[wombatmobile]

Not sure what you mean by "big Amazonian civilisations".

It's full of trees. People traditionally live in small villages.

There are no roads.

The Inca didn't live in the jungle. The administrative, political and military center of the empire was in the city of Cusco. The Inca civilization arose from the Peruvian highlands.

[ncmncm]

You have a great deal to learn about the prehistory of South American civilization. (So do we all.)

Before old-world explorers showed up, the Amazon population was on the order of 100 million. Most of Amazon jungle was, essentially, a big orchard. We find remains of elevated causeways tens of miles long, evidently for getting around during flood times, and levees and berms to retain water long after the flood receded. The dominant trees today all show evidence of domestication.

10,000 years ago they were already well along with their tree breeding program. The Amazon basin never froze, so people living there were able to start civilization well ahead of people in temperate areas. The main mystery is why it started as late as it did, and not 100,000 years earlier.

[wombatmobile]

> Most of Amazon jungle was, essentially, a big orchard.

What is your understanding of the word "orchard"?

What is your understanding of the word "jungle"?

> You have a great deal to learn about the prehistory of South American civilization.

I am always interested to investigate and learn. Could you link to a source for the estimate of 100 million Amazonian jungle inhabitants?

[ncmncm]

Jungle is what we have left of the Amazon flora that has not been cleared for pasture or oilseed.

An orchard is a collection of trees cultivated for their product. Their orchards, unlike those we keep, had a mix of different, complementary species. Tribes in the Pacific Northwest, approximately British Columbia today, also farmed trees this way. Those orchards are distinctive in maintaining their characteristic species mix, untended, into the present.

It is hard to say how much of the "modern" avoidance of multi-cropping traces back to biblical injunction. Nowadays people are likely to blame mechanization and difficulty of making machines compatible with such a practice, but that might be a sort of "just-so" story.

You will need to exercise your google-fu to bring up publications, mostly in the last 10 years. I suggest starting with "pre-columbian amazonian civilization".

[mysecretaccount]

> Before old-world explorers showed up, the Amazon population was on the order of 100 million.

I have not seen any estimate this high even for the total population of the Americas at this time.

[namarie]

> The main mystery is why it started as late as it did, and not 100,000 years earlier.

Well, there were no humans in the americas 100,000 years ago, for a start.

[ncmncm]

But there were people, and tropics, and people in the tropics. Africa, for example, and Sundaland (mountaintops of which are now Indonesia).

We don't know there weren't people in the Americas then. We have good evidence somebody butchered a mastodon near what is now San Diego, what, 130kya? Might have been H. erectus, they really got around. Any way probably not H. sap.