Axolotl (Ambystoma mexicanum): Facts & Species Wiki

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The Peter Pan of Amphibians

While its close relative the tiger salamander is known to always go through metamorphosis and head for a boring, mostly land-based adult life, the Axolotl (Ambystoma mexicanum) said “no thank you”. It usually keeps its larval features into adulthood and lives its whole life cycle in water, a condition called neoteny. In the wild it rarely, if ever, metamorphoses. It spends its days swimming around with feathery external gills that look like high-tech cybernetic antenna arrays.

Sixty days to a new leg In one lab study, most adult axolotls had regrown a complete front leg by 60 days after amputation. The new limb comes from a blastema, a mass of stem-like cells that grows, lays out the pattern and turns into the missing parts.

Wolverine-Level Regenerative Biology

The axolotl is biology’s ultimate cheat code. Mammals like us patch a deep skin wound with a permanent scar; an adult axolotl regrows the skin with no scar at all. Cut off a limb and cells from the stump form a blastema of stem-like cells that rebuilds the whole thing. Axolotls can also regrow a tail with its spinal cord, part of a damaged heart, and several kinds of neuron lost from an injured patch of brain. Scientists study them in the hope of better regenerative treatments for humans.

Published August 30, 2026Updated September 12, 2026

Traits

Amphibian Freshwater Insectivore Regeneration

Intel
& FAQ

01What body parts can an axolotl regenerate?

A long list: whole limbs, a tail complete with its spinal cord, a missing section of lower jaw, part of the heart's ventricle, and several kinds of neuron lost from an injured patch of the pallium, a forebrain region likely to hold basic versions of some neuron types found in our cerebral cortex. At a lost limb, cells from the stump form a blastema, a mass of stem-like cells that grows, lays out the pattern and turns into the missing parts. Deep skin wounds heal without a scar. A patch of heart damaged by freezing heals without a permanent one too, as long as immune cells called macrophages are there early on: remove them and the heart scars for good. The brain has a limit: its new neurons don't rebuild their old long-distance connections.

Source: McCusker, Bryant & Gardiner 2015

02Why do axolotls keep their larval form as adults?

Through paedomorphosis, often called neoteny: axolotls keep larval features like their feathery external gills and finned tail into breeding adulthood, and in the wild they rarely, if ever, metamorphose. Thyroid hormone drives amphibian metamorphosis, and in the tiger salamander a rise in it triggers the change. An axolotl's thyroid hormone stays low through larval development and doesn't rise at the point where its close relative, the tiger salamander, metamorphoses. Studies suggest a fault in the chain of signals from the hypothalamus to the pituitary to the thyroid gland, perhaps at the hypothalamus or pituitary, but the exact mechanism is still unknown. Give an axolotl thyroid hormone and it can go through metamorphosis anyway.

Source: Crowner et al. 2019

03Are axolotls endangered in the wild?

Yes, critically endangered. Axolotls are a much-loved aquarium pet and lab animal around the world, but in the wild they live only in Lake Xochimilco, now a scattering of canals and swamps at the southern edge of Mexico City. A 2009 habitat model picked out just 11 sites there still suitable for them, and surveys at the time had found only one axolotl in the whole study area. Introduced carp and tilapia came to dominate the canals and overlap heavily with axolotls in what they eat, while untreated wastewater, farm runoff and a spreading city have fouled the water and driven a marked decline.

Source: Ramos et al. 2025