With its wide head, lidless eyes, and bandana of external gills, the axolotl (Ambystoma mexicanum) is an unusual amphibian native to a group of lakes in the Valley of Mexico. Although surveys of Lake Xochimilco at the turn of the century recorded thousands of axolotls per square kilometer, this charismatic little salamander was listed as critically endangered in 2006, with some experts estimating that there could be as few as 50 adult individuals remaining in the wild.
Centuries of urban expansion have severely reduced the axolotl’s native habitat, with water pollution and the introduction of predatory fish species further challenging their survival. Lake Xochimilco, located in southern Mexico City, is now the only place where axolotls are found in the wild.
However, there is new hope for the recovery of this smiley-faced creature, with researchers discovering that axolotls bred in captivity can be successfully reintroduced to the wild. In a recent study, a total of 18 captive-bred axolotls fitted with radio trackers were released in two sites near Mexico City: Lake Xochimilco and an artificial wetland on the site of a disused quarry. The monitoring revealed that these axolotls not only survived but thrived, as they appeared to have gained weight from hunting. This was an unexpected yet welcome result, considering the high mortality rates often faced by captive animals released into native habitats.
This biologically fascinating species, which has the extraordinary ability to regrow lost limbs and even regenerate certain portions of its brain, has long been a focus of captive breeding programs. Now, conservationists hope, the hundreds of thousands of axolotls that exist in laboratories and as pets in aquariums may be joined by a recovering wild population, as efforts to restore and conserve their native wetland habitats continue.
An icon among amphibians:
- The species is named after the Aztec god of fire and lightning, Xolotl. Aztec legend describes the axolotl as a deity in salamander form.
- The curious form of the axolotl has inspired characters in the Pokémon and How to Train Your Dragon franchises. Its popularity was further boosted after being included in the wildly successful game Minecraft in 2020. Back in the real world, the axolotl was also featured in the design of the 50-peso Mexican banknote in 2021.
- The axolotl’s ability to regenerate many of its bodily tissues and readily accept organ transplants from other individuals makes the species of great scientific interest. Various studies have been undertaken to explore whether this extraordinary ability could be put to medical use.
