Britain's only venomous snake. They have the most highly developed venom injecting mechanism of all snakes, but they are not aggressive animals and only strike as a last resort in defence. Adult Males grow up to 60 cm in length weighing in at between 50 to 60 grams. Adult females are bigger growing up to 75cm in length and weighing in at between 80 to 100 grams.
Long lived animals the oldest recorded Adder being 32 years old. The pattern on the back of their heads are unique to each animal and can be used to identify individuals absolutely. They are relatively common in areas of rough, open countryside and are often associated with woodland edge habitats. They prey on small rodents, lizards, frogs and newts, and are known to take young from the nests of ground nesting birds.