There are three types of snake native to the UK – adder, grass snake and smooth snake. Dating back as far as the Bible, serpents have been perceived as evil and perhaps due to this misrepresentation, many people possess an unnecessary fear of snakes. However attitudes are changing and in fact snakes and other reptiles are one of the fastest increasing types of pet.

Adder (Vipera berus)

The adder is the only venomous snake native to the UK however the poison they carry is designed to kill small mammals and is not particularly potent.

Rarely exceeding 65 cm in length, the average is just over half that in size. Markings can vary enormously but in general males are most often a light grey with a well marked black zigzag along their back. Females are brown with darker zigzag markings.

Distribution

Adders are distributed throughout England, Scotland and Wales in localised colonies There is little information available on the present status of the species but there is increasing evidence to suggest that numbers are declining in many parts of the country.

Habitat in the UK

Adders can be found in a variety of habitats. Although they favour heathland areas they also frequent sunny woodland glades, grassy banks, quarries and sand dunes. Common features found near adder colonies are a south facing slope for basking in the sun and scrub providing cover. It is very rare for adders to be found in gardens or in built up areas.

Breeding

Adders give birth to live young after the eggs have hatched inside the female’s body and this practice has fed the common myth that snakes swallow their young for protection. Between five and 20 young are born every other August or early September (the females breed in alternate years) but only a few will reach maturity. Mating takes place following hibernation in early spring as the males perform the ‘dance of the adders’ rising up against each other in a show of dominance, entwining in a bid to force their opponent to the ground. This combat and mating activity subsides by mid-April. Young adders are independent from birth and of the three British species of snake only the grass snake lays eggs.

Food

Adders feed on small mammals such as mice, shrews and voles but can also frequently eat baby birds and other reptiles including lizards. Prey is dispatched with a venomous bite and the swallowing of large prey is made possible by the dislocation of the jaw. The majority of feeding takes place in a separate summer habitat commonly comprising marshes, bogs and wet heaths, which is different to the winter hibernation area.

Hibernation

As with all cold-blooded reptiles, adders rely on the warmth of their surroundings to regulate their body temperature. During the winter months when the weather is too cold for them to achieve the necessary metabolic rate for daily functioning, they hibernate under leaves, logs, brushwood and in compost heaps, burrows and hollow trees. These areas must be well drained and free from frost and are therefore usually situated on relatively high ground. It is possible to find up to a dozen adders hibernating together and they will happily co-exist between October and April, until they emerge to bask in the spring sunshine.

Threats

Snakes are particularly vulnerable as they cannot easily travel great distances to escape danger and find new habitat.

People also have an unnecessary fear of snakes and persecution over the years has resulted in declining numbers. Other threats include hedgehogs and fire, which can sweep through their preferred dry heathland habitat.

What can be done to help?

All snakes in England, Scotland and Wales are protected by law under the Wildlife and Countryside Act 1981 which means it is illegal to catch, collect, sell, injure or kill them.

Habitat containing long grass, compost heaps, log piles and rocks for basking and shelter is essential for snakes. Try to leave these areas undisturbed.

Sending records of snake sightings to your local reptile group will help them to gain a clearer picture of their status, distribution and habitat which is essential for their conservation.

Your local Wildlife Trust should be able to put you in contact with a local reptile conservation group. The Wildlife Trusts UK office telephone number is 01636 677711.

The warmer temperatures that Britain may experience owing to climate change is good news for reptiles as populations are likely to increase.

Adder bites

Adders are shy creatures and will move away from humans if discovered. A cornered or provoked adder may bite as a form of self defence and fingers and toes are parts of the body most at risk. In fact less than twelve deaths this century have been attributed to adder bites, which is considerably less than those caused by bee stings. As with bee stings these fatalities are usually due to an allergic reaction to the venom rather than its strength.

When bitten a sharp pain is felt, followed by swelling, dizziness and in some cases vomiting. Shock is often caused by panic and the best course of action is to remain calm and visit a doctor or hospital as soon as possible. 

Veterinary Nursing Journal • VOL 25 • No7 • July 2010