British Wildlife of the Week


An adder coiled up
Image Source: Natural England/Allan Drewitt

Last week, I heard that someone had been bitten by an adder while examining some movement in the undergrowth around the Clennon Valley Lakes in Paignton – the site of The Nature Nook’s latest wildlife walk, which you can read about here. The person in question, thankfully, was fine (after a night in hospital on anti-venom), but it inspired me to write a post about my favourite British snake.

Not that Britain has many snakes to choose from, mind you. In fact, it has only three native species: the grass snake, smooth snake, and the adder. Of these, the adder is not only our most beautifully patterned, it’s also the only one that is venomous.

I should stress at this point that the adder bite mentioned above was a very rare, isolated incident. Contrary to media hype, adders are not aggressive snakes. However, they may occasionally bite in self-defence, especially if startled during attempted handling or capture (which should only be performed by those with a proper licence), or if accidentally stepped on. Although an adder’s upper fangs are normally folded back along its jaw, they can tilt downwards in an instant to strike.

The venom of an adder is not particularly strong, especially when compared to other viper species, but you should still seek medical attention if you are ever bitten. Symptoms include immediate and intense pain, followed by a tingling sensation, swelling, drowsiness, vomiting, and diarrhoea. Fortunately, unless the venom triggers an anaphylactic reaction, adder bites are seldom serious and fatalities are extremely rare. In Britain, there have only been 14 deaths caused by adders since 1876, and the last one was a 5-year-old child in 1975.

An adder coiled up
Adders are widespread across England, Wales and Scotland, and live in a variety of habitats, although they are rare or absent in many areas of the country. Sadly, the conservation of this species is hampered by negative public attitudes and misconceptions.
Image Source: Benny Trapp

Adders emerge from hibernation as early as February, and on sunny days they spend much of their time basking. They lie in loose, flattened coils to maximise their exposure to the sun, becoming efficient reptilian solar panels. Long periods of basking such as this allow the males to boost sperm development, ready for mating.

Once these snakes have finished their sunbathing, the serious business of courtship begins. A male, upon finding a female, must guard her against rivals, so it’s important that he is in peak physical condition. If another male arrives, the two rear up and entwine their bodies. Though this almost looks like a kind of dance, it is actually a contest of strength and stamina, with each male trying to push his rival to the ground in order to win mating rights.

The wrestling rituals that male adders engage in usually occur during April and May.
Image Source: Peter Trimming

Whereas many snakes lay eggs, female adders incubate their eggs internally until they hatch and then ‘give birth’ to live young. The babies are therefore insulated against cold temperatures that eggs laid outside probably wouldn’t be able to withstand. In fact, in addition to being the most widely distributed viper in the world, the adder also lives further north than any other snake species – right up to the Arctic Circle in Scandinavia and Siberia.

Sadly, I’ve been seeing a lot of sensationalist ‘anti-adder’ headlines recently, which only damages the public perception of these remarkable reptiles. They are not dangerous serpents waiting in the undergrowth to strike, as some articles would have you believe – they are scarce, secretive, timid snakes that are rarely a threat if treated with respect and caution.

In the next British Wildlife of the Week, we’ll be looking at a small, shy bird with a lot of character – the wren.


  • Jason Woodcock

    With a background in conservation and animal behaviour studies, Jason's passion lies in the natural world. He adores all things nature and enjoys nothing more than spotting rare and interesting species out in the wild. He has also worked in a zoo and knows plenty about keeping the animals inside our homes healthy and happy, too.

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