Common Adder Fact File


A common adder has a stocky body. This is covered with scales that are colored grey, brown, cream, whitish or yellowish-cream. Running down the back is a distinctive pattern which looks like a series of zig-zags or joined Xs. On top of their flat head is a V-shaped black mark. Their scales extend over the eyes and make them appear to be lidded. Females and young are typically more reddish in color.

Common adders have a forked tongue. This is used to help them smell. It is flicked out of the mouth and picks up small particles.

Some common adders exist which are entirely black or ‘melanistic.’

Their length may be up to 80cm (31.5in) long. Females are larger than males and weigh 80-100g (2.8-3.5oz) while males weigh 50-70g (1.8-2.5oz).


The common viper is a carnivore. They feed on a range of small rodents, frogs, birds and lizards. Food is swallowed headfirst.

Often they are an ambush predator who will wait for food to come to them but they will also hunt down prey items.

Once they bite prey and inject their venom they will use their sense to track them until the prey item succumbs to the effect of their venom. Once this occurs they are much easier to consume.

Their venom is effective against prey though in most cases bites to humans are not fatal and only cause swelling. If bitten by a snake always seek medical treatment.

common adder

Scientific Name

Vipera berus

Conservation Status

Least Concern



80-100g (2.8-3.5oz)


50-70g (1.8-2.5oz)


80cm (31.5in)


19 years



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Common vipers are the most widespread member of the viper family. Their range extends across Europe and Asia. Here they can be found in the following countries; Albania, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, China, Croatia, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Korea, Democratic People's Republic of, Latvia, Lithuania, Moldova, Mongolia, Montenegro, Netherlands, North Macedonia, Norway, Poland, Romania, Russia, Serbia, Slovakia, Slovenia, Sweden, Switzerland and the United Kingdom.


They make their home in a number of habitats including Arctic tundra, the alps, forest, shrubland, grassland, wetlands, alpine meadows, dunes and marshes.

Typically areas which they call home are humid.

common adder


Breeding takes place in the spring though females typically only breed once every two to three years.

Males gather at a site know as the mating ground where females will come and select a mate. These females will be swarmed by a selection of males and can select one to mate with.

Once the female selects her mate they will remain together for hours and mate repeatedly. If another male attempts to steal his female they will battle by raising their body and intertwining it with their opponent. The males then attempt to force one another to the ground.

A male can mate with multiple females throughout the same breeding season.

The eggs develop inside the female and they give birth to live young. Each litter can include 20 young. These snakes may each have different fathers if their mother had multiple mates.

Soon after birth the females leave their mother and are independent from then on.

Young common adders are 16-18cm (6.3-7.1in) long.

In some areas the young adders are born during hibernation. At birth they have a fat reserve off of which they can survive for the rest of the hibernation till it is warm enough to emerge.

Sexual maturity is reached at 3-4 years old.


Common adders emerge during the day to bask in the sun.

In the southern areas of their range the common adder will be active year round. In colder northern areas they will hibernate. In some areas this lasts for up to 8 months. They spend the hibernation in a burrow underground. Typically this has been formed by a mammal or reptile beforehand.

Each hibernation burrow can provide housing for up to 100 snakes.

Outside of mating and hibernation the common adder spends most of its time alone.

common adder

Predators and Threats

They face predation from a number of species including the foxes, badgers, birds of prey, owls and larger snakes.

To avoid predation their main defense if to camouflage with the environment and this is assisted by their colouration. If a predator does challenge them they can bite with their venom to scare them away.

Humans affect their population through deforestation. The main threat presented by humans though is killing due to the perceived threat due to them being venomous.

Quick facts

The common adder has many different names including the common viper, crossed viper or Northern palaearctic viper.

They are the only venomous snake which can be found in northwest Europe.

Photo Credits


Photo taken by Artur Mikołajewski / CC BY-SA (

Middle and Bottom

Public Domain


Burnie, D., 2011. Animal. 3rd ed. London: DK

Ambrose, J., 2015. Wildlife Of The World. 1st ed. London: Dorling Kindersley, p.337.

Muir, K. 2006. "Vipera berus" (On-line), Animal Diversity Web. Accessed August 04, 2020 at

Jelka Crnobrnja Isailovic, Milan Vogrin, Claudia Corti, Paulo Sá-Sousa, Marc Cheylan, Juan M. Pleguezuelos, Ljiljana Tomović, Bogoljub Sterijovski, Ulrich Joger, A. Westerström, Bartosz Borczyk, Benedikt Schmidt, Andreas Meyer, Roberto Sindaco, Dušan Jelić. 2009. Vipera berus. The IUCN Red List of Threatened Species 2009: e.T157248A5059709. Downloaded on 04 August 2020. 2020. Northern Palaearctic Viper (Vipera Berus) Longevity, Ageing, And Life History. [online] Available at: <> [Accessed 4 August 2020]. 2020. Adder | The Wildlife Trusts. [online] Available at: <> [Accessed 4 August 2020].

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