An image purports to show a unique seven-headed snake discovered in Honduras. Polycephaly(having several heads) is a phenomenon that many different kinds of animals(most notably snakes and turtles) display on occasion, and it is unique enough that discoveries of polycephalic creatures typically becom the topic of news reports.
Polycephalic animals, in general, fare poorly ( particularly in the wild) and have very short life spans, while seven-headed snakes have been recorded to survive long enough to breed and live out typical lifespans.
You would be forgiven in this age of deep fakes for wondering whether you can believe what you see when it comes to reports about two-headed snakes and other animals.
But this eye-catching developmental abnormality — known as bicephaly or dicephaly— is a phenomenon that has been around for at least 150 million years.
And over the years there have been reliable reports of a veritable menagerie of two-headed creatures, including snakes, bulls, sharks, turtles and prawns — and then there are two-faced kittens.
So how common are two-headed animals and what causes them?
Among the most common reports are two-headed snakes, yet these are certainly still rare enough to surprise us.
Take the two-headed eastern copperhead snake discovered recently in a flower bed outside the front door of a home in Woodbridge, Virginia.
State herpetologist John Kleopfer, who collected the snake, said he was familiar with two-headed snakes resulting from inbreeding in captivity, but was “dumbfounded” by the discovery of one in the wild.
Without special care, such animals usually die early because they have difficulty escaping predators and foraging for food, Dr Kleopfer, from the Virginia Department of Game and Inland Fisheries, said.
Indeed, while the copperhead — which has a single stomach — is now feeding well, its two heads don’t always co-oper ate.
“Sometimes with two-headed animals you’ll get one head that’s a little bit more dominant over the other one,” Dr Kleopfer said.
“Sometimes the heads go in different directions”
An even more unusual two-headed snake was studied by Gordon Burghardt of the University of Tennessee some years ago. In his decades of studying of animal behaviour, Dr Burghardt has encountered four two-headed snakes.
This two-headed black rat snake had two separate stomachs — and its two heads fought over prey.
Black rat snake eating prey
This black rat snake’s two heads fought over prey. In this case the left head won.(Supplied: Gordon Burghardt, University of Tennessee)
But it managed to survive for 20 years.
In more recent years, a two-headed yellow anaconda snake with two hearts, three lungs, two livers, and two stomachs was discovered in Brazil.
Over the centuries, hundreds of two-headed snakes have been reported, and it is worth asking why they seem to be more common than two-headed mammals.
We may well have a deep-seated fear handed down over the years of anything that sounds like a multi-headed serpent, and so take more notice of these creatures.
But might there also be a biological explanation for the observations?
According to Justin Adams of Monash University, who studies anatomy across the animal kingdom, including humans, there is.
Reptiles more likely than mammals to have two heads
Two heads can result from the incomplete splitting of an embryo (also called axial bifurcation), Dr Adams explained.
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This process leads to conjoined twins in humans, although only a very small number of conjoined twins have two heads and one body.
It is also possible for two separated embryos to incompletely fuse to form a two-headed animal.
Two-headedness results from factors that cause malformation of a developing embryo, which can be both genetic or environmental. But it does not tend to be inherited, since two-headed animals do not usually live long or reproduce.
In mammals, “fact-checking” by the mother’s body also tends to prevent the implantation of embryos that carry errors like this, Dr Adams said.
“If there are errors in development, there are miscarriages and spontaneous abortions,” he said.
Dr Adams said animals with irregularities like two-headedness were likely to be conceived at a much higher frequency than we realised — with far fewer surviving long enough to be born.
He said there were two reasons why reptiles would be more likely to have two-headed offspring than mammals.
First, they have many more offspring: “So, it’s a numbers game.”
Second, reptile eggs are exposed to the environment, which means they can be more easily exposed to more factors that can affect the developing embryo.
“Things like temperature, radiation, chemical toxicity,” Dr Adams said.
In addition, snakes are often bred in captivity, where inbreeding increases the chance of irregularities, and individuals with them are given support to survive.
Controversy over cause of two-headed
Recently an adorable dog went viral for having a face that looked more human than canine.
The cute pooch, named Nori, baffled people online who thought his face had been digitally altered.
But now there’s another strange animal shocking people on the internet, only this one lives in water instead of on land.
A rather unusual fish has been spotted in a lake in China, which appears to have some very odd markings on its face, causing it to look quite human.
It looks like it has a human face
A visitor to a village outside the city of Kunming in south China captured a video of the creepy carp.
The video was shared on Weibo, a Chinese social media platform and in the clip the fish can be seen swimming to the edge of the lake and poking its head above the surface of the water.
On the fish’s head are dark dots which look like two eyes, two vertical lines which resemble the sides of a nose and one horizontal one underneath where a mouth would be.
During the clip a woman can be heard saying: “The fish has turned into a fairy.”
The fish was spotted in China
People were understandably freaked out by the sight.
One person commented: “This is scary.”
Another replied: “Who dares to eat it?”
The video was later shared on Twitter by a user called @Unexplained where it creeped out more people.
“Holy s***,” proclaimed one user.
Someone else wrote: “I am so freaked out right now.”
Others compared the fish to Voldemort, an alien and the animated fish from the 2004 film Shark Tale.
This isn’t the first time someone has seen a human-like carp.
Back in 2010, a 44-year-old British man claimed that a carp he had bought five months before had begun to develop human-like facial features.
Brendan O’Sullivan from Dagenham, Essex, said: “It was astonishing. I could easily make out from the markings two eyes, a nose and a mouth.
“I thought I was suffering from sunstroke.”
The fish was believed to be worth an estimated £40,000.