Scientific name: Vipera berus
Size: The male is around 60cm long, and the female is approx 75cm
Distribution: Found throughout England, Scotland and Wales.
Months seen: March to October. During the winter adders hibernate underground. The young are usually born around August.
Habitat: Adders are normally found on heathland or sand dunes. They can often be seen warming up their bodies (basking) in the sunshine.
Food: Mice, voles and lizards.
Special features: Sometimes called the 'viper'. Of the three types of snake found in Britain, the adder is the only one which is venomous.
Adders can be recognised by the dark zig-zag pattern running down the length of their back, and by the dark V-shaped marking on the back of their head. The background colour of the males tends to be more grey in colour while the females are more brown.