Axoloti: Treasured by Ancient Aztecs and Modern Scientists

We recently read an alarming statistic: it’s possible that only one hundred axolotl salamanders (Ambystoma mexicanum) exist in the wild.  Why should anyone care that a strange Mexican salamander may soon be extinct in its native habitat?

It turns out that this salamander is a remarkable creature. It intrigued the ancient Aztecs because of its strange looks and regenerative powers and was believed to be a manifestation of the god Xolotl, who like Charon in Greek mythology, was the ferryman of the dead to the underworld. To the Aztecs, the salamander’s regenerative  power was like that of the lake system that sustained them.

Most salamanders are able to regenerate body structures to some extent. But the axolotl is unique in that it can regenerate not only limbs, but also its jaws, spinal cord, and more. After these body parts regenerate, there is no evidence of scarring. Axolotls can even receive transplanted organs from other individuals and accept them without rejection.  They are one thousand times more resistant to cancer than mammals. This, of course, has made them of great interest to scientists who study them in captivity.

The axolotl is also one of the few animals that exhibit neoteny, that is, it retains its juvenile characteristics, such as the external gills, which gives the creature its cute looks.

By th1098 (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

By th1098 (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

But this animal, despite its “smile,”  has a lot to be unhappy about. Its only habitat is the canal system of Xochimilco in Mexico, which is what is left from what was an extensive lake and canals that connected most of the Aztec settlements of the Valley of Mexico. These canals, along with artificial islands called chinampas, attract tourists and other city residents who ride on colorful gondola-like boats around the hundred or so miles of canals. This canal and chinampa system, as a vestige of the area’s pre-Hispanic past, has made Xochimilco a World Heritage Site.

Unfortunately the canals are polluted with both garbage and fecal matter, as well as industrial fertilizers. Other problems include the damage by introduced plant and animal species. Carp and tilapia fish, for example, introduced in the 1960s, eat the eggs of the axototl.

The axolotl faces long odds for survival. It seems that only a complete regeneration and clean up of the historic canals will save this animal that is often considered a metaphor for the soul of Mexico.

Information for this post came primarily from an article and blog post from the LA Times and a Scientific American blog post. Note: the axototl is also know as the ajolote.



Giant Salamander: Earth's Largest Amphibian

We confess to paying most of our attention in our posts on Frogs Are Green to the stars of the amphibian world—frogs—and not so much on other amphibians. So to make up for that, we’d like to introduce you to Earth’s largest amphibian—the giant salamander of China and Japan.


This creature is considered a living fossil because it hasn’t changed much in 30 million years. To put things in perspective, 30 million years ago our ancestors were little primates hanging from trees. It would be millions of years before some of these primates descended from the trees, and millions of years after that before the first humans.

The giant salamander lives in mountain streams and lakes and can grow up to 6 feet long. It has four digits on its front legs and five digits on its back legs and is covered with a slimy protective mucous. It spends most of its time walking on the river bottom, though it can swim quickly. On land, its small legs won’t carry it and it must drag itself along.

Like many amphibians, the giant salamander is endangered due to habitat loss. Construction of dams converts  their free-flowing stream habitats into standing water or dries them up completely. They are also vulnerable to water pollution from mining activity and farming throughout their range.

Other threats to their habitat includes deforestation around the streams. This exacerbates soil erosion and causes increased runoff and siltation of the streams, reducing water quality and making it difficult for the salamanders to get enough oxygen through their skin. In addition, the giant salamander  is considered a delicacy and is also used in traditional Chinese medicine.*

On the BBC News site, Dr. Takeyoshi Tochimoto, director of the Hanzaki Institute near Hyogo in western Japan, gives a guided tour of this unusual creature.  (“Hanzaki” is the local name for the giant salamander.) After watching this video, however, I have decided not to hug a giant salamander if I ever meet one.  They have a very large mouth and several hundred small teeth on the top and bottom and can bite if angry, causing serious injury. Generally, however, this is a shy and secretive animal and is unfortunately relatively easy to catch.

*Information from BBC Wildlife Finder. Image above courtesy of National Geographic.