Collapse: How Societies Choose to Fail or Succeed (18 page)

plant species grown
—four times higher yields averaged over the 16 species,
and 50 times higher yields of the species most benefited by the mulch. Those are enormous advantages.

Chris Stevenson interprets his surveys as documenting the spread of
rock-assisted intensive agriculture on Easter. For about the first 500 years of
Polynesian occupation, in his view, farmers remained in the lowlands
within a few miles of the coast, in order to be closer to freshwater sources
and fishing and shellflshing opportunities. The first evidence for rock gardens that he can discern appears around
a.d.
1300, in higher-elevation inland areas that have the advantage of higher rainfall than coastal areas but
cooler temperatures (mitigated by the use of dark rocks to raise soil temper
atures). Much of Easter's interior was converted into rock gardens. Interest
ingly, it seems clear that farmers themselves didn't live in the interior,
because there are remains of only small numbers of commoners' houses
there, lacking chicken houses and with only small ovens and garbage piles.
Instead, there are scattered elite-type houses, evidently for resident upper-
class managers who ran the extensive rock gardens as large-scale plantations
(not as individual family gardens) to produce surplus food for the chiefs' labor force, while all the peasants continued to live near the coast and walked
back and forth several miles inland each day. Roads five yards wide with
stone edges, running between the uplands and the coast, may mark the
routes of those daily commutes. Probably the upland plantations did not re
quire year-round effort: the peasants just had to march up and plant taro and other root crops in the spring, then return later in the year for the harvest.

As elsewhere in Polynesia, traditional Easter Island society was divided into
chiefs and commoners. To archaeologists today, the difference is obvious
from remains of the different houses of the two groups. Chiefs and mem
bers of the elite lived in houses termed
hare paenga,
in the shape of a long and slender upside-down canoe, typically around 40 feet long (in one case,
310 feet), not more than 10 feet wide, and curved at the ends. The house's walls and roof (corresponding to the canoe's inverted hull) were of three
layers of thatch, but the floor was outlined by neatly cut and fitted foundation stones of basalt. Especially the curved and beveled stones at each end
were difficult to make, prized, and stolen back and forth between rival clans. In front of many
hare paenga
was a stone-paved terrace.
Hare paenga
were
built in the 200-yard-broad coastal strip, 6 to 10 of them at each major site,

immediately inland of the site's platform bearing the statues. In contrast,
houses of commoners were relegated to locations farther inland, were
smaller, and were associated each with its own chicken house, oven, stone
garden circle, and garbage pit
—utilitarian structures banned by religious
tapu
from the coastal zone containing the platforms and the beautiful
hare
paenga.

Both oral traditions preserved by the islanders, and archaeological surveys, suggest that Easter's land surface was divided into about a dozen (ei
ther 11 or 12) territories, each belonging to one clan or lineage group, and each starting from the seacoast and extending inland
—as if Easter were a pie cut into a dozen radial wedges. Each territory had its own chief and its
own major ceremonial platforms supporting statues. The clans competed
peacefully by seeking to outdo each other in building platforms and statues,
but eventually their competition took the form of ferocious fighting. That
division into radially sliced territories is typical for Polynesian islands else
where in the Pacific. What is unusual in that respect about Easter is that, again according to both oral traditions and archaeological surveys, those
competing clan territories were also integrated religiously, and to some ex
tent economically and politically, under the leadership of one paramount
chief. In contrast, on both Mangareva and the larger Marquesan islands
each major valley was an independent chiefdom locked in chronic fierce
warfare against other chiefdoms.

