Originally written in 2012 and last updated: 24th March 2021
 


It often comes as a surprise to most people to learn that we have scorpions living and breeding here in the UK. The small Yellow-Tailed Scorpion (Euscorpius flavicaudis) has managed to set up at least one thriving colony in an isolated area in SE England despite the generally cool and mild climate here in the UK . These scorpions have occasionally been found at several coastal towns across the south of England over the years but the best known and most successful population can be found on the Isle of Sheppy in Kent, around the dock-land town of Sheerness. This Yellow-Tailed Scorpion population has an estimated size of up to 10-15,000 specimens! This population was the first ever recorded in the UK with many sources claiming that the first record was from the 1860's. There is a preserved Yellow-Tailed Scorpion specimen kept in The Natural History Museum, dating back to 1870, which was collected from within the grounds of the Sheerness Docks and was identified at the time by J. J. Walker. The Yellow Tailed Scorpion has been living in the south-facing walls, rock crevices, abandoned buildings and railway sleepers of these docks for over 150 years now and still thrives there today in 2020. Although no one knows for sure it is widely accepted that these small scorpions originally found there way into the UK accidentally as stowaways amid the shipments of Italian masonry that were brought to the docks aboard sailing ships during the reign of Edward VII.




Although the majority of the Sheerness scorpions live within the relative safety of the private docks some specimens can be found on the south-facing wall that surrounds the docks, which is accessible to the public. Other reported possible sightings of these scorpions in the UK have come from Harwich Docks, Pinner, Tilbury Docks, Portsmouth Docks and Southampton Docks, Swanage pier in Dorset, as well as Whitemoor and Ongar Underground Station. However none of these other reported populations have managed to survive for many years unlike the long established and successful scorpions of Sheerness. The scorpion population at Ongar Underground Station was once featured in a report by the BBC back in the 1970's but this is now reported to have been a hoax orchestrated by the station foreman who deliberately released scorpions bought from a local pet shop. 

Yellow-Tailed Scorpions were also sighted in 2012 on Erith Pier, in SE London, by night fishermen. However I have since thoroughly investigated this Erith site in ideal conditions and there were no scorpions present there in 2020. In 2015 a number of Yellow-Tailed Scorpions were reportedly collected from a stone wall at the bottom of a residential garden in the coastal town of Seaton, East Devon. 

There are also two unconfirmed records of single specimens of Yellow-Tailed Scorpion found in the UK on the NBN Atlas website: 

First: Yellow-Tailed Scorpion found in church grounds of Croydon Minister, in South London. 2nd July 2014. LINK 

Second: Yellow-Tailed Scorpion found on a farmland site in Charltons, Saltburn-by-the-sea, Cleveland, North-East England. 8th July 2009. LINK



The Yellow-Tailed Scorpions are the most northerly species of scorpion in the world and it is their tolerance to cold temperatures and their ability to adapt that has allowed them to thrive in the UK's cooler climate. During the colder months these scorpions remain inactive within the dock wall or under rocks and railway sleepers etc. 

No one knows exactly why the Yellow-Tailed Scorpions have managed to successfully breed and thrive at the Sheerness Docks when all other introduced populations of these scorpions have failed within a few years at other sites across the UK. It could be significant factor that the Isle of Sheppey has a relatively low mean annual rainfall of just 18 inches, compared to that of 24 inches for London and 60 inches for Devon and Cornwall? Sheerness Port was originally built in 1665 as a Royal Navy dockyard and fort and was rebuilt with the Great Dockyard Wall in 1823. The Great Dockyard Wall, along with the now ruined army barracks and various other old buildings within the docks, are all constructed using the same brickwork that appears to be particularly favourable to the Yellow-Tailed Scorpions. Maybe it's the soft mortar between the bricks that allows the scorpions to tunnel into the walls? Within the grounds of the docks are gardens, allotments and areas of rough ground which favour all manor of insect life, providing an ample and constant supply of insect prey for the Yellow-Tailed Scorpions. In addition, areas of the north face of the old Dock Wall have ivy climbing the wall and overhanging trees which also provide a rich environment for insect prey for the scorpions.

One reason why these scorpions haven't spread much beyond the confinement of the docks is the remote location of the Sheerness Docks. With the river on one side of the docks and man-made defence moats and busy roads surrounding the docks they are stranded on an island within an island at Sheerness Docks. Although escapes must occur they don't happen in large enough numbers to establish any viable new colonies of scorpions away from the docks.


