The 40 Million-Year-Old Ecosystem In Your Mouth

The hardened residue scraped off your teeth at the dentist is called your dental calculus, and your dental calculus is the only part of your body that actually fossilizes while you’re alive! And scientists have figured out how to study & trace the evolutionary history of these microbes over tens of millions of years.

Season 4 Episode 15 Length 08:14 Premiere: 12/09/21

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S8 E11 Length 10:45 Premiere Date 02/10/26

When Ancient Weeds Fooled Us

S8 E10 Length 11:37 Premiere Date 01/27/26

How Brawn Led to Brains

S8 E9 Length 12:14 Premiere Date 01/13/26

When a Tiny Land Bridge Triggered an Ice Age

S8 E8 Length 10:27 Premiere Date 12/17/25

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Length 09:15 Premiere Date 07/22/25

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Length 12:22 Premiere Date 06/17/25

Season 4 Episodes

Show Episodes

Show Clips & Previews

The Fungi That Turned Ants Into Zombies

S4 E40 Length 08:13 Premiere Date 08/23/22

How Whale Evolution Kind Of Sucked

S4 E39 Length 09:49 Premiere Date 08/16/22

Did An Ancient Pathogen Reshape Our Cells?

S4 E38 Length 07:40 Premiere Date 08/09/22

Why Does Caffeine Exist?

S4 E37 Length 08:29 Premiere Date 07/28/22

How Plate Tectonics Transformed Los Angeles

S4 E36 Length 12:34 Premiere Date 07/21/22

When Giant Millipedes Reigned

S4 E35 Length 07:02 Premiere Date 07/12/22

Giant Viruses Blur The Line Between Alive and Not

S4 E34 Length 09:19 Premiere Date 06/29/22

Something Has Been Making This Mark For 500 Million Years

S4 E33 Length 09:42 Premiere Date 06/15/22

We Can “Bring Back” The Woolly Mammoth. Should We?

S4 E32 Length 06:40 Premiere Date 06/08/22

Is This The Oldest Dad In The Fossil Record?

S4 E31 Length 06:37 Premiere Date 05/26/22

The Curious Case of the Cave Lion

S4 E30 Length 08:09 Premiere Date 05/17/22

When Ants Domesticated Fungi

S4 E29 Length 09:05 Premiere Date 05/10/22

The Ancient Human Species With A Missing Body

S4 E28 Length 07:56 Premiere Date 04/27/22

Why Sour May Be The Oldest Taste

S4 E27 Length 07:02 Premiere Date 04/20/22

How the Smallest Animal Got So Simple

S4 E26 Length 06:52 Premiere Date 04/13/22

The Extreme Hyenas That Didn't Last

S4 E25 Length 07:50 Premiere Date 03/29/22

The Sudden Rise of the First Colossal Animal

S4 E24 Length 08:44 Premiere Date 03/22/22

When a Giant Pterosaur Ruled the European Islands

S4 E23 Length 08:50 Premiere Date 03/15/22

Why We Only Have Ten Toes (It's a Long Story)

S4 E22 Length 09:12 Premiere Date 02/23/22

How Horses Went From Food To Friends

S4 E21 Length 06:32 Premiere Date 02/16/22

How Vertebrates Got Teeth... And Lost Them Again

S4 E20 Length 08:52 Premiere Date 02/08/22

Did Eating Insects Shrink These Dinos?

S4 E19 Length 10:21 Premiere Date 01/27/22

Primates vs Snakes (An Evolutionary Arms Race)

S4 E18 Length 07:53 Premiere Date 01/18/22

How Our Deadliest Parasite Turned To The Dark Side

S4 E17 Length 08:06 Premiere Date 01/11/22

When Pterosaurs Walked

S4 E16 Length 09:38 Premiere Date 12/16/21