These baby faced limb regenerating Mexican canal puppies with hypothyroidism bear the name of an ancient god, are incredibly useful in medical research, and are on the verge of extinction in the wild.
Today’s Moment of Science… What is an axolotl?
It’s a… a reptile with a fancy collar? The velociraptor’s lone surviving cousin? A smirking canal gecko with the best accessories this side of Lake Xochimilco? Originally hailing from just a few waterways in the Mexico City area, the axolotl is a species of salamander. Their name comes from the Nahuatl language of the ancient Aztecs, roughly translating to “water dog.”
Or water monstrosity.
Their six pronged crowns are actually fantastically fuzzy gills. These external windbags can vary wildly in color depending on the individual bugger’s hue. Though axolotl skin technically only produces a few pigments, through the magic and mayhem of mutations there exists a kaleidoscopic variety of these permababymanders. Amongst other coats of many colors, they come in pink, albino, golden albino, split mosaic, lavender (also referred to as the silver dalmatian because marine biologists were bored that day, idk), blue, and various shades of copper.
These peterpanamanders can grow and regrow limbs perfectly “up to five times.” I have many questions and yet no questions about what happens the sixth time and what the experimental design was to determine this. They can regrow quite a bit, including nerves, heart and eye tissue, and even a smidge of brain. Sometimes when regrowing a limb, they grow an extra one.
Now, a quick word about amphibian development and why axolotls are in no rush to move out of their parents’ basement. This semi-aquatic class of lovely beasties typically undergoes a metamorphosis before achieving their final form. For example, in outgrowing tadpole life, adult frogs trade gills for lungs, enabling these eighth grade science projects to ribbit away on dry land.
As amphibians, salamanders also typically undergo metamorphosis. However, it’s a bit of a ‘results may vary’ situation from species to species, sometimes even from one population of a species to another. In the eastern tiger salamander, some populations fully metamorphose, while some hold onto their gills their entire lives. The common mudpuppy is anything but common and goes through their prolonged adolescence as the amphibian most likely to be mistaken for the elusive trouser snake.
In the case of the axolotl, metamorphosis without some kind of outside intervention is rare. Unless these salamandacious fashion goals are exposed to an external source of iodine or thyroid stimulating hormone, they’re gonna keep looking like baby axolotls forever. The form we’re familiar with has been described as ‘outsized larvae.’
When dosed with a bit of youth-begone medicine, the muscles in their limbs get stronger while fins are absorbed. Gills all but disappear as lungs become fully developed. These staring contest champs even grow eyelids. However, their impressive ability to regrow limbs suffers. They can also become weak, disinterested in food, and typically die within a year of induced metamorphosis.
So please exercise caution in any decision to dose your pet axolotl with iodine “for science” or whatever. They can live up to fifteen years in the comfort and safety of their extended adolescence.
Should you get one as a pet? Yes, and goddamnit, this is one time when Mrs. Auntie SciBabe isn’t going to try to stop you. They’re critically endangered due to the usual suspects of habitat destruction and invasive species. At this point, there are far more of them in suburban fish tanks and regeneration research labs than in their native canals. A forty gallon tank is recommended for just one of these colorful babies.
If you get more than one? Along with a bigger tank, do take care that they’re all one sex, lest you accidentally breed (and, more to the point, inbreed) a few generations of highly interesting water sprites.
This has been your Moment of Science, taking measurements in my room for a fish tank worthy to hold the mischief god Xolotl’s cousins.
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