A Quick Guide to Adders

The adder may be the UK’s only venomous snake but it is also one of the shyest. Found in many areas of Britain, its zig-zag markings are highly distinctive.

Here we take a closer look at this amazing creature and why its conservation is so important.

What is an Adder?

An adder (Vipera berus) is a smallish snake that is found in many parts of Western Europe and into some areas of east Asia. The average length of the snake is between 60 and 80 cms and it is a member of the viper family. [1]

What Does an Adder Look Like?

There is a difference in appearance between male and female adders, though this is not always easy to see. The best way is to look at the distinctive zig-zag pattern down the back. The zig-zag in males is black whereas the zig-zag in females is brown.

Where Can You Find Adders?

You can find adders in most parts of Britain. Adders are not found in Ireland. They prefer areas like woodlands, moors, and heaths and are most numerous in undisturbed areas with a good mosaic of vegetation – open areas for basking as well as plenty of scrub for cover.

Are Adders Venomous?

Adders are venomous but their bites very, very rarely cause death. Adders will only bite a human or dog as a defence mechanism. The venom is used to paralyse small mammals and fledgelings which are their main diet.

You may suffer from soreness and swelling in the affected area after a bite but it should heal over a few days. The last fatality from an adder bite was way back in 1975. [2]  If you are worried about a bite, the Amphibian and Reptile Conservation Trust has a helpful set of resources.

Adders in Folklore

Snakes are often the subject of superstition, even today. Much of this may have come from our folklore. The Welsh for ‘adder’ is Gwiber and in ancient times was associated with a snake that could fly. It was especially important to the druids in Wales who believed the adder had mystical powers.

The adder also plays a role in the story of King Arthur. According to legend, an adder sparked the battle with Mordred’s army which led to Arthur’s death. [3]

5 Interesting Facts About Adders [4]

  • Adders are shy: Adders are not often found out in the open and prefer staying in the undergrowth where they can catch their prey.
  • Female adders give birth to live young: Males normally seek out females for mating in April or even earlier. The young are born in late summer.
  • Adders hibernate: During the winter, adders find frost and flood free areas, typically underground with a sunny aspect higher and drier places to spend the winter, emerging again in early spring.
  • Adders can live up to 15 years, with the oldest wild UK adder living over 30 years. Juvenile adders are left to fend for themselves soon after they are born and become independent quickly. The average life span is between 5 and 10 years.
  • Adder’s dance: Adder males will entwine around each other and fight to show a female who is the fittest.

Are Adders an Endangered Species?

In the UK, adders are protected by law and it is an offence to kill or injure them on purpose. Although not strictly endangered, the adder population has been dropping for the last 80 years.

Initiatives such as Connecting the Dragons in Wales are focused on amphibian and reptile conservation, including creating new habitats for adders to thrive and raising awareness with the general public. [5]



[1] Jessie Szalay, 2016. Facts About Adders. [Online]. [March 30, 2016]. Available from:  https://www.livescience.com/54227-adder-facts.html

[2] Emily Osterloff. Should we be scared of British snakes? [Online]. Available from: https://www.nhm.ac.uk/discover/should-we-be-scared-of-british-snakes.html

[3]  Everyday adders – the Adder in Folklore. [Online]. Available from: http://adder.narrs.org.uk/folklore.php

[4] Adder, Surrey Amphibian and Reptile Group [Online]. Available from: http://surrey-arg.org.uk/SARGWEB.php?app=SpeciesData&Species=adder

[5] Kim Boughey, 2019. Connecting the Dragons – Cysylltu’r Dreigiau. [Online]. [11th February, 2019]. Available from: https://www.arc-trust.org/connecting-the-dragons


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