Axolotls are fascinating animals with an interesting history and special abilities. Next are the 12 most exciting axolotl facts!
1. Wild Axolotl only live in one area in the world
All axolotls originate from Lake Xochimilco and Lake Chalco near Mexico City. These lakes used to be larger and more extensive, but have gotten smaller as Mexico City grew.
Humans and axolotls first came into contact in the 13th century when the Aztecs settled near what is now Mexico City. They named the axolotl after one of their gods “Xolotl”, the god of fire and lightning. Loosely translated, the name axolotl means “water monster” or “water god”.
2. Axolotls remain in the larval stage their entire live
Other amphibians, such as frogs and salamanders, start out as aquatic larvae after hatching from eggs and undergo metamorphosis. During this process, they lose their gills, develop legs, and grow into land-living animals.
Axolotls, on the other hand, live as aquatic larva and don’t develop into their adult terrestrial form.
Since axolotls reach sexual maturity even in their larval stage, this is called “neoteny.” During evolution, axolotls have developed a congenital thyroid defect that is responsible for the lack of metamorphosis.
3. In very rare cases, Axolotl can morph into their adult, salamander-like form
In extremely rare cases, an axolotl can go through metamorphosis and develop into its adult form. Due to the thyroid defect, the axolotl lacks the hormone thyroxine, which normally triggers metamorphosis.
When axolotls are exposed to large amounts of iodine, this can trigger metamorphosis due to increased thyroxine production. Another reason for metamorphosis may be in the genes of the axolotl. Many axolotls are crossed with the tiger salamander in order to breed special color varieties, such as albino axolotls. These animals may still carry functioning genes for metamorphosis, so natural metamorphosis can occur.
However, these cases are extremely rare, most axolotls are very weakened after metamorphosis and don’t live long afterwards. Therefore you should never try to induce a metamorphosis in your axolotl.
Click here for an article with more information about the metamorphosis of axolotls.
4. Axolotl can regrow many parts of their body
Axolotls have a strong regenerative ability; axolotls can regrow the following parts of their bodies:
- Limbs, such as arms, legs and toes.
- Part of their heart
- Parts of their brain
- Spinal cord
- Skin and tail
- Gill branches
Axolotls can regrow parts of complex organs, such as the brain and heart, in addition to entire limbs.
In this article we explain how regeneration works in the axolotl.
5. Axolotl can lay up to 1000 eggs
Usually female axolotls lay between 200 and 500 eggs, but they can also lay up to 1000 eggs in one clutch.
Axolotl babies hatch after about 10 days, depending on water temperature, and eat only live food during their first weeks. If you are interested in how axolotls reproduce, you can read this article.
6. Axolotls are almost extinct in the wild
Due to the introduction of non-native fish species that eat axolotls and pollution, they have been threatened with extinction for several years. They are also threatened by the growth of Mexico City, as this shrinks their natural habitat. Lake Chalco has been almost completely drained and Lake Xochimilco is now mostly canals.
Here is more information on why axolotls are nearly extinct and what is being done about it.
7. Axolotl comes in different color varieties
Wild axolotls usually have a dark color, such as black, brown or grayish. Basically, axolotls have three types of color cells, called chromatophores, which give the axolotl skin its individual coloration.
- Melanophores contain the pigment melanin and provide dark colors
- Iridophores contain guanine crystals and look shiny white-silver
- Xanthophores contain the pigments carotenoids and pterins and provide yellow, orange and reddish colors
Over time, many different color varieties have been bred.
- Wild type: gray to black, partly with spots and patterns
- White/ Leucist: White ground color with dark pigment spots distributed over the body, have dark eyes in contrast to albinos
- Melanoid: black to brown with dark gills
- Axanthic: black to brown with shiny spots
- Golden albino/ Humphrey albino: whitish yellow to yellow with red gills
- Axanthic albino: light yellow, with red eyes and gills
- Copper/ cookie: copper base color, light and dark spots and red gills
Here is a whole article about all color variations of Axolotl.
8. Young axolotls are cannibalistic
Especially young and newly hatched axolotls have cannibalistic tendencies, they snatch at the toes and gills of their siblings. Therefore, young axolotls should always have plenty of space and be well fed so that they don’t try to eat their siblings out of hunger.
Starting from a size of approx. 6 inches (15 cm) Axolotl become less cannibalistic and the danger that they try to eat each other is considerably smaller.
However, adult axolotls would still eat baby axolotls if you tried to keep them together.
9. Axolotls are popular lab animals
There are a large number of axolotls in research laboratories, they are used especially in regeneration and stem cell research. In fact, axolotls have been studied by scientists for over 200 years.
Their ability to regrow limbs and organs and their resistance to cancer are particularly interesting.
10. Axolotls have external gills and lungs
Although axolotls spend their entire lives in the water and can’t survive on land, they do have lungs as well as gills. Their lungs aren’t fully formed, but they use them in between swimming to the water’s surface and swallowing air.
Axolotls gills, on the other hand, are not located inside their body like fish, but on the outside of their head. They have 3 gill branches on each side of their head and can regenerate their gills if they are damaged or bitten off by another axolotl.
If you want to know more about the axolotl breathing methods, you can read on here.
11. Axolotls are farsighted and can’t see well
Axolotls are farsighted, so they can see far away things sharply, but close things are only very blurry. Albino axolotls in particular often seem to have poorer vision than other axolotls.
When hunting for food, axolotls rely mainly on their other senses, such as the “remote sense of touch” of the lateral line organ and their sense of smell. Here is an article with more details about the axolotl’s vision and other sensory organs.
12. Axolotls are very cancer resistant and can live up to 20 years
Usually axolotls live 10 to 15 years, but with very good care there are also some that have lived up to 20 to 25 years.
In addition, axolotls are very cancer resistant and on average get cancer much less often than other animals. According to current estimates, they are about 1000 times more resistant to cancer than mammals.
Conclusion
Axolotls are fascinating animals that have been around for many centuries. In addition to keeping them in domestic aquariums, they also help us to better understand diseases and discover new medical possibilities.
So if we can regrow a new finger or arm in the distant future with the help of modern medicine, we will certainly also have the axolotl to thank.