Scientific name: Natrix natrix
Size: Females around 110cm in length (sometimes longer), males 80 to 90cm
Distribution: Found in most parts of England and Wales. A few sightings in Scotland (see text below), but absent from Northern Ireland
Months seen: April to October. During the winter grass snakes hibernate under logs or in leaf litter
Habitat: Usually seen near water, often beside ponds and ditches
Food: Fish, frogs, toads and newts
Special features: Grass snakes are the largest of our 3 native snakes. They can be recognised by their distinctive yellow collar and black bars along their flanks. The body is an olive-green colour, but some specimens can be a much darker. The eye has a round pupil, unlike the adder which has a slit shaped pupil. Grass snakes are nonvenomous.
Grass snakes are expert swimmers and a large part of their diet is made up of fish and amphibians.
Grass Snakes will only show aggression if they feel cornered. They can hiss loudly and move in a way that looks as if they might suddenly strike. This is all a show. They rarely bite and if handled will often pretend to be dead. Their body goes limp and they lie motionless with their mouth open. Another defense mechanism is to exude a foul smelling liquid from their anal vent.
Most of the text books tell you that grass snakes are absent from Scotland, but Hazel Stevenson emailed us in 2007 to say they've been sighted at Loch Faskally, Pitlochry, Perthshire on several occasions, and at Ballumbie, a farming area and golf course north-east of Dundee.
In this photo of a hibernation site you can see a group of adders coming out from under a log to bask. Notice the single grass snake amongst them. Apparently the two species have no problem sharing the same hibernation site.