Are blind snakes truly primitive, or did they evolve their subterranean lifestyle later?

Nature · Published 3 October 2026 Swipe more like this →

In short: For decades, scientists assumed that the ancestors of all snakes were burrowers with poor vision. Recent genetic analysis of scolecophidians—the group known as blind snakes—challenges this narrative. By mapping their visual systems, researchers have discovered that these snakes lost key genes, suggesting their subterranean traits are specialized evolutionary adaptations.

Scolecophidians, a group comprising roughly 460 of the 3,850 known snake species, have long been considered a window into the past. As one of the oldest lineages in the snake evolutionary tree, they diverged from their relatives, the alethinophidians, over 65 million years ago. These creatures are typically small and cylindrical, characterized by reduced eyes and mouths, which led many to believe they retained the primitive traits of the very first snakes.

However, a 2021 study published in Genome Biology and Evolution provides evidence to the contrary. By analyzing the genetic makeup of two Australian species—the dark-spined blind snake and the prong-snouted blind snake—scientists found that these animals lack seven of the 12 genes typically associated with bright-light vision in other reptiles. This significant genetic loss indicates that the ancestral snake likely possessed much better eyesight than these modern burrowers.

This finding is critical because it refutes the hypothesis that all snakes evolved from extreme burrowers. Instead, it suggests that the subterranean habits and diminished visual systems of scolecophidians are specialized traits developed over tens of millions of years. This process mirrors the convergent evolution seen in burrowing mammals, which have also shed similar vision-related genes. Because re-evolving such complex genetic structures is considered highly improbable, researchers conclude that the common ancestor of all snakes was likely not a dedicated burrower.

Understanding these genetic shifts helps clarify the ecological history of snakes. Rather than being a relic of a primitive, underground existence, the blind snake represents a distinct evolutionary path. This research highlights how specialized environments can drive profound physiological changes, reshaping our understanding of how snakes transitioned from their ancestral forms to the diverse array of species seen across the globe today.

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