Axolotls are one of 5 paedomorphic, neotenic aquatic salamanders, meaning they do not undergo metamorphosis and retain larval characteristics while living permanently in water.
Axolotls are paedomorphic or neotenic aquatic salamanders, meaning they retain certain larval characteristics in the adult, reproductive state. They are one of only 5 species of the Ambystoma genus which exhibits varying degrees of neotony.
Unlike typical amphibians, the axolotl does not change from an aquatic to an air-breathing lifeform through the result of metamorphosis. They, instead, undergo a process called “paedogenesis” becoming sexually mature in the aquatic larval form and living permanently in the water for up to 10-15 years.
Sources: (Brunst, January 1955; Griffiths, Bride, et al., 2004; Majchrzak, 2004; Zambrano, et al., 2010)
Image: Fred Langridge