Grass snake (Natrix natrix)

The British grass snake is often misidentified as an Adder but it is a non venomous snake sometimes called the water snake or Ringed snake in Europe. It is a grey brown snake (almost black in colder regions) which can grow to over a meter long and can be positively identified (in UK) by a yellow band behind the head.  It is the largest native UK reptile with females reaching up to nearly two meters although typical size is half that with the males being slimmer and about 20% shorter than the females.
As mentioned it is non venomous and rarely bites but if cornered will inflate its body in an aggressive stance and hiss although some have been seen faking death by rolling onto its back becoming limp and leaving its tongue flopping out, they can also vent a noxious smelling fluid which contains asafoetida.


The Grass snake is often found near water as the majority of its prey are amphibians such as frogs and toads, although they will eat small mammals and fish and even take earthworms offered by hand, they will not eat carrion.

As the bite is non toxic prey is swallowed alive and whole as they do not use constriction either with the prey being held by the bite and backwards facing teeth ideal for keeping hold of slippery prey.  As with many reptiles they are ambush hunters rather than actively seeking prey as this conserves energy, in fact energy conservation is something the grass snake does well and some research indicates that an adult can survive on half a dozen frogs for over a year.


Grass snakes prefer to be near water with unsurprisingly long grass which gives them protection. They are strong swimmers like many snakes but don’t use the water all year round as it becomes too cold in winter months. Thye also like open woodland as it gives some protection from the elements but on warm days allows them to bask. During winter they will hibernate seeking shelter and may travel many miles for a good winter spot, mostly underground where the tempreture remains stable.


The males are first to emerge from hibernation followed by the females a few weeks later in April. Mating takes place soon afterwards with the females seeking a warm place (at least 21° C) to lay the eggs such as a compost heap where the decaying matter releases heat. Young females lay around 10 eggs with older females laying upto 40 eggs. The pencil sized young hatch ten weeks later.

The Grass snake can be found in lowland areas of England and Wales but not in highland areas nor in Scotland as these are too cold for the animal, It is not found in Ireland which has no native snakes. In Europe it can be found as far north as Scandinava and as far south as Italy and North Western Africa. Predators include crows, owls and foxes as well as domestic cats and dogs. The Grass snake is covered by the Wildlife and Countryside Act 1981 and it is illegal to harm them or to handle them as this can also cause distress and harm the animal