred and a few dozen individuals, respectively--were so low that people must have had trouble finding marriage partners not forbidden by incest taboos. Hence exchanges of marriage partners would have been an additional important function of the trade with Mangareva. It would also have served to bring craftspeople with technical skills from Mangareva’s large population to Pitcairn and Henderson, and to reimport crops that by chance died out in those islands’ small cultivable areas. In the same way, more recently, the supply fleets from Europe were essential not only for populating and stocking but also for maintaining Europe’s colonies in America and Australia, which required a long time to develop even the rudiments of self-sufficiency.
From the perspective of Mangarevans and Pitcairn Islanders, there would have been still another probable function of the trade with Henderson. The journey from Mangareva to Henderson would take three or four days by Polynesian sailing canoes; from Pitcairn to Henderson, about one day. To Pacific seafaring peoples, who sail their canoes five days just to buy cigarettes, such journeys are part of normal life.
For the former Polynesian inhabitants of Mangareva or Pitcairn, a visit to Henderson for a week would have been a wonderful picnic, a chance to feast on turtles, birds, and their eggs. To Pitcairn Islanders, living on an island without reefs or calm inshore waters or rich shellfish beds, Henderson would also have been attractive for fish, shellfish, and just for the chance to hang out on the beach. Descendants of the Bounty mutineers today, bored with their tiny island prison, jump at the chance for a vacation on the beach of a coral atoll a hundred miles away.
Trade within southeast Polynesia continued from about A.D. 1000 to 1450, as gauged by dates assigned to artifacts on Henderson. But by A.D. 1500 the trade had stopped. Later archeological layers on Henderson contain no more imported pearl shell, volcanic glass, fine-grained basalt for cutting tools, or basalt oven stones. Apparently the canoes were no longer arriving from either Mangareva or Pitcairn. Because trees on Henderson itself are too small to make canoes, Henderson’s tiny population was now trapped on one of the most remote, most daunting islands in the world. Henderson Islanders confronted a problem that seems to us insoluble: how to survive on a raised limestone reef without any metal, without stones other than limestone, and without imports of any type.
They survived in ways that strike me as a mixture of ingenious, desperate, and pathetic. For the raw material of adzes, in place of stone, they turned to shells of giant clams. For awls, they fell back on bird bones. For oven stones, they turned to limestone or coral or giant clamshell, all of which are far inferior to basalt because they retain heat for less time, tend to crack after heating, and cannot be reused as often. They now made their fishhooks out of purse shells, which are much smaller than black-lipped pearl shells, yielding only one hook per shell and restricting the types of hooks that can be fashioned.
Radiocarbon dates suggest that, struggling on in this way, Henderson’s population of originally a few dozen people survived for several generations, possibly a century or more, after all contact with Mangareva and Pitcairn was cut. But by 1606, the year of Henderson’s discovery by Europeans, when a boat from a passing Spanish ship landed on the island and saw no one, Henderson’s population had ceased to exist. Pitcairn’s population we know disappeared by 1790 (the year when the Bounty mutineers arrived to find the island uninhabited), and probably much earlier.
Why did Henderson’s contact with the outside world come to a halt? Because of environmental changes on Mangareva and Pitcairn. All over Polynesia, when people settled on islands that had developed for millions of years in the absence of humans, habitat damage and mass extinctions of plants and animals inevitably followed. Mangareva was no exception.
After the islanders deforested most of the island’s hilly interior to plant their gardens, rain carried topsoil down the steep slopes, and a savanna of ferns, which were among the few plants able to grow on the now-denuded ground, replaced the forest. Eventually, little land was left for gardening and tree crops. Deforestation indirectly reduced yields from fishing as well, because no trees large enough to build canoes remained: when Europeans came to Mangareva in 1797, the islanders had no canoes, only rafts.
With too many people and too little food, hunger on Mangareva became chronic. Modern islanders tell how, starved for protein, people turned to cannibalism, not only eating freshly dead people but also digging up buried corpses. Chronic warfare broke out over the precious remaining cultivable land; the winning side redistributed the land of the losers. Instead of an orderly political system based on hereditary chiefs, nonhereditary warriors took over. All that political chaos alone would have made it difficult to muster the manpower and supplies necessary to cross the ocean, even if there had been trees left for canoes. While much less is known about environmental changes on Pitcairn, Weisler’s limited archeological excavations indicate massive deforestation and soil erosion there as well.
Henderson itself also suffered environmental damage that reduced its human carrying capacity. Half its species of land birds, and colonies of four of its species of breeding seabirds, were exterminated. Those extinctions probably resulted from a combination of hunting for food, habitat destruction for gardens, and depredations of rats that arrived as stowaways in Polynesian canoes. Today those rats continue to prey on the remaining seabirds, which evolved in the absence of rats and so are unable to defend themselves.
Thus, environmental damage, leading to social and political chaos and to loss of timber for canoes, ended southeast Polynesia’s interisland trade, cutting Mangarevans off from Pitcairn’s sources of high-quality stone for making tools. For the inhabitants of Pitcairn and Henderson, the results were even worse: eventually no one was left alive on those islands.
