Collapse: How Societies Choose to Fail or Succeed (25 page)

fore Pitcairn and Henderson, as seems likely because Mangareva is the clos
est 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, in addition to their later role as a permanent
lifeline.

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 archaeological 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 con
sumed mainly by chiefs
—like truffles and caviar nowadays. A second candi
date is red feathers from Henderson's parrot, fruit dove, and red-tailed
tropicbird, red feathers being another prestigious luxury item used for or
naments and feather cloaks in Polynesia, analogous to gold and sable fur
today.

However, then as now, 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 of marriageable
age would have found few potential partners on the island, and most of
those partners would have been close relatives subject to incest taboos. Hence exchanges of marriage partners would have been an additional im
portant function of the trade with Mangareva. It would also have served
to bring skilled craftspeople with technical skills from Mangareva's large
population to Pitcairn and Henderson, and to reimport crops that by
chance had died out in Pitcairn's and Henderson's small cultivable areas. In
the same way, more recently the supply fleets from Europe were essential
not only for populating and stocking but also maintaining Europe's over
seas colonies in America and Australia, which required a long time to de
velop even rudiments of self-sufficiency.

From the perspective of Mangarevans and Pitcairn Islanders, there
would have been still another likely function of the trade with Henderson.
The journey from Mangareva to Henderson would take four or five days by
Polynesian sailing canoes; from Pitcairn to Henderson, about one day. My

own perspective on sea journeys in Pacific native canoes is based on much
briefer voyages, which left me constantly terrified of the canoe's capsizing or
breaking up and in one case nearly cost me my life. That makes the thought
of a several-day canoe voyage across open ocean intolerable to me, something that only a desperate need to save my life could induce me to under
take. But to modern Pacific seafaring peoples, who sail their canoes five days
just to buy cigarettes, the 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 nesting turtles and their eggs and on Henderson's millions of nesting seabirds. To Pit
cairn Islanders in particular, living on an island without reefs or calm
inshore waters or rich shellfish beds, Henderson would also have been at
tractive for fish, shellfish, and just for the chance to hang out on the beach.
For the same reason, the descendants of the
Bounty
mutineers today, bored
with their tiny island prison, jump at the chance of a "vacation" on the beach of a coral atoll a few hundred miles distant.

Mangareva, it turns out, was the geographic hub of a much larger trade network, of which the ocean journey to Pitcairn and Henderson a few hun
dred miles to the southeast was the shortest spoke. The longer spokes, of
about a thousand miles each, connected Mangareva to the Marquesas to the north-northwest, to the Societies to the west-northwest, and possibly
to the Australs due west. The dozens of low coral atolls of the Tuamotu
Archipelago offered small intermediate stepping-stones for breaking up
these journeys. Just as Mangareva's population of several thousand people
dwarfed that of Pitcairn and Henderson, the populations of the Societies
and Marquesas (around a hundred thousand people each) dwarfed that of
Mangareva.

Hard evidence for this larger trade network emerged in the course of
Weisler's chemical studies of basalt, when he had the good fortune to iden
tify two adzes of basalt originating from a Marquesas quarry and one adze
from a Societies quarry among 19 analyzed adzes collected on Mangareva.
Other evidence comes from tools whose styles vary from island to island,
such as adzes, axes, fishhooks, octopus lures, harpoons, and files. Similarities of styles between islands, and appearances of examples of one island's
type of tool on another island, attest to trade especially between the Mar
quesas and Mangareva, with an accumulation of Marquesas-style tools on
Mangareva around
a.d.
1100-1300 suggesting a peak in interisland voyag
ing then. Still further evidence comes from studies by the linguist Steven Fischer, who concludes that the Mangarevan language as known in recent

times is descended from the language originally brought to Mangareva by its first settlers and then heavily modified by subsequent contact with the
language of the southeastern Marquesas (the portion of the Marquesas
Archipelago closest to Mangareva).

As for the functions of all that trade and contact in the larger network, one was certainly economic, just as in the smaller Mangareva/Pitcairn/
Henderson network, because the networks' archipelagoes complemented
one another in resources. The Marquesas were the "motherland," with a big
land area and human population and one good basalt quarry, but poor ma
rine resources because there were no lagoons or fringing reefs. Mangareva, a
"second motherland," boasted a huge and rich lagoon, offset by a small land
area and population and inferior stone. Mangareva's daughter colonies on Pitcairn and Henderson had the drawbacks of a tiny land area and popula
tion but great stone on Pitcairn and great feasting on Henderson. Finally,
the Tuamotu Archipelago offered only a small land area and no stone at all,
but good seafood and a convenient stepping-stone location.

