The Axolotl: Mexico's "Walking Fish"
The Axolotl: Quick Facts
Binomial Name: Ambystoma mexicanum
Species: A. mexicanum
Synonyms: Gyrinus mexicanus (Shaw and Nodder, 1798); Siren pisciformis (Shaw, 1802); Siredon axolotl (Wagler, 1830); Axolotes guttata (Owen, 1844); Siredon Humboldtii (Dumeril, Bibron and Dumeril, 1854); Amblystoma weismanni (Wiedersheim, 1879); Siredon edule (Duges, 1888)
Conservation Status: Critically Endangered
Behavioral Traits and Characteristics of the Axolotl
The Axolotl, also known as the “Mexican Walking Fish” or “Mexican Salamander,” is a neotenic salamander that is closely related to the Tiger Salamander. Informally known as the “walking fish,” the Axolotl is actually not a fish, but an amphibian. In contrast to most amphibian species of the world, Axolotls are unusual in that they reach adulthood without undergoing any form of metamorphosis (change). Rather than developing lungs, the adult Axolotl maintains a set of gills and remains aquatic for the entirety of its life.
As of the early 2000s, the Axolotls have been listed as “critically endangered,” and on the brink of extinction due to urbanization and water pollution in their natural habitats. The invasion of Tilapia and Perch has also played a role in the destruction of Axolotls. By 2013, an investigative research team found only two surviving Axolotls in the wild, compared to the findings of a 1998 investigation that uncovered nearly 6,000 Axolotls per square mile in the Lake Xochimilco region.
Characteristics of the Axolotl
Fully matured at eighteen to twenty-four months, Axolotls are approximately six to eighteen inches long, with external gills and caudal fins that are similar to salamanders. The Axolotl possesses a wide head, lidless eyes, and scrawny limbs dotted with long, thin fingers. Although the Axolotl possess small teeth, its primary form of feeding is through suction. Four different pigmentations have been noticed in regard to their color with wild Axolotls being brownish-tan with gold speckles, while others (in captivity) tend to be pink, albino, grey, or solid black. Researchers believe that the Axolotl may have the ability to alter their color for camouflage (similar to a Chameleon); thus, explaining this wide array of color variations. They do this, it is believed, by changing the size and thickness of their melanophores.
Distribution Area of the Axolotl
The Axolotl's Natural Habitat
The Axolotl is only native to Lake Xochimilco and former Lake Chalco, in Mexico. The average temperature of the lake is approximately 20 Degrees Celsius, and as low as 6 Degrees Celsius during the winter months. Due to urbanization efforts in Mexico, Lake Xochimilco’s size had reduced dramatically in recent decades, and is dotted by numerous canals. Lake Chalco, on the other hand, was drained and no longer exists. It is currently used as a flood control area during extensive rains and hurricanes. For these reasons, the natural habitat of the Axolotl has shrank dramatically in recent years; forcing the animal to come into greater contact with natural predators.
Prey and Natural Predators of the Axolotl
Axolotls are carnivorous by nature, and consume small prey. This includes small worms and insects, along with the occasional fish (if they are small enough). It is believed that Axolotls locate their food through the use of smell, and use their mouth to suck food into their stomachs with a vacuum-like force. Because of their relatively small size, and inability to properly defend themselves, the Axolotl faces numerous challenges underwater; particularly since the introduction of non-native fish, such as Tilapia, Carp, and Perch have recently been introduced into the Axolotl’s environment. Not only do these fish serve as a direct threat, but they also consume much of the Axolotl’s natural food sources.
One of the most fascinating characteristics of the Axolotl is its remarkable ability to regenerate entire limbs after being harmed. In addition, some Axolotls have even been observed regenerating parts of vital organs and bodily-structures, including parts of their brain. For this reason, researchers and geneticists are hopeful that additional research on the Axolotls may prove beneficial in curing various diseases of the human body; particularly, those that affect major organs. Because of the Axolotl’s ability to readily accept organ transplants from other members of its species with no complications, additional research on these animals may help thousands of organ recipients (and donors), as “matches” between donor and recipient would no longer be needed, or easier to accomplish compared to current needs.
“The axolotl is a complete conservation paradox, because it’s probably the most widely distributed amphibian around the world in pet shops and labs, and yet it’s almost extinct in the wild.”— Richard Griffiths
The Axolotl is a popular pet (exotic) due to its remarkable characteristics. However, it should be noted that Axolotls require extensive care, as they are prone to disease and death if temperature and water components are not properly maintained. Tapwater alone is incapable of sustaining Axolotls, as the chlorine and other chemicals that are added often play havoc with their bodies. Axolotls require pure water combined with various salts, such as “Holtfreter’s Solution,” to aid in their development and to prevent disease or infection. Common foods for captive Axolotls include salmon pellets, bloodworms, waxworms, earthworms, and various feeder fish. Because the Axolotl is prone to gastrointestinal obstructions, it should also be noted that small gravel should not be used in their tanks, as the animal is prone to swallow rocks with diameters less than three centimeters.
Before reading this article, how familiar with the Axolotl were you?
In closing, the Axolotl is a remarkable creature due to its unusual appearance, peculiar traits, and amazing ability to regenerate. With their population dramatically shrinking with each passing year, the IUCN has listed the animal as “Critically Endangered” in the wild, prompting local and federal officials in Mexico to establish conservation efforts in an attempt to save the animal. In the city of Xochimilco, government officials have begun constructing numerous “axolotl shelters” to encourage their growth and stability in the wild. Other efforts have been made to conserve the Axolotl’s natural habitats, with promising results. There is still much to be learned about these extraordinary creatures, and the potential for new information has never been better as researchers and geneticists continue to unlock clues about the Axolotl’s remarkable abilities. Only time will tell what new medical advancements and treatments can be developed as a result of increased research into this incredible animal.
Images / Photographs:
Wikipedia contributors, "Axolotl," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Axolotl&oldid=903569613 (accessed July 5, 2019).
© 2019 Larry Slawson