What might account for Easter's integration, and how was it detectable archaeologically? It turns out that Easter's pie does not consist of a dozen identical slices, but that different territories were endowed with different valuable resources. The most obvious example is that Tongariki territory (called Hotu Iti) contained Rano Raraku crater, the island's only source of
the best stone for carving statues, and also a source of moss for caulking ca
noes. The red stone cylinders on top of some statues all came from Puna Pau quarry in Hanga Poukura territory. Vinapu and Hanga Poukura terri
tories controlled the three major quarries of obsidian, the fine-grained vol
canic stone used for making sharp tools, while Vinapu and Tongariki had
the best basalt for
hare paenga
slabs. Anakena on the north coast had the
two best beaches for launching canoes, while Heki'i, its neighbor on the
same coast, had the third best beach. As a result, artifacts associated with
fishing have been found mainly on that coast. But those same north-coast territories have the poorest land for agriculture, the best land being along
the south and west coasts. Only five of the dozen territories had extensive areas of interior uplands used for rock-garden plantations. Nesting seabirds

eventually became virtually confined to a few offshore islets along the south
coast, especially in Vinapu territory. Other resources such as timber, coral for making files, red ochre, and paper mulberry trees (the source of bark pounded into tapa cloth) were also unevenly distributed.

The clearest archaeological evidence for some degree of integration
among the competing clan territories is that stone statues and their red cylinders, from quarries in the territories of the Tongariki and Hanga
Poukura clans respectively, ended up on platforms in all 11 or 12 territories
distributed all over the island. Hence the roads to transport the statues and
crowns out of those quarries over the island also had to traverse many terri
tories, and a clan living at a distance from the quarries would have needed
permission from several intervening clans to transport statues and cylinders across the latter's territories. Obsidian, the best basalt, fish, and other local
ized resources similarly became distributed all over Easter. At first, that
seems only natural to us moderns living in large politically unified countries like the U.S.: we take it for granted that resources from one coast are routinely transported long distances to other coasts, traversing many other
states or provinces en route. But we forget how complicated it has usually been throughout history for one territory to negotiate access to another territory's resources. A reason why Easter may thus have become integrated, while large Marquesan islands never did, is Easter's gentle terrain, contrasting with Marquesan valleys so steep-sided that people in adjacent valleys
communicated with (or raided) each other mainly by sea rather than overland.

We now return to the subject that everyone thinks of first at the mention of Easter Island: its giant stone statues (termed
moat),
and the stone platforms
(termed
ahu)
on which they stood. About 300 ahu have been identified, of
which many were small and lacked moai, but about 113 did bear moai, and
25 of them were especially large and elaborate. Each of the island's dozen
territories had between one and five of those large ahu. Most of the statue-
bearing ahu are on the coast, oriented so that the ahu and its statues faced
inland over the clan's territory; the statues do not look out to sea.

The ahu is a rectangular platform, made not of solid stone but of rubble fill held in place by four stone retaining walls of gray basalt. Some of those
walls, especially those of Ahu Vinapu, have beautifully fitted stones reminis
cent of Inca architecture and prompting Thor Heyerdahl to seek connec
tions with South America. However, the fitted walls of Easter ahu just have

stone facing, not big stone blocks as do Inca walls. Nevertheless, one of Easter's facing slabs still weighs 10 tons, which sounds impressive to us until we compare it with the blocks of up to 361 tons at the Inca fortress of Sac-sahuaman. The ahu are up to 13 feet high, and many are extended by lateral wings to a width of up to 500 feet. Hence an ahu's total weight
—from about 300 tons for a small ahu, up to more than 9,000 tons for Ahu Tongariki— dwarfs that of the statues that it supports. We shall return to the significance of this point when we estimate the total effort involved in building Easter's ahu and moai.

An ahu's rear (seaward) retaining wall is approximately vertical, but the front wall slopes down to a flat rectangular plaza about 160 feet on each side. In back of an ahu are crematoria containing the remains of thousands of bodies. In that practice of cremation, Easter was unique in Polynesia, where bodies were otherwise just buried. Today the ahu are dark gray, but originally they were a much more colorful white, yellow, and red: the facing slabs were encrusted with white coral, the stone of a freshly cut moai was yellow, and the moai's crown and a horizontal band of stone coursing on the front wall of some ahu were red.

