Ambystoma mexicanum (/aeksltl/; from Classical Nahuatl: xltl [aolot] (listen)), is a paedomorphic salamander related to the tiger salamander. Axolotls are unique among amphibians in that they mature without going through metamorphosis. Adults remain aquatic and gilled rather than moving to land. The species was discovered in several lakes beneath what is now Mexico City, including Lake Xochimilco and Lake Chalco. Following the conquest of the Aztec Empire, Spanish settlers drained these lakes, destroying much of the axolotl's natural habitat.