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All Seasons

Season 2017

  • S2017E01 The Trouble With Trilobites

    • June 26, 2017
    • YouTube

    Trilobites are famous not just because they were so beautifully functional, or because they happened to preserve so well. They’re known the world over because they were everywhere!

  • S2017E02 When Did the First Flower Bloom?

    • July 3, 2017
    • YouTube

    During the Cretaceous Period, dinosaurs were more diverse, more fierce, and more strange than ever. But something else was happening under the feet of the terrible lizards: for the first time in history, there were flowers.

  • S2017E03 The Tully Monster & Other Problematic Creatures

    • July 11, 2017
    • YouTube

    There are animals in the fossil record that challenge some of our most basic ideas about what animals are supposed to look like. If there ever was a monster on this planet that was worthy of the name, it might have been the Tully Monster.

  • S2017E04 Stegosaurs: Tiny Brains & Thagomizers

    • July 17, 2017
    • YouTube

    If you take it as a given that extinct dinosaurs were all weird and wonderful, then you gotta at least consider that Stegosaurus was one of the weirdest and wonderfulest.

  • S2017E05 What Colors Were Dinosaurs?

    • July 24, 2017
    • YouTube

    We know a lot about dinosaurs but there’s one question that has plagued paleontologists for decades: what color were they?

  • S2017E06 The Story of Saberteeth

    • July 31, 2017
    • YouTube

    Smilodon was a fearsome Ice Age cat, the size of a modern-day tiger, that had a pair of fangs nearly 18 centimeters long. But it was only the last and largest of the great sabertooths: ridiculously long canines had already been a trend for millions of years by the time Smilodon was prowling around. And you know what? Those giant teeth just might make a comeback.

  • S2017E07 That Time Oxygen Almost Killed Everything

    • August 7, 2017
    • YouTube

    What if we told you that there was a time when oxygen almost wiped out all life on Earth? 3 billion years ago, when the world was a place you’d never recognize, too much of a good thing almost ruined everything for everybody.

  • S2017E08 The Biggest Thing That Ever Flew

    • August 14, 2017
    • YouTube

    Today, we’re familiar with two types of flying vertebrates -- birds and bats. But over 66 million years ago, there was a giraffe-sized reptile that soared through the sky.

  • S2017E09 Dimetrodon: Our Most Unlikely Ancestor

    • August 21, 2017
    • YouTube

    With its lizard-like appearance and that distinctive sail on it back, Dimetrodon is practically the mascot of the Palaeozoic Era, a time before flowers, birds, mammals, and even crocodiles. But if you take a close look at this sail-backed animal, you might see a little bit of yourself.

  • S2017E10 The Extinction That Never Happened

    • August 28, 2017
    • YouTube

    Natural history is full of living things that were long thought to have gone extinct only to show up again, alive and well. Paleontologists have a word for these kinds of organisms: They call them Lazarus taxa.

  • S2017E11 The Strange Case of the Buzzsaw Jaws

    • September 11, 2017
    • YouTube

    There are many fossils that challenge our ability to form even the most basic idea of how a living thing looked, or lived, or functioned. One of the longest-running of these mysteries involved a 270-million-year-old sea creature called Helicoprion that once swam the seas around the supercontinent of Pangea.

  • S2017E12 The Age of Giant Insects

    • September 18, 2017
    • YouTube

    Insects outnumber humans by a lot and we only like to think we're in charge because we're bigger than they are. But insects and other arthropods weren’t always so small. About 315 million years ago during the Carboniferous Period, they were not only abundant: they were enormous.

  • S2017E13 History's Most Powerful Plants

    • September 26, 2017
    • YouTube

    Fossil fuels are made from the remains of extinct organisms that have been exposed to millions of years of heat and pressure. But in the case of coal, these organisms consisted largely of some downright bizarre plants that once covered the Earth, from Colorado to China.

  • S2017E14 How Did Dinosaurs Get So Huge?

