This perpetually youthful-looking Mexican salamander possesses a superpower that defies biology as we know it: the ability to regenerate entire limbs, parts of its heart, and even its spinal cord. But how does an amputated limb know whether to regenerate an entire arm from the shoulder down or just a hand from the wrist? A team at Northeastern University, led by James Monaghan, has unraveled a key piece of this biological puzzle. Monaghan’s lab houses about 500 axolotls cared for by a team ranging from undergraduate students to postdocs. His lab’s research focuses on uncovering why nerves are essential to this process and what unique cellular properties allow axolotls to regenerate tissues that other animals cannot.