The Axanthic Axolotl is an amazing creature that many pet owners find fascinating. The Axolotl is sometimes referred to as the “Mexican walking fish” because it does in fact look like a fish with legs. Despite appearances, the Axolotl is a salamander. Salamanders are amphibians, like frogs and toads, but they look more like lizards. They have slender bodies and short limbs that are kept close to their bodies.
Axanthic means lacking either red or yellow pigments or both. Axolotls can have different color variants as determined by their four pigmentation genes. The salamander in the wild will look either brown or tan with some specks of gold. Axanthic axolotls in captivity are bred for a mutant color that gives them gray skins and black eyes. It is this quality that makes the salamander a popular choice for home aquariums.
The Axanthic Axolotl is a neotenic mole salamander. Neotenic means that its development is slowed or delayed. Basically, it can stay in its juvenile stage of development indefinitely even though it can reproduce. To give you a better idea, imagine a tadpole that never turns into a frog. These traits make this salamander a very interesting amphibian to have as a pet and of course, amphibian and reptile owners love the various mutant colors that these animals are bred for. Here is a list of other fascinating facts about the Axanthic Axolotl salamander!
15 Amazing Facts About the Axanthic Axolotl
1. Axolotl Keep Their Larval Traits
Unlike many other salamander species, the Axolotl does not dramatically change its physical characteristics upon reaching its reproductive stage of adulthood. These aquatic salamanders keep their external gills and the reddish caudal fin. This is the fin that extends from the back of the salamander’s head and neck region to the gills. Their skeleton also won’t completely calcify. Instead, the skeleton remains primarily cartilaginous.
2. Only Exist Naturally in One Location
Previously, this unique salamander could be found at two locations – Lakes Xochimilco and Chalco. Unfortunately, due to destructive annual flooding, Lake Chalco was drained. This destroyed one of the salamanders’ native habitats.
Axolotls can still be found in Lake Xochimilco where they may spend their entire lives underwater. This endangered species thrives in large, high-altitude bodies of water that maintain an almost constant temperature of 68 degrees Fahrenheit.
3. Wide Range of Prey
This aquatic salamander might have a fragile appearance due to its cartilaginous skeleton but it does exist on a wide variety of prey. These salamanders are not that picky when it comes to dining on smaller species.
Some of their food preferences include mollusks, fish, insect larvae, crustaceans, and freshwater arthropods. If this prey is in short supply, the Axolotl will also eat various types of terrestrial worms, along with small amphibians that live in freshwater, along with zooplankton and even salmon eggs.
4. Also Known as the “Water Dog”
The Axolotl or water dog derives its name from the Aztec people. ‘Atl’ refers to water and ‘xolotl’ denotes dog. The round, lidless eyes and wide head do give the Axolotl a ‘doglike’ appearance.
Telling male and female ‘water dogs’ apart is easier than you might expect. Males have narrower heads and longer tails. Their cloaca is also swollen and is lined with papillae. Females are typically smaller than males. Their cloacas are smaller and they tend to have rounder bodies.
5. Axolotls Come in Different Colors
These salamanders have permeable skin and often hide under rocks. This can cause their skin to have an albino appearance. Dark-colored speckles or freckles aren’t uncommon. The speckles can also be green, brown, or olive. Black, copper, and golden are other color variations that can appear on these salamanders.
Some Axolotls that glow neon colors under blacklight. Known as GFP (green fluorescent protein) Axolotls, they can even appear to have a green hue in regular light. The neon-effect was artificially introduced but now can be passed from parents to offspring.
6. Their Gills are ‘Feathery’
Unlike fish and other marine dwellers, the gills on the Axolotl come with an additional feature. While there are gill slits on this salamander, they are also lined with filaments. These filaments are extremely fine and their sole purpose is to increase the surface area for gaseous exchanges. For example, inhaling and exhaling. This function is performed through the external gills though aided by the filaments.
