This long and cylindrical salamander can reach 30 centimetres. Its most notable feature is external gills, which projected from the back of the head and remain throughout adult life. Although it lives underwater, if the locale where it live dries up, the axolotl metamorphoses into a terrestrial salamander.
The major threats are habitat degradation, urban pressure, pet trade. Searches for the last years in its natural habitat found no surviving individuals in the wild.
The axolotl can regenerate entire lost appendages in a period of months, and, in certain cases, more vital structures.