| Summary: | This chapter traces the paleo-history of South America to tackle evolutionary questions about anacondas. Going back in history 150 million years ago, the current continents of South America and Africa were joined in a single mega-continent that also included current Australia and Antarctic. In the northern part of this continent (current South America and Africa) was a large river that started roughly where the current Congo River starts and drained the continent out of what is currently western Ecuador. Approximately 110 million years ago, South America separated from Africa and drifted west. The continent was drained by the paleo-Amazon. As South America drifted west, it collided with the Nazca plate in the eastern Pacific. As the two landmasses moved against each other, the Nazca plate subsided under South America, pushing up the western border of the latter, giving rise to the Andes. The creation of the Andes would result in the eventual closing of the drainage of the paleo-Amazon into the Pacific Ocean. The chapter looks at the significance of this paleo-history to the evolution of anacondas. It seems like the conditions in the paleo-history of the continent of constant flooding were not all that different from the conditions that anacondas encounter currently in the llanos.
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