“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. Though two-headed snakes are a rarity, they are more common than other animals with two heads. 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.