The disappearance of Pitcairn’s and Henderson’s populations must have resulted somehow from the severing of the Mangarevan umbilical cord. Life on Henderson, always difficult, surely became far more so with the loss of all imported volcanic stone. Did everyone die simultaneously in a mass calamity, or did the populations gradually dwindle down to a single survivor living alone with memories for many years? That actually happened to the Indian population of San Nicolas Island off Los Angeles, reduced finally to one woman who survived in complete isolation for 18 years. Did the last Henderson Islanders spend time on the beaches, generation after generation, staring out to sea in the hopes of sighting the canoes that had stopped coming, until even the memory of what a canoe looked like grew dim?
While the details of how human life flickered out on Pitcairn and Henderson remain unknown, I can’t tear myself free of the mysterious drama. In my head, I run through alternative endings of the movie, guiding my speculation by what I know actually did happen to some other isolated societies. When people are trapped together, enemies can no longer resolve tensions merely by moving apart. Those tensions may have exploded in mass murder, which later nearly destroyed the colony of Bounty mutineers on Pitcairn. Islanders could also have eaten each other, as happened to the Mangarevans, Easter Islanders, and--closer to home for Americans--the Donner party in California. Perhaps people grown desperate killed themselves, or gave way to insanity, like some members of the Belgian Antarctic Expedition, whose ship was trapped by ice for more than a year in 1898-1899. Or they may simply have starved, like Japan’s garrison stranded on Wake Island during World War II.
Then my mind turns to gentler possible endings of the movie. After a few generations of isolation on Pitcairn or Henderson, everyone in their microsociety of a hundred or a few dozen people would have been too closely related to marry without violating incest taboos. Hence people may just have grown old together and stopped having children, as happened to California’s last surviving Yahi Indians, the famous Ishi and his three companions. If the small population continued to interbreed, congenital physical anomalies probably proliferated, as deafness has on Martha’s Vineyard Island off Massachusetts and on the remote Atlantic island of Tristan da Cunha.
We may never know which way the movies of Pitcairn and Henderson actually ended. Regardless of the final details, though, the main outline of the story is already clear. The populations of Mangareva, Pitcairn, and Henderson all inflicted heavy damage on their environments and destroyed many of the resources necessary for their own lives. Mangarevans were numerous enough to survive, albeit under chronically terrifying conditions and with a drastically reduced standard of living. But the inhabitants of Pitcairn and Henderson depended on imports of agricultural products, technology, raw materials, and people from Mangareva. Once Mangareva could no longer sustain exports, not even the most heroic efforts to adapt could save them.
Pitcairn and its neighbors seem exotic and remote to Americans, and it’s easy to think that nothing similar could ever happen to us. Looking around us, we see no signs of imminent collapse. Our forests are green, water flows fresh, food is abundant, and peace reigns. But all that was once true on Mangareva and Pitcairn too, when starvation and universal death loomed in the near future. What we should examine are not current conditions but current trends--and those are ominous.
An obvious difference between modern America and ancient southeast Polynesia is in our increasing connectedness. The societies of Mangareva, Pitcairn, and Henderson were joined only to one another, so when they collapsed or died out, no other societies were affected. Today all human societies are interconnected, even those of southeast Polynesia. Although Pitcairn may still rank as the most remote inhabited island in the world, modern Pitcairn Islanders look to ships from New Zealand for supplies. New Zealand in turn depends on Australia and Europe and America, which depend on each other and on everybody else. A survey of garbage washed up on the beaches of pristine uninhabited atolls near Pitcairn revealed 130 glass bottles from at least 14 different countries (dominated by Suntory whiskey bottles from Japan), plus a remarkable assortment of other objects, including 65 lightbulbs, 32 shoes, a bicycle pedal, a football, and a Watney’s beer barrel.
As a result of modern high-speed travel, trouble in any part of the world can lead to trouble anywhere else, no matter how distant. We Americans, who 60 years ago clung to the isolationist notion of Fortress America, have recently become painfully aware that environmental disasters abroad pose as much risk to us as do disasters at home. Political instability in ecologically ravaged faraway lands has required the dispatch of American troops to Somalia and Bosnia, involved us in full-scale war in the Persian Gulf, led to an oil embargo and high gas prices, and propelled streams of illegal immigrants desperate enough to swim ashore from ships.
Looming especially large in America’s future are the awful environmental problems of neighboring Mexico, compounding our superabundance of homegrown ecological disasters. With its fragile environment, shrinking natural resources, and growing population, Mexico suffers from widespread poverty and political unrest. How much more enormous will be the stresses on Mexico, hence on us, 20 years from now, when Mexico has even more people and far fewer environmental resources?
Now as then, neighbors stand or fall together. But the definition of neighbors has changed to encompass the world. The bad news is that we are exporting our problems to all countries, which are in turn exporting their problems to us. The good news is that we have a choice, which the ancient Polynesians never had. We now know, as they could not, of the fates that environmental mismanagement visited upon past societies.