Axolotl
The neotenic salamander that never grows up.
The axolotl (Ambystoma mexicanum) is a species of mole salamander. It is neotenic, reaching sexual maturity without undergoing metamorphosis, and the adults remain fully aquatic with obvious external gills. Axolotls originally inhabited a system of interconnected wetlands and lakes in the highlands of Mexico. They have been driven to near extinction by the introduction of invasive species such as tilapia and carp; with a decreasing population of around 50 to 1,000 adult individuals, the species has been assessed as critically endangered by the International Union for Conservation of Nature (IUCN) and is listed under Appendix II of the Convention on International Trade in Endangered Species (CITES).
Quick Facts
- Scientific name
- Ambystoma mexicanum
- Family
- Ambystomatidae
- Native range
- Xochimilco lake complex, Mexico
- Conservation status
- Critically Endangered (IUCN)
- Distinctive trait
- Neoteny (retention of larval features)
Lore & Background
The term 'axolotl' is a Nahuatl word which has been translated variably as 'water slave', 'water servant', 'water sprite', 'water player', 'water monstrosity', 'water twin', or 'water dog'. The word refers to Xolotl, the Aztec god who holds dominion over fire, lightning, the dead and the resurrected, dogs, games, grotesque or ugly beings, and twins (as he is the twin of Quetzalcōātl).
Reader's Guide
Axolotls possess features typical of salamander larvae, including external gills and a caudal fin extending from behind the head to the vent. They have wide heads and lidless eyes, and their limbs are underdeveloped with long, thin digits. The wild type is brown or tan with gold speckles and an olive undertone. Common mutant colors include leucistic (pale pink body, black eyes), xanthic (grey body, black eyes), albinistic (pale pink or white body, red eyes), and melanistic (black or dark blue body with no gold speckling or olive tone). Axolotls are used extensively in scientific research because of their unusual ability to regenerate body parts, including limbs, gills and parts of their eyes and brains. They have become a common exhibit in zoos and public aquariums, as well as an occasional pet in home aquariums.
Did You Know?
- Axolotls can regrow entire lost appendages, such as limbs and tail, over a period of months.
- The axolotl genome is about 32 billion base pairs long, about ten times the size of the human genome.
- Axolotls have barely visible vestigial teeth and feed primarily by suction.
- Males can be identified by their swollen cloacae lined with papillae, while females have noticeably wider bodies when gravid.
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