The Axolotl (pronounced ACK-suh-LAH-tuhl) is a fascinating creature with button-like eyes and a permanent grin across its lovely face. It is a paedomorphic salamander related to the tiger salamander, and its scientific name is Ambystoma mexicanum. Australians and New Zealanders refer to the Axolotl as the Mexican Walking Fish, despite being an amphibian belonging to the Caudata/Urodela order. Axolotls and other salamanders are also mistakenly thought to be lizards or reptiles.
This species used to be found in various lakes in southern Mexico City, including Xochimilco and Chalco, but its population has plummeted. On the annual Red-List of Threatened Species, the Axolotl is classified as Critically Endangered. “The axolotl is a total conservation paradox,” says Richard Griffiths of the University of Kent in Canterbury. Thousands live in home aquariums, pet stores, and research labs worldwide, yet the species is endangered in the wild.
The Aztec name “Axolotl” means “water-dog” (atl for water and “xolotl” for dog) and derives from the Nahuatl language. The Axolotl is associated with Xolotl, the God of fire, lightning, deformities, and death. Legend has it that Xolotl disguised himself as a salamander to evade sacrifice.
Adult Axolotls are 18–26 months old and range in size from 15–45 cm (6–18 in) in length, however, most are closer to 23 cm (9 in). Axolotls larger than 30 cm are unusual (12 in). They have big heads and no eyelids. Limbs are undeveloped with long thin digits Males have inflated cloacae lined with papillae. In contrast, females have broader bodies filled with eggs.
Axolotls and salamander larvae both have external gills and a caudal fin that extends from behind the head to the vent. Three pairs of external gill stalks (rami) protrude from behind their heads, and their purpose is to transport oxygenated water. The gill stalks are lined with filaments (or fimbriae), which give them the appearance of soft feathers. These enhance the surface area available for gas exchange, allowing the amphibian to breathe when submerged. Underneath the exterior gills are four-gill slits lined with gill rakers that prevent food from entering while allowing particles to filter through. Axolotls are far more aquatic than other salamander species. Although having rudimentary lungs, they primarily breathe through their gills and their skin to a lesser extent.
In collaboration with several charity organizations, the Mexican government is working to save the axolotls by rehabilitating many parts of their watery habitat and boosting eco-tourism so that people can view these strange salamanders in the wild. This comprises scientists and farmers collaborating to build chinampas, or floating islands constructed of aquatic flora, wood, and lake mud, to help filter contaminated water.