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. Through our regional projects, such as in South Wales we are undertaking habitat management to create and reconnect adder populations.

We undertake a range of communications activities, including helping the public identify adders, and giving advice on what to do when adders are found in gardens. We work with the media to provide helpful and accurate advice on adder issues. We organise meetings and conferences either wholly or partly on adder conservation, including Vanishing Vipers the first ever national conference dedicated solely to adders, led by ARG UK in October 2016.

We provide advice and training on technical and legal issues relating to adders for conservation practitioners, and we include adder-related advice in our broader work on reptiles. For example, we publish a leaflet on how agri-environment schemes can benefit reptiles including the adder, and we produced advice for the “Farm Wildlife” initiative to help farmers manage adder habitat.

The National Amphibian and Reptile Monitoring Programme includes surveys that tell us about the status of adders, and we work with others to generate and share data on the species, especially ARG UK through the Record Pool and Make the Adder Count.

Our policy work aims to ensure that adder requirements are better considered, for example in advising government agencies on ways to improve the protected site series, and producing the first IUCN Red List assessment of the species at country level.

Through our involvement in the Back from the Brink programme, we aim to help conservationist deal better with species like the adder, and we are working with Butterfly Conservation in Rockingham Forest specifically on an adder project as part of Roots of Rockingham. We work with a range of external initiatives that help adders, for example the Garden Wildlife Health project which investigates ill health, and the Bearing Witness for Wildlife project which aims to improve enforcement of legislation and prevent crime.

We work with scientists to promote research that will help adder conservation, and we hold an annual conference to allow researchers to feed back their findings to the conservation community.

Read more about the ARC Adder Status Report 2012

Facts and advice on adder bites

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