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Today I’m going to expand my evolution series to specific wonders of the natural world. Each post will explore the inexplicable details of animals and plants with their own special niches of the ecosystem.
I’m going to start with quite a famous little monster – The Axolotl. And trust me, we have a lot to learn. So let’s get to it.
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The Axolotl, or Mexican salamander, has some of the most unique features I’ve ever read upon. It’s an amphibian that either breaks amphibious rules or enhances them at its own leisure.
Bio
An axolotl can live between 10-15 years, typically grow to about 9-10 inches in length and display a wide range of appearances. It is a critically endangered species due to mass urbanization, and if functionally extinct in the wild. In 2013, just two were found in surveys throughout their single habitat in Mexico.
Appearance
Depending on what’s going on in an axolotl’s life and how they mutate, colours can range from white, black, grey, pink, brown, yellow or even red. Typically, there are 4 main pigmentation genes; pink, gold, grey and black. They are rarely white in the wild.
Axolotls have lidless black eyes, underdeveloped limbs with long fingers, and have feathery branches on their heads that are actually gills. The feathery style increases surface area to maximize gas exchange.
They have vestigial teeth that are barely noticeable. These would develop during metamorphosis, but this ain’t no normal amphibian, and metamorphosis is just something that’s not on the cards.
Neotemy
Metamorphosis is that time in life when you have to grow up from a little tadpole or larvae, grow a pair of lungs, drop the gills and head for land, among other things. This happens in all amphibians, except, well, a bunch of them. But in the grand scheme of things, it’s pretty unique.
There are three types of Neotemy; mandatory, where amphibians actually lose the ability to metamorphize; optional, in which some newts might decide when to metamorphose based on environmental conditions; and ‘almost mandatory’, and this is where the axolotl fits in.
Scientists discovered that if they simply put iodine into an axolotl’s water tank, its thyroid gland will kick in and release hormones that start the process of metamorphosis. Their bodies are swiftly transformed from aquatic creatures with gills, to land lubbers with lungs. But before scientists interfere, an axolotl can fully ‘mature’ – even able to sexually reproduce - whilst simultaneously maintaining its juvenile characteristics, gills and all. ETERNAL YOUTH! Kind of.
Regeneration
Scientists are flocking together trying to find the secret to eternal youth, and many believe the secrets are locked away in this salamander.
Regeneration is not unheard of in amphibians, but the axolotl seems to regenerate on steroids. They are capable of regenerating entire limbs, jaws, spine and even the brain and other vital organs. The regeneration is fast, limbs being able to regrow in about a month and a half without any scar tissue to be seen.
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As stated by 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.
Naturally, scientists want a piece of this natural technology and are working tirelessly to figure it out. This isn’t just in hopes of living forever, but in real-world medical situations where donors are in short supply and rarely suitable for each other, being able to regenerate one’s own body parts could save the lives of millions.
What they have discovered is that macrophages, a type of immune cell, is vital for the regenerative process. Removing these halted regeneration and scar tissue emerged. These macrophages are present in humans and mammals, and serve as important healing material as well as embryonic development, and although it’s all incredibly complicated and very, very far in the future, it would be premature to say human regeneration is impossible.
Don’t start looking out for entire leg growth though, it’s likely we lack the genes for that.