SHY, SECRETIVE AND SURPRISING: MEET THE UK’S SNAKES

They might not be a common sight, but snakes are a vital part of the ecosystem in the UK. Three native species live in Britain (there are none at all in Ireland), but numbers are sadly in decline, largely because of habitat loss. Like all native UK reptiles, snakes are protected by law. Often feared and misunderstood, they’re fascinating creatures that are crucial to biodiversity – here’s a glimpse into their hidden worlds.  

THE GRASS SNAKE

File:Grass Snake (Natrix natrix helvetica) after a copious meal (14175223381).jpg by Bernard DUPONT from FRANCE, licensed under CC BY-SA 2.0.

The most common native snake in Britain is also the biggest: the barred grass snake, which can grow up to 150cm in length. It’s usually a khaki colour with darker stripes or spots and a yellow and black collar behind its head

Grass snakes mostly live in the Midlands and southern parts of Britain. They can be found in fields, hedgerows and parks, but because their favourite food is amphibians, they especially love marshes, ditches and wet heathlands. They’re brilliant swimmers and will often slither underwater in search of frogs, toads and newts to eat.

Many grass snakes like gardens, where ponds provide them with food – and warm, dark compost heaps offer the perfect place to lay eggs. Females lay up to 40 eggs at a time in June or July. In late summer, the tiny hatchlings, said to be perfect, miniature versions of their parents, emerge.

Most grass snakes in gardens are just visiting. If you’re lucky enough to spot one, it’s best to leave it to do its thing. They’re harmless, non-venomous and want to avoid people. In fact, if a grass snake feels threatened, rather than bite, it either emits a foul-smelling liquid (gross!) or plays dead for up to 15 minutes.

Slow worms are often seen in gardens and mistaken for snakes, but they’re actually legless lizards! Read more about how to make grass snakes, slow worms and other UK reptiles welcome in your garden in this guide from the Amphibian and Reptile Conservation Trust.

THE ADDER

Adder by Danny Chapman, licensed under CC BY 2.0.

Adders are Britain’s only venomous snake, which means they’re often feared. But they’re very shy creatures, so you’re unlikely to encounter one. And the purpose of their poison is to subdue prey, usually tiny rodents or ground-nesting birds – so the risk to people is minimal. 

Sadly, adders are endangered, but they can still be found throughout Britain, favouring moorlands, heathlands and the edge of woodlands. If you’re very lucky, you might spot one sunbathing in a clearing on a bright spring day.

Adders are easy to identify: they’re small (around 60-80cm long), and have red eyes and a signature black zig-zag pattern on their backs. Males are silver, while females have copper-like colouring – although occasionally they can be completely black.

In spring, male adders compete for a mate by wrestling, twisting and entwining in a ritual that looks more like a dance than a battle. Females don’t lay eggs but give birth to up to 20 babies.

THE SMOOTH SNAKE

File:CoronellaAustriaca2.jpg by Christian Fischer, licensed under CC BY-SA 3.0.

Even more elusive than other UK snakes is the rarest: the smooth snake. This especially secretive creature is native to the sandy heaths of Surrey, Dorset and Hampshire – although populations have been successfully reintroduced to Devon and West Sussex.

As their name suggests, smooth snakes’ scales are flatter than those of adders and grass snakes, which have a ridge, called a keel, in the middle. Smooth snakes are slender and relatively short, measuring up to 70cm. They’re grey or brown, with black dots or bars on their back and heart-shaped marking on their head.

Smooth snakes’ preferred food is the sand lizard, which they coil themselves around to constrict before eating. Like the adder, they give birth to live babies – usually between 4 and 15. And like the grass snake, they can emit a foul-smelling liquid if they feel threatened.

THE NON-NATIVE SNAKE

"Zamenis longissimus in romania" by Mircea Nita, licensed under CC BY 2.0.

There's a fourth snake living in the UK, but it's not a native species. Aesculapian snakes are native to central, southern and eastern Europe and parts of Asia – but there are at least two breeding populations in Britain. In London, they can be seen in Regent’s Park and the grounds of London Zoo (they’re thought to have escaped or been released from a nearby research facility, rather than the zoo itself). They can also be found in Colwyn Bay, Wales, where they’re believed to have bred from escapees from the Welsh Mountain Zoo. These grey, brown or khaki-coloured snakes are constrictors, feeding on small birds and mammals.

Aesculapian snakes can grow up to two-metres long, making them much bigger than native snakes (and the subject of some scary headlines!) – but they’re non-venomous and harmless to humans.