Adder
Vipera berus
Quick answer
The adder, or common European viper, is the United Kingdom's only venomous snake, recognised by the bold dark zigzag stripe running down its back. It is shy and rarely bites people, using its venom mainly to subdue small mammals and lizards. Adders are about 60–90 cm long, give birth to live young, and bites, while painful, are very rarely dangerous to healthy adults.
Adder facts at a glance
| Scientific name | Vipera berus |
|---|---|
| Diet | Carnivore (small mammals, lizards, frogs) |
| Habitat | Heathland, moorland, woodland edges, dunes |
| Lifespan | 10–15 years |
| Length | 60–90 cm (24–35 in) |
| Venom | Venomous; bites rarely fatal to humans |
| Conservation status | Least Concern (IUCN) |
| Kingdom | Animalia |
|---|---|
| Phylum | Chordata |
| Class | Reptilia |
| Order | Squamata |
| Family | Viperidae |
| Genus | Vipera |
What is a group of adders called?
Group name (collective noun)
A group of Adders is called a nest. It is also known as a pit or a bed.
Baby name
A baby Adder is called a snakelet.
Explore more animal collective nouns and baby animal names .
Venom and bites
The adder is venomous, but it is a shy snake that bites people only when trodden on, cornered, or handled. Its venom is designed to immobilise small prey, and serious harm to a healthy adult is rare — most bites cause pain and swelling rather than lasting injury. All bites should still be treated as a medical emergency, as reactions vary; children, older people, and pets are most at risk, and antivenom is available where needed.
Appearance and identification
Adders are unmistakable thanks to the dark zigzag band along the back and a row of dark spots down the sides, set against a grey, brown, or reddish ground colour; some individuals are entirely black. There is usually a dark 'V' or 'X' mark on the head and red eyes with vertical pupils. Males tend to be greyer and females browner, and the species is relatively stocky for its modest length.
Diet and behaviour
Adders are ambush predators that feed on small mammals such as voles and mice, along with lizards, frogs, and the eggs and chicks of ground-nesting birds. They use venom to subdue prey, then track and swallow it whole. Cold-blooded and dependent on the sun, adders bask to warm up and hibernate through winter, often returning to the same communal sites year after year.
Range and conservation
The adder has one of the widest ranges of any snake, stretching across Europe and Asia all the way to the Pacific, and it lives farther north than any other snake, even within the Arctic Circle. Globally it is listed as Least Concern, but in Britain it has declined due to habitat loss and disturbance and is a conservation priority. It gives birth to live young rather than laying eggs.
Frequently asked questions about the Adder
Is the adder dangerous?
Adders are venomous but not aggressive, and they bite people only in self-defence. Bites are painful and need medical attention, but they are very rarely fatal to healthy adults; children, older people, and pets are most at risk.
What does an adder look like?
Adders have a bold dark zigzag stripe down the back, dark side spots, and a 'V' or 'X' mark on the head, over a grey, brown, or reddish body. Some are all black, and they have red eyes with vertical pupils.
Where do adders live?
Adders favour heathland, moorland, woodland edges, and coastal dunes across Europe and Asia. They are the only venomous snake native to Britain and range farther north than any other snake.
What do adders eat?
Adders are carnivores that ambush small mammals such as voles and mice, as well as lizards, frogs, and ground-nesting birds' eggs and chicks. They use venom to subdue prey and swallow it whole.
Do adders lay eggs?
No. Unlike most British reptiles, adders give birth to live young in late summer. The eggs develop inside the female, and she produces around six to twenty tiny snakelets.
What is a group of adders called?
A group of Adders is called a nest. It is also known as a pit or a bed.
What is a baby adder called?
A baby Adder is called a snakelet.
Sources & references
This guide is compiled and reviewed against established zoological and conservation references. Key sources for the Adder:
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IUCN Red List of Threatened Species
Conservation status (Least Concern) reflects the IUCN Red List category for Vipera berus.
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