04-06-2025
34-million-year-old snakes discovered in US reveal surprising clues about evolution
A rare snake discovery in western Wyoming has revealed four nearly complete snake fossils dating back 34 to 38 million years, providing rare insights into snake evolution, anatomy, and behaviour.
The fossils, identified as a new species called Hibernophis Breithaupti, were uncovered in a fine layer of mudstone and are among the most intact ever found. Preserved with skulls, ribs, and over 200 vertebrae still in place, these ancient snakes offer a glimpse into how modern boas may have evolved and even hint at early forms of social behaviour like communal hibernation.
34-million-year-old snakes: A rare and perfect discovery in US
Unlike most snake fossils, which are usually limited to disjointed vertebrae and rib fragments, these four specimens were almost fully articulated.
Their exceptional condition allowed scientists to map their entire skeletal structure from head to tail, something rarely achieved with snake fossils. This discovery has opened new avenues for understanding how various skeletal features develop and function in both juvenile and adult snakes.
A new species: Hibernophis Breithaupti
Initially mistaken for known genera such as Ogmophis and Calamagras, further examination revealed consistent differences in jaw shape, tooth arrangement, and vertebral features.
These distinctions led scientists to classify them as a new species, Hibernophis Breithaupti. Small in size, these snakes were likely burrowers. The discovery of differently sized specimens provided a rare chance to observe both juvenile and adult stages within a single species.
Insights into Boa evolution
Through detailed anatomical comparisons and DNA analysis, scientists placed Hibernophis close to the Boa family. The findings suggest that early boas were modest in size and had already started diversifying by the Oligocene period.
The articulated spines allowed researchers to trace how individual bones change during growth, a breakthrough for evolutionary biology and museum fossil classification.
Evidence of social behaviour
The four snakes were found curled together in what is believed to be a hibernaculum, a winter shelter used for group hibernation. This is particularly fascinating, as such communal behavior is rare among modern reptiles. The fossil arrangement mirrors behavior seen in modern garter snakes, suggesting that group sheltering for warmth may have existed tens of millions of years ago.
Preserved by volcanoes and mud
The snakes owe their pristine condition to unique geological events. Volcanic ash clouds and seasonal flooding quickly buried their underground shelter in fine sediment, creating airtight conditions ideal for fossilization. These perfect preservation circumstances allowed researchers to study the snakes' bones in detail and make groundbreaking conclusions.
Rewriting the snake family tree
The discovery of Hibernophis Breithaupti not only enriches our understanding of snake evolution but also challenges previous assumptions about their social behavior and development. As paleontologists continue to study the specimens, these ancient snakes may help rewrite significant chapters in the evolutionary history of reptiles.
