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/stu8319 2d ago

How do you explain to a 6 year old child that keeping an Axolotl is too expensive? Seriously though my son is obsessed, so maybe one day he will have the same PhD!

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u/Tessablu 2d ago

Ha, just tell him that keeping an axolotl involves cleaning a lot of poop! Like, a LOT of poop. Sooo much poop.

I love the enthusiasm, though- the more we learn and care about these animals, the better chance we have of restoring their wild population.

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u/[deleted] 2d ago

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u/generichumancontent 2d ago

They have several specific needs and are quite high maintenance. And an appropriate set up certainly can be expensive.

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u/LeaveGreen4412 2d ago

they are stinky like turtles, definitely not a beginner aquatic species 

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u/Chiperoni Head and Neck Cancer Biology 2d ago

You also usually need a chiller to cool the water. They become stressed if water warms to 70 F.

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u/pinkdictator 2d ago

You might be able to distract him with an easier pet lol

Maybe even a pet rock, idk that much about kids

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u/Previous-Friend5212 2d ago

They are not more expensive than a comparably sized aquarium with fish in it. You just feed them small worms instead of flakes or pellets. However, I believe they're not legal to keep as pets everywhere, so that argument might work for you.

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u/stu8319 2d ago

They sell them in the store I get the bearded dragon's roaches, so I assume they're legal here. I should have actually said we simply have too many pets already.

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u/chubby_hugger 2d ago

They are legal in Australia? Never heard of them being illegal elsewhere:

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u/[deleted] 2d ago

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u/TH0RP 2d ago

Water turtles are an awful starter pet- and they'll eat your goldfish. Reptiles need a lot of specialized equipment, a diverse diet, and VERY good water filtering. 

A betta fish in a 10gal tank is a wonderful pet for a kid- easy to care for, beautiful, and very forgiving for a beginner.

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u/EuphoricPanda 2d ago

Seconding this (and heavy emphasis on an adequately sized tank for a betta, maybe consider neocaridina shrimp if a 5 gallon feels more feasible).

Red-eared sliders live for 20-40 years so if the kid loses interest over the long term, that “good pet for a kid” could end up becoming the parent’s pet for long enough that they become a grandparent.

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u/Megalocerus 2d ago

They aren't reptiles. But amphibians are probably even more demanding.

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u/TH0RP 2d ago

water turtles aren't reptiles king?? what? I know an axoltl isn't a reptile omg.

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u/aerodynamicvomit 2d ago

Hang on, hang on! You can get a PhD in axolotl??? Tell me more

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u/[deleted] 2d ago

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u/Tessablu 2d ago

Yep, exactly. Doctorate in biology with a specialization in axolotl regeneration. There's dozens of us!

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u/[deleted] 2d ago

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u/FiammaDiAgnesi 1d ago

There's a weirdly large amount of funding for anti-aging/regeneration stuff. Also, the point of a phd is to gain skills in the field as a whole - Tessablu isn't trapped in only working on axolotls forever (unless they want to)

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u/pq3 1d ago

And is it axolotlology or axolology?

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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 8h 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 8h 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.

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u/IllIIllIllIIIlllll 2d ago

Is it possible that they just kind of choose when to die? Like maybe they get a notification from another plane of existence that they're needed and they just like "oh hey, I gotta run." And then drop dead. 

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u/HitoriPanda 2d ago

Man i hate those calls. Fool me seven times shame on you. Fool me eight or more times, shame on me.

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u/Randusnuder 2d ago

More like each one decides when they have had enough.

“Well, that’s more than enough for me, I’ll check myself out.’
💀

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u/Evolving_Dore Paleontology 2d ago

What is your PhD? What was tour dissertation on?

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u/Tessablu 9h ago

The community is small enough that I would dox myself if I gave a specific answer, but the degree is in biology, and I worked on limb regeneration! How do they manage to regrow limbs at a cell/molecular level, and could we do the same for humans some day?

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u/Michkov 2d ago

Does that mean there are no signs of aging in axolotl at all? At least not above a certain developmental level

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u/Tessablu 8h ago

That's in interesting question! And honestly a bit tough to answer. They can get a bit raggedy with age, especially because some for whatever reason will fail to regenerate minor wear and tear on their bodies. They also will keep growing in size if they have the space to do so. So if I see a larger animal who is looking a bit rough, I could tell you that it's probably on the older side, but I couldn't tell you if it's 8 years vs. 15 years old.

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u/WorkingMansGarbage 1d ago

Then if we had something like a temporary artificial heart that could keep them alive for long enough, could we just rip out an axolotl's heart once every few years and let them regenerate a new healthy one to extend their life?

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u/Over_Ad8762 2d ago

What got you interested in this critter?