    • October 2, 2017
    • YouTube

    Part of why we’re so fascinated with extinct dinosaurs it’s just hard for us to believe that animals that huge actually existed. And yet, they existed! From the Jurassic to the Cretaceous Periods, creatures as tall as a five-story building were shaking the Earth.

  • S2017E15 When The Earth Was Purple

    • October 9, 2017
    • YouTube

    Besides the blue of the oceans, the dominant color of our planet, as we know it, is green. But imagine a time when the Earth looked a little … purple.

  • S2017E16 'Living Fossils' Aren't Really a Thing

    • October 16, 2017
    • YouTube

    Crocodiles, horseshoe crabs and tuatara are animals that have persisted for millions of years, said to have gone unchanged since the days of the dinosaurs. But even the most ancient-looking organisms show us that evolution is always at work.

  • S2017E17 When Whales Walked

    • October 23, 2017
    • YouTube

    We know whales as graceful giants bound to the sea. But what if we told you there was actually a time when whales could walk.

  • S2017E18 An Illustrated History of Dinosaurs

    • October 30, 2017
    • YouTube

    Our image of dinosaurs has been constantly changing since naturalists started studying them about 350 years ago. Taken together, these pictures can tell us a whole lot about just how much we have learned. Let's explore the history of dinosaur science as seen through the history of dinosaur art.

  • S2017E19 A Brief History of Geologic Time

    • November 6, 2017
    • YouTube

    By looking at the layers beneath our feet, geologists have been able to identify and describe crucial episodes in life’s history. These key events frame the chapters in the story of life on earth and the system we use to bind all these chapters together is the Geologic Time Scale.

  • S2017E20 The Search for the Earliest Life

    • November 20, 2017
    • YouTube

    More than 4 billion years ago, the crust of the Earth was still cooling and the oceans were only beginning to form. But in recent years, we’ve started to discover that, even in this hellish environment, life found a way.

  • S2017E21 The Facts About Dinosaurs & Feathers

    • November 27, 2017
    • YouTube

    Over the past 20 years, dinosaurs of all types and sizes have been found with some sort of fluff or even full-on plumage. These fuzzy discoveries have raised a whole batch of new questions so we're here to tell you everything we know about dinosaurs and feathers.

  • S2017E22 The Last Time the Globe Warmed

    • December 4, 2017
    • YouTube

    Imagine an enormous, lush rainforest teeming with life...in the Arctic. Well there was a time -- and not too long ago -- when the world warmed more than any human has ever seen. (So far)

  • S2017E23 What Happened to the World's Greatest Ape?

    • December 11, 2017
    • YouTube

    Probably twice the size of a modern gorilla, Gigantopithecus is the greatest great-ape that ever was. And for us fellow primates, there are some lessons to be learned in how it lived, and why it disappeared.

  • S2017E24 When Giant Fungi Ruled

    • December 18, 2017
    • YouTube

    420 million years ago, a giant feasted on the dead, growing slowly into the largest living thing on land. It belonged to an unlikely group of pioneers that ultimately made life on land possible -- the fungi.

Season 2018

  • S2018E01 How Two Microbes Changed History

    • January 15, 2018
    • YouTube

    What if I told you that, more than two billion years ago, some tiny living thing started to live inside another living thing … and never left? And now, the descendants of both of those things are in you?

  • S2018E02 The Time Terror Birds Invaded

    • January 22, 2018
    • YouTube

    About 5 million years ago, a new predator made its way from the south and onto the coastal plains of North America. It was a giant, flightless, carnivorous bird and came to be known by one of the coolest and most richly earned nicknames in all of paleontology: the terror bird.

  • S2018E03 Untangling the Devil's Corkscrew

    • January 29, 2018
    • YouTube

    In the late 1800s, paleontologists in Nebraska found huge coils of hardened sand stuck deep in the earth. Local ranchers called them Devil's Corkscrews and scientists called them Daemonelix. It was clear these corkscrews were created by some form of life, but what?

  • S2018E04 The Great Snake Debate

    • February 5, 2018
    • YouTube

    90 million years ago, an ancient snake known as Najash had...legs. It is by no means the only snake to have limbs either. But what’s even stranger: we’re not at all sure where it came from.

