Until a few years ago, it was thought that grass snakes were the same as those found across much of Europe. But genetic studies have revealed something surprising: our snakes are genetically different. And they now have their own name, Natrix helvetica, or the barred grass snake, a reference to the dark stripes along their flanks.

Despite their size and mysterious air, grass snakes pose no danger to people. They’re non-venomous hunters, preferring a stealthy ambush to brute force. Their menu is a slippery one: frogs, toads, newts, the occasional fish, and sometimes small mammals. And they’re excellent swimmers. On a summer’s day, you may spot one gliding silently across a pond or ditch, just its head breaking the surface.

As shy creatures, they are keen to avoid encounters with humans. If threatened, however, they put on quite a performance. They may hiss and flatten their heads to appear larger, or – in a truly theatrical twist – roll onto their backs and play dead, tongue lolling for dramatic effect. 

Grass snakes live life to the rhythm of the seasons. They emerge from hibernation as early as March, with males often appearing first to warm themselves in the spring sunshine. Mating takes place in April and May, and by midsummer females lay their eggs in warm, damp places. Around six weeks later, dozens of miniature snakes – perfect replicas of their parents – hatch and immediately face the world alone, with predators ranging from foxes to herons waiting in the wings.

Grass snakes will normally begin to hibernate in October or November. They will use a variety of hibernation sites – just as long as they are warm and humid - compost heaps are perfect so do please be careful not to distribute them if you happen upon one.

Although still widespread, sightings of grass snakes are becoming less frequent. Their reliance on healthy wetland habitats and abundant amphibians makes them vulnerable to habitat loss, water pollution and changes in land use. They are now protected by law in Great Britain and listed as a priority species under the Biodiversity Action Plan.