Yellow-Tailed Scorpion glowing under UV light. Found at Sheerness Docks Wall February 2012

The Yellow-Tailed Scorpion is a fairly small scorpion species reaching a maximum size of around 20-25mm body-length and 35-45mm including tail and pincers. The Yellow-Tailed Scorpion has large pincers for its size and a short, thin, stinging tail. This tail can only deliver a very mild sting to a human. The Yellow-Tailed Scorpion is usually very reluctant to use its sting, even when hunting and instead relies mainly on its powerful pincers to subdue its prey. The effect of the sting to humans is a mere pin-prick to most people and is said to be less painful than the sting of a bee or wasp. The sting usually poses no threat to healthy adult humans at all, although medical advice should be sought if you feel unwell following a sting in case of an allergic reaction. In southern Europe, where these scorpions are native, there are recent records though of more severe reactions to the sting of the Yellow-Tailed Scorpion by human children. One such incident was in the South of France back in 2019 where a 10 year old boy was stung on the hand whilst handling a Yellow-Tailed Scorpion. His symptoms included localised pain, sweating, nausea, abdominal cramps, decreasing muscular strength and an inability to raise his arm above shoulder level. These symptoms past after 72 hours with no long-term effects. It is likely that this extreme reaction is partly due to the child's sensitivity to the venom and the time of year the incident occurred. The venom of the scorpion would have been of a much higher concentration than usual as the sting occurred in winter when the scorpion would have been inactive for some time.  LINK 1    LINK 2

I have handled several specimens of these scorpions myself with my bare hands and have never experienced any signs of aggressive or defensive behaviour from any of them. However this doesn't mean that I would encourage anyone else to ever handle wild scorpions.

These scorpions hide themselves away for most of their lives becoming active only to feed and breed, usually on warm evenings. They have been recorded at Sheerness in December and I have personally seen them at Sheerness in both November and February in small numbers when the evening temperatures were around 7-9 degrees. Yellow-Tailed Scorpions feed on any insects or spiders that come within range, with a preference for woodlice. Because of their incredibly slow metabolism it is thought that they may only need to feed as few as 4-5 times a year during the summer months and can survive for long preiods between meals.


Yellow-Tailed Scorpion glowing under UV light. Found at Sheerness Docks Wall February 2012

During the day these nocturnal scorpions can be almost impossible to find as they hide themselves away in the smallest of gaps and cracks in the rocks and bricks that they make their home. However some specimens have been seen active during the day which is fairly uncommon for scorpions of most species apart from forest-dwelling scorpions.

Scorpions are easiest to find once they become active at night a couple of hours after the sun has set. Under a UV lamp scorpions glow bright turquoise making them much easier to spot, whether climbing the walls or hiding in rock crevices. It is not understood exactly how scorpions could benefit from glowing under UV light but it is known that the fluorescence is caused by the accumulation of a chemical called beta-carboline in the exoskeleton, which glows under UV light. One theory is that this florescence may help to shield scorpions from harmful UV rays emitted by the sun by converting UV light into harmless visible light. Other possible theories include: the emitted glow from UV light could attract moths and other insects that scorpions prey upon or the glow could help scorpions looking for potential mates. Other scientists believe that the florescence may be purely by chance of evolution and have no significant purpose at all.



Yellow-Tailed Scorpion glowing under UV light. Found at Sheerness Docks Wall February 2012

As scorpions grow they periodically shed their hard exoskeleton in one complete shell. The few hours following a shed of the old exoskeleton is quite a dangerous time for the scorpion until the new soft shell hardens up. The old discarded shell still glows under UV light however the new shell will not glow immediately but the fluorescence slowly returns as the scorpion ages and the beta-carboline begins to build up in the new exoskeleton once again.





Yellow-Tailed Scorpion photographed on a mirror.

Scorpions are not insects, but they are classed along with spiders and harvestmen as arachnids. They are very basic creatures and early fossil records show that scorpions have been on the earth for over 400 million years! Early Sea Scorpions, that could have been as long as 2.5 metres, were capable of walking on land as well as living beneath the water like modern crabs. There is even consideration over whether these ancient scorpions may have been one of the first creatures to leave the sea and begin living a terrestrial existence.  LINK




 

Yellow-Tailed Scorpion photographed on a mirror.