  • S2018E05 The Whole Saga of the Supercontinents

    • February 12, 2018
    • YouTube

    The study of natural history is the study of how the world has changed but Earth itself is in a constant state of flux -- because the ground beneath your feet is always moving. So if we want to know how we got here, we have to understand how "here" got here.

  • S2018E06 From the Cambrian Explosion to the Great Dying

    • February 20, 2018
    • YouTube

    The first era of our current eon, the Paleozoic Era, is probably the most deceptively fascinating time in Earth’s history. With near constant revolutions in life, punctuated by catastrophic extinctions, it is also one of the most chaotic.

  • S2018E07 How Sex Became a Thing

    • February 26, 2018
    • YouTube

    We don’t know which living thing was the very first to arrive at the totally revolutionary process that is sexual reproduction but we can follow the history of how (and why) sex became a thing.

  • S2018E08 The Other Explosion You Should Know About

    • March 5, 2018
    • YouTube

    Fossils found around the world suggest that multi-cellular life was not only present before the Cambrian Explosion, it was much more elaborate and diverse than anyone thought. This is the story of the sudden burst of diversity that marked the dawn of truly complex life on our planet.

  • S2018E09 How the Turtle Got Its Shell

    • March 12, 2018
    • YouTube

    Where did turtles come from? And how did the they get their shells? The answers to these questions would eventually cause scientists to rethink the entire history of reptile evolution.

  • S2018E10 What a Dinosaur Looks Like Under a Microscope

    • March 19, 2018
    • YouTube

    We traveled to Bozeman, Montana to meet with Dr. Ellen-Thérèse Lamm who explores ancient life by studying it at the cellular level. Kallie and Dr. Lamm discuss how she does this, and what she’s learned by putting dinosaur bones under a microscope.

  • S2018E11 The Most Useful Fossils in the World

    • March 26, 2018
    • YouTube

    For decades, one of the most abundant kinds of fossils on Earth, numbering in the millions of specimens, was a mystery to paleontologists. But geologists discovered that these mysterious fossils could basically be used to tell time in the deep past.

  • S2018E12 Inside the Dinosaur Library

    • April 2, 2018
    • YouTube

    We're back in Bozeman, Montana this week talking to Amy Atwater, Collections Manager at the Museum of the Rockies. MOR has among the largest collections of North American dinosaurs in the United States. We talk to Amy about her job and the collection she manages.

  • S2018E13 What Was the Ancestor of Everything?

    • April 11, 2018
    • YouTube

    The search for our origins go back to a single common ancestor -- one that remains shrouded in mystery. It’s the ancestor of everything we know and today scientists call it the last universal common ancestor, or LUCA.

  • S2018E14 How the Squid Lost Its Shell

    • April 17, 2018
    • YouTube

    The ancestors of modern, squishy cephalopods like the octopus and the squid all had shells. In ancient times, their shell was their greatest asset but it eventually proved to be their biggest weakness.

  • S2018E15 How the Chalicothere Split In Two

    • April 24, 2018
    • YouTube

    Two extinct relatives of horses and rhinos are closely related to each other but have strikingly different body plans. How did two of the same kind of animal, living in the same place, end up looking so different?

  • S2018E16 The Age of Reptiles in Three Acts

    • May 2, 2018
    • YouTube

    Reptiles emerged from the Paleozoic as humble creatures, but in time, they grew to become some of the largest forms of life ever to stomp, swim, and soar across the planet. This Age of Reptiles was a spectacular prehistoric epic, and it all took place in a single era: the Mesozoic.

  • S2018E17 The Weird, Watery Tale of Spinosaurus

    • May 8, 2018
    • YouTube

    In 1912, a fossil collector discovered some strange bone fragments in the eerie, beautiful Cretaceous Bahariya rock formation of Egypt. Eventually, that handful of fossil fragments would reveal to scientists one of the strangest dinosaurs that ever existed -- the world’s only known semi-aquatic dinosaur.

