Axolotl: The Limb That Regrew Twice

In Mexico City’s old University labs, 1920, an axolotl named Xochi lost her left front leg, and within 40 days, cell clusters-called blastemas-swarmed to the stump and began remaking bone, muscle, and nerves from scratch. Xochi’s regrown limb didn’t just look right: in lab records, scientists noted every digit matched the original, down to the pink-tipped claw. Then, the unimaginable-Xochi lost the same leg again months later, this time sliced closer to her body, and the process repeated, but even faster, in 33 days. When researchers stained the growing new limb with alizarin red, they found not just healthy bone, but intact blood vessels and working nerves connecting seamlessly to her old tissue. How did Xochi’s body keep this up, with no scars and no sign of wear? The secret starts with her immune system, which floods injury sites with macrophages that prevent scarring and jump-start unlimited stem cells, all mapped to a complex genetic blueprint axolotls carry from birth. Xochi’s second regrown limb functioned as well as the first, and it’s her unique cells’ refusal to age or form scar tissue that gives axolotls power beyond any other mammal or reptile tested to this day.