Anaconda Giants: Size Unchanged for 12 Million Years

New research indicates that anacondas achieved their massive form around 12.4 million years ago and have remained consistently large since. Analysis of numerous giant anaconda fossils from South America by a University of Cambridge-led team challenges the assumption that ancient snakes were bigger due to a warmer world.

Contrary to expectations of much larger ancient snakes, the study found that anacondas from the Middle to Upper Miocene were approximately 4 to 5 meters long, similar to modern green anacondas. This stability in size persisted even as other megafauna like giant caimans and turtles eventually went extinct.

Researchers attribute the anacondas' enduring size to the persistent availability of suitable habitats, including swamps and extensive river systems like the Amazon. These environments provided ample prey and waterlogged terrain, allowing the snakes to sustain their considerable dimensions for millions of years.