The common adder lives in a variety of habitats, often where water is present or in damper regions and can also be found in salt marshland. Prey is sought at dawn and dusk as a general rule and it consists of small mammals, birds, amphibians and lizards. Unlike most other vipers it is a good swimmer and often takes to the water. Hibernation takes place from October until March / April.
The common adder is only to be found in the north of France, the east of France and the Massif.
It grows to a maximum of 90cm. It has a slightly flattened head and is round nosed, eyes with red iris and vertically slit oval pupils. Colouration varies regionally and also between the sexes, males are more varied in colour than females. Their backs can be almost any colour from pale grey to a dark olive green with darker bands which give a zig zag pattern, underneath they are a greyish blue with intense dark marks. They can also be entirely black; these are normally to be found in high regions above the tree line.