With bears and wolves eradicated from Britain, a single native venomous snake, the adder, and only the occasional nasty stinging insect, our island home is largely a ‘deadly-free’ zone.
Or it was until we brought over a menagerie of critters that not only don’t belong here, but also hunt for a living – not forgetting the ones that turn up here under their own steam (or fin power). On second thoughts, are you sure that was a log you saw in your local stream?
The Bristol crocodile
A crocodile of unknown origin and species was first spotted in the River Avon in Bristol by a bus driver, and other unproven sightings followed. Today, there are still signs warning people of the #BRISTOLCROC, though whether that is scarier than the microscopic nasties in the water is hard to say. An account of a “caiman” lunging out of the Gloucester and Sharpness Canal at a mallard was contained in a report published 20 years ago, but the beast has proved oddly elusive in the intervening years.
The Sheerness scorpions
Not, not the metal band (they were from Germany), but a colony of yellow-tailed scorpions that established themselves in Sheerness Dockyard after arriving on Italian masonry in the 1800s. But at just 4.5cm long, and with a sting in their tale described as being no worse than a bee’s, they are hardly monsters of the mythic imagination. Also spotted at Tilbury, Portsmouth and Southampton docks, as well as Ongar railway station, though the population at Sheerness is by far the biggest and best-established.
The Gwent vulture
Bearded vultures or lammergeiers, also known as quebrantahuesos – bonebreakers! – are renowned for their habit of smashing bones by dropping them from a great height to consume the fragments. They’re native to mountainous regions such as the Pyrenees or North Africa, but in 2016, one turned up in the Gwent Levels in South Wales. The size of the bird – its wingspan can reach 3m – caused one local walker to comment, “It was so big, I thought it was going to pick up my dog.” Happily, we believe Fido survived.
Another bearded vulture also turned up in the UK in 2020
The Cornish siphonophores
In the autumn and early winter, westerly winds frequently carry a strange armada of pink-frilled creatures with blue-ish sails resembling fancy jellyfish – Portuguese man o wars, a species of, yes, siphonophore, bizarre organisms that are made up of multiple, genetically identical individuals that perform different functions.
One of those functions are 30-metre-long trailing tentacles whose sting can leave you in severe pain, difficulty breathing and even kill you. The coasts of Cornwall, Devon and Pembrokeshire are common places for these pirates to land, an alien invasion to match any sci-fi imaginings.
The Andover raccoon dog
Native to the Asian Far East, the raccoon dog – neither a raccoon nor a dog, it’s most closely related to foxes – has spread to a Central and Western Europe having been brought over for the fur trade. In recent years, individuals have also been spotted in Andover in Hampshire, Nottinghamshire and on the edge of the Brecon Beacons after escaping from private collections. People keep them because they think they look cute, though the man in Clarborough who saw one attacking a goat probably didn’t share that view.
The Cumbrian alligator snapping turtle
Growing to 80kg and a length of 1.5 metres, the alligator snapping turtle is the largest freshwater turtle in the world, and that snapping beak is said to be sufficiently powerful to bite a wooden broomstick in half, so imagine what it could do to your fingers. A parish councillor near Ulverston, in the Lake District, pulled one from a tarn in 2024 – and didn’t lose any digits. Luckily, it’s not warm enough here for any turtles to breed, so this particular alien is unlikely to spread any further.
The Herne Bay sea squirts
These sea squirts could be called ‘The Thing’ because they resemble something from an alien B movie, though sea vomit is also a good description. Originally from the waters off Japan, the sea squirt may becoming invasive here, experts warn, as it has already done off New Zealand, Massachusetts and the Netherlands. Though not remotely dangerous to humans, sea squirts exude a toxin that prevents other species, such as mussels and scallops, from colonising the seabed. Also seen in other areas around the UK.
The Cumbrian coatis
A small colony of coatis, carnivores classed in the same family as raccoons, became established in the wild in the south of Cumbria in the mid-2000s after escaping from a local zoo. Exactly what they survived on was never clear, though it’s unlikely to have been lost fell-walkers because they eat spiders, other invertebrates and fruit. Reports of them breeding were never confirmed, and the local Wildlife Trust says it is not aware of any recent sightings.
The Hebridean great white shark
A reported encounter with a great white shark off the Isle of Lewis in 2016 is just one of seven possible sightings of this most-feared of marine predators since the mid-1960s. Experts such as Richard Peirce not only don’t discount them as shaggy sea stories, but question why they don’t happen more often, because not only is the sea temperature off Devon and Cornwall the same as that off South Africa (where great whites thrive), but there is also an abundance of grey and harbour seals, essential prey items, around the UK.
British big cats
Is there a part of the UK that hasn’t reported sightings of black panthers or puma-like felids? Perhaps Central London, but otherwise, they have almost certainly been seen in every county in the country. Just how many of those sightings can be relied upon remains a matter of both doubt and fierce debate, but many people are absolutely convinced they are here. Most sightings are what are described as black panthers, which would be black or melanistic leopards, but tawny-coloured puma-like animals are also reported.