Another interesting thing about salamanders is that different species have different respiratory systems or ways of breathing. While the Axolotl has the feathery gills mentioned above, some types of these amphibians breathe with lungs or through their skin.
7. Their Limbs Can Grow Back
The Axolotl might look like an overgrown tadpole but its limbs, which include two legs and a dorsal tail, serve a purpose. The tail provides balance and motion, while the legs help with traction on the lake bed. The reason these salamanders never go beyond the larval stage is due to a lack of a specific hormone. However, this also allows the limbs to grow back if the salamander discards them trying to evade a predator. This has made them a popular animal for scientific studies.
8. Female Axolotls Can Lay Hundreds of Eggs
Females can become fertile from six to twelve months. When the female is fertilized she can drop an estimated 300 to 1,000 eggs into the water. Each egg is laid and placed individually on plants or rocky surfaces. This is where the eggs will have the most protection from natural predators. It typically takes two weeks for the eggs to hatch and an additional two for the juveniles to be independent.
Females do not nurse their young so weening processes aren’t necessary for captive breeding.
9. Lonely, Night-Feeding Salamanders
Axolotls are solitary amphibians that rarely interact with each other. Typically, they only meet during mating, which occurs once a year in nature. In captivity, females can breed two or three times a year. When it’s time to reproduce, females emit pheromones that attract males. From there the female will choose a suitable mate.
10. Threats to Existence
The Axanthic Axolotl is an endangered species that is facing several threats.
One is the loss of their habitat. This species now only exists naturally in a freshwater lake located near Mexico City in a lake system called Xochimilco (pronounced SO-chee-MILL-koh). They are quite content to stay at the bottom of these lakes their entire lives. As water is drained from these lakes, this salamander loses its habitat. The introduction of invasive species to their native habitat, along with man-made pollution, are also problems.
Another threat to this salamander is scientific research. This tiny salamander is used extensively in several studies. Also, roasted Axolotl is considered a delicacy in Mexico which further reduces their numbers, and of course, their growing popularity in the aquarium trade puts them in great danger of becoming extinct in the wild.
11. Axolotls Started Scientists Researching Neoteny
In 1863, six adult Axolotls were shipped to Paris, France from Mexico City, Mexico. At the time the neoteny principles of this salamander were unknown. Once discovered by August Dumeril, it began the study of neoteny that has grown into researching the effects of adding the missing hormone to try to generate a typical metaphoric change.
For example, from egg to tadpole to frog. Axolotls are also studied for their ability to regenerate their own limbs.
12. Eyes are a Distinguishing Characteristic
Axolotls differ in color (the axanthic variety is gray in color) and even the length of their fringed gills will vary. However, there is one characteristic that all of these amphibious salamanders have in common. This physical feature also helps to distinguish Axolotls. Axolotls typically have a yellowish ring around the pupil.
13. Small Size and Long Lifespan
These freshwater salamanders may only grow, on average, 15 -30 cm in length. Smaller ones – less than .05 cm. — can become cannibalistic meaning they will eat each other. In an ideal environment, these small amphibians can live up to 12 years, however, some axolotls have been known to live as long as 15 years. Their average weight is 60 to 225 grams.
14. Small and Hearty Eaters
Axolotls might be small in size but they are voracious eaters. They are carnivores so they eat mean and their primary diet is blood and earthworms, along with tadpoles and feeder fish. They eat primarily by suction. The fringe gills act as rakes, locking together to block the gill slits during feeding.
15. Very Few Natural Threats
In their natural habitat, these salamanders are often at the top of the food chain and like to dine on mollusks and crustaceans. When bigger fish are introduced into their environment, such as carp and tilapia, these fish become a threat to the Axolotl as well. Larger birds such as herons will also feed on these salamanders when given the opportunity. Perhaps the biggest threat to Axolotls is humans.
The limited natural environment already places the aquatic salamanders at risk. While encroaching civilization is a threat the salamanders also have a few in the wild.