  • S2018E18 From the Fall of Dinos to the Rise of Humans

    • May 16, 2018
    • YouTube

    After taking you on a journey through geologic time, we've arrived at the Cenozoic Era. Most of the mammals and birds that you can think of appeared during this era but perhaps more importantly, the Cenozoic marks the rise of organisms that look a lot like us.

  • S2018E19 That Time It Rained for Two Million Years

    • May 22, 2018
    • YouTube

    At the beginning of the Triassic Period, with the continents locked together from pole-to-pole in the supercontinent of Pangea, the world is hot, flat, and very, very dry. But then 234 million years ago, the climate suddenly changed for the wetter.

  • S2018E20 Why Triassic Animals Were Just the Weirdest

    • June 5, 2018
    • YouTube

    The Triassic was full of creatures that look a lot like other, more modern species, even though they’re not closely related at all. The reason for this has to do with how evolution works and with the timing of the Triassic itself: when life was trapped between two mass extinctions.

  • S2018E21 Where Did Viruses Come From?

    • June 12, 2018
    • YouTube

    There are fossils of viruses, of sorts, preserved in the DNA of the hosts that they’ve infected. Including you. This molecular fossil trail can help us understand where viruses came from, how they evolved and it can even help us tackle the biggest question of all: Are viruses alive?

  • S2018E22 When Fish First Breathed Air

    • June 19, 2018
    • YouTube

    385 million years ago, a group of fish would undertake one of the most important journeys in the history of life and become the first vertebrates to live on dry ground. But first, they had to acquire the ability to breathe air.

  • S2018E23 How the T-Rex Lost Its Arms

    • June 26, 2018
    • YouTube

    Tyrannosaurus rex was big, Tyrannosaurus rex was vicious, and Tyrannosaurus rex had tiny arms. The story of how T-Rex lost its arms is, itself, pretty simple. But the story of why it kept those little limbs, and how it used them? Well, that’s a little more complicated.

  • S2018E24 FAQs From Our First Year

    • July 3, 2018
    • YouTube

    Over the first season of PBS Eons, we’ve explored the history of Earth from the very origins of life right up to the Cenozoic Era that we’re in now. To celebrate our first anniversary together, we’d like to answer some of your most frequently asked questions.

  • S2018E25 When Insects First Flew

    • July 10, 2018
    • YouTube

    Insects were the first animals to ever develop the ability to fly, and, arguably, they did it the best. But this development was so unusual that scientists are still/working on, and arguing about, how and when insect wings first came about.

  • S2018E26 The Mystery of the Eocene’s Lethal Lake

    • July 17, 2018
    • YouTube

    In 1800s, miners began working in exposed deposits of mud near the town of Messel, Germany. They were extracting oil from the rock and along with the oil, they found beautifully preserved fossils of animals from the Eocene. What happened to these Eocene animals? And why were their remains so exquisitely preserved?

  • S2018E27 When Fish Wore Armor

    • July 24, 2018
    • YouTube

    420 million years ago, some fish were more medieval. They wore armor, sometimes made of big plates, and sometimes made of interlocking scales. But that armor may actually have served a totally different purpose, one that many animals still use today.

  • S2018E28 When Birds Had Teeth

    • August 7, 2018
    • YouTube

    Experts are still arguing over whether Archaeopteryx was a true bird, or a paravian dinosaur, or some other kind of dino. But regardless of what side you’re on, how did this fascinating, bird-like animal relate to today’s birds? It turns out its teeth were a clue that this story goes all the way back to what we now call the non-avian dinosaurs.

  • S2018E29 How Horses Took Over North America (Twice)

    • August 14, 2018
    • YouTube

    The ancestors of modern horses became so successful that they spread all over the world, to Europe, Asia, South America, and Africa. But in their native range of North America, they’ll vanish for 10,000 years. Until another strange mammal brings them back.

  • S2018E30 How a Supervolcano Made the Cenozoic’s Coolest Fossils

    • August 22, 2018
    • YouTube

    One of the most dynamic, transformative, and potentially dangerous features in North America is also responsible for some of the continent’s most amazing fossil deposits. It’s a supervolcano we now call Yellowstone.

