Durham Biodiversity Partnership: Snakes FAQ

Britain has three native species of snake - the Grass Snake, Adder and the very rare Smooth Snake. Smooth Snakes are only found on small numbers of heathland sites in Surrey, Dorset and Hampshire. Here we look at the Adder and Grass Snake, both found in the north-east.

Where do snakes live?

Grass Snakes often live near water, where they swim and feed. They also live in damp woodlands and meadows. For over-wintering they like high, dry banks covered with brambles and rabbit burrows, and also garden rockeries.

Adders are found in a variety of habitats, but not generally in areas of human habitation.

How can I tell the difference between a Grass Snake and an Adder?

Adders are rarely more than 65cm in length. The usually have a greyish/brown colouration with a continuous black zigzag on their back and roundish blotches on each side. The zigzag is usually preceded with a V-shape mark on the back of the head, though this mark may be X- or H-shaped.

Grass Snakes are longer than Adders - adults reach between 80cm and 120cm. Their background colour is olive-green, grey or brownish with a distinctive, usually whitish-yellow and black, collar. This collar is occasionally absent in larger individuals. Black vertical bars and spots run along each side.

Grass Snakes feed mainly on frogs and toads, but also eat fish, newts and small rodents. They will occasionally take nestling birds. They swallow their prey head first and usually alive!

Adders feed on voles, mice, lizards, nestling birds, eggs, frogs and toads, and insect larvae. The Adder injects its prey with venom and then follows it, waiting for it to die.

The snake could be removed to another suitable habitat, but we would not encourage this. Nothing will deter a Grass Snake from visiting a pond. Any netting is likely to trap the snake, so why not enjoy the honour of being visited by such a lovely animal. For a thriving wildlife pond goldfish are best left out anyway - they eat everything!

Snakes hibernate any time from the end of September onwards, depending on the weather. They hibernate underground using, for example, the holes made by mammals or tree roots. They may also hibernate in manure heaps, straw, rock piles and hedgerows. They may hibernate singly or in groups.

Adders bear their young live, as the young snakes develop from the eggs within the mother's body. She gives birth between July and October. The young are enclosed in a membrane from which they emerge shortly after birth.

Grass Snakes lay eggs, mainly from late June to August. The eggs are laid anywhere where conditions are humid, including manure and compost heaps, piles of straw or logs, walls and foundations of buildings.

Slow Worms are not snakes but legless lizards, and are about 45cm in length. They look like a snake but have eyelids and a sheddable tail. Slow Worms are semi-nocturnal and feed on slugs, snails and insects. They have a 'polished' appearance with shades of coppery gold and vivid dark brown sides when young. They are far more common than Adders or Grass Snakes.

Of the three British snakes, only the Adder is venomous. An Adder will not bite unless provoked. Never disturb or try to pick up an Adder.

A Grass Snake may bite if seriously provoked, but the bite is not harmful. It is more likely to spray an evil-smelling liquid from its rear end!

The bite itself is not painful and may not be felt at the time. For most people an Adder bite will cause only mild discomfort and swelling. The swelling is characteristically blackened and subsides after a few days. However, babies, toddlers, the elderly, and those people who are allergic to bee and wasp stings may be seriously affected by Adder bites. Complete recovery takes about one to two weeks.

To put this in perspective only around 10 people are known to have died from Adder bites in the last 100 years (at least 5 of these as a result of a reaction to the anti-serum given). By comparison some 200 people have died from bee and wasp stings in the last 100 years, and on average 2 people die each year from dog bites.

Treat as a medical emergency and seek medical help. Reassure the patient and keep them calm and quiet. Do not let them move (carry a child if necessary). Don't use a tourniquet or cut the bite open. Shock can be a major problem, and local swelling, with throbbing and discomfort can occur. In severe cases drowsiness or dizziness may be experienced. Symptoms usually peak within 6-48 hours.

In most cases it is best to leave the snake alone. Never attempt to capture an Adder. Snakes have amazing powers of recovery - from even the most horrific injuries.

Both the Grass Snake and Adder are protected under the 1981 Wildlife and Countryside Act. Under this act it is illegal to intentionally kill, injure or sell Adders or Grass Snakes.

with thanks to Kent Wildlife Trust for permission to reproduce this FAQ section.