One of the largest snakes in Europe the Aesculapian snake can be more than 2 metres long. Easily recognisable by its long thin body with small pointed head, prominent eyes and round pupils. Uniform back coloring being yellowish-brown, greyish-brown, greyish-black, or olive green and sometimes speckled with a pale underside. Juveniles can easily be confused with juvenile grass snakes (Natrix natrix), because juvenile Aesculapian snakes also have a yellow collar on the neck that may persist for some time in younger adults. Juvenile Aesculapian snakes are light green or brownish-green with various darker patterns along the flanks and on the back. Two darker patches appear in the form of lines running on the top of the flanks. The head in juveniles also features several distinctive dark spots, one hoof-like on the back of the head in-between the yellow neck stripes, and two paired ones, with one horizontal stripe running from the eye and connecting to the neck marks, and one short vertical stripe connecting the eye with the 4th to 5th upper labial scales.
They are to be found in most regions of France with the exception of the extreme north and north-east. They prefer a dry sunny habitat and generally lives in dense vegetation, brambles, thickets and woodland, this in combination with their colouring make it very difficult to observe them. They can sometimes be seen by the edges of these habitats or on a stone wall or roadside. Their principle diet is composed of small mammals, birds and their young from nests in trees, lizards and young snakes. They kill by constriction and suffocation by eating their prey head first.
Their main period of activity is during the day until nightfall and although perhaps principally a land dweller they are also a spectacular tree climber able to climb vertically old rough barked trees or wind their way through the branches of bushes. They are a generally calm snake with very little aggression, sometimes known when provoked to point its head at whatever is annoying it and makes strange “mouth” sounds in an attempt to frighten. Hibernation takes place in October/November until March/April under an old tree stump, in an abandoned badger set or somewhere of a similar nature.
Coupling starts in May with some simulated combat, which although sometimes spectacular is completely harmless for those taking part. Females will produce between 5 and 20 eggs in June/July; these are laid under a stone, in a stone wall, under decomposing vegetation / compost heap or in the rotting base of a tree stump, hatching is about 8 weeks later.