There are three types of snakes native to the UK: the grass snake, the adder and the smooth snake, but none of these species is found throughout the whole of the UK. There are no wild snakes of any type in Northern Ireland, the Channel Islands, the Isles of Scilly, the Isle of Man and most of the Scottish Islands, and you are unlikely to see one in densely built-up urban areas.
Even in places where snakes are locally common, such as undisturbed heathland, moors, open woodland and sand dunes, they are not easy to find. They are well camouflaged in their natural habitats and avoid contact with people wherever possible. Most will slip away and hide as soon as they detect an approaching human.
Another factor that would-be snake spotters must take into account is the time of year. All UK snakes hibernate from October until spring, so there is no point in looking for them during the winter.
Grass snake (Natrix natrix)
The grass snake is the UK’s largest type of snake growing to over 1 metre (39 inches), and there are occasional sightings of individuals reaching 2 metres. They are mainly a dull, greenish colour with darker vertical bars on their sides, and a collar marking of black and yellow or cream just behind the head. They are common in England and Wales but rare in Scotland, and are usually found near fresh water where they can hunt for their favourite prey: frogs, newts and small fish. They pose no threat to humans or domestic animals, as they are not venomous.
If you find a snake in your garden it will almost certainly be a grass snake. Although they are very timid they will visit gardens, especially those that have ponds and neglected areas of long grass. A female might also choose a garden compost heap as a warm, dry place in which to lay her eggs.
Adder (Vipera berus)
The adder, sometimes called a viper, is the UK’s only venomous snake. Their bite is certainly painful and can cause sickness and fever, but it is very rarely fatal to humans. Small children and adults with health problems such as a weak heart are most at risk but, as a precaution, anyone who is bitten should seek medical treatment as soon as possible. The adder is not aggressive and normally only bites creatures larger than itself as a last resort means of defence, for example, if it is accidentally trodden on or picked up.
Fortunately, the adder is fairly easy to identify. The average length of a full grown male is about 60 cm (2 feet), and females can be a little longer. The ground colour is a shade of grey or brown with some individuals appearing much lighter in colour than others, but they all have a noticeable dark zigzag line all the way down the back and a dark ‘V’ shape on the head.
Very dark adders – commonly called black adders although they are not a different species – are sometimes found, mainly in the north of the UK. The zigzag line is not so easy to distinguish on these but if you see a snake that appears to be completely black, keep well away. It can only be an adder!
Smooth snake (Coronella austriaca)
The smooth snake is the rarest snake in the UK and is only found in a few areas of sandy heathland along the south coast of England. It gets its name from its very smooth scales. (Grass snakes and adders have scales with a slight ridge along the centre.) It is non-venomous and kills the lizards that are its main prey by wrapping its body around them and squeezing to suffocate them.
The smooth snake rarely grows to more than 70 cm (28 inches). Its colour varies from bluish grey to reddish brown with darker spots along its back and a dark patch on the top of its head. The spots tend to be more obvious and closer together on juvenile smooth snakes and may sometimes be mistaken for the zigzag pattern of an adder.
If you are lucky enough to find a British snake in the wild observe it from a distance, take photos if you can, but don’t try to touch it or pick it up. All UK snakes are protected by law and it is illegal to kill, harm or trade them. Because of its endangered status, it is also an offence to disturb a smooth snake in any way or to damage its habitat. Offenders can be fined up to £5,000 and may face six months’ imprisonment.