Helpful tips and friendly advice on how to care for your axolotl

Is it a fish? Is it a lizard? Neither actually! The axolotl is a very special salamander which lives its entire life underwater. Its scientific name is Ambystoma mexicanum, as classified by Shaw and Nodder, 1798.
For those of you who are interested in classifications, the axolotl fits here:
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Caudata
Family: Ambystomatidae
Genus: Ambystoma

In basic terms, this means that axolotls fit into the wider group of amphibians, along with frogs; and they
are a type of salamander: with a difference! They are more commonly called axolotl, pronounced “axe-ahlot-
l”.

The word axolotl comes from the Aztecs language Nahuatl, and could mean water-doll, water-dog or servant of the water. Some people believe that the name is linked with the Aztec God, Xolotl. Axolotls are also known by the name Mexican Walking Fish, but this can be a little misleading; as they are not fish. They do live underwater, and they do have gills, but they have legs as well; which is why it is difficult, at a glance, to decide just what these wonderful creatures are.

The Ambystoma mexicanum at a glance

Now, I’ve seen axolotls described as “grotesque”, but I beg to differ! With their permanent smiles and protruding feathery gills, they have a rather appealing aspect. A quick search of Google images or YouTube will show you exactly what I mean. Axolotls are long-bodied, with tails and four legs; with five digits on the back feet and four on the front. They can be many colours in captivity. These include golden albino, white albino, white with black eyes, grey, shades of brown; and almost black. Axolotls that are wild, rather than
bred, are usually almost black, chocolate brown or cream. These natural colour varieties are known as “wild types”. More rarely, axolotls can be “piebald” with coloured spots, and piebald in more than one colour, which is known as “harlequin” colouring.
Their closest relatives are the Mexican Tiger Salamander, but axolotls differ in a very important way. All salamander eggs are fertilized and hatched underwater. Ordinary salamanders begin their lives as underwater creatures, but as they mature from the larval stage they metamorphose (change) into land dwellers; returning to the water only to breed and lay eggs, or for the occasional swim. Axolotls, on the other hand, do not metamorphose under normal conditions. They retain some larval stage characteristics including gills and fins; and therefore remain underwater throughout their lives. This specific trait is known as neoteny, or paedomorphosis. This means that although axolotls become sexually mature and breed; they remain in an otherwise permanently larval state. They are sometimes referred to as the “Peter Pan of the aquatic world” because of this.

The Life cycle of the Ambystoma mexicanum

Stage 1: The egg stage is typically amphibian. The egg contains a 2mm long embryo and is surrounded by a
jelly composed of water and a substance that is secreted around the egg when it is laid.
Stage 2: The embryo stage, approximately 11mm long, prior to hatching.
Stage 3: The larval stage is prior to the growth of limbs. The larvae are transparent for the first few weeks.
This stage lasts about two weeks.
Stage 4: Legs develop: first front; and then hind legs. Unlike frogs and salamanders, the axolotl does not
lose its gills and fins at this stage.
Stage 5: The adult stage: Full adult size is reached after eighteen months to two years, with sexual maturity
and the ability to breed occurring at one year to eighteen months. The average adult size is about 23-25
cm (9-10 inches). Large axolotls may grow to about 25-30 cm (10-12 inches). The size and rate of growth is
dependent on environmental factors such as feed and water temperature. They have a life span of
approximately fifteen years, with some living to as many as twenty.

Do axolotls ever “grow up”?

There is some evidence that axolotls will metamorphose into something similar to the adult tiger salamander if their aquatic environment becomes too hostile for survival. They can also be forced to metamorphose through scientific intervention, but this is very stressful for the axolotl and can drastically shorten its life expectancy. Very, very rarely a pet axolotl will metamorphose for genetic reasons; but attempting to force this will cause great distress and most likely death. Where do they come from?
As you may have guessed already, axolotls originate in Mexico, specifically in two fresh water lakes near New Mexico City. They used to be found in both Lake Xochimilco and Lake Chalco; but the second has now been completely drained, leaving only one place in the entire world for axolotls to live in their natural habitat. This, among other factors, has led to a drastic decline in their population and the International Union for Conservation of Nature (IUCN) have put them on their Red List as critically endangered. The IUCN Red List is designed to determine the relative risk of extinction; and they have established, through careful study, that axolotls are almost extinct in the wild.

Fortunately though, axolotls are very popular aquatic pets and are of vital interest to scientists, so they will
continue to live on through captive breeding.

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