Vipera berus

The adder is one of our three native snake species, most often found on heaths, moors and coastal areas. However, its secretive nature and camouflaged markings mean it often goes unnoticed. Whilst it has a large range across the UK, recent declines especially in central England, mean it is of major conservation concern. The adder is the UK’s only venomous snake. Though potentially serious, adder bites to humans or dogs are very rarely fatal. There are only around ten recorded cases of death from adder bite in the last 100 years, and most bites occur when the snake has been disturbed or deliberately antagonised.

Where to find them

The adder is the most northerly member of the viper family and is found throughout Britain, from the south coast of England to the far north of Scotland. In Scandinavia its range even extends into the Arctic Circle. It is not found in Ireland. Adders like open habitats such as heathland, moorland, open woodland and sea cliffs, typically on free-draining soils such as chalk or sand. In most of their range adders rarely enter gardens.


The adder is easily recognised by a dark, continuous 'zig-zag' stripe along its back. There is also a row of dark spots along each side. The background colour varies from grey-white in the male to shades of brown or copper in the female. Young adders are copper, light brown or reddish, with darker brown markings. Completely black adders occur in some areas. Adders can grow to around 60cm in length and have rather a stocky appearance.


Mating takes place in April/May and female adders incubate their eggs internally, rather than laying shelled eggs (which the grass snake does). Adders give birth to around 6 to 20 live young in August or September. Adders feed largely on small rodents and lizards. They hibernate from around October to February, depending on local conditions. Adders typically live to 5-10 years. Their main predators include birds such as crows and buzzards.


Adders are protected by law in Great Britain. It is illegal to intentionally kill or injure adders, or to trade in them.

Download our Adder leaflet:


ARC’s adder conservation work

ARC supports adder conservation in a number of ways. Adders live on many of our nature reserves, and we are undertaking survey and habitat management to conserve these populations. At some of our reserves we are trialling a programme of mapping adder hibernation areas, to help ensure these critical areas are looked after. We work with a wide range of other landowners to promote adder-friendly habitat management. 

To see an overview of ARC's conservation work, take a look at our Saving Species pages. 

Read more about the ARC Adder Status Report 2012

Free adder photo library

ARC is now offering free online access to a selection of beautiful high resolution adder photos, as part of our efforts to try and protect the welfare of this species by reducing disturbance. We encourage their use for educational or creative projects which portray snakes in a positive light. Find out more about the Free Adder Photo Library.

Photo Gallery