Trade within Southeast Polynesia continued from about
a.d.
1000 to 1450,
as gauged by artifacts in radiocarbon-dated archaeological layers on Hen
derson. But by
a.d.
1500, the trade had stopped, both in Southeast Polynesia
and along the other spokes radiating from Mangareva's hub. Those later ar
chaeological layers on Henderson contain no more imported Mangareva
oyster shell, no more Pitcairn volcanic glass, no more Pitcairn fine-grained
basalt for cutting tools, and no more Mangareva or Pitcairn basalt oven stone. Apparently the canoes were no longer arriving from either Man
gareva or Pitcairn. Because trees on Henderson itself are too small to make canoes, Henderson's population of a few dozen was now trapped on one of
the most remote, most daunting islands in the world. Henderson Islanders
confronted a problem that seems insoluble to us: 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, desper
ate, and pathetic. For the raw material of adzes, in place of stone, they
turned to shells of giant clams. For awls to punch holes, they fell back on bird
bones. For oven stones, they turned to limestone or coral or giant clamshell, all of which are 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 shell, which is much smaller than black-lipped

pearl oyster shell, so that it yields only one hook per shell (instead of a
dozen hooks from an oyster shell) and restricts 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 genera
tions, possibly a century or more, after all contact with Mangareva and Pitcairn was cut. But by
a.d.
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 own population had disappeared at least by 1790 (the year when the
Bounty
mu
tineers arrived to find the island uninhabited), and probably disappeared
much earlier.

Why did Henderson's contact with the outside world come to a halt? That outcome stemmed from disastrous environmental changes on Man
gareva and Pitcairn. All over Polynesia, human settlement on islands that
had developed for millions of years in the absence of humans led to habitat damage and mass extinctions of plants and animals. Mangareva was espe
cially susceptible to deforestation for most of the reasons that I identified
for Easter Island in the preceding chapter: high latitude, low ash and dust
fallout, and so on. Habitat damage was extreme in Mangareva's hilly inte
rior, most of which the islanders proceeded to deforest in order to plant
their gardens. As a result, rain carried topsoil down the steep slopes, and the
forest became replaced by a savannah of ferns, which were among the few
plants able to grow on the now-denuded ground. That soil erosion in the
hills removed much of the area formerly available on Mangareva for gardening and tree crops. Deforestation indirectly reduced yields from fishing
as well, because no trees large enough to build canoes remained: when Eu
ropeans "discovered" Mangareva in 1797, the islanders had no canoes, only
rafts.

With too many people and too little food, Mangareva society slid into a
nightmare of civil war and chronic hunger, whose consequences are recalled
in detail by modern islanders. For protein, people turned to cannibalism, in
the form not only of eating freshly dead people but also of digging up and
eating buried corpses. Chronic fighting broke out over the precious remain
ing cultivable land; the winning side redistributed the land of the losers. Instead of an orderly political system based on hereditary chiefs, non-
hereditary warriors took over. The thought of Lilliputian military dictatorships on eastern and western Mangareva, battling for control of an island
only five miles long, could seem funny if it were not so tragic. All that politi-

cal chaos alone would have made it difficult to muster the manpower and
■ supplies necessary for oceangoing canoe travel, and to go off for a month and leave one's garden undefended, even if trees for canoes themselves had
not become unavailable. With the collapse of Mangareva at its hub, the
whole East Polynesia trade network that had joined Mangareva to the Mar
quesas, Societies, Tuamotus, Pitcairn, and Henderson disintegrated, as docu- I mented by Weisler's sourcing studies of basalt adzes.
I
While much less is known about environmental changes on Pitcairn,

I
limited archaeological excavations there by Weisler indicate massive defor-
; estation and soil erosion on that island as well. Henderson itself also suf
fered environmental damage that reduced its human carrying capacity. Five
out of its nine species of land birds (including all three large pigeons), and
i colonies of about six of its species of breeding seabirds, were exterminated.
; Those extinctions probably resulted from a combination of hunting for food, habitat destruction due to parts of the island being burned for gar-i dens, and depredations of rats that arrived as stowaways in Polynesian ; canoes. Today, those rats continue to prey on chicks and adults of the remaining species of seabirds, which are unable to defend themselves
i because they evolved in the absence of rats. Archaeological evidence for gar
dening appears on Henderson only after those bird disappearances, suggesting that people were being forced into reliance on gardens by the dwindling
of their original food sources. The disappearance of edible horn shells and
decline in turban shells in later layers of archaeological sites on Henderson's northeast coast also suggest the possibility of overexploitation of shellfish.

Thus, environmental damage, leading to social and political chaos and

to loss of timber for canoes, ended Southeast Polynesia's interisland trade.

That end of trade would have exacerbated problems for Mangarevans, now

cut off from Pitcairn, Marquesas, and Societies sources of high-quality

i
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.

Those disappearances of Pitcairn's and Henderson's populations must

'; have resulted somehow from the severing of the Mangarevan umbilical

cord. Life on Henderson, always difficult, would have become 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, who lived on alone with his or her 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 much time on the