A colony of eight-foot Aesculapian snakes that can squeeze a small child to death has been living in Regent's Canal in London.
While the snakes are not venomous, they are powerful enough to kill a cat or dog.
The Independent reports that the snakes have been spotted up trees, on rooftops and climbing up drains in North London over the past few weeks.
They are believed to originate from central Europe but their ancestors may have escaped from London Zoo several years ago.
Mum-of-three Sylvia Taylor, 33, told the Daily Star: "If they are capable of killing small animals then surely they could constrict small children?"
According to the Daily Mail, the animals face a possible cull after the London Invasive Species Initiative, marked them as a 'non-native species of high concern'.
Dr Wolfgang Wuster of Bangor University said: "Any attempt to eradicate the Aesculapian snake would require justification of resources to be devoted to an almost certainly non-problematic introduced species with little prospects of spread, as opposed to the many far more damaging species already out there.
"From a wider and more philosophical point of view, we should ask ourselves what we can really conserve."
Aesculapian snakes are among the largest snakes in Europe and juveniles can easily be confused with grass snakes. A colony of the snakes has lived peacefully in North Wales for decades after escaping from the Welsh Mountain Zoo.
World's strangest animals
Deadly eight-foot snakes that can kill cats and dogs invade London
Where can I find one? These endangered nocturnal primates are typcially found in the eastern rainforests of Madagascar. They're also known to hang out on the island of Nosy Mangabe, on the country's eastern coast.
Tell me a secret: According to legend, the aye-aye is an evil omen. It's so feared by the people of Madagascar that it is still often killed on sight.
Where can I find one?Alpaca are kept in herds for their wool on the level heights of the Andes of southern Peru, northern Bolivia, Ecuador and northern Chile.
Tell me a secret: Alpaca spit at each other (and humans) when they're cross.
Where can I see one? Sometimes referred to as a sea cow, the dugong lives in the shallow coastal waters of northern Australia, where they can live for up to 70 years.
Tell me a secret: Although an acquatic mammal, the dugong is actually more closely related to the elephant than the whale or dolphin.
Where can I find one? This primate lives in southwest Amazon Basin, north Bolivia, west Brazil and Peru.
Tell me a secret: The emperor tamarin allegedly got its name because of its similarity in appearance to the German emperor, Wilhelm II.
Where can I find one? The flightless kiwi bird can only be found in New Zealand. It's semi-nocturnal and very shy - so very few New Zealanders have seen their national bird in the wild.
Tell me a secret: Despite its awkward appearance, a kiwi can outrun a human.
Where can I find one? The probiscis monkey is found exclusively on the island of Borneo in south east Asia, primarily in mango swamps. Their long noses are thought to attract females.
Tell me a secret: The probiscis monkey is an expert swimmer and has the longest nose out of all primates.
Where can I find one? Along the southern and western coasts of Australia. Leafy sea dragons have become endangered through pollution and are now a protected species.
Tell me a secret: Because of their excellent camouflage, leafy sea dragons don't have any natural predators.
Where can I find one? These strange-looking animals remain furless all their lives and live in parts of Sub-Saharan Africa. They are virtually blind but have acute hearing.
Strange fact: Naked mole rats live in colonies led by one dominant rat (the queen). Like some insect species, the queen is the only naked mole rat female to breed and bear young.
Where can I find one? The platypus is unique to Australia, inhabiting fresh water streams, rivers, lakes and farm dams.
Tell me a secret: The male platypus has a venomous spur on the inside of each hind claw. The poison can kill a dingo and is said to be leave humans helpless for several weeks.
Where can I find one? The soft-shelled turtle can be found in the waters of China and south east Asia as well as Russia.
Tell me a secret: Using its long nostils, the Chinese soft-shelled turtle can snorkel in shallow water using its long nostrils.
These bugs have extremely long and powerful legs that make them look like they are doing wacky dance moves. Native to Peru, the insects resemble stick insects but have distinctly horse-shaped faces - hence their names...
Where can I find one? The largest and heaviest lizards on earth, komodos are also the most lethal. They're native to Indonesia, and will eat anything, including deer, pigs, water buffalo and even humans. Their saliva teems with bacteria, so within 24 hours of being licked or bitten, most animals will die of blood poisoning. They are classified as an endangered species and protected under Indonesian law.
Tell me a secret: Komodo dragons have lived for millions of years, but were only discovered by humans 100 years ago.
Where can I see one? One of the world's smallest primates, the tarsier lives in the forests of Sumatra, Borneo and the Philippines.
Tell me a secret: Tarsiers have the biggest eyes of any land mammal. In fact, their eyes are so large that they'd be the equivalent to the size of a grapefruit in a human being.
Where can I see one? These nocturnal creatures are Australian egg-laying mammals who live in rainforests and deserts.
Tell me a secret: An echidna can lift an object twice its weight.
Where can I see one? You'll have to dive pretty deep - they inhabit the extreme depths off the coasts of Australia and Tasmania as well as Japan - but even if you did that you'd be very unlikely to see one as they're pretty rare, thanks to overfishing.
Tell me a secret: The blobfish has no muscles - it floats above the sea bed as a gelatinous mass.
Where can I see one? These distinctive tentacled underground mammals are native to north America.
Tell me a secret: Star-nosed moles have 22 tentacles with more than 25,000 receptive organs - all in a space smaller than one square centimetre.
