The oldest two-headed animal is a good 120 million years old. The fossil of this ancient lizard discovered in 2007 proves that animals with multiple heads are an ancient phenomenon. There are two variants – animals with two heads (bi/dicephalus) and animals with two faces on one head (diprosopus). These are all instances of congenital cephalic disorders, i.e. genetic disorders that lead to anomalies in embryos. Is pollution of natural resources playing a key role in increasing the number of such cases?
FootNote ~ There is yet no conclusive answer to the debate.