Axolotls are awesome

David Stark / Zarkonnen
2014-01-29 08:56
Image Credit: Wikipedia/LoKiLeCh

Axolotls are essentially salamanders that have refused to grow up. Salamanders, being amphibians, start their life as aquatic larvae, but eventually metamorphose into at least partially land-dwelling lizard-like animals. Axolotls are the exception, spending their whole life in their larval form, becoming sexually mature without metamorphosing.

In the wild, they only live in one lake in central Mexico, subsisting on a diet of worms, insects and small fish. Sadly, due to competition and predation from invasive species, and the transformation of its habitat into a series of agricultural canals, they are considered critically endangered.

Which is an enormous shame, especially as they have some amazing properties. They are capable of great feats of regeneration. They can regrow entire limbs, regaining full functionality. They can recover from spinal injuries and in some cases regrow organs and parts of their brains. It's even possible to transplant limbs or heads from one animal to another!

It's possible to artificially induce an axolotl to metamorphose. In salamanders, metamorphosis is controlled by the thyroid gland, which can be stimulated with iodine, or its output simulated directly with thyroid hormone. As a result, the axolotl morphs into something looking very much like a mexican tiger salamander, a species whose habitat overlaps that of the axolotl.

Unsurprisingly, the regenerative abilities of axolotls are an area of active research. Given that it's theoretically possible for a complex vertebrate to regenerate limbs back to full functionality, we would very much like to be able to induce something like this in human beings. Our reaction to injury tends to be the production of scar tissue, which was arguably adaptive in prehistoric times, when it was most important to heal a wound quickly. In an age of hygiene and modern medicine, though, it would be possible and preferable to take the time to grow things back completely.