  • S2018E31 The Rise and Fall of the Bone-Crushing Dogs

    • August 28, 2018
    • YouTube

    A huge and diverse subfamily of dogs, the bone-crushers patrolled North America for more than thirty million years, before they disappeared in the not-too-distant past. So what happened to the biggest dogs that ever lived?

  • S2018E32 Life, Sex & Death Among the Dire Wolves

    • September 6, 2018
    • YouTube

    This is not a Game of Thrones fan fiction episode. Dire wolves were real! And thousands of them died in the same spot in California. Their remains have taught us volumes about how they lived, hunted, died and way more about any animal’s sex life than you’d ever want to know.

  • S2018E33 When We First Walked

    • September 11, 2018
    • YouTube

    Fossilized footprints have proved that human ancestors were already striding across the landscape 3.6 million years ago. But who started them on that path? What species pioneered this style of locomotion? Who was the first to walk?

  • S2018E34 Did Raptorex Really Exist?

    • September 18, 2018
    • YouTube

    Paleontologists have been studying and drawing totally different conclusions about the fossil LH PV18 for almost a decade. Is it just one of many specimens of a theropod called Tarbosaurus bataar or is it an entirely different theropod named Raptorex kriegsteini? In order to answer this question, you have to understand the many ways in which we can--and can’t--determine the age of a fossil.

  • S2018E35 Can We Get DNA From Fossils?

    • October 2, 2018
    • YouTube

    In 1993, scientists cracked open a piece of amber, took out the body of an ancient weevil, and sampled its DNA. Or, at least, so we thought. It took another few decades of research, and a lot of take-backs, before scientists could figure out how we could truly unlock the genetic secrets of the past.

  • S2018E36 When Giant Amphibians Reigned

    • October 9, 2018
    • YouTube

    Temnospondyls were a huge group of amphibians that existed for 210 million years. And calling them ‘diverse’ would be putting it mildly. Yet in the end, two major threats would push them to extinction: the always-changing climate and the amniote egg.

  • S2018E37 Your Place in the Primate Family Tree

    • October 16, 2018
    • YouTube

    Purgatorius, a kind of mammal called a plesiadapiform, might’ve been one of your earliest ancestors. But how did we get from a mouse-sized creature that looked more like a squirrel than a monkey -- to you, a member of Homo sapiens?

  • S2018E38 The Two People We're All Related To

    • October 23, 2018
    • YouTube

    Due to an odd quirk of genetics and some unique evolutionary circumstances, two humans who lived at different times in the distant past managed to pass on a very small fraction of their genomes to you. And to me. To all of us.

  • S2018E39 When Rodents Rafted Across the Ocean

    • November 6, 2018
    • YouTube

    The best evidence we have suggests that, while Caviomorpha originated in South America, they came from ancestors in Africa, over 40 million years ago. So how did they get there?

  • S2018E40 When Birds Stopped Flying

    • November 14, 2018
    • YouTube

    Ratites have spread to Africa, Australia, New Zealand, and South America. And there are fossils of Ratites in Europe, Asia, and North America too. That’s a lot of ground to cover for birds that can’t fly. So how did Ratites end up all over the world?

  • S2018E41 When Camels Roamed North America

    • November 20, 2018
    • YouTube

    Camels are famous for adaptations that have allowed them to flourish where most other large mammals would perish. But their story begins over 40 million years ago in North America, and in an environment you’d never expect: a rainforest.

  • S2018E42 How Sloths Went From the Seas to the Trees

    • November 28, 2018
    • YouTube

    The story of sloths is one of astounding ecological variability, with some foraging in the seas, others living underground, and others still hiding from predators in towering cliffs. So why are their only living relatives in the trees?

  • S2018E43 When Sharks Swam the Great Plains

    • December 4, 2018
    • YouTube

    If you’ve ever been to, or lived in, or even flown over the central swath of North America, then you’ve seen the remnants of what was a uniquely fascinating environment. Scientists call it the Western Interior Seaway, and at its greatest extent, it ran from the Caribbean Sea to the Canadian Arctic.

