THE fact that a diet of mammalian thyroid will induce frog-tadpoles to metamorphose precociously into the adult ... effect in a form which usually does not metamorphose—the Axolotl.

Adult axolotls have lungs but rely primarily on these gills to breathe. Axolotls were named after Xolotl, the Aztec god of fire and lightning, who could take on the form of a salamander. Xolotl was ...