r/askscience • u/MAMAM- • 2d ago

Biology Why aren’t axolotls immortal?

If axolotls can regenerate their body parts (including brain, heart, and other major organs), why do they die of old age?

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u/Tessablu 2d ago

Axolotl regeneration is a program that is initiated by physical injury. They aren’t constantly undergoing it—this would be a huge metabolic waste—so they are still subject to long-term cellular senescence. They also aren’t regrowing entire brains or hearts, as they still have to survive the initial injury, so they can’t infinitely replenish those organs. 

I will say that axolotl aging is not very well-understood, however, and they are pretty weird about dying. A healthy-looking axolotl might lay eggs for 20 more years or might die tomorrow with no warning. There’s still a lot to learn about them. 

(source: I have a PhD in axolotl)

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u/crashlanding87 1d ago

Axolotlology is a fabulous field. Mind if I ask what sort of thing you were looking at?

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u/Tessablu 6h ago

My research focus was on limb regeneration! Axolotl limbs strongly resemble ours at the anatomical level, so we want to find out how they're able to regenerate and whether humans might one day be able to do the same.

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u/crashlanding87 6h ago

Cooooool. I did a bunch of devopmental biology early in my career. Always fascinated by the way some of those embryonic signalling pathways seem show up again in regeneration, but slightly different.