When you think of axolotls, you probably think of goofy-smile-wearing tadpole-type creatures swimming around in a tank. Did you know that these little guys are some of the Peter Pans of the animal kingdom? They just don’t grow up!Although other species of salamander spend a portion of their lives as gilled water-dwelling larvae, they eventually grow up and crawl onto land. Like their relatives, axolotls are able to undergo metamorphosis to achieve a land dwelling form. The catch is that axolotl metamorphosis is exceedingly rare, both in the wild and captivity.
Why is axolotl metamorphosis so uncommon?
Unlike other types of salamanders, axolotls actually do not need to go through metamorphosis to complete their life cycle. Axolotls exhibit a trait called neonoteny, meaning that unlike other other salamanders they reach sexual maturity while still in their larval form. In fact, for axolotls going through metamorphosis is often a death sentence. After becoming a land-dweller, the axolotl is often left weak and tend to reject food. Most die within a year or two of metamorphosis.
The way that axolotls got to be this way is actually quite fascinating. The failure of axolotl metamorphosis to occur is actually caused by a lack of iodine in their natural environment. Usually, when salamanders transition from their aquatic larval stage to their adult land-swelling form they use iodine to produce the thyroid hormones that fuel their transformation. Lacking crucial iodine, axolotls evolved to make the last step in their life cycle unnecessary for reproduction. As a result, short of a genetic quirk or induced metamorphosis, they will live their entire lives happily underwater.
Over the course of long study (axolotls are an important research animal due to their regenerative abilities), scientists have found that axolotl metamorphosis can be induced with an iodine injection. This gives axolotls the required amount of iodine to begin production of thyroxine, which fuels metamorphosis. This should never be attempted at home, as iodine is extremely toxic and you will almost certainly kill your axolotl. That’s besides the fact that you’d be dooming them to a short and unhappy life even if they survived the transformation.
Although axolotl metamorphosis is technically possible, it’s never something you should aim for as an axolotl owner. Love you pet for what it is, a cute water dwelling creature that evolution has designed to stay that way. If you’re looking for a land-dwelling salamander, go for a tiger salamander. They go through the same life cycle, and after metamorphosis they greatly resemble metamorphosed axolotls.
For more information on axolotls, visit our Axolotl Home Page.