Of the three snake species we have in Britain the adder (Vipera berus) is the only one, which is venomous. They can be identified by a V or an X on the back of their head and a zig-zag pattern that runs the entire length of their body.
Male adders are grey in colour with a very dark zig-zag pattern, whereas the female is brown or bronze in appearance with a dark brown zig-zag.
Female adders can be considerably larger than the males and can reach a length of up to 90cm when mature. Males typically grow to a length of 70cm and are a much slimmer bodied snake.
A bite from the adder is not usually considered serious unless the victim suffers a rare allergic reaction called anaphylaxis.
The adder is protected under the Wildlife and Countryside Act, 1981 Schedule 5 from Trade, Injury and Killing