Two-headed Snake

Axial bifurcation, "two-headedness," is not unknown in snakes. The Division of Amphibians and Reptiles collection at Field Museum has at least three examples. Two are garter snakes and one is an eastern massasauga rattlesnake. All are from the Chicago area. A monographic study entitled "Axial bifurcation in serpents: an historical survey of serpent monsters having part of the axial skeleton duplicated" was published in 1937. Work is currently underway on an update.