When humans began to colonize South America, they grew like an invasive species, putting strain on the environment and decimating other animals species, new research suggests.
Researchers analyzed 1,147 archaeological sites dating between 14,000 and 2,000 years ago, painting a clearer picture of where and when people lived.
Settlement density appears to have spiked between 13,000 and 9,000 years ago, when humans spread out across the continent to take advantage of its resources. This time period, known as the Pleistocene era, also saw the extinction of dozens of animals species, many from over-hunting.
That population boom was followed by a leveling off of growth about 9,000 years ago.
According the researchers, this pattern is consistent with several invasive species that are introduced to a hospitable environment: They tend to spread quickly, use up available resources and then level off.
Researchers then noted a second population boom, around 5,000 years ago, when people transitioned from hunting and gathering to farming.
It's theorized the sedentary lifestyle brought about by agriculture allowed for people to have larger families.
An invasive species is defined as a species that can cause ecological (or in the instance of plant and animal-based species, economical) harm in an environment where it is not native.
The complete study can be found in the journal Nature.
Source: Nature