There’s more to sloths than slowness. They’re great at saving energy, hanging upside down, and swimming! In this episode, Sloth Appreciation Society founder Lucy Cooke stops by to tell us all about these amazing animals. We also get into a sloth mystery: The Case of the Perilous Poop Journey. Luckily, there’s a sloth sleuth on the case. And sloths aren’t the only animals who aren’t in a hurry — a few others show off their slowest skills.

There’s also a Mystery Sound for you to guess. Stay sloooooooooow!

Guests

Lucy Cooke, zoologist and founder of the Sloth Appreciation Society

Jonathan Pauli, UW-Madison Forest and Wildlife Ecology

Dr. Sushma Reddy, Breckenridge Chair of Ornithology, Bell Museum

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Have you ever heard of Lake Natron? It’s located in Tanzania, Africa, and, if you believe the internet, it can instantly petrify anything that touches it. Lucky for us, we have a direct line to the Hoax Hunters (aka Sanden and Marc) - they love myths, and they hate getting tricked.

Along the way to saying yea or nay to this stoney phenomenon, the Hoax Hunters speak with Neovitus Sianga. Not only does he have firsthand knowledge of the lake, but he works for African People and Wildlife, where he helps protect the environment around Lake Natron.

We also have a brand new Mystery Sound… and Marc and Sanden start a cleaning service?!?

Guest: Neovitus Sianga

Want more Hoax Hunters? Here are a few more episodes featuring our hoax hunting pals:

Are UFOs real?
Lost Cities
Mermaids, Kraken and Loch Ness Monster
Bigfoot, Unicorns and Dragons

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Skunks can stink, no doubt about it. But that stink is actually a superpower! Join Molly and co-host Diya as they find out how these critters use their smell to scare away enemies, what the smell is made of, and how to make your own de-skunking potion. Plus, Wombat Pete drops by to promote his new music festival, we speak to some skunk experts, and we try our best to guess a new Mystery Sound.

Don't forget the de-skunking potion mnemonic: 

4 Cats Had Problems

Queen Coughed Beside Suzie's Tenth Lasagna, Don't Sneeze

Translation: 

4 Cups hydrogen peroxide

Quarter Cup baking soda

Teaspoon Liquid Dish Soap

Guest: Marie Tosa, Research Scientist with the Washington Department of Fish and Wildlife. 

Guest: Ted Stankowich, Professor in the Department of Biological Sciences and CSU Long Beach.

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 We're on a little winter break and we're gonna be back with a new Brains On episode next week. This week we have an episode of our Sister show forever ago to share with you. If you're interested in origin stories or history, this is the show for you. You can subscribe wherever you listen to Brains On.

Get ready for an out-of-this-world episode! Joy and co-host Elsa are trapped in a black hole with a baby elephant and a mountain of old junk! 

They’ll explore the history of a super secret astronaut testing program for women called the “Fellow Lady Astronaut Trainees.” This group of bold, highly-trained pilots spent years making a case for why women are just as qualified to become astronauts as men! 

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 We're on a little winter break here, but we're gonna be back with a new episode of Brains On January 6th. Until then, we have an episode of our sister podcast, smash Boom. Best to share with you the episode. Features some familiar voices. Me, mark, and Sandon, enjoy the show!

Whether you like your wheels big or small, this debate is for you! It’s Monster Trucks vs Hot Wheels. It’s a battle between Brains On besties Marc Sanchez and Sanden Totten. Marc goes full throttle for Team Monster Trucks and Sanden speeds toward victory for Team Hot Wheels. Who will win? Head over to smashboom.org to vote and listen to see who our judge crowns the king of cars.

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The Brains On crew is hitting the road in 2026, and our first shows have just been announced. If you like fun, games, dancing, optical illusions and... Mystery Sounds, check out Your Brain is Magic.

Head to brainson.org/events to get tickets for the following shows:

1/17 Newark, NJ Victoria Theater

1/18 Red Bank, NJ The Vogel

1/23 San Diego, CA The Observitory

1/24 Aneheim, CA House of Blues

2/21 Vancouver, BC Playhouse Theater (JFL Festival)

2/22 Seattle, WA Neptune Theater

If you don't see your city listed, we're adding more dates, so keep checking back!

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In our final look at metal, we explore how metal wires changed the world. Once humans figured out how to send little blasts of electricity through metal, we quickly developed lots of uses for this. One was a new way of communicating called the telegraph. Join Molly and co-host Ava as they team up with Dylan Thuras, co-founder of Atlas Obscura to learn how people laid hundreds of miles of wire in hopes of sending messages across oceans. Plus, the new Brains On Headquarters is having an opening ceremony, and there’s a brand new Mystery Sound to guess!

Guest: Dylan Thuras, co-author of The Atlas Obscura Explorer's Guide to Inventing The World.

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Humans have been fascinated by metal for thousands of years. But it took us a long time to master making things with metal. In this episode we go back in time to learn how Japanese swords were forged, how swings were used to make thin metal wires and why steel cables saved so many lives. Molly and co-host Ava are joined by Dylan Thuras, co-founder of Atlas Obscura for part two of this deep dive on all things metal. Plus, Marc meets some talking boxes and there’s an all new Mystery Sound.

Guest: Dylan Thuras, co-author of The Atlas Obscura Explorer's Guide to Inventing the World.

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Metal is amazing. It can be super strong like a steel beam. Or super flexible, like a copper wire. Humans have been obsessed with metals of all kinds for a very long time. This is part one a three-part look at how humans have used metal throughout history. Molly and co-host Ava are joined by Dylan Thuras, co-founder of Atlas Obscura, to look at how Earth got metal in the first place, how humans first found and used this stuff, and when we started making primitive tools with it. Plus, Marc and Sanden have some problems unpacking the new Brains On library. All that and a Mystery Sound!

Guest: Dylan Thuras, co-author of The Atlas Obscura Explorer's Guide to Inventing the World.

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Most of us take listening to music or podcasts for granted. You can find them on your phone, in the car or just about anywhere you can imagine. But, have you ever wondered how those sounds were captured in the first place? To find out, Molly and Co-host Canyon shrink down and follow a sound waves as it is recorded and stored. They meet a robot who really loves to eat old school media, like cassettes and CDs. And they learn how speakers turn information into the music we hear. All that plus a new mystery sound.

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We treat dogs like they're part of the family. But do they know they are a different species, or do they think they're just short, four-legged people?

In this episode, canine cognition researcher Alexandra Horowitz helps us puzzle out this question. We’ll also find out what happens (or doesn’t) when a dog looks in the mirror. Dogs are always dozing, and we’ll check in to see if they are dreaming too. And, we take a quick trip around the world in the language of barks. All that, plus a brand new Mystery Sound!

Guest: Alexandra Horowitz - Dog Cognition Lab

Guest: Vanessa Woods - Duke Puppy Kindergarten

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