Despite the dangerous reputation that scorpions have, due to their venomous sting, out of the 2200+ species of scorpion found throughout the world it is thought that only about 104 species are considered to be any threat to healthy adult humans if stung. Scorpions are one of the most resilient creatures on the earth. They are capable of surviving fairly low temperatures and extremely hot temperatures such as those experience in dessert environments. During US nuclear testing, both scorpions and cockroaches were found surviving near ground zero showing no adverse effects from the radiation. One species of scorpion, Orobothriurus crassimanus, has been recorded at an altitude of 5550 metres above sea level where oxygen levels are low and many creatures could not survive. Scorpions are also one of the species of terrestrial life-forms that usually survives flooding. Tests have shown that many species of scorpion can survive being submerged in water for several hours due to their ability to slow their metabolism down enabling them to retain sufficient oxygen supplies in their body. Some scorpions can last indefinitely without water and obtain the necessary fluids to survive from their prey.

LINK    LINK 2


 

Yellow-Tailed Scorpion glowing under UV light. Found at Sheerness Docks Wall February 2012

Yellow-Tailed Scorpions are not generally a communal species and cannibalism does occur if keeping more than one of these scorpions in the same enclosure, just as it does in the wild. Following mating the long gestation period of the female scorpion is between 10 and 14 months depending on the temperature and the quantity and quality of food available. The female then gives birth to eggs which hatch immediately to tiny scorplings ranging in numbers of 4-30 individuals that are born soft and white. The female carries these tiny scorpions on her back until they are too large to all fit on her back. This can vary from one to eight weeks.




 


Scorpions have a very basic digestive system. All prey is caught using the powerful pincers and then brought to the jaws where it is effectively chopped into very fine particles and reduced to liquid form that can be sucked up into the mouth of the scorpion. As with snakes the venom of the scorpion not only stuns or kills its prey but also aids with the digestion process too.




 

Ongar Underground Station scorpions

The scorpion population at Ongar Underground Station was once featured in a report by the BBC back in the 1970's but this "wild" population of scorpions was later reported by The Independent to have been a hoax orchestrated by the station foreman "Fred" who deliberately released five scorpions bought from a local pet shop in Camden. The scorpions may have bred or one of the released specimens may have been a gravid female but some former employees at the Railway Station and some visitors and local residents claim the end result was a small population of more than a dozen scorpions that lived in the brickwork of the station for several years.


The Independent Newspaper article Sunday 9th July 1995

"At its peak in 1971, 750 passengers were making the return trip. But even then the track was hardly an economic proposition although the staff did their utmost to drum up business. In 1965, an Ongar station foreman bought five (harmless) European scorpions in a Camden pet shop and let them loose in his goods yard. This formed the basis of one of the few scorpion colonies in Britain, which became an attraction. The staff kept quiet about its real origins, and encouraged speculation that it arrived in a banana van in the 1860s."


Dean Sullivan, a former employee at Ongar Railway Station claimed on 'www.districtdavesforum.co.uk' that when David Attenborough arrived with a film crew to record the Ongar Railway scorpion population they were unable to find any specimens. This former employee also claims that the film crew brought their own captive-bred scorpions which they filmed and then claimed were found living wild at the Ongar Railway Station.  See report here.


Wikipedia.org - Ongar Railway Station

"The sand drag at the very end of the rails — intended to help slow trains that overshot the stopping mark — was said to be home to a breed of harmless scorpion and featured in a 1979 episode of the BBC's Wildlife On One. They had been released there by a station foreman who was a keeper of exotic pets."




iPhone recording of the Yellow-Tailed Scorpions at Sheerness Docks, 2020.

This video was filmed at 9pm on 30th September 2020. The air temperature was very mild at 15 degrees and the weather was dry and calm with no wind. Perfect conditions for Yellow-Tailed Scorpions to be found at Sheerness. In 25 minutes I had found 23 specimens ranging from adults, with a body-length of around 25mm (excluding tail and pincers), to young juveniles of just a few mm in length. Several specimens were spotted actively wandering along the south face of the wall that surrounds the docks. However most specimens were found hiding away in cracks and crevices of the wall.






Yellow-Tailed Scorpion found at Sheerness Docks Wall 24th April 2013

The Yellow-Tailed Scorpion is native to much of Western and Southern Europe, including France, Italy and Spain as well as Northwest Africa, where it is usually recorded at altitudes below 500m. They prefer dry and humid habitats including forests, fields and parks but are often found in or around human habitations as well. Like other species of scorpion the Yellow-Tailed Scorpion's body is covered in tiny hairs that detect the slightest movements or vibrations.







Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.

This image of a Yellow-Tailed Scorpion, with a body-length of 20mm, not only shows how small these scorpions are but also demonstrates how placid they are if treated with respect.







Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.








Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.








Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.








Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.









Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.








Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.








Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.








Yellow-Tailed Scorpion (Euscorpius flavicaudis) found at Sheerness Docks 30th September 2020.








Yellow-Tailed Scorpion (Euscorpius flavicaudis), with a body-length of 20mm, on the Sheerness Docks Wall, 25th November 2020.

