What is a butt? That’s what science journalist Katherine Wu wanted to know. Her quest for an answer leads her into a web of big butt questions, and a search to find the top butt scientists in the world. She discovers a debate over where butts come from, and a very strange butt that could rewrite the annals of butt history.

This episode features an original song called, “Sometimes Butt.” Trust us, it’s a fun one! (And yes, we say the word “butt” and other butt-related words a lot.)

Can’t get enough of butt science? There’s plenty more! Listen to a bonus interview episode with Katherine Wu, available to Patrons who support Tumble at a level of $1 a month or more. You’ll get access to an ad-free feed with all our bonus episodes, at patreon.com/tumblepodcast

This episode is based on Katherine’s article, “The Body’s Most Embarrassing Organ is an Evolutionary Marvel.” Find more butt science resources on the blog on our website, sciencepodcastforkids.com.