  • S2018E44 When Apes Conquered Europe

    • December 11, 2018
    • YouTube

    Today, our closest evolutionary relatives, the apes, live only in small pockets of Africa and Asia. But back in the Miocene epoch, apes occupied all of Europe. Why aren’t there wild apes in Europe today?

  • S2018E45 Why Megalodon (Definitely) Went Extinct

    • December 19, 2018
    • YouTube

    For more than 10 million years, Megalodon was at the top of its game as the oceans’ apex predator...until 2.6 million years ago, when it went extinct. So, what happened to the largest shark in history?

Season 2019

  • S2019E01 When Humans Were Prey

    • January 8, 2019
    • YouTube

    Not too long ago, our early human ancestors were under constant threat of attack from predators. And it turns out that this difficult chapter in our history may be responsible for the adaptations that allowed us to become so successful.

  • S2019E02 How Blood Evolved (Many Times)

    • January 15, 2019
    • YouTube

    Blood is one of the most revolutionary features in our evolutionary history. Over hundreds of millions of years, the way in which blood does its job has changed over and over again. As a result, we animals have our familiar red blood. But also blue blood. And purple, and green, and even white.

  • S2019E03 The Humans That Lived Before Us

    • January 29, 2019
    • YouTube

    As more and more fossil ancestors have been found, our genus has become more and more inclusive, incorporating more members that look less like us, Homo sapiens. By getting to know these other hominins--the ones who came before us--we can start to answer some big questions about what it essentially means to be human.

  • S2019E04 The Island of Shrinking Mammoths

    • February 5, 2019
    • YouTube

    The mammoths fossils found on the Channel Islands off the coast of southern California are much smaller than their relatives found on the mainland. They were so small that they came to be seen as their own species. How did they get there? And why were they so small?

  • S2019E05 The Evolution of the Heart (A Love Story)

    • February 13, 2019
    • YouTube

    In order to understand where hearts came from, we have to go back to the earliest common ancestor of everything that has a heart. It took hundreds of millions of years, and countless different iterations of the same basic structure to lead to the heart that you have today.

  • S2019E06 How 7,000 Years of Epic Floods Changed the World

    • February 27, 2019
    • YouTube

    Strange geologic landmarks in the Pacific Northwest are the lingering remains of a mystery that took nearly half a century to solve. These features turned out to be a result one of the most powerful and bizarre episodes in geologic history: this region experienced dozens of major, devastating floods over the course of more than 7,000 years.

  • S2019E07 The Island of Huge Hamsters and Giant Owls

    • March 5, 2019
    • YouTube

    Back in the late Miocene epoch, there was an island--or maybe a group of islands-- in the Mediterranean Sea that was populated with fantastic giant beasts. It’s a lesson in the very strange, but very real, powers of natural selection.

  • S2019E08 The Giant Bird That Got Lost in Time

    • March 12, 2019
    • YouTube

    The California condor is the biggest flying bird in North America, a title that it has held since the Late Pleistocene Epoch. It's just one example of an organism that we share the planet with today that seems lost in time, out of place in our world.

  • S2019E09 When We First Made Tools

    • March 26, 2019
    • YouTube

    The tools made by our human ancestors may not seem like much when you compare them to the screen you’re looking at right now but their creation represents a pivotal moment in the origin of technology and in the evolution of our lineage.

  • S2019E10 When Giant Scorpions Swarmed the Seas

    • April 2, 2019
    • YouTube

    Sea scorpions thrived for 200 million years, coming in a wide variety of shapes and sizes. Over time, they developed a number of adaptations--from crushing claws to flattened tails for swimming. And some of them adapted by getting so big that they still hold the record as the largest arthropods of all time.

  • S2019E11 When We Tamed Fire

    • April 9, 2019
    • YouTube

    The ability to make and use fire has fundamentally changed the arc of our evolution. The bodies we have today were, in many ways, shaped by that time when we first tamed fire.

