The two-headed monsters of myth, as a matter of fact, have a basis in reality. Two-headed snakes are very rare odd creatures but not unheard of, and one two headed snake recently found in Spain is giving scientists an opportunity to study how the anomaly affects their ability to hunt and mate.
"Polycephaly is a condition of having more than one head. The term is derived from the stems poly- meaning 'many' and kephal- meaning "head", and encompasses bicephaly and dicephaly (both referring to two-headedness). A variation is an animal born with two faces on a single head, a condition known as diprosopus. In medical terms these are all congenital cephalic disorders.”
How many of us believe in the existence of two headed snakes? Well, as with any living creature, they do exist and are a much more common sight than any other two headed animals.
While a normal snake gives most people the creeps, the sight of a two headed snake must be tremendously gruesome, but captivating. In truth, two headed snakes are merely conjoined twins, connected to each other via their organs or body parts as with other twins that are connected. This means that a two headed snake could be joined to the other sharing the same organs, but one being a parasitic head.
Even in captivity, there are problems. Snakes operate a good deal by smell, and if one head catches the scent of prey on the other's head, it will attack and try to swallow the second head.
Two-headed snakes do exist, but they are rare. Two-headed snakes are actually conjoined twins, or sometimes, a fully formed individual with a parasitic twin that only consists of a head. Though two-headed snakes are a rarity, they are more common than other animals with two heads and are sometimes on display at zoos or in traveling animal side shows. Some museums have preserved specimens of two-headed snakes.
Two-headed snakes do not have a long life expectancy, particularly in the wild. Each head has a brain and, usually, some control over the shared body, and the two cannot communicate with each other. Movement is therefore difficult, as each head may try to travel in a different direction, and in the worst case scenario, the heads may fight or try to eat each other.
Some two-headed snakes share a stomach, while others have a stomach for each head. In a two-headed snake with separate stomachs, one of the heads may die if it routinely loses fights over food. Even if there is only one stomach, two-headed snakes may not be able to capture prey if the heads are competing for food.
Despite these difficulties, two-headed snakes have been known to live up to 20 years in captivity. Thelma and Louise, a two-headed snake that lived at the San Diego Zoo in California, had 15 offspring during her lifetime. Researchers have theorized that the inbreeding of snakes for zoos and pets may lead to an increased incidence of two-headed snakes, but this is very difficult, if not impossible, to verify, as it would entail getting an idea of how often two-headed snakes are born in the wild. The fact that they would not live very long makes the task even more daunting.
In 2000, a two-headed snake named We earned a bid of $150,000 US dollars (USD) on eBay, but the site's policy against the auction of live animals prevented the sale. Instead, Nutra Pharma Corporation adopted the snake in 2006 to aid in their study of the pharmacological benefits of snake venom.