An axolotl is a self-regenerating salamander whose ongoing existence is threatened by pollution, loss of habitat, and inbreeding in scientific labs.

“Self-regenerating” means that if the axolotl loses a limb or even a piece of its heart, it can grow a new one with nary even a scar. The regeneration is smart: the salamander regrows just the part it needs, and in the correct place, and the new part functions just like the original.

“Fascinating—and somewhat grotesque—experiments from the past 150 years brought us much information about the axolotl’s ability to regenerate and heal. For example, amputated axolotl limbs regenerate completely, and even after multiple amputations, they are as functional as the original limb. The axolotl’s cells “know” which structure to regrow: When an arm is amputated at the level of the shoulder, the entire arm regrows. But when the arm is amputated at the elbow, only the lower arm and hand regrow; when the arm is amputated at the wrist, only the hand regrows.”

https://qz.com/1304554/the-axolotl-natures-miracle-healer-is-on-the-brink-of-extinction/

I can well imagine why scientists like to study this tiny creature. The ability to regrow a body part, if we could replicate it in humans, would be transformative. We’re studying the axolotl so hard to find out how the miracle happens that we’re contributing to its likely extinction. There has to be a better way to unlock the axolotl’s secrets.