How To Identify UK Snakes: A Guide For Walkers

Shy and elusive, there are just three native snakes in the UK, plus the slow worm. I’ve seen a few out on my walks, and each time I’ve been more excited than a child in a sweetshop! Here’s everything the walker needs to know about UK snakes, from when and where to see them to what to do if you encounter one.

What Snakes Can You See In The UK?

The three snakes native to the UK are:

• the adder — Vipera berus
• the grass snake — Natrix helvetica
• and the smooth snake — Coronella austriaca

There’s also a small look-alike snake:

• the slow worm — Anguis fragilis

However, the slow worm, often seen in our compost heaps, isn’t actually a snake — it’s a totally harmless legless lizard.

How To Identify UK Snakes

The Adder

The adder is probably the most distinctive of our native snakes, with a dark zig-zag stripe down its back.

Overall, it’s grey/brown in colour, with a thick, stocky body and slit eyes. The female is larger than the male and grows to about 70cm in length.

The Grass Snake

Grass snakes are generally olive green overall, but can be easily identified by their yellow and black neckband. They also have distinct black bars along their sides, and, unlike the adder, they have round eyes.

The grass snake is the largest of our native snakes, by some margin — the males can be a metre long and females up to 1.3 metres.

The Smooth Snake

The smooth snake is the rarest snake in the UK. It’s a slim snake and overall it’s a brownish-grey colour. It has a double row of brown or black spots along its back which sometimes appear joined and look more like horizontal bars.

The female grows to about 70cm, and young snakes have a completely black-coloured head.

The Slow Worm (Not Actually A Snake!)

These beautiful legless lizards are a glisteny, silvery colour, although juvenile slow worms can be more golden. New-born and adult females have a narrow dark stripe along their backs, which the males lack, but the males can sometimes have small blue spots.

Slow worms are small creatures: an adult grows to about 40-50cm long. They’re ‘neat’ with their heads barely differentiated from their bodies. Apart from their size, their small eyes are covered by blinking eyelids, which easily differentiates them from snakes.

Where Will I See UK Snakes?

Surprisingly, there are no snakes at all in Ireland, and some of our native snakes are only found in particular geographic areas. For example, the smooth snake is only found in Dorset, Surrey and Hampshire, and the adder is most common in the south and south west. The grass snake (and the slow worm) can be seen across Britain.

When you’re out walking, these are the habitats where you might encounter them:

Heathland And Moorland

Open heaths and moorland, where there’s plenty of heather and gorse, are the natural habitat of adders and the smooth snake.

Adders also live in dense woodland, where they feed on small ground nesting birds, mammals, amphibians and lizards.

The smooth snake is only found on dry heaths and spends most of its time underground, which means you’re unlikely to see one.

Ponds And Wet Areas

This is where you’re most likely to spot a grass snake — it’s our only native snake that can swim!

They eat amphibians like frogs and toads, so you’ll find them in wetlands near standing water (ponds, lakes etc) throughout England and Wales — they’re not found elsewhere in the UK.

Coastal And Sunny Paths

You might see adders sunning themselves on rocks (or find them underneath them) and sunny paths, especially along the coast.

Gardens

Slow worms eat slugs and worms, so you’ll often find them at the bottom of your compost heap. They’re also commonly found on heathland, at the edge of woodlands and in longer grass where invertebrates are plenty.

What Should I Do If I See A Snake When I’m Out Walking?

If you’re lucky to see a snake when you’re out walking, give it plenty of space and leave it alone. If it senses you’re there, it’ll most likely slither off into the undergrowth.

Are UK Snakes Dangerous?

No, UK snakes aren’t dangerous to people.

If you come across a grass snake and it feels threatened, it might mount a mock attack (a bit of a scary hissy fit!), or play dead.

Smooth snakes generally stay below ground, but a bite can be painful — I wouldn’t stick my hand down a hole to find out!

The only venomous snake in the UK is the adder. They’re not dangerous to humans, but if they feel threatened they might bite (most likely a dry bite) — more info below.

If you’re bitten by any snake, though, you need get medical attention as soon as possible.

Tip: The NHS advise walkers to wear long trousers and boots that cover the ankles — but the most common way people get bitten is by trying to pick them up.

What Happens If An Adder Bites Me?

If you’re bitten by an adder, stay calm and take off any jewellery. To prevent any venom spreading through the body, try and keep the bite area as still as possible and go straight to the local hospital.

If there’s any sign of anaphylaxis (a severe allergic reaction) call 999 immediately.

For more detailed medical advice read this article on the NHS website: Snake bites.

Can An Adder Kill My Dog?

Adders aren’t an aggressive species, but dogs love to explore, so the most likely site for an adder bite is to its face or paws. A bite is considered an emergency, so you should take your dog to a vets immediately.

To stop any venom being carried around its body, it’s important to reduce your dog’s movements — if you need to get to a car, for example, you should carry it with the bitten area lower than its heart.

I’m not a dog owner so I don’t have any direct experience, but the PDSA has lots of practical information about adder bites, including first aid.

When Are You Most Likely To See A Snake?

Typically, UK snakes are most active during the warmer months of the year: late spring, summer and early autumn, depending on the species.

During the colder months, they enter a state of dormancy called brumation, when their activity is greatly reduced. Brumation happens when the environmental temperature drops, so if you happen to take a walk during a warm spell over winter, it’s not impossible to see a snake, though it’s unlikely.

A Few Things You Might Not Know About UK Snakes (And The Slow Worm!)

• Scotland only has one native snake: the adder
• The grass snake is the only UK snake that lays eggs; adders and smooth snakes give birth to live young
• Slow worms can live up to 30 years in the wild, and live considerably longer in captivity
• As well as the slow worm, all the three of our native snakes are protected under The Wildlife and Countryside Act 1981, which means “it’s an offence to intentionally kill, remove them from the wild, offer for sale, advertise for sale, transport, etc”

Seeing A Snake Is Wonderful, Not A Problem!

The first grass snake I ever saw was on a bike trail in some old mine workings here in Cornwall, where there are lots of wildlife ponds nearby. It seemed to fly across the track in front of me at the speed of light — and I was elated for days.

I feel the same whenever I see the elusive adder. Most times I’ve spotted them they’ve been sunning themselves on a warm path or between clumps of heather on the coast — and they’ve slithered off before I could even get my phone out.

I’ve had lots of encounters with slow worms too; they’re really beautiful. The only species I haven’t seen is the smooth snake — maybe I need to plan a hike in Dorset!

It feels such a privilege to catch a glimpse of a snake (and slow worms!) that I can’t understand why they might be seen as a problem. How about you, have you seen any when you’ve been out hiking? I’d love to know if you get as excited as me! Let us know in the comments.

Thanks for reading and happy hiking!