Scientific name: Ambystoma mexicanum
A sexually mature adult axolotl, at age 18–24 months, ranges in length from 15–45 cm (6–18 in), although a size close to 23 cm (9 in) is most common and greater than 30 cm (12 in) is rare. Axolotls possess features typical of salamander larvae, including external gills and a caudal fin extending from behind the head to the vent. Their heads are wide, and their eyes are lidless. Their limbs are underdeveloped and possess long, thin digits. Males are identified by their swollen cloacae lined with papillae, while females are noticeable for their wider bodies full of eggs. Three pairs of external gill stalks (rami) originate behind their heads and are used to move oxygenated water. The external gill rami are lined with filaments (fimbriae) to increase surface area for gas exchange. Four gill slits lined with gill rakers are hidden underneath the external gills. Axolotls have barely visible vestigial teeth, which would have developed during metamorphosis. The primary method of feeding is by suction, during which their rakers interlock to close the gill slits. External gills are used for respiration, although buccal pumping (gulping air from the surface) may also be used in order to provide oxygen to their lungs. Axolotls have four different colours, two naturally occurring colors and two mutants. The two naturally occurring colors are "wildtype" (varying shades of brown usually with spots) and melanoid (black). The two mutant colors are leucistic (pale pink with black eyes) and albino (golden, tan or pale pink with pink eyes). mexican axolotl are able to shed their skin just like snakes. Australians and New Zealanders frequently refer to the Axolotl as the Mexican Walking Fish, though the Axolotl is not a fish but an amphibian, a salamander, part of the...