The Axolotl is related to the Tiger Salamander Species and popularly known as Mexican Walking Fish.
Although colloquially known as walking fish, it is not a fish but an amphibian where it is capable to survive both on land and water. The species is usually found at lakes of Mexico but most commonly at Lake Xochimilco which is underlying Mexico City.
Axolotls are unusual amphibians as they do not undergo metamorphosis and instead of developing lungs, they remain in the water and breathe through gills. However, we should not get confused with waterdogs which are usually found in lakes in North America, these creatures are closely related during the larval stage.
Axolotls were near extinction during their last census, the main reason being rapid developments of Mexico City and water pollution that is affecting their habitat. Currently, Axolotls are in the critically endangered list by IUCN with over 100 of this species found per square-kilometer of water surface.
Taxonomy of Axolotls
- Kingdom: Animalia
- Phylum: Chordata
- Class: Amphibia
- Order: Urodela
- Family: Ambystomatidae
- Genus: Ambystoma
- Species: Mexicanum
The Axolotls are native to Lake Xochimilco and Lake Chalco in the Valley of Mexico. Currently, Lake Xochimilco is the only habitat for these creatures as Lake Chalco has been drained as part of flood control measures. These are amphibians which have porous skin and which helps them to respond quickly for changes in the environment.
The Axolotls can exhibit various colors such as grey, tan, brown, white, golden albino, white albino, blue, etc. They have a lifespan of 15 years and weighs around 300g. A mature Axolotl can range from 15-45cm however most commonly size around 23cm is found. They attend sexual maturity during 6-12 months and the incubation period is around 2-3 weeks. During single spawning, an axolotl can lay around 200-1000+ eggs at a time.
The larvae of Axolotl possess around similar features like salamander larvae which includes external gills and caudal fin extending from behind from head to vent. The head is wide and the eyes are lidless, their limbs are underdeveloped with long thin digits. There are three pairs of external gills that are used to move oxygenated water. Male Axolotl is identified by swollen cloacae lined with papillae and females with wider bodies. They have barely visible vestigial teeth which would have developed via metamorphosis, however, their primary medium of feeding is through suction. Their primary food includes small prey such as worms, insects, small fish, etc.
The axolotl creatures that exhibit neoteny, which means when they reach sexual maturity, they do not undergo metamorphosis. This metamorphosis failure is caused by a lack of TSH (Thyroid Stimulating Hormone) which is responsible for the larvae to transform into a salamander. This may have been a survival mechanism which is due to a shortage of food available on land in mountainous regions.
Axolotls are studied by scientists due to their ability of regeneration where it is seen that they have the ability to repair a damaged limb as well as try to regenerate the lost limb. They also readily accept transplants from other individuals where they restore the alien organs to work for them in full functionality. This feature makes Axolotl an attractive pet for pet owners.
Also read: Top 10 Endangered Species In The World