The Amazing Axolotl

The lake in the first section of Chapultepec Park

Last weekend Alejandro and I went to the zoo in Chapultepec Park to see the new museum of the axolotl.  However, there was a long, long line awaiting to enter, and Alejandro did not want to wait.  So, on Thursday, I returned to Chapultepec by myself, and there was no line at all to enter the museum.

So. what is an axolotl? ("ajolotl" in Spanish)

As shown in this mural at the entrance to the building, the axolotl is an aquatic animal in the salamander family.  But unlike other amphibians, it does not metamorphosize into a land animal (such as a tadpole which changes into a frog).  It is characterized by external gills behind the head.  I did not realize until visiting this museum that there is more than one species of axolotl. 

The Toluca axolotl (ambystoma granulosum) lives in a small area on the outskirts of the city of Toluca. It is one species of axolotl that does metamorphosize into a salamander.  In fact, this fellow in the aquarium has made the transition and has lost its external gills.

The Pátzcuaro axolotl (ambystoma dumerilii) lives in Lake Pátzcuaro in the state of Michoacán.  This species remains aquatic with gills its entire life.

The best-known species is the Xochimilco axolotl (ambystoma mexicanum).  Its habitat was the system of lakes which once covered most of the Valley of Mexico where Mexico City stands today.  As the city grew, and the lakes were drained, all that remains of its habitat are the canals in the district of Xochimilco on the south side of the city.  Even that area is becoming degraded because of pollution and the introduction of tilapia.  Tilapia was brought in as a fish crop, but it eats axolotl and has become invasive.  The axolotl of Xochimilco is an endangered species in the wild, and it is estimated that only between 50 and 1000 of the creatures remain in the canals.  In the wild, the Xochimilco axolotl is a dark brown color, but when raised in captivity they display a variety of colors.

 

Upstairs there is a laboratory for the propagation of axolotls.  You can see tanks full of eggs, newly hatched axolotls, and adults.

 Although it is an endangered species in the wild, there is no lack of axolotls in captivity.  The animal is widely studied by scientists for its amazing regenerative properties.  If an axolotl loses a leg or tail, or even if part of its spine, heart or brain is injured, within eight hours it forms a little bag of mother cells, and within a few days the missing member or injured organ is completely regenerated.

WARNING!  Do not stare into the eyes of an axolotl for a prolonged period of time!

The first time I ever heard of this strange animal was when I was in graduate school and read the short story "Axolotl" by the 20th century, Argentinian writer Julio Cortázar.  In this fantastical story that is like an episode from "The Twilight Zone", the protagonist is fascinated with the axolotl and spends hours at the zoo staring at the animal.  At the end of the story he realizes that he has been transformed in an axolotl and is in the aquarium staring at the human form that was once he.