Skip to main content

The charity making life better by water

How to identify snakes in the UK

There are three native snakes in the UK: grass snakes, adders, and smooth snakes. If you’re by our canals and rivers, you’re most likely to spot the shy grass snake – a pro swimmer and water lover.

A grass snake with a green-brown body and black markings curls up, sticking out its forked tongue. A grass snake with a green-brown body and black markings curls up, sticking out its forked tongue.

Identifying native UK snake species

Snakes are reptiles from the Serpentes suborder with long, thin, forked tongues. They’re identified by their lack of limbs, eyelids, or ear openings.

Grass snake

The snake you're most likely to see near canals and other wetland areas. Grass snakes are often found by water, where they hunt amphibians and fish, but you might also see them in grassland and gardens. They are non-venomous, greenish in colour, and can grow quite large – sometimes over a metre in length.

Grass snake swims away through shaded water, towards a fallen branch. Grass snake swims away through shaded water, towards a fallen branch.

Grass snakes have a yellow and black collar with a pale underside and dark markings on their side. If threatened, these shy snakes sometimes play dead by dramatically tossing their head back and lolling their tongues. If caught, they release a foul odour from their anal gland.

Adder

Although adders are more common in heathlands, moorlands, and woodlands, they can occasionally be found near bodies of water. Adders are the only venomous snake native to the UK, but they are generally shy, and bites are rare.

Adders are grey in colour with a distinctive dark zig-zag pattern along their back with a ‘V’ or ‘X’ marking on their heads. Males are silvery in colour, while females might be more reddish-brown. Compared to grass snakes, adders are small, reaching 60-80cm.

Smooth snake

This species is the rarest of the UK’s native snakes and is mostly found in southern England, particularly in heathland habitats. They prefer to hide under stones and logs than bask out in the open. It is less likely to be seen near canals compared to grass snakes.

Smooth snakes are similar in appearance to adders, with slender bodies and less well-defined dark markings along their backs. They’re grey or dark brown and reach 60-70cm.

What’s the difference between snakes and slow worms?

At first glance, these limbless reptiles are easy to mistake for snakes. However, slow worms are much smaller than snakes, with a golden tinge to their smooth grey skin. Their heads are the same width as their bodies, making them distinct from the snake’s wider heads.

A shiny, green slow worm curls its body while on old leaves and bark. A shiny, green slow worm curls its body while on old leaves and bark.

Unlike snakes, slow worms have eyelids and can blink. They also have a detachable tail that can break off as a defence mechanism to escape predators, which will later regrow (though it never looks quite the same as the original).

Family nature guide 2019

Download your free nature guide

Identify footprints and read fascinating facts about the creatures who make their homes along our canals and rivers

Last Edited: 02 October 2024

photo of a location on the canals
newsletter logo

Stay connected

Sign up to our monthly newsletter and be the first to hear about campaigns, upcoming events and fundraising inspiration