The axolotl is an amphibian with a maximum lifespan of 15 years. It is a neotenic salamander with lizard-like limbs, related to the family of tiger salamanders, and is endemic to Mexico City, Lake Xochimilco, and Lake Chalco. Axolotl facts include its other names like Mexican walking fish, Mexican salamander, and water monster, and its binomial name is Ambystoma mexicanum.
It is typically challenging to find axolotl in other freshwater lakes except when someone is keeping it as a pet.
What makes this salamander species special and different from other animals? Here are interesting facts about axolotl.
Related: For more from the oceans, you might also like to check out our features on the different types of sharks, our compilation of whale facts, and ocean facts. And for more unexpected cuteness, our compilation of cute bugs is sure to surprise!
Axolotls have a variety of colors as their pigmentation cells produce different color variations4. Melanophores contain eumelanin, which is responsible for black and brown pigmentation. The second pigmentation cell is xanthophores, which contain carotenoids and pteridines.
These compounds are responsible for the colors yellow and red. Lastly, Iridophores are a pigment that contains crystalized purines, which causes iridescence.
These pigments give axolotls different colors like pink, gray, silver, white, golden, black, green, and copper. There are also axolotls with silver dalmatian, firefly, and enigma colors.
You'll most commonly find lighter-colored axolotls kept in captivity.
Axolotls are amphibians but remain aquatic throughout their lives instead of evolving like other amphibian animals (e.g., tadpoles into frogs). Do not mistake axolotl for a small fish. They retain their larvae features, which include their feathery gills and fin tails, unlike other tiger salamander species that lose their external gills and develop lungs.
Although axolotls retain gills, they also develop lungs and can breathe through their thin, moist skin. In fact, the axolotl respiratory system contains four methods of breathing: through their gills and skin, and axolotls breathe air through their lungs and buccal respiration (inflating their cheeks to pass air to their lungs).
One of the fun facts about axolotls is that they are famous for their ability to remain young forever. They don’t undergo metamorphosis before they become adults like other salamander species.
They still hold on to their juvenile characteristics and larval traits. These larval features include their finned tail, feathery gills, and aquatic lifestyle. They spend their entire life underwater, unlike the other salamander family members.
The previous axolotl fact mentioned axolotl’s everlasting youth. While axolotls can maintain their juvenile features, scientists discovered a way to metamorphose them into adult salamanders forcefully1.
Administering thyroid hormone led to the reorganization of axolotl’s organs to adapt to terrestrial life. Some organs are shifted and destroyed while new organs grow.
Research conducted by a group of scientists showed that axolotl lost weight within three weeks of inducing metamorphosis. Also, its fin and gills gradually disappeared, changing over three months into a terrestrial salamander. The experiments further showed significant changes in the structure and composition of the microbiota in the skin and digestive system.
The axolotl salamander is a critically endangered species. Do not be deceived by how common it is to find an axolotl salamander in private or public aquariums. They are facing a threat of extinction if the Mexican government does nothing about it. What is the cause of these cute axolotl's threatened extinction?
It is us, humans. Back in 1998, scientists recorded 2,340 axolotls per square mile of Lake Xochimilco. However, we do not have an accurate count of axolotl populations since 2014.
Over time, invasive species like carp, tilapia, and large birds prey on adult and young axolotls. Also, urbanization of the surrounding areas of natural habitat has caused habitat degradation, destruction, and loss.
There is no surviving the polluted water they call home. Sadly, these fascinating creatures have lost vast portions of their natural habitat to the drainage of large areas of Lake Xochimilco2, including Lake Chalco, to prevent flooding.
However, in 1984, Lake Xochimilco was deemed a biological reserve, and later, in 1987, it became a UNESCO World Heritage Site, both aiding its ongoing conservation. Further, local farmers have teamed up to create axolotl-friendly floating islands out of lake mud, reedy plants, and logs - this helps filter polluted water.
Furthermore, Mexicans eat a lot of axolotls. This high consumption rate further reduced the population of the Mexican walking fish.
How many axolotls are left in the wild? Estimates by the IUCN put the species population at between 50 and a thousand. However, you can find an axolotl for sale in pet stores, and there are said to be about a million pet axolotls in captivity. Captive axolotls can live for up to fifteen years.
One of the most unique axolotl facts is their regenerative abilities. They can regrow body parts like their spinal cord and lost limbs. Also, they can regenerate tissue and some parts of the central nervous system.
As such, if an axolotl loses its tail or limbs, it can regrow them, like a superpower. Tons of scientific research has tried to understand the mechanics of the regenerative capacity of the young axolotl to learn how to slow down the aging process in humans.
In the search to understand regeneration in axolotl salamanders, scientific research showed that three things are necessary: the wound epithelium (a protective layer of tissue), nerve signaling, and stem cells from the same limb6.
As they grow older, this unique ability to regenerate lost limbs declines, and they start to generate scar tissue instead of new limbs. However, it still exceeds the regenerative powers of humans or other mammals.
Axolotl reaches sexual maturity between 6 months to a year, with the female axolotl taking a bit longer than the male. The breeding season is usually around springtime.
To reproduce, the male axolotl performs a hula dance by nudging the female axolotl with his snout. While performing several minutes of this tail-shaking display mating dance, he opens his cloaca and shakes the posterior part of his body.
The female responds by nudging his posterior region. She then picks up the sperm cap dropped from the male's cloaca region with her cloaca. The sperm cap is a cone-shaped mass. According to Heather Eischen, skin contact is necessary for transferring spermatophores7.
