With big branch-like gills, lizard-like limbs, and a cute perma-smile, it’s hard not to fall in love with the axolotl.
1. Don’t worry, we’ll help you pronounce it.
Phonetically, it’s “Ax-oh-lot-ul.” Atl means "water" and xolotl means "dog," after the Xolotl, the canine Aztec deity.
2. Wild axolotls are rarely white.
While you might see plenty of white ones in captivity, the animal is normally greenish brown or black. White ones are known as “leucistic” and descend from a mutant male that was shipped to Paris in 1863. They were then specially bred to be white with black eyes (different from albinos, which generally have red eyes).
3. Their feathery headdress is not just for show.
The impossibly silly branches that grow from the axolotl’s head might not seem practical, but they’re actually the salamander’s gills. The filaments attached to the long gills increase surface area for gas exchange.
4. Wild ones can only be found in one place.
While you can find axolotls in aquariums and laboratories all over the world, it’s much harder to find them in the wild. The animals can only be found in the lakes and canals of Xochimilco, Mexico. The axolotl eats small fish, worms, and anything it can find that will fit in its mouth.
5. They’re critically endangered.
As a result of habitat loss, pollution, and the introduction of invasive species like tilapia and carp, these salamanders are being pushed closer and closer to extinction.
In an attempt to revive the species, researchers have built “shelters” made from reeds and rocks to filter the water and create a more desirable living space. Unfortunately, the numbers continue to decline. There were about 6000 wild axolotls documented in a 1998 survey, but today, researchers are lucky to find any. For a brief amount of time in 2014, biologists failed to find a single water dog, and feared the salamanders had gone extinct in the wild. Luckily, some have since been found roaming the water. And although it's not ideal, even if the elusive animal disappears from the wild entirely, the species continues to thrive in captivity.
6. You can eat them.
Before the axolotl was an endangered species, Xochimilco natives would chow down on the salamanders. Axolotl tamales were a favorite, served whole with cornmeal. In 1787, Francesco Clavigero wrote that, "the axolotl is wholesome to eat, and is of much the same taste with an eel. It is thought to be particularly useful in cases of consumption.”
Today, you can still taste one of these creatures—but you might have to travel to Japan to do it. A restaurant in Osaka serves whole axolotls, deep-fried. They apparently taste like white fish meat, but with a crunch.
7. They have a mythological background.
Xolotl was a dog-headed god from Aztec mythology. God of all things grim, the deity would lead the souls of the dead to the underworld. As with all mythology, there a lot of mixed accounts about what happened next, but some believe that Xolotl was fearful of being killed and transformed into an axolotl to hide. The salamander is trapped in the water of Xochimilco, unable to transform and walk on land.
8. Axolotls exhibit Neoteny.
Neoteny means that a creature can reach maturity without going through metamorphosis. In less extreme cases, it’s simply exhibiting juvenile traits after reaching adulthood. Axolotls are a great example of neoteny because as they grow bigger, they never mature. Unlike tadpoles or similar animals, axolotls hold on to their gills and stay in the water, despite actually growing lungs.
“The one thing that neotenic species have as an advantage is that if you don’t undergo this metamorphosis, you’re more likely to reproduce sooner. You’re already one step ahead,” biologist Randal Voss told WIRED.
9. But sometimes they can grow up with a little push.
Sometimes as a result of a mutation, or a shot of iodine from a scientist, axolotls can be forced out of their safe watery home. The shot gives the animal a rush of hormones that leads to a sudden maturation (in humans, this known as “getting kicked out of your parent’s basement"). The axolotls become strikingly similar to their close relative, the tiger salamander, but they continue to only breed with their own kind.
Transforming your aquatic friend into a land-dweller might seem cool, but leave it to the professionals; Axolotl.org strongly urges owners to never interfere with their pets’ biology, because it will likely be fatal.
10. Regeneration is no problem for them.
It’s not unusual for amphibians to be able to regenerate, but axolotls take it to the next level. On top of being able to regenerate limbs, the animal can also rebuild their jaws, spines, and even brains without any scarring. Professor Stephane Roy of University of Montreal explained to Scientific American:
You can cut the spinal cord, crush it, remove a segment, and it will regenerate. You can cut the limbs at any level—the wrist, the elbow, the upper arm—and it will regenerate, and it’s perfect. There is nothing missing, there’s no scarring on the skin at the site of amputation, every tissue is replaced. They can regenerate the same limb 50, 60, 100 times. And every time: perfect.
Scientists have also transplanted organs from one axolotl to another successfully.
11. Scientists are looking to harness that ability.
The Salk Institute for Biological Studies is studying how regeneration works in animals like axolotls, and released two studies in 2012 with their findings. The hope is that if we can fully understand regeneration, we can recreate the phenomenon in human beings.
Unfortunately, results so far have shown that the process might be even more complicated than expected. The scientists worry that humans might not even have the necessary genes to successfully regenerate. But there's a silver lining: While regrowing limbs might not be on the table, future studies can shed some light on smaller healing techniques.
“It is important to understand how regeneration works at a molecular level in a vertebrate that can regenerate as a first step," said the studies' senior author, Tony Hunter. "What we learn may eventually lead to new methods for treating human conditions, such as wound healing and regeneration of simple tissues."