WATCH NOW: Axolotls Are the Cutest Little Monsters
Found only in Lake Xochimilco and Lake Chalco in central Mexico, Axolotls are critically endangered in the wild.
While readily found in aquariums and in captivity as pets, wild populations of axolotls are dwindling in numbers due to urbanization causing pollution and the introduction of invasive species. Wild axolotls are currently on the endangered species CITES list and classified as critically endangered by IUCN.
Commonly mistaken as reptiles, these amphibians make great pets as they are incredibly adaptable and hardy. They live only underwater, using the external gills on the back of their heads. These gills are lined with filaments to increase surface area to help with gas exchange. Their lifespan can reach 15 years.
Axolotls (Ambystoma mexicanum) exhibit what is called neoteny, which is when they stay in their larval form, or juvenile form, into adulthood without going through metamorphosis. This is caused by a lack of thyroid hormones. Once they reach sexual maturity in adult form they can get up to 18 inches long. They are carnivores and in the wild survive on a diet of mollusks, worms, small fish, larvae, and crustaceans. For the first few weeks of life, axolotls are transparent and all their organs can be seen.
There are four types of pigmentation in the species:
- leucistic axolotls: pale pink with black eyes
- albino axolotls: golden with gold eyes
- axanthic axolotls: grey with black eyes
- melanoid axolotls: all black with no gold speckling or olive tone
Because of their adaptability, pet axolotls can handle water changes and impurities in their environment. However, water temperature should never drop below 61 degrees Fahrenheit since low temperatures results in slower metabolism.
These little neotenic salamanders are commonly known as Mexican walking fish and Mexican salamanders. They should not be confused with waterdogs, the larval stage of the tiger salamander (Ambystoma tigrinum), though they are close relatives.
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Off the back of their head, axolotls have branch-like gills. The little pieces off the gills increase surface area for gas exchange to help them breathe underwater.
Small, stump-like teeth are used to grip and maneuver their food into position so they can swallow it whole.
One reason axolotls are so readily researched is due to the fact that they can completely regrow their limbs and feet. The light and albino colored axolotls toes look "dirty" once they reach sexual maturation.
They range from 10-12 inches in length. Axolotls have also developed rudimentary lungs. While they breathe primarily through their gills, they do sometimes rise to the surface to take a breath before returning to the bottom of their habitat.
Females typically have a more rounded body because their belly is full of eggs.
Axolotls range in color from grey to shades of brown, albino and golden albino as well as melanistic (black).
Do you have a Mexican axolotl? Tell us and show us in the comments below!