As for the moai, which represent high-ranking ancestors, Jo Anne Van Tilburg has inventoried a total of 887 carved, of which nearly half still remain in Rano Raraku quarry, while most of those transported out of the quarry were erected on ahu (between 1 and 15 per ahu). All statues on ahu were of Rano Raraku tuff, but a few dozen statues elsewhere (the current count is 53) were carved from other types of volcanic stone occurring on the island (variously known as basalt, red scoria, gray scoria, and trachyte). The "average" erected statue was 13 feet tall and weighed about 10 tons. The tallest ever erected successfully, known as Paro, was 32 feet tall but was slender and weighed "only" about 75 tons, and was thus exceeded in weight by the 87-ton slightly shorter but bulkier statue on Ahu Tongariki that taxed Claudio Cristino in his efforts to reerect it with a crane. While islanders successfully transported a statue a few inches taller than Paro to its intended site on Ahu Hanga Te Tenga, it unfortunately fell over during the attempt to erect it. Rano Raraku quarry contains even bigger unfinished statues, including one 70 feet long and weighing about 270 tons. Knowing what we do about Easter Island technology, it seems impossible that the islanders could ever have transported and erected it, and we have to wonder what megalomania possessed its carvers.

To extraterrestrial-enthusiast Erich von Daniken and others, Easter Island's statues and platforms seemed unique and in need of special expla-

nation. Actually, they have many precedents in Polynesia, especially in East
Polynesia. Stone platforms called
marae,
used as shrines and often support
ing temples, were widespread; three were formerly present on Pitcairn Is
land, from which the colonists of Easter might have set out. Easter's ahu differ from marae mainly in being larger and not supporting a temple. The Marquesas and Australs had large stone statues; the Marquesas, Australs,
and Pitcairn had statues carved of red scoria, similar to the material used
for some Easter statues, while another type of volcanic stone called a tuff
(related to Rano Raraku stone) was also used in the Marquesas; Mangareva and Tonga had other stone structures, including on Tonga a well-known big
trilithon (a pair of vertical stone pillars supporting a horizontal crosspiece,
each pillar weighing about 40 tons); and there were wooden statues on
Tahiti and elsewhere. Thus, Easter Island architecture grew out of an exist
ing Polynesian tradition.

We would of course love to know exactly when Easter Islanders erected
their first statues, and how styles and dimensions changed with time. Un
fortunately, because stone cannot be radiocarbon-dated, we are forced to
rely on indirect dating methods, such as radiocarbon-dated charcoal found
in ahu, a method known as obsidian-hydration dating of cleaved obsidian
surfaces, styles of discarded statues (assumed to be early ones), and succes
sive stages of reconstruction deduced for some ahu, including those that
have been excavated by archaeologists. It seems clear, however, that later
statues tended to be taller (though not necessarily heavier), and that the
biggest ahu underwent multiple rebuildings with time to become larger and more elaborate. The ahu-building period seems to have fallen mainly in the years
a.d.
1000-1600. These indirectly derived dates have recently gained support from a clever study by J. Warren Beck and his colleagues, who ap
plied radiocarbon dating to the carbon contained in the coral used for files and for the statues' eyes, and contained in the algae whose white nodules
decorated the plaza. That direct dating suggests three phases of construc
tion and reconstruction of Ahu Nau Nau at Anakena, the first phase around
a.d.
1100 and the last phase ending around 1600. The earliest ahu were
probably platforms without any statues, like Polynesian marae elsewhere. Statues inferred to be early were reused in the walls of later ahu and other
structures. They tend to be smaller, rounder, and more human than late
ones, and to be made of various types of volcanic stone other than Rano
Raraku tuff.

Eventually, Easter Islanders settled on the volcanic tuff from Rano
Raraku, for the simple reason that it was infinitely superior for carving. The

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