Amphibians aren't exactly charismatic, but, somehow, the axolotl
attracts a lot of attention from people who may normally get squeamish
around frogs. Perhaps it's their goofy smile and cute little frills that
disarm people.
But these salamanders have a number of other special traits that
may explain such keen interest all around, from scientists to
conservationists to folks who just really love animals.
1. Axolotls stay 'babies' for their whole lives.
Axolotls are neotenic creatures meaning they achieve sexual maturity
without losing any of their larval features. So while many amphibians,
like the salamander, will eventually develop lungs and head to land,
axolotls keep their trademark feathery external gills and remain
aquatic. This also means that their teeth never develop and that they
must rely on a suction method to consume food.
2. Axolotls, however, can be given a little boost to become 'full' salamanders. Scientists discovered that if an axolotl is given a shot of iodine,
it will experience a rush of hormones that triggers the animal's growth
processes, and it will "grow up" and resemble a mature tiger
salamander, their closest relative. However, this is not the axolotl's
natural state. "Grown-up" axolotls are typically listless and die about a
year after the injection.
Four genes affect the colors of axolotls. (Photo: Faldrian/Wikimedia Commons)
3. Axolotls are native to one spot in the world (and they may not even be there any longer).
These aquatic amphibians are only found in the wild in one location:
Lake Xochimilco, located in southern Mexico City. They once also resided
in Lake Chalco in central Mexico City, but that lake was drained to
avoid flooding. Xochimilco is only a shell of it former self, reduced to
a series of canals. Given Xochimilco's diminished state, the axolotl is
considered critically endangered, and a 2013 survey failed to find any specimens in the wild.
4. Axolotls come in a variety of color patterns. Four genes control the pigmentation of axolotls
and can result in significant variation in their colors patterns.
Typically, however, they're brown or black with specks of gold or olive.
The white axolotls with black eyes are more common as a result of
breeding among pet traders, so they are rarely seen in the wild.
Axolotl have a huge genome that we are only now beginning to decipher. (Photo: Ulmus Media/Shutterstock)
5. Axolotls can regenerate pretty much any body part. A number of amphibians are capable of regenerating limbs, but axolotls take this habit up a notch by regenerating jaws, spinal cords, skin and even portions of their brain. Axolotls can also receive organ transplants and will not reject the new organ.
Their regenerative abilities are obviously of interest to researchers
hoping to understand how it works and if this amazing quality could
translate to humans.
6. Axolotls have a genome 10 times the size of the human genome.
Across organisms, genomes have plenty of junk, repetitive DNA that
doesn't have a function, and the axolotl, with its 32 billion DNA bases,
is no different. But this also means sequencing and isolating the genes
that may help us understand the creature's regenerative abilities is
difficult. A 2018 study in Nature
finally made a small breakthrough, identifying five genes that aren't
present in other reptiles, amphibians or humans but are active in
regenerating limbs.
