Britain’s New Snake Species: Aesculapian Snake Location & Safety

It’s not every day that Britain gains a new snake species. But the Aesculapian snake (Zamenis longissimus), a non-venomous constrictor reaching up to 2 metres, has quietly established itself in London and Wales by taking up residence in attics and walls (Bangor University research). Now the UK government must decide whether to let this ancient lineage stay or order its removal.

New UK snake species: Aesculapian snake (Zamenis longissimus) ·
Length: Up to 2 m (6.5 ft) ·
Venom: Non-venomous constrictor ·
UK habitat: London, Wales; attics and walls ·
Conservation status: Listed as alien species of special concern (2025)

Six key facts about this new resident, one pattern: the Aesculapian snake’s survival depends on urban warmth and human tolerance. Here’s what we know.

The implication: the snake’s future hinges on a regulatory decision that pits ecological adaptation against strict alien-species policy.

Where are Aesculapian snakes in the UK?

The Aesculapian snake has been reported in two main areas: along the Regent’s Canal in London and around Bangor in north Wales (Bangor University research). These populations originated from accidental escapes from the Welsh Mountain Zoo and possibly the pet trade (Timeout UK).

Are Aesculapian snakes found in London?

• Yes, a breeding population lives along the Regent’s Canal corridor in north London (Bangor University).
• They favour warm, sheltered spots near water and human structures.

Do Aesculapian snakes live in Wales?

• Yes, a population exists in the Bangor area of north Wales, descended from zoo escapees (Timeout UK).
• Researchers from Bournemouth University tracked 21 individuals over two summers in north Wales (Country Living UK).

Why do they live in attics and walls?

• These snakes seek warm, insulated spaces such as attics and cavity walls, especially during cooler UK weather (Countryfile).
• This adaptive behaviour allows them to survive in a climate colder than their native southern European range.

Is the Aesculapian snake venomous?

No. The Aesculapian snake is a non-venomous constrictor – it kills prey by squeezing, much like a boa (Timeout UK). It poses no venom threat to humans.

What is the difference between venomous and poisonous?

• Venomous animals inject toxins via bites or stings; poisonous animals release toxins when eaten or touched.
• The Aesculapian snake is neither venomous nor poisonous.

Are there any venomous snakes in the UK?

• Yes, the adder (Vipera berus) is the UK’s only native venomous snake (Countryfile).
• Adder bites are rare and fatalities extremely uncommon; prompt medical treatment resolves most cases.

The implication: Britain’s new snake is harmless – the real risk is misunderstanding what non-venomous means.

What is the UK’s deadliest snake?

The adder (Vipera berus) holds that title by default – it is the only venomous snake native to Britain (Countryfile). But “deadliest” is hyperbolic: adder bites cause pain and swelling, but only 14 deaths have been recorded in the last 150 years (Bangor University).

What is an adder?

• A medium-sized viper with a distinctive zigzag pattern on its back.
• Found across the UK in heathland, moors, and woodland edges.

How dangerous is an adder bite?

• Adder bites are painful and can cause swelling, nausea, and in rare cases anaphylaxis (Country Living UK).
• Fatalities are extremely rare – the last recorded death from an adder bite in the UK was in 1975.

What other snakes live in the UK?

• Grass snake (Natrix helvetica) – non-venomous, grows up to 1.5 m (Countryfile).
• Smooth snake (Coronella austriaca) – non-venomous, rare and protected.
• Slow worm – actually a legless lizard, not a snake.

The pattern: the UK’s reptile community is overwhelmingly harmless, and the adder’s fearsome reputation dwarfs its actual risk.

What animal are snakes most afraid of?

Snakes have natural predators that they actively avoid, including large birds of prey, mongooses, honey badgers, and humans (Country Living UK). Strong scents like cinnamon, clove, ammonia, and garlic are known to repel snakes.

Which smells do snakes hate?

• Cinnamon, clove, and eucalyptus oils are natural deterrents (Timeout UK).
• Ammonia and garlic are also effective.

What animals hunt snakes?

• Birds of prey (hawks, eagles), mongooses, honey badgers, and large carnivores (Bangor University).
• Hedgehogs in the UK will prey on smaller snakes.

What animal is not afraid of snakes?

• Honey badgers are famously aggressive toward snakes and highly resistant to venom (Country Living UK).
• Mongooses also show little fear and can kill venomous snakes.

Will a snake chase me if I run?

No. Snakes do not chase humans. They perceive people as predators and will flee. Running may actually provoke a defensive strike if the snake feels cornered (Bangor University).

What should I do if I encounter a snake?

• Stop moving, back away slowly, and give the snake an escape route (Countryfile).
• Do not wave arms, shout, or attempt to capture it.

Do snakes actually chase people?

• No – the myth likely arises from defensive strikes that appear as charging (Timeout UK).
• Snakes have no interest in chasing something that is much larger than they are.

How fast can a snake move?

• Most snakes move at 1–2 metres per second – slower than a human’s walking pace (Country Living UK).
• You can easily outpace any snake in the UK.

The catch: the only thing you should worry about is trampling the snake by accident – it’s more scared of you than you are of it.

Timeline: How the Aesculapian snake arrived in Britain

• 2020s: Aesculapian snakes escape from the Welsh Mountain Zoo and possibly private collections, establishing breeding populations in north Wales and London (Bangor University).
• Early 2025: Multiple news outlets report on the established populations, bringing the species to public attention (Timeout UK).
• February 2025: The UK government announces a formal review of the Aesculapian snake for addition to the list of alien species of special concern (Countryfile).

The signal: the government’s decision will set a precedent for how the UK handles non-native species that thrive because of climate change.

Clarity check: what we know and what we don’t

Confirmed facts

• Aesculapian snake is non-venomous and kills prey by constriction (Timeout UK).
• It is found in London (Regent’s Canal area) and Wales (Bangor) (Bangor University).
• It lives in attics, walls, and other warm structures near humans (Country Living UK).

What’s unclear

• Whether the UK government will allow the snake to stay or require removal (Countryfile).
• The long-term population growth and ecological impact on native UK wildlife.
• The exact number of individuals currently living in the UK.

Expert perspective

“The Aesculapian snake will be considered by the government for addition to the list of alien species of special concern, which would be grounds for restriction.”

Dr Tom Major, postdoctoral research fellow in herpetology at Bournemouth University (Country Living UK)

“The 6.5-foot-long snakes have adapted to surviving in attics and walls in the UK.”

Timeout UK reporter (Timeout UK)

For the UK government, the decision is clear: allow the Aesculapian snake to remain as a climate change adaptation, or risk undermining biodiversity goals by removing a species that has already adapted. The trade-off is between ecological pragmatism and legislative precedent.

Frequently asked questions

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