system
Given the following post, respond as if you're commenting on Reddit:
human
If European diseases killed off US and Canadian Indians, how come South American countries have such large indian populations?

I recognize the history of colonizations was different. In South America, the spanish did not settle in large numbers as was the case in North America and there were more intermarriages. 

Does this mean the low number of American Indians in the US and Canada was planned?
gpt
Well, here's one explanation with fairly unspecific explanation: ALL amerindian populations were practically wiped out during the columbian exchange. Some contributing factors for regional disparity in the damage done by the Europeans include, but are not limited to:
* The environment to which the native populations could move to (the Cherokee and Iroquois, for example, were repeatedly relocated and destroyed time and again whereas some populations could more successfully melt into their environment for large periods of time, like the Inca at their second "capital" or the Maya in the Peten jungle)
* The ability of some of the native population to assimilate more successfully than others (Like the Aztec remnants, who shared Tenochtitlan with the Castilians as the capital of either empire in successive periods)

There's a kind of contemporary resurgence in really readable work in this area if you're really interested, I'd recommend the two books Charles Mann wrote on the exchange, or 'Stolen Continents' by Ronald Wright.