Article: Some agriculturalists also regularly hunt and gather (e.g., farming during the frost-free season and hunting during the winter). Still others in developed countries go hunting, primarily for leisure. In the Brazilian rainforest, those groups that recently did, or even continue to, rely on hunting and gathering techniques seem to have adopted this lifestyle, abandoning most agriculture, as a way to escape colonial control and as a result of the introduction of European diseases reducing their populations to levels where agriculture became difficult.[citation needed][dubious – discuss]

Now answer this question: Why would they leave agricultural lifestyle?
to escape colonial control