Skip to main content

Britain's Rarest Snake

Britain's Rarest Snake

It is a common misconception that Britain's rarest snake is the Smooth Snake Coronella austriaca . This is incorrect. The rarest resident snake to be found within the British Isles is the Aesculapian Snake Elaphe longissima! (Zamenis longissima)

There are four species of snake living wild and breeding within the UK. These are:

  • Adder Vipera berus
  • Grass Snake Natrix natrix
  • Smooth Snake Coronella austriaca
  • Aesculapian Snake Elaphe longissima (Zamenis longissima)

The first three species are long term official residents. The fourth, the Aesculapian Snake only became established in the late 1960s when a gravid female escaped from the Welsh Mountain Zoo in Colwyn Bay, North Wales. A smaller more recently established population now lives in central London.

Aesculapian Snakes have been recorded in every month of the year in and around the Welsh Mountain Zoo, though in the cooler part of the year this is in and around buildings. Hatchling snakes have been seen and recorded every year in a twenty year period starting from the early 1980s. Hatch-lings are often mistakenly believed to be Grass Snakes which they resemble so much when young.

The Aesculapian Snake is a non venomous egg laying 'Rat' snake which can reach up to six feet in length. It is very shy of man and sightings by visitors or staff within the Welsh Mountain Zoo are not common but are not unusual either. The larger snakes spend much of their time in the higher branches of mature trees, younger ones stick to the grass and around buildings.

Larger snakes are quite territorial and may be found basking in the sun in set locations every day during the summer. Often there will be several snakes together. Such behaviour can be dangerous. In the mid 1980s an unscrupulous pet shop owner caught up several large (and identifiable by scarring) snakes from the Welsh Mountain Zoo and offered them for sale in his establishment in Colwyn Bay. Nothing could be done to retrieve them.

As the British population of the Aesculapian Snakeis not officially recognised in all quarters (though listed as British in The Guinness Book Of Animal Records in the 1980s) the law is somewhat hazy over how they are treated. Picking up an Aesculapian Snake would not be illegal but putting it down again would be. The same law applies to the introduced Grey Squirrel Sciurus carolinensis . You could rescue an injured squirrel and nurse it back to health but you would be breaking the law if you released it once it had recovered.

The Aesculapian Snake in North Wales would appear to be restricted to the Welsh Mountain Zoo and the surrounding gardens. Specimens have been found up to quarter a mile away. Every year a dozen or so are killed on the roads outside the zoo. No doubt others are killed by the large resident Badger Meles meles population or meet their fate from strimmers.

The Welsh Mountain Zoo is possibly unique amongst zoos in that it does not have a rat problem. Availibility of food, warm dry buildings and abundance of nesting material have always made the modern zoo an attractive location for rats to settle. Most zoos fight a running battle to eliminate at best or keep numbers down. The Welsh Mountain Zoo does not have this problem. There are no rats! In twenty years working there I only ever saw two and I believe these were passing through. I have always theorised that it was the Aescelepian Snakes which ate the rats as they arrived.

Photo By:

Photo By:




The snake gets its name from Aesculapius, the Greek God of Medicine. Aesculapius was the son of Apollo and granted miraculous healing powers. Aesculapius was reputed to be able to change himself into the harmless rat snake Elaphe longissima . Snakes were believed to have mystical powers of rejuvenation, to live forever and to select healing herbs and plants.

The snakes too had their sexual symbolism and barren women would go to the temples to pray that they would become child bearing.

Moving out of the era of myth and legend many temples were built to honour Aesculapius. The temples were always located next to fresh water springs. These were the first hospitals. The sick and injured went to the temples to give offerings and rest and stay. People would collect the locally occurring rat snakes which were used in temple rituals and release them afterwards.

Although the cult of Aesculapius was Greek it was adopted by the Romans in 293 B.C. when the plague in Rome was killing so many Roman citizens. The Roman Gods had not helped so why not try a Greek God with a healing reputation?

Asclepius Temple

Scroll to Continue

It can be assumed that in line with temple tradition that snakes were brought in to the new temples. These would of course eat the rats which carried the fleas which in turn spread the plague. So less rats, less fleas and the plague would reduce or even disappear.

So delighted were the Romans with their adopted God that they took him with them wherever they went. Where the God went the snakes went too. To this day this Southern European snake still lives in isolated areas in Switzerland, Germany and Austria where Aesculapius Temples are believed to have previously existed. There is a village in Northern Germany called 'Schlangenbad' which translates as 'Snake Bath' which refers to the snakes at the temple which previously existed there. Others theorise that these 'pocket' populations are relics of a much wider former distribution. There is existing evidence to show that they were found in Britain and Scandinavia before the last Ice Age. Whatever the truth it could be believed then, that in theory that the Romans actually brought the Snakes to Wales. The 'Old Highway' which runs outside the Welsh Mountain Zoo is a Roman road. Escape or naturalised resident? Will we ever know?

Fight or Romance - You decide

Wild snake caught on film in north Wales


Tom D-B on March 28, 2015:

A nice article but a misleading title that I am sorry to say demeans invasive species biology. At one point in the UK's history, the Grey Squirrel was the rarest squirrel in the UK. Crayfish plague was the rarest pathogen in Europe the day it was released. If I release my Corn Snake now, should I write a page rivalling your one for the rarest snake in Britain?

Aesculapian Snakes have now established a population in Regent's Park, London, and there are reports in the north of England now. So the rarity is becoming less so, and is beginning to look like an actual biological invasion rather than an isolated, quirky case on a Welsh hill. The impacts are not clear, this may be a benign invasion or even in the long run, an unsuccessful one, but with 20 years on the trot, its not looking like that. The saving grace could be it being a within-Europe transplant, the native species being adapted to this species having experienced it in earlier geologic time.

Maybe its time the Welsh Mountain Zoo stopped looking at these as a curiosity and started collecting them up? London Zoo too. That would be an interesting study in itself - population size estimate based on depletion; effectiveness of non-lethal eradication, etc.

Peter Dickinson (author) from South East Asia on April 18, 2011:

Thank you Alastar,

Glad you enjoyed it.

Alastar Packer from North Carolina on April 18, 2011:

Thanks for this one Peter. Have been waiting on one about U.K. snakes: saw it in the featured. Excellent.

KRC from Central Texas on June 26, 2009:

My hubby swears you don't have any in the UK either! He came to Texas and within a matter of weeks he saw his first snake here on our front porch!

LondonGirl from London on June 26, 2009:

Great hub. I've never seen a snake at all in Britain, I reckon they keep a low profile!

shamelabboush on June 24, 2009:

Interesting facts.

Related Articles