Narwhals are whales, and super cool ones at that. But that cool thing coming out of their heads is a tusk, not a horn. Which means it’s a tooth! And it’s the only known spiral tooth to boot!

In this episode, we learn all about narwhals (what that tusk is for and how they’re connected to the myth of the unicorn) and the evolution of teeth (from scale-like nubbins to the versatile chompers we have today).

Plus our Moment of Um explores whether or not water has a taste.

Today’s episode is sponsored by KiwiCo (kiwico.com/brainson), Khan Academy Kids (khan.co/freekidsapp) and iD Tech (idtech.com/brains).

Brains On is a non-profit public radio podcast. You can support Brains On at brainson.org/fans.