Easter Island

Maps and pictures

Moai at Rano Raraku -- the volcanic cone of "tuff" which served as quarry for the whole island.

estimated 30,000 people on a 66 square [mile] island

...or, according to the rat theory, maybe never more than about 3,000 people.

Looking up areas

  • 20 mi^2: City of Goshen (population ~35,000)
  • 28 mi^2: City of Elkhart (population ~54,000
  • 42 mi^2: City of South Bend
  • 468 mi^2: Elkhart County

66 miles^2 is slightly smaller than the areas of the cities of Goshen and Elkhart together. About 1/7 the size of Elkhart *County*.

Population density (using 33,000 peak population): Imagine spreading the population of Goshen over the area of Goshen + Elkhart.

Q 7: What questions occurred to you as you read this chapter? Or what did you wonder about?

  • I'll ask this about most of our readings. I want you to exercise your "curiousity muscle" and use your own reflections to engage with the reading. Don't leave this question blank. If nothing occurs to you right away, think back on the reading and see what remains interesting or unexplained in your own mind.

Image from ca. 1880 - for scale with humans

Ahu Tahai: with restored eyes and a pukao (top-knot thing-made of different rock) resting on top.

Contemporary view of island

How do we know there were trees on Easter Island (before the Polynesians arrived...)

Pollen analysis- boring out a column of sediment deposited in a swamp or pond.

Plants and trees spread pollen in the wind every spring. It lands everywhere.

Scientists have drilled down in sediments on the bottom of lakes. The further down sediments come from longer ago.

Under a microscope you can see and try to identify different kinds of pollen.
Britannica: Palynology - The study of pollen and spores.

Jubaea Chilensis: Chilean wine palm .
This is thought to be a modern relative of the palm whose pollen disappeared from the fossil record on Easter Island around 1650.

Manavai (rock shelter for plants) and lithic mulch in background

...the islanders would have never experienced issues from deforestation.

Several of you also mentioned, as evidence for trees, that charcoal from fires revealed that trees *had* been burned. But there is evidence for a transition from burning wood to burning grass.

Also fish remains from early settlements (and canoes), and later no fish.

Map showing location of Easter Island (A) and the closest land, Pitcairn Island (B). This distance, is 1900 km. Some cities that are about this far from Goshen: San Antonio, TX; Miami, FL; Denver, CO.

Polynesians arrived on the island (with rats) in about 900 AD. Diamond says that forests on the island disappeared from different parts of the island between 1400-1600. (First European ships visited in late 1700s.)

Somewhat more factual questions:

  • What kind of food were Easter Islanders eating in the years immediately after arriving? What were they eating several hundred years later, closer to the time that forests disappeared?
  • Which of Diamond's five important factors played a major role, and which played little or no role in the collapse of Easter Island culture?
      • human's effect on the environment
      • fragility
    2. climate change
    3. hostile neighbors [*From the point of view of the whole island, not from the point of view of one clan within the island society.]
    4. friendly trading partners[*]

  • What was the culture and political organization of the society like?
  • Describe how the environment changed over time, and how the **society responded and changed (or did not).
  • What was the importance and role of "volcanic ash" that Diamond raised at the end of the chapter? ["Did other islands experience the same fate?"]
    This was a big deal:
    • Volcanic ash contains nutrients that can replenish nutrients lost from soils when crops are grown.
    • Other islands had volcanoes of their own, or were close enough to receive dust (dried soil) from other islands, or from Southeast Asia.

Synthesizing questions

  • Were the Easter Islanders *to blame* for the collapse of their society and the deforestation of their island? Why or why not?
  • "What were they thinking as they chopped down the last tree?" What responses did you have to this?
    I wonder if they recognized the path they were headed down.
    how long did it take for them to chop down all the trees?
    I think that the biggest issue was that they did not realize to what extent their actions would lead to. They probably just kept on cutting down due to their political pressure, and did not realize that they were living in a spot that would lack many factors that would prevent new growth of trees that would then result in the collapse of their society. I think this is too complex of a situation to know what was going on at the time, what knowledge did they have about the scientific world at that time?

    Can you think of any ways we have of knowing things about the environment (both in different places and in different times) that we have that they didn't?

  • Questions this raises for you? What could have happened differently?

Rats!

In "Rethinking the Fall of Easter Island" (American Scientist) Anthropologist Terry Hunt (University of Hawaii) presents evidence supporting an alternative narrative of the timeline of settlement and decline of trees, in which rats play a major role:

Tom Dunne in American Scientist

Hunter and his collaborator Carl Lipo laid out their ideas more fully in a popular book "The Statues That Walked", so there is a lively debate! Some of the pieces of evidence that are in contention:

  • Date(s) of early settlement: radiocarbon dates from *current* beach.
  • Rat destruction
  • Cannabalism and major conflict? Both sides agree on a ~2.5% rate of "violent" death based on skulls. (But see Mark Golitko's review(Rapa Nui Journal, 2011) points out higher rates based on damage to chest bones.)
  • How did the statues get moved into place: Log rolling vs "walking" the Moai.
  • Both sides agree on pollen and charcoal evidence for depletion of palm trees, and a transition from burning wood to burning grass.

See also Whitney Dangerfield's review in Smithsonian magazine.

Robert Krulwich (NPR science writer) wonders if this new scenario--less of a total collapse, and more "muddling through" and getting used to rat meat and a new, ecologically poorer "normal" -- might be even scarier.

People can't remember what their great-grandparents saw, ate and loved about the world. They only know what they know. To prevent an ecological crisis, we must become alarmed. That's when we'll act. The new Easter Island story suggests that humans may never hit the alarm.

It's like the story people used to tell about Tang, a sad, flat synthetic orange juice popularized by NASA. If you know what real orange juice tastes like, Tang is no achievement. But if you are on a 50-year voyage, if you lose the memory of real orange juice, then gradually, you begin to think Tang is delicious.

On Easter Island, people learned to live with less and forgot what it was like to have more. Maybe that will happen to us.

Image credits

Moai at Rano raraku (Wikimedia), 1880 image (Wikimedia), Ahu Tahai, Jubaea, Arian Zwegers Marcio Cabral do Moura, Michael & Karen Crisafulli