Image taken with the Venus Laowa 15mm f/4 Wide Angle 1:1 Macro lens. Hand-held using manual exposure, manual focus and manual flash settings.
3.2 second exposure, f/32 aperture, ISO 1600. Diffused flash.






Yellow-Tailed Scorpion (Euscorpius flavicaudis) hiding in the Dock Wall at Sheerness Docks 25th November 2020.

The scorpion pictured above was one of twelve Yellow-Tailed Scorpions I saw hiding in the wall at Sheerness Docks on a mild, drizzly night at around 7pm on 25th November when the air temperature was around 8-9 degrees. As the drizzle arrived and the temperature began to drop further the scorpions all began to disappear out of sight deeper into the wall. The Yellow-Tailed Scorpion in this image shows its exoskeleton is starting to split open along the side as the scorpion begins to shed its skin. The scorpion will be highly vulnerable with its soft new skin exposed so it will need to stay hidden away until the new skin hardens and forms the new exoskeleton. The new skin has yet to build up the chemical, beta-carboline, so is not yet fluorescent under UV light. 




Yellow-Tailed Scorpion (Euscorpius flavicaudis) hiding in the Dock Wall at Sheerness Docks 25th November 2020.

Yellow-Tailed Scorpions take three or more years to reach maturity and adult specimens can live for around two years, giving the scorpion a lifespan of around five years. With much of the adult female's life spent during the gestation period, when they are carrying fertilised eggs inside them, they remain largely inactive are rarely leave their hiding place. It was reported by Professor Tim Guy Benton, who studied the Yellow-Tailed Scorpions at Sheerness extensively between 1987 - 1989, that female Yellow-Tailed Scorpions may leave their hiding place as few as ten times during their entire life time. Professor Tim Benton studied this scorpion population for 18 months and marked and tracked 162 individual specimens at Sheerness in the course of his studies. 

Male Yellow-Tailed Scorpions are far more active and can on occasion be seen hunting for food and for a mate out in the open on warm, dry evenings. The activity of Yellow-Tailed Scorpions is not only affected by the air temperature, time of year, and rainfall, but also the lunar cycle. Many species of Scorpions are known to be less active when there is a full moon.





Yellow-Tailed Scorpion (Euscorpius flavicaudis) hiding in the Dock Wall at Sheerness Docks 25th November 2020.

In many cases the protruding pincers of the scorpion is all that is seen as it hides itself away in the cracks within the mortar on the Sheerness Docks Wall. 






Tube-Web Spider (Segestria florentina) hiding in the Dock Wall at Sheerness Docks 25th November 2020.

The Yellow-Tailed Scorpions are not the only ambush predators that hide away within the crumbling mortar of the old Dock Wall at Sheerness. There is also an abundance of Tube-Web Spiders with their distinctive tube webs, radiating signal lines and menacing green chelicerae that lie in wait for passing prey. The Tube-Web Spider is another non-native species of Mediterranean origin that has become naturalised in the UK since 1816, more than 200 years ago.

Dead specimens of Yellow-Tailed Scorpions have been found in the webs of Tube-Web Spiders and likewise, Yellow-Tailed Scorpions have been seen feeding on adult Tube-Web Spiders. This species can be readily identified by the metallic green chelicerae that are not found on either of the other two Segestria species found in the UK.











In September 2020 I was contacted by Sergio Henriques and Olga Sivell, from the Natural History Museum in London, and asked if I would be able to collect specimens of Yellow-Tailed Scorpion from Sheerness Docks for inclusion in the Darwin Tree Of Life Project, a project that aims to fully sequence the genomes of all 70.000 species of eukaryotic organisms in Britain and Ireland. Permission was sought and granted from Swale Council, Kent County Council, Sheerness Docks, Peel Ports and Edward Harris Law, on behalf of Spitalfields Trust, to collect the samples and two specimens were collected and submitted for inclusion in this project.


The Darwin Tree of Life Project uses genomic data to understand the evolution of the diversity of life, to explore the biology of organisms and ecosystems, to aid conservation efforts and to provide new tools for medicine and biotechnology. The Darwin Tree of Life Project is one of several initiatives across the globe working towards the ultimate goal of sequencing all complex life on Earth, in a venture known as the Earth BioGenome Project.    















All Photographs on this page were taken using the Canon 40D and Canon 7D cameras and the Canon 100mm 2.8IS, Canon 70-300mm IS L, Canon 17-85mm IS, 

and Venus Laowa 15mm f/4 Wide Angle 1:1 Macro lenses.




 

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