The adder is the UK’s only poisonous snake and because of this has developed a bad reputation. Despite this the Adder is a shy, timid and non-aggressive species. They are short and fat with a distinct zigzag pattern along the whole length of the back and tail, and dark blotches on the sides, although black individuals are quite common.
Males are usually about 550mm long, generally grey in colour with a black zigzag. Females are usually about 600mm long, generally sandy or reddish in colour with a dark brown zigzag. The head has either a V, X or H shaped mark, but this is not as obvious as the zigzag. The eye is small and red with a vertical pupil.
Adders are found on heathland, moorland and chalk downland. They hide under logs, rocks and shrubby vegetation, and occasionally come out into the open to bask in the sun. Adders hibernate through the winter in places such as disused rabbit burrows on dry, south facing slopes