Deadly eight-foot snakes that can kill cats and dogs invade London
Although they might look cumbersome and cute, hippos are actually one of the most feared animals in Africa, and can outrun a human. When a male feels its territory is threatened, or a female thinks her offspring her in danger, these animals can be particularly dangerous. And with huge teeth and mouth that can open four feet wide, it's a good idea to steer clear. Kills: An estimated 100-150 people a year. Deadly technique: Hippos will charge, trample and gore its victims, and have been known to upturn boats and canoes without warning. Lives in: Africa
Many people might not realise that the cape buffalo is one of the most dangerous animals in Africa, and will react with force when it feels threatened. These beasts can weigh up to 1.5 tons and stand at 1.7 metres high; they're so intimidating that even lions don't usually consider them dinner. Cape buffalos will charge, and then gore its victim to death with its impressive horns. Kills: An estimated 200 people a year. Deadly technique: These animals will charge and gore their victims to death with their huge horns. Lives in: Africa
Out of the world's 2,000 species of snake, around 250 are thought to be capable of killing a man. The Asian cobra does not have the deadliest venom, but is believed to be responsible for the biggest portion of the thousands of snakebite deaths every year. In Africa, the black mamba is the largest venomous snake and, during an attack, can strike up to 12 times, each time delivering enough neuro and cardio-toxic venom to kill a dozen men within 1 hour. Kills: An estimated 50-125,000 people a year. Deadly technique: A snake will use its fangs to pierce the skin and inject its paralysing venom. Lives in: Africa, Asia, Australia, North America
Box jellyfish can have up to 60 tentacles as long as 15 feet. And each tentacle contains enough venom to kill 50 humans, making it one of the most venomous marine creatures in the world. If stung, a box jellyfish can kill a man within minutes. Kills: An estimated 100 people a year. Deadly technique: Jellyfish use their tentacles to pump venom and paralyse its prey. Deaths in humans are usually a result of cardiac arrest. Lives in: Northern Australia, Papua New Guinea, Malaysia, Indonesia, the Philippines, Thailand and Vietnam.
Apart from humans, the mosquito is the deadliest creature on the planet. It kills millions of people every year through the spread of diseases like malaria, yellow fever, and dengue fever. Many of the malaria victims are children under the age of five. Kills: Two to three million people a year. Deadly technique: Female mosquitos pierce the skin with serrated mouth parts, and inject a saliva with a thinning agent to liquidise the blood. Lives in: Worldwide, more harmful in Africa, Asia and North America
The great white shark, which can grow up to six metres in length and weigh up to five tons, seems to have the most ferocious reputation. But, while they have been known to attack humans, most of these incidents are thought to be 'test bites', where the animal is deciphering whether he wants to eat you. And, generally, they humans are not on the menu. It is thought the aggressive bull shark is responsible for the most attacks on people. Out of the 360 shark species, only four are known killers: the great white, the bull, tiger, and the oceanic white tip. Kills: An estimated 100 people a year. Deadly technique: Sharks use their razor-sharp teeth to rip chunks out of its victims. Great whites usually take a big single bite, drag their victims into deeper waters, and wait until the prey bleeds to death before they eat it. Lives in: Florida, Australia, Hawaii and South Africa.
The are lots of different species of bear, but the polar, black and grizzly are the deadliest. Native to the Arctic, polar bears could decapitate a human being with one swipe of their massive paws. Bears generally attack when they are hungry, so it's a good idea to keep food away from your camp. Kills: An estimated 5 to 10 people a year. Deadly technique: Bear will use their teeth and claws to maul and trample their victims. Lives in: North America, Canada, North Pole, and Russia.
Crocodiles have been around for 200 million years, and are fearsome predators. The saltwater crocodile, or saltie, is the largest living reptile in the world, and can grow up to 21ft long and weigh 1.6 tons. These animals can run extremely fast on land, and, in the water, can swim as fast as dolphin. Many fatalities occur when people are washing or gathering food near river banks. Kills: An estimated 600-800 people a year. Deadly technique: Crocodiles will grab their victims with terrifying speed, and often launch into a 'death roll', weakening its prey, dragging it under water and drowning the victim. Lives in: Africa and Australia
Out of the 1,500 species of scorpion, the African spitting scorpion is thought to be the most deadly, and can spray its venom up to a metre. Arounf 25 species of scorpion are thought to be deadly to humans. Kills: An estimated 800-2,000 people a year. Deadly technique: Scorpions use their tail stingers to paralyse their prey with venom. Lives in: Worldwide; particularly Africa, the Americas and Central Asia.
Weighing in at up to eight tons, although beautiful creatures, elephants can be lethal. African elephants in particular can be aggressive, especially older bulls and young males. These creatures, unsurprisingly, are more aggressive in areas where poaching is rife or when their habitat is threatened. Kills: An estimated 300-500 people a year. Deadly technique: Most human deaths are result of the elephant trampling on its victim. Lives in: Africa and India
African lions are the biggest of the big cats, and are known to kill around 70 people in Tanzania alone every year. With the destruction of their habitat, human attacks by leopards in India, and the North American mountain lion are thought to be on the increase. Kills: An estimated 800 people a year. Deadly technique: African lions will often use strangulation to kill their prey, while tigers will attack from the back and aim for the jugular, and mountain lions will maul their victims. Lives in: Africa, North America, and India