Axolotl

 

Axolotl is one of the neotenic animals endemic to lake Xochimilco in Mexico city. 

As a neotenic, Axolotls don't undergo metamorphosis but attain adulthood characteristics. As a result, they don't develop lungs fully to live on land but retain their gills and fins which maintain their aquatic life.

In water bodies where Axolotls are found, there's low iodine which is the stimulating element for thyroid gland responsible for growth in animals and humans.

They're listed as critically endangered species because of human settlements in Mexico city. Pollution and introduction of aquatic species like African Tilapia which competes for the Axolotl's food and eats their eggs is another reason. Hence, their survival in the wild is almost extinct.

Axolotls exhibit variations in their skin colour due to four mutant genes they possess. Colours are black, grey, golden, pale pink and all are with different eye colour.

Axolotls shouldn't be confused with Tiger salamanders or mudpuppies due to their similar appearance. Axolotls are studied scientifically for their regenerating ability - after losing a a limb or other body part, they can heal and regrow it back. This ability for renewal is however connected to not undergoing metamorphosis.

Axolotls feed on worms, insects, small fish as a carnivorous amphibian. Because of their aquatic life, they're called "Mexican walking fish" but they don't belong to the fish family but are amphibians.