Eggs form and mature in the female axolotl’s reproductive organs 12-72 hours later, after which she lays the eggs on plants. A female axolotl lays up to a thousand eggs—the eggs hatch in 15 days at a temperature of around 72 degrees Fahrenheit.
A curious axolotl fact is that they do not have eyelids, so they sleep with their eyes open, making it difficult to tell when your pet axolotl is awake or asleep. Knowing if axolotl is awake or asleep at night is more difficult.
However, as a nocturnal creature, it is active at night and sleeps during the day. Some signs that show when an axolotl is asleep include stillness of gills and other body activities. It will also most likely retreat to its hiding space when it wants to sleep.
A genome is a set of chromosomes present in the cells of a multicellular organism. All living organisms have genomes. However, scientists discovered that axolotls have the second largest gnome in the world.
The animal with the largest genome sequence in the world is the Australian lungfish, with a 43 billion base pair length. Axolotl comes close with 32 billion base pairs, which are ten times longer than the human genome5.
The axolotl is an iconic animal in Mexico City. Aztecs believed that Xolotl, a dog-headed god, transformed into an axolotl because he was afraid of being killed. Xolotl, a twin of Quetzalcoátl, is the god that leads dead souls into the underworld and runs when Ehecat came to murder him. Legend has it that he initially turned into a corn stem that local farmers called xolotl, but Ehecatl found him.
He ran away again and transformed into maguey and became mexolotl. However, Ehecatl found his hiding spot again and ran once again. Then, he transformed into the axolotl. They captured and killed him, making him one of the favorite delicacies of Aztec princes.
You can find axolotls in Lake Xochimilco. However, Xochimilco was a part of other lakes: Texcoco, Zumpango, Xaltocan, and Calco. Lake Xochimilco was a part of Lake Texcoco, but climate change caused the lake to dry up. Later on, Xochimilco became a bay in southern Texcoco. The 24th century came, and the creation of dams split the lake again.
These lakes are likely never to exist again, but Xochimilco canals remain. It is in these canals that you will find axolotls. You can find parts of Xochimilco lakes in Xochimilco Ecological Park and Plant Market, a natural reserve.
Axolotls are as cute as they look, and many consider them even cuter because they pose no harm to humans. These cute amphibians cannot injure us in any way and do not have strong dental structures that can bite us hard enough to cause any damage. Also, they do not have toxic substances or venoms in their body that can cause harm.
Due to their harmless nature, the so-described delicious white fish meat is a popular form of protein in Mexican cuisine, where people eat axolotls. Mexican walking fish has served as food for Mexicans since 1200 BC3.
You might think an animal as cute as an axolotl would be a herbivore. However, these carnivorous solitary creatures feed on other sea animals.
An axolotl in the wild feeds on small fish, crustaceans, insects, mollusks, and insect larvae. On the other hand, axolotls people keep in aquariums as pets typically feed on black, white, and blood worms. They also eat brine shrimp, salmon fish pellets, live daphnia, and sometimes other salamanders.
In the case of extreme hunger, they often turn cannibalistic, biting off parts of their fellow axolotls to quench their hunger. They eat by sucking in their prey through their mouth and do not chew because they do not have sharp teeth. So, they swallow their prey whole.
No list of axolotl facts would be complete without mentioning that Mexicans refer to them as the Mexican walking fish because of their physical appearance. Axolotls look like fish with webbed feet attached to their bodies. There are four toes on axolotls’ front feet and five toes on their back feet. They use their legs and tails to swim underwater. Also, they perform a scuttle walk around on the grounds of their habitat.
However, they are better swimmers than walkers because they spend more time in the water than on land. Also, an axolotl can climb over surfaces with stumpy legs.
Axolotls are cute animals that need saving before they go extinct. The axolotl is a salamander species with unique DNA characteristics, with its larval gills and long quillings distinct from the tadpole. Furthermore, the axolotl is a popular aquarium choice that can survive for many years in good condition.
Related: To further explore the animal kingdom, check out some of the other animals that start with A.
Demircan, T., Ovezmyradov, G., Yıldırım, B. et al. Experimentally induced metamorphosis in highly regenerative axolotl (ambystoma mexicanum) under constant diet restructures microbiota. Sci Rep 8, 10974 (2018). https://doi.org/10.1038/s41598-018-29373-y
Zambrano, L., Vega, E., Herrera M., L.G., Prado, E. and Reynoso, V.H. (2007), A population matrix model and population viability analysis to predict the fate of endangered species in highly managed water systems. Animal Conservation, 10: 297-303. https://doi.org/10.1111/j.1469-1795.2007.00105.x
Tate, Carolyn. (2010). The Axolotl as Food and Symbol in the Basin of Mexico, from 1200 BC to today (pdf). 10.1007/978-1-4419-0471-3_21.
Sally K. Frost, Fran Briggs, George M. Malacinski, A color atlas of pigment genes in the Mexican axolotl (Ambystoma mexicanum), Differentiation, Volume 26, Issues 1–3, 1984, Pages 182-188, ISSN 0301-4681, https://doi.org/10.1111/j.1432-0436.1984.tb01393.x
Nowoshilow, S., Schloissnig, S., Fei, JF. et al. The axolotl genome and the evolution of key tissue formation regulators. Nature 554, 50–55 (2018). https://doi.org/10.1038/nature25458
Vieira, W. A., Wells, K. M., & McCusker, C. D. (2020). Advancements to the Axolotl Model for Regeneration and Aging. Gerontology, 66(3), 212–222. https://doi.org/10.1159/000504294
Heather L. Eisthen. Courtship and Mating Behavior in the Axolotl.
Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.
Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.