Yes, they really 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.
