There is some speculation that the inbreeding of snakes in captivity increases the chances of a two-headed birth. One or two beings? It is difficult to draw the line between what is considered "one animal with two heads" or "two animals that share a body". Abigail and Brittany Hensel, born in 1990, were given two distinct names at birth. They identify as two people, and are recognised as two people legally and socially. On the other hand, Syafitri, born 2006 in Indonesia, were given one name by their parents because they only had one heart. In early Germany, conjoined twins that could not be separated were legally considered one person. Millie and Christine McKoy were often referred to in the singular, including by themselves, with the name "Millie-Christine", as well as plural.In Peter Mogila’s 17-century Catechism, the following instructions are given for baptism of polycephalic infants: should there be distinct heads and distinct chests, this means there are separate people each of whom must be baptised normally; if the heads and chests are not completely distinct from each other, however, one person must be baptised normally but baptism of the other(s) should be preluded by the formula "if not already baptised".With other animals, polycephaly is usually described as "one animal with two heads". One of the heads, especially in three-headed animals, may be poorly developed and malformed, and not "participate" much.
A full taxidermy of a two-headed calf can be seen advertising ice cream for College of the Ozarks in Branson, Missouri, where it was delivered by the students. Two full body taxidermies of two-headed calves can be seen at the Huron County Museum in Goderich, Ontario. A full taxidermy of a two-headed calf is on display at the Miami County Museum in Peru, Indiana
A full body taxidermy of a two-headed calf is on display at the Finnish Museum of Natural History in Helsinki
A taxidermy of a two-headed calf can be found in St. Petersburg, FL in the U.S. at the St. Petersburg Museum of History. A two-headed calf is displayed at the Bay Beach Wildlife Sanctuary in Green Bay, Wisconsin. The Woolly Mammoth Antiques & Oddities shop in Chicagos Andersonville neighborhood displays a two-headed calf named Brussels Sprouts, originally from Belgium. Pigs
The Deformed Animals Museum of Llubí, Spain, preserves a two-headed pig. A preserved two headed piglet can be seen at the Museum of Witchcraft, Boscastle, Cornwall, England. A two-headed piglet can be found at the Old State House in Hartford, Connecticut. In 1998, Rudy, a two-headed pig, was born in Iowa. A two-headed piglet appeared on one episode of Oddities. A two-headed piglet was a display at the Stearns County Museum in St. Cloud, Minnesota, until the mid-1970s, but cannot be confirmed; it may have been creative taxidermy. Goats and sheep
In 1577, a lamb with 3 heads was born in Blandy, France, and illustrated in Ambroise Pares Of Monsters and Prodigies.