Does the Mexican Walking Fish actually walk?
The Mexican Axolotl (Ambystoma mexicanum) is a freshwater amphibian in the salamander family. It is also known as the Mexican Walking Fish, but it is not a fish. Toads, frogs, newts, salamanders and axolotl are amphibians, living partly in water and partly on land.
Unlike other amphibians, the Mexican Axolotl never leaves the water – it remains aquatic and never goes on land, so it does not walk on land.
The female Mexican Axolotl lays 100-300 eggs, which hatch after 10-14 days into larvae. It remains in the amphibian tadpole (larva) form, with gills, and never becomes an ‘adult’ with lungs. This is called partial metamorphosis. So, they do not undergo the full metamorphosis of egg to larva to adult. It stays forever in the larval stage. This is called neoteny.
A frog, when it goes from tadpole to adult, loses its tail. The Mexican Axolotl keeps its long tail. A fin extends from the back of its head to the tip of its tail. A lower fin extends from between the hind (back) legs to the tip of the tail. It measures about 30 centimetres (12 inches) in length.
It has little, under-developed legs with long, thin digits (toes) and webbing in between so that it can swim. It has four digits on its front feet and six digits on it back feet.
If one of its legs is damaged and comes off, it can re-grow another leg. This is called regeneration.
Its legs are too small to really walk on the bottom of the river. It does stay on the bottom of the river, where it forages for food, but it is not really walking on the river bed.
So, the Mexican Walking Fish does not walk on land and it does not walk under water.
Location: Paris Zoo, France
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM