Ancient Anaconda Fossils Reveal Snakes Have Maintained Gigantic Size for Millions of Years
VENEZUELA – Fossils unearthed in Venezuela reveal that anacondas have remained remarkably consistent in size – massive – for at least 4 million years,challenging expectations that the snakes would have shrunk alongside other giant reptiles as the climate cooled. The revelation, led by researchers at the University of Cambridge, provides a new understanding of the evolutionary history of these apex predators.
The study, recently published, centers around fossilized vertebrae discovered in the region.Analysis of these bones indicates that anacondas achieved gigantism alongside other large reptiles like the 12-meter-long caiman Purussaurus and the 3.2-meter-long freshwater turtle Stupendemys during the Miocene epoch. However, unlike those contemporaries which eventually became extinct and were replaced by smaller relatives in the Pliocene, anacondas not only persisted but maintained their enormous size.
“4 million years ago,and their size hasn’t changed as,” says Andrés Alfonso-Rojas,a PhD student in the Department of Zoology at the University of Cambridge and the lead author of the study.
Scientists had initially anticipated finding evidence of even larger anacondas in the warmer Miocene period. “This is a surprising result as we expected to find the ancient anacondas were seven or eight metres long. But we don’t have any evidence of a larger snake from the Miocene when global temperatures were warmer,” Alfonso-Rojas explained.
Instead of diminishing in size as the climate cooled, anacondas bucked the trend observed in other wetland animals of northern South America. The origin of their gigantism is thought to be linked to warmer temperatures and a rich, diverse prey base during the Miocene. However, the reason for their continued large size remains a mystery.
The research team hopes that further fossil discoveries will provide additional insights into the evolutionary story of these enigmatic snakes. The anaconda’s spine is comprised of over 300 vertebrae, and the five fossilized vertebrae analyzed in this study represent a crucial piece of the puzzle.
