The Axolotl Quiz

Axolotl: A Critically Endangered Salamander with Regenerative Abilities

• The axolotl is a paedomorphic salamander that does not undergo metamorphosis and remains aquatic and gilled throughout its life.

• It was originally found in several lakes in Mexico City, but its natural habitat was destroyed by Spanish settlers who drained the lakes.

• Axolotls are critically endangered in the wild, with a decreasing population of around 50 to 1,000 adult individuals, due to urbanization and water pollution in Mexico City, as well as the introduction of invasive species.

• Axolotls are used extensively in scientific research due to their ability to regenerate limbs, gills, and parts of their eyes and brains.

• They are carnivorous, consuming small prey such as mollusks, worms, insects, other arthropods, and small fish in the wild.

• The axolotl is currently on the International Union for Conservation of Nature's annual Red List of threatened species.

• The axolotl's genome was published in 2018 and revealed species-specific genetic pathways that may be responsible for limb regeneration.

• The axolotl's healing ability is unique in that it does not heal by scarring and is capable of regenerating entire lost appendages, as well as vital structures such as the tail, limb, central nervous system, and tissues of the eye and heart.

• The axolotl is neotenic, meaning it reaches sexual maturity without undergoing metamorphosis, and its lack of thyroid stimulating hormone prevents it from metamorphosing into a terrestrial salamander.

• The genes responsible for neoteny in laboratory animals may have been identified, but they are not linked in wild populations, suggesting artificial selection is the cause of complete neoteny in laboratory and pet axolotls.

• The axolotl is listed under Appendix II of the Convention on International Trade in Endangered Species (CITES).

• The axolotl's habitat is limited to the freshwater of Lake Xochimilco and Lake Chalco in the Valley of Mexico.

• Axolotls have four pigmentation genes; when mutated, they create different color variants. The normal wild-type animal is brown/tan with gold speckles and an olive undertone.Axolotl: A Unique Salamander Species

• Neoteny is a survival mechanism observed in all salamander families. It allows them to survive in aquatic environments that have little food and iodine.

• Salamander larvae require a lower quantity and quality of food than adults. They can transform into bigger terrestrial adults by ingesting a sufficient amount of iodine.

• Dwarf forms of salmonids are found in high mountain lakes due to deficiencies in food and iodine. This causes cretinism and dwarfism due to hypothyroidism, as it does in humans.

• The native axolotl population is now limited to Lake Xochimilco, a small series of artificial channels, small lakes, and temporary wetlands.

• Lake Xochimilco has poor water quality due to the region's aquaculture and agriculture demands.

• The presence of invasive species such as Nile tilapia and common carp threatens axolotl populations by eating their eggs or young and out-competing them for resources.

• A reduction in activity caused by the invasive species greatly impacts the axolotls' foraging and mating opportunities.

• A lack of genetic diversity is dangerous for the remaining population, causing an increase in inbreeding and a decrease in general fitness and adaptive potential.

• Scientists are focusing their conservation efforts on translocation of captive-bred individuals into new habitats or reintroduction into Lake Xochimilco.

• The axolotl is a popular exotic pet and requires a 150-litre tank with temperatures between 16°C and 18°C.

• Substrates are an important consideration for captive axolotls, as they tend to ingest bedding material together with food and are prone to gastrointestinal obstruction and foreign body ingestion.

• Axolotls can eat a variety of readily available foods, including trout and salmon pellets, frozen or live bloodworms, earthworms, and waxworms.