  • S2019E12 The Mystery Behind the Biggest Bears of All Time

    • April 23, 2019
    • YouTube

    The short-faced bears turned out to be remarkably adaptable, undergoing radical changes to meet the demands of two changing continents. And yet, for reasons we don’t quite understand, their adaptability wasn’t enough to keep them from going extinct.

  • S2019E13 The Croc That Ran on Hooves

    • May 1, 2019
    • YouTube

    In the Eocene Epoch, there was a reptile that had teeth equipped for biting through flesh, its hind legs were a lot longer than its front legs and instead of claws, its toes were each capped with hooves. How did this living nightmare come to evolve?

  • S2019E14 When We Took Over the World

    • May 7, 2019
    • YouTube

    From our deepest origins in Africa all the way to the Americas, by looking at the fossils and archaeological materials we have been able to trace the path our ancestors took during thee short window of time when we took over the world.

  • S2019E15 The Ghostly Origins of the Big Cats

    • May 16, 2019
    • YouTube

    All of today’s big cat species evolved less than 11 million years ago and yet their evolutionary history remains an almost total mystery. But scientists have recently discovered a major clue about the origins of the big cats, one that could provide a whole new starting place for solving this puzzle.

  • S2019E16 The History of Climate Cycles (and the Woolly Rhino) Explained

    • May 30, 2019
    • YouTube

    Throughout the Pleistocene Epoch, the range of the woolly rhino grew and shrank in sync with global climate. So what caused the climate -- and the range of the woolly rhino -- to cycle back and forth between such extremes?

  • S2019E17 The Hellacious Lives of the "Hell Pigs"

    • June 5, 2019
    • YouTube

    Despite the name, we don’t know where the so-called “hell pigs” belong in the mammalian family tree. They walked on hooves, like pigs do, but had longer legs, almost like deer. They had hunched backs, a bit like rhinos or bison. But as is often, if not always, the case, there is some evolutionary method to this anatomical madness.

  • S2019E18 How Evolution Works (And How We Figured It Out)

    • June 11, 2019
    • YouTube

    As a scientific concept, evolution was revolutionary when it was first introduced. With the help of all three of our hosts and the Smithsonian National Museum of Natural History’s new Deep Time Hall, we’ll try to explain how evolution actually works and how we came to understand it.

  • S2019E19 When the Synapsids Struck Back

    • June 19, 2019
    • YouTube

    Synapsids were the world’s first-ever terrestrial megafauna but the vast majority of these giants were doomed to extinction. However some lived on, keeping a low profile among the dinosaurs. And now our world is the way it is because of the time when the synapsids struck back.

  • S2019E20 When Ichthyosaurs Led a Revolution in the Seas

    • June 25, 2019
    • YouTube

    The marine reptiles Ichthyosaurs arose after The Great Dying, which wiped out at least 90 percent of life in the oceans, changing the seas forever and triggering a new evolutionary arms race between predator and prey.

  • S2019E21 When We Met Other Human Species

    • July 9, 2019
    • YouTube

    We all belong to the only group of hominins on the planet today. But we weren’t always alone. 100,000 years ago, Eurasia was home to other hominin species, some of which we know our ancestors met, and spent some quality time with.

  • S2019E22 How Volcanoes Froze the Earth (Twice)

    • July 17, 2019
    • YouTube

    Over 600 million years ago, sheets of ice coated our planet on both land and sea. How did this happen? And most importantly for us, why did the planet eventually thaw again? The evidence for Snowball Earth is written on every continent today.

  • S2019E23 How Earth's First, Unkillable Animals Saved the World

    • July 30, 2019
    • YouTube

    They have survived every catastrophe and every mass extinction event that nature has thrown at them. And by being the little, filter-feeding, water-cleaning creatures that they are, sponges may have saved the world.

  • S2019E24 When Giant Deer Roamed Eurasia

    • August 7, 2019
    • YouTube

    Megaloceros was one of the largest members of the deer family ever to walk the Earth. The archaeological record is full of evidence that our ancestors lived alongside and interacted with these giant mammals for millennia. But what happened when they did interact, when humans met this megafauna?

  • S2019E25 Was