Regeneration is easier for some creatures than others. If a salamander loses a leg, it will grow a new one within a few weeks. Humans are constantly making new cells, but regrowing a bone that has been lost? For that, our skillset is bone dry. We've been trying to find more effective ways to heal serious wounds and fight old age for generations. Again and again. But humans are not salamanders yet. Do we follow the axolotl (a salamander that never undergoes metamorphosis)?