"Experts differ on when Polynesian inhabitants first reached the island. While many in the research community cited evidence that they arrived around the year 800, a 2007 study provided compelling evidence suggesting their arrival was closer to 1200."
"By the time of European arrival in 1722, the island's population was estimated to be 2,000 to 3,000."
That implies a huge boom and near-total depopulation crash in only 500 years.
The total area is 163.6 km2 (63.2 sq mi), but usable area is only about 1/2 of that. It is 2,300 miles west of South America and 1,100 miles from the nearest island.
"... new findings by archaeologist Terry Hunt of the University of Hawaii may indicate a different version of events. In 2000, Hunt, archaeologist Carl Lipo of California State University, Long Beach, and their students began excavations at Anakena, a white sandy beach on the island's northern shore. The researchers believed Anakena would have been an attractive area for the Rapanui to land, and therefore may be one of the earliest settlement sites. In the top several layers of their excavation pit, the researchers found clear evidence of human presence: charcoal, tools—even bones, some of which had come from rats. Underneath they found soil that seemed absent of human contact. This point of first human interaction, they figured, would tell them when the first Rapanui had arrived on the island.
"Hunt sent the samples from the dig to a lab for radiocarbon dating, expecting to receive a date around 800 A.D., in keeping with what other archaeologists had found. Instead, the samples dated to 1200 A.D. This would mean the Rapanui arrived four centuries later than expected. The deforestation would have happened much faster than originally assumed, and the human impact on the environment was fast and immediate."
"Hunt suspected that humans alone could not destroy the forests this quickly. In the sand's layers, he found a potential culprit—a plethora of rat bones. Scientists have long known that when humans colonized the island, so too did the Polynesian rat, having hitched a ride either as stowaways or sources of food. However they got to Easter Island, the rodents found an unlimited food supply in the lush palm trees, believes Hunt, who bases this assertion on an abundance of rat-gnawed palm seeds."
"Under these conditions, he says, "Rats would reach a population of a few million within a couple of years." From there, time would take its toll. "Rats would have an initial impact, eating all of the seeds. With no new regeneration, as the trees die, deforestation can proceed slowly," he says, adding that people cutting down trees and burning them would have only added to the process. Eventually, the degeneration of trees, according to his theory, led to the downfall of the rats and eventually of the humans. The demise of the island, says Hunt, "was a synergy of impacts. But I think it is more rat than we think."
They must have been walking around on a carpet of rats at some point.
For comparison, NYC has an area of 1223.59 km² and somewhere in the ballpark of 3 million rats ( https://mandmpestcontrol.com/pests/rats/3-million-rats-in-ny... ), which is a lower total density, but also Rapanui doesn't have quite the same multi-level infrastructure.
owenversteeg•5h ago
>That implies a huge boom and near-total depopulation crash in only 500 years.
There is a fierce debate on the history of Rapa Nui - whether the population was stable until European contact or if there was a large boom and bust. The evidence for the boom-bust has always seemed pretty strong to me. There are the classic arguments of the obvious deforestation, collapse of biodiversity, erosion, islanders moving into caves, etc. But there is one aspect that is, I think, underestimated: heat.
It is a small, isolated island with cooler weather than most other Polynesian islands. The heat really does make a difference, it gives you substantially higher energy requirements; most of the year mean daily temps are 60s F versus 80s on many other Polynesian islands, and the winds are strong. You will need both more calories and more heating (trees.) Then, consider that the period of collapse would line up with the Little Ice Age, which we already suspect to have caused severe drought on the island. [0] Cut down a relatively small number of trees to burn and now your crops and homes will be sprayed with salty, cold sea spray, so you move inland, and to move inland you have to cut down more trees!
There are, of course, other causes of the deforestation, but there is strong evidence [1] suggesting that the people killed the trees, not the rats. Why would you cut down trees? 1) you need more agricultural land, 2) building, 3) heat. Spend all day on a small island with strong salty sea winds on a cool day and you too would enjoy a nice big fire to warm up...
People killed the trees. The rats ate the tree seed fruit. A palm probably produces 200 pounds of seed fruit per year. The only native palm was Paschalococos disperta, which is extinct.
Hilift•6h ago
"By the time of European arrival in 1722, the island's population was estimated to be 2,000 to 3,000."
That implies a huge boom and near-total depopulation crash in only 500 years.
The total area is 163.6 km2 (63.2 sq mi), but usable area is only about 1/2 of that. It is 2,300 miles west of South America and 1,100 miles from the nearest island.
"... new findings by archaeologist Terry Hunt of the University of Hawaii may indicate a different version of events. In 2000, Hunt, archaeologist Carl Lipo of California State University, Long Beach, and their students began excavations at Anakena, a white sandy beach on the island's northern shore. The researchers believed Anakena would have been an attractive area for the Rapanui to land, and therefore may be one of the earliest settlement sites. In the top several layers of their excavation pit, the researchers found clear evidence of human presence: charcoal, tools—even bones, some of which had come from rats. Underneath they found soil that seemed absent of human contact. This point of first human interaction, they figured, would tell them when the first Rapanui had arrived on the island.
"Hunt sent the samples from the dig to a lab for radiocarbon dating, expecting to receive a date around 800 A.D., in keeping with what other archaeologists had found. Instead, the samples dated to 1200 A.D. This would mean the Rapanui arrived four centuries later than expected. The deforestation would have happened much faster than originally assumed, and the human impact on the environment was fast and immediate."
"Hunt suspected that humans alone could not destroy the forests this quickly. In the sand's layers, he found a potential culprit—a plethora of rat bones. Scientists have long known that when humans colonized the island, so too did the Polynesian rat, having hitched a ride either as stowaways or sources of food. However they got to Easter Island, the rodents found an unlimited food supply in the lush palm trees, believes Hunt, who bases this assertion on an abundance of rat-gnawed palm seeds."
"Under these conditions, he says, "Rats would reach a population of a few million within a couple of years." From there, time would take its toll. "Rats would have an initial impact, eating all of the seeds. With no new regeneration, as the trees die, deforestation can proceed slowly," he says, adding that people cutting down trees and burning them would have only added to the process. Eventually, the degeneration of trees, according to his theory, led to the downfall of the rats and eventually of the humans. The demise of the island, says Hunt, "was a synergy of impacts. But I think it is more rat than we think."
https://en.wikipedia.org/wiki/Easter_Island
https://www.smithsonianmag.com/travel/the-mystery-of-easter-...
Y_Y•5h ago
For comparison, NYC has an area of 1223.59 km² and somewhere in the ballpark of 3 million rats ( https://mandmpestcontrol.com/pests/rats/3-million-rats-in-ny... ), which is a lower total density, but also Rapanui doesn't have quite the same multi-level infrastructure.
owenversteeg•5h ago
There is a fierce debate on the history of Rapa Nui - whether the population was stable until European contact or if there was a large boom and bust. The evidence for the boom-bust has always seemed pretty strong to me. There are the classic arguments of the obvious deforestation, collapse of biodiversity, erosion, islanders moving into caves, etc. But there is one aspect that is, I think, underestimated: heat.
It is a small, isolated island with cooler weather than most other Polynesian islands. The heat really does make a difference, it gives you substantially higher energy requirements; most of the year mean daily temps are 60s F versus 80s on many other Polynesian islands, and the winds are strong. You will need both more calories and more heating (trees.) Then, consider that the period of collapse would line up with the Little Ice Age, which we already suspect to have caused severe drought on the island. [0] Cut down a relatively small number of trees to burn and now your crops and homes will be sprayed with salty, cold sea spray, so you move inland, and to move inland you have to cut down more trees!
There are, of course, other causes of the deforestation, but there is strong evidence [1] suggesting that the people killed the trees, not the rats. Why would you cut down trees? 1) you need more agricultural land, 2) building, 3) heat. Spend all day on a small island with strong salty sea winds on a cool day and you too would enjoy a nice big fire to warm up...
[0] https://eartharxiv.org/repository/view/6509/
[1] https://www.sciencedirect.com/science/article/abs/pii/S03054...
Hilift•2h ago
https://en.wikipedia.org/wiki/Paschalococos