Researchers examined 12.4 million-year-old fossils from Venezuela to understand how much larger ancient anacondas were than their present-day relatives. They found that these early snakes would have averaged 13 to 16 feet (4 to 5 meters) long. This is consistent with the general size of today’s anacondas, meaning these tropical reptiles have remained huge for millions of years.
Unlike other mammoth species, which reached their peak size during the Miocene before becoming extinct and being replaced by smaller species in the Pliocene, “large Eunectes persisted in tropical South America to the present,” the researchers write in their study, published today in the journal Vertebrate Paleontology.
long term veteran
Specifically, the team measured 183 fossilized spinal bones from at least 32 anacondas. Anacondas may have as many as 300 vertebrae, but the size of only one allows researchers to reliably reconstruct how long the snake was. This analysis, along with fossil data from elsewhere in South America, showed that anacondas reached their maximum size 12.4 million years ago. They remained giant, even when many other giant species became extinct.
“Other species like giant crocodiles and giant tortoises have gone extinct since the Miocene, probably due to global warming and shrinking habitat, but giant anacondas have survived – they’re super-resilient,” Andres Alfonso-Rojas, lead author of the study and a PhD student in the Department of Zoology at the University of Cambridge, said in a statement. “By measuring the fossils we found that anacondas grew to a large body size soon after they appeared in tropical South America about 12.4 million years ago, and their size has not changed since then.”
Double check their results
Alfonso-Rojas and colleagues also used an approach called ancestral state reconstruction, which involved reconstructing the length of the giant anaconda and related species of extant snakes along the snake family tree. This method confirmed that when anacondas first emerged during the Miocene, they would have been an average of 13 to 16 feet (4 to 5 m) long.
“This is a surprising result because we expected ancient anacondas to be seven or eight meters long,” explained Alfonso-Rojas. He is approximately 23 to 26 feet tall. “But we have no evidence of any large snakes from the Miocene period, when global temperatures were warmer.” Snakes are particularly sensitive to temperature, so researchers thought the snakes must have been large at that time.
Anacondas are some of the largest snakes in the world and thrive in swamps, marshes, and large rivers like the Amazon. They found it very interesting during the Miocene, when all of northern South America would have been similar to the present-day Amazonian region. There are significantly fewer anacondas today than there were then, but they still have enough habitat and food to maintain their vastness.
The good thing is that other species did not stay in their original size. Can you imagine if we still had megalodon swimming around?
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