Sssssstake your money on it! Two-headed snake defies overwhelming odds of one in a hundred million to stun scientists and survive 17 years
- The two-headed black rat snake has already grown to five feet long
- Odds of survival for the snake have been put at one in a hundred million
- Two sisters were found in a back yard in by a boy in Missouri in 2005
- The heads are 'competitive' when they eat and are fed separately
An extremely rare two-headed snake has stunned its handlers by bucking all predictions of its imminent demise as it approaches its 17th year.
The black rat snake, which is really snakes sharing one slithering body, has grown to five feet long and has already exceeded the life expectancy of its regular counterparts in the wild.
The rare serpent was found by a boy in his yard in the small town of Delta, Missouri, in 2005 and brought to Cape Girardeau Conservation Nature Center.
The existence of a two-headed snake was already a one-in-a-100,000 long shot, and that it would live to such a ripe old age made it a one-in-a-hundred-million wonder, according to Snake expert Steve Allain, a council member of the British Herpetological Society.
He said: 'I know of another two-headed snake that survived until it was 20, so it's isn't impossible for them to survive that long.
'However, it is extremely unlikely. I'd say that it's likely one in a hundred million.'
This extremely rare two-headed snake, found in a back yard in Missouri in 2005, has managed to survive into its seventeenth year
The black rat snake, which is really two black rat snakes sharing one slithering body, has grown to five feet long and has already exceeded the life expectancy of its regular counterparts in the wild
Pictured: An x-ray of the two-headed snake. The snakes share a stomach so technically handlers only need feed one of them but they feed them both to stimulate their natural instincts and provide some mental enrichment
Alex Holmes, a naturalist at the conservation center, described some of the challenges he faced keeping such an unusual snake alive.
'A normal snake their size would be capable of eating full-sized mice with ease,' he said.
'But their conjoined spine makes it more difficult to swallow all but very small, young mice, which they take thawed from frozen.
'The heads are quite competitive when they eat so we cover one head at a time with a drinking cup and feed each individually.
'We wait a period of time to make sure the food has passed their junction to avoid a 'traffic jam' from the left and right head's meals meeting in the esophagus.
'They share a stomach but we feed them both to stimulate their natural instincts and provide some mental enrichment.'
In the wild, the snake - which strictly-speaking is two snakes sharing one body - might never have made it.
'Most conjoined hatchlings would not survive,' said Alex.
'Our 'twins' have a hard time deciding which way to go, arguing as sisters do - which is fine for a life of leisurely captivity.
'But if a hungry hawk, skunk, or raccoon came along in the wild that slow reaction to danger would make them an easy meal.' Even in captivity, however, survival is rare.
The existence of a two-headed snake was already a one-in-a-100,000 long shot, and that it would live to such a ripe old age made it a one-in-a-hundred-million wonder
The heads are quite competitive when they eat so handlers cover one head at a time with a drinking cup and feed each individually
Snakes can be born with two heads when an individual egg is fertilized and starts to divide into twins, but doesn't fully separate. In this case, the developing embryo split partially at the top but failed to separate further down, as can be seen in this x-ray
Paul Rowley, a herpetologist at the Liverpool School of Tropical Medicine, said it was impossible to calculate such long odds.
He said: 'It's difficult enough with any normal hatchling or newborn snake - within a group there will be some that are gonna die for no known real reason.
'But with animals that are conjoined like snakes with two heads, you've got problems with how compatible are they to each other, what organs are shared, and how they're cared for.
'And, again, it's like any conjoined twins - if one gets ill or one has organ failure or problems, it's obviously going to affect the other one. So you're doubling the problem.
'To last 17 years is a real achievement.'
Snakes can be born with two heads when an individual egg is fertilized and starts to divide into twins, but doesn't fully separate.
In this case, the developing embryo split partially at the top but failed to separate further down. It's exact date of birth is unknown.
Black rat snakes reach sexual maturity at seven years for males and nine years for females.
Their main predators are foxes, hawks and owls, which they scare away by imitating the rattle of a rattlesnake by coiling its body and vibrating its tail in dead leaves.
They are shy creatures which shun confrontation, but have been known to strike when feeling threatened. They are not venomous.