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? There is yet no conclusive answer to the debate.
Frank and Louie, a gray feline with two mouths, two noses and three eyes, turned 12 years old and is the world's oldest, living two-faced cat. (AP Photo/Steven Senne)
Leonard Sonnenschein, president of the World Aquarium in St. Louis , holds a two-headed albino rat snake. The eight-year-old oddity of nature was known affectionately by fans worldwide as "We" died of natural causes in 2007.
Oct. 28, 2011 photo provided by Daniel Parker of Sunshineserpents.com, a two-headed albino Honduran milk snake is shown in Ridge Manor, Fla. Parker, a University of Central Florida biologist, says that most two-headed snakes have typical coloration. Albino snakes don't have dark pigmentation in their skin. Albino milk snakes appear in bright shades of red, orange and white. The biologist says two-headed snakes have been documented to live as long...
A turtle born with two heads and an extra set of legs between them is held by an employee of a Jenkintown, Pa. , pet store on Sept. 22, 1986. The owner of the store said while it was the strangest thing he'd ever seen he had no idea how long it would live. (AP Photo/Rusty Kennedy)
Hakob Avetyan (not pictured) holds a two-headed calf in the Armenian village of Sotk , on January 28, 2011. The two-headed calf was born on January 25 in the Avetyans' cow house. Two-headed people and animals, though rare, have long been known to exist, and been documented. AFP PHOTO/ KAREN MINASYAN
An official shows a two-headed baby crocodile at Samut Prakarn Crocodile Farm on the outskirt of Bangkok . TAn official shows a two-headed baby crocodile at Samut Prakarn Crocodile Farm on the outskirt of Bangkok Monday, June 25, 2001. The crocodile, which shares the bottom part of the body, has eight legs and two tails, was born at this farm three days ago. It is measured at 17-centimeter long and weighs at 70 grams. (AP Photo/Sakchai Lalit)
A Palestinian farmer holds a two-headed sheep outside his family home in the West Bank al-Fawar refugee camp, near Hebron , on November 9, 2008. AFP PHOTO/HAZEM BADER
An unnamed two headed bobtail lizard, a type of skink, is seen at its new reptile park home at Henley Brook on April 22, 2010 in Perth , Australia . The two-headed reptile was rescued from Coogee by the Park and appears to be doing well, despite the life expectancy of such mutated births to be short. It eats from both heads but the larger head has also tried to attack the smaller one, and its movement is difficult as both heads control its back .
An x-ray of a rescued two headed bobtail, a type of skink, at the Henley Brook Reptile Park on April 22, 2010 in Perth , Australia .
Janus, the Geneva Museum of Natural History's two-headed Greek tortoise, is presented to the press and the public during the official celebration of its 10th birthday on 05 September 2007. AFP PHOTO / FABRICE COFFRIN
A two-headed snake named Tom and Jerry is pictured 08 May 2008 at the Vivarium exposition in Offenburg , western Germany . AFP PHOTO JOHANNA LEGUERRE
An animal keeper shows a two-headed American Rat Snake in an animal park in Tilburg.AFP PHOTO EPA-ANP / ROBIN UTRECHT
A two-headed red slider turtle is displayed at Big Al's Aquarium Supercenter in East Norriton, Pa. , Wednesday, Sept. 26, 2007. (AP Photo/Matt Rourke)
A vet feeds five month two-headed calf "Milagritos" (Little Miracle) in Cajamarca , Peru , on August 19, 2009. AFP PHOTO/ANDINA -Eduardo Lozano
A Hereford calf with two joining heads is bottle fed at a veterinary clinic in Elk Grove , California on April, 2, 1987 where it was taken by owner Dick Harry. The twelve day old female calf can eat with both mouths but the one being fed is more dominant. (AP Photo/Walt Zeboski)
A two-headed young tortoise is held by its owner, Noel Daniels, in Wellington , South Africa , Wednesday, May 28, 2003. Daniels says that the tortoise does all the things a normal tortoise does and that the rare phenomena occurs during the embryonic stage of development. (AP Photo/Obed Zilwa)
Australian scientists discovered a two headed blue tongue lizard in Sydney on 17th January 2001.The lizard named Trixie has one eye on the far side of each of her heads, as well as a third eye where the two heads connect, and one blue tongue.