For over a century, the adder has held the dubious honor of being the United Kingdom’s only venomous snake—a reputation that’s sent more than a few hikers scurrying for boots and a healthy respect for the undergrowth. But a recently published scientific paper has upended this long-standing belief, revealing that the smooth snake (Coronella austriaca), one of Britain’s rarest reptiles, also deserves the label "venomous." Before you start eyeing your garden with suspicion, though, the experts are clear: there’s no need to panic.
On September 24, 2026, herpetologists Alessandro Paterna and Grégoire Meier published groundbreaking findings in the journal Zootaxa (DOI: 10.11646/zootaxa.5873.1.8), suggesting the smooth snake should be reclassified as venomous. Their research focused on the snake’s anatomy, particularly the teeth at the back of its maxilla—the outer upper jaw. These teeth are grooved and surrounded by a sheath of gum tissue, a hallmark of so-called rear-fanged snakes. This specialized structure allows the snake to inject small quantities of venom into its prey. According to The Conversation, this discovery has generated lively headlines and a fair share of confusion among the public.
How could the venomous nature of a native British snake have gone unnoticed for so long? And does this mean a new threat is slithering across the English countryside? The answer, as it turns out, is less dramatic than it might first appear.
The smooth snake is, by all accounts, a master of discretion. It is Britain’s smallest and rarest snake, restricted to lowland heaths in southern England. Its habitat is so limited that it’s listed as endangered by the International Union for Conservation of Nature (IUCN). The species lives a secretive life, feeding mainly on lizards, but occasionally on other snakes or small mammals. It’s so rarely seen in the open that most people—even lifelong residents of its home turf—have never spotted one in the wild. Conservation efforts are robust: as a European Protected Species, the smooth snake benefits from habitat preservation and reintroduction programs to former sites, as reported by The Conversation.
For biologists, the news isn’t so much a plot twist as a loose end being tied up. Most of the world’s 4,000 or so snake species belong to the "advanced" snakes, or Caenophidia. Their last common ancestor, which likely slithered through prehistoric landscapes around 65 million years ago, is thought to have already possessed small venom-producing glands—Duvernoy’s glands—and slightly enlarged, grooved teeth at the back of the jaw. As The Conversation explains, from this common ancestor, different snake lineages have taken divergent evolutionary paths: some developed the hypodermic-needle fangs of vipers and elapids, while others lost their venom systems altogether. Many, however, retained a modest version of the ancestral setup—small glands paired with grooved teeth, specialized in some species, barely modified in others.
Venomousness in snakes, it turns out, isn’t a simple on-off switch. It’s a spectrum, ranging from snakes with no venom apparatus at all to those with the fully developed fangs of a viper. In this light, the discovery of the smooth snake’s more specialized rear teeth is less of a revolution and more of an evolutionary footnote. In fact, its venom gland was discovered over a century ago. The new research doesn’t so much "reclassify" the smooth snake as it nudges it a bit further along this continuum of venomousness.
But here’s the crucial point: being venomous does not necessarily mean being dangerous. Paterna and Meier themselves stress that the smooth snake remains as harmless now as it was before their paper. The idea that a snake can be both venomous and harmless may seem counterintuitive, but it’s actually quite common in the animal kingdom. As The Conversation notes, “wherever you’re reading this, you are almost certainly within a few meters of a free-living, unconfined venomous animal: a spider.” Almost every native spider is technically venomous—it's how they subdue insects. Yet only a handful can even pierce human skin, and none produce symptoms worse than a mild local sting.
The same logic applies to the smooth snake. Its venom system evolved to subdue small prey—lizards, other snakes, and the occasional small mammal—not to threaten humans or pets. Its bite is not dangerous to people; at worst, it could inflict a few small scratches. Only the adder remains a concern for humans, and even then, its bite is rarely life-threatening, though it will likely earn you a trip to the emergency department and a week of discomfort, according to both The Conversation and the Zootaxa paper.
Interestingly, the grass snake (Natrix helvetica), another native British species long considered nonvenomous, also possesses venom glands and slightly modified, sheathed teeth. Like the smooth snake, it uses these features to help subdue its primary prey—amphibians—but is harmless to humans. This means that, paradoxically, Britain has no truly nonvenomous native snakes at all. Instead, it boasts two harmless venomous snakes and just one that poses any real risk to people.
For conservationists, this technical reclassification presents something of a public relations challenge. The distinction between "venomous" and "dangerous" is subtle and, for many, confusing. Most people are likely to wonder only whether the smooth snake is a threat to themselves, their children, or their pets. The answer, as Paterna and Meier emphasize, remains unchanged: the smooth snake is harmless. The venom story, while fascinating for herpetologists and evolutionary biologists, does not alter the risk for the average rambler or gardener.
So what’s the real significance of this discovery? For scientists, it’s an important clarification of snake evolution and anatomy. For the public, it’s a reminder that nature is full of surprises, but not always the kind that call for alarm. Britain’s smooth snake continues its quiet existence on the heath, unchanged in its behavior or its relationship to humans. The only thing that’s shifted is our understanding of where it fits on the complex spectrum of venomousness in snakes.
With conservation efforts ongoing and the smooth snake’s habitat still under threat, perhaps the most important takeaway is that knowledge—like the smooth snake itself—sometimes emerges quietly from the undergrowth, offering a deeper appreciation of the wild world just beyond our doorsteps.