Why do humans usually have five fingers on each hand? And what if one day, we could grow a new finger if we lost one?

In this episode, a question from six-year-old listener Ayla sends us on a journey from tiny developing embryos to one of the most amazing animals on Earth: the axolotl. 

We talk with Dr. Jessica Whited, a Harvard-based biologist who studies how axolotls regrow their limbs - and why humans can’t do the same… for now! Along the way, we discover how our hands develop before we’re born, why evolution settled on five fingers, and axolotls might show us the way to regrow our own limbs. 

Plus: why axolotls have to live in separate tanks (hint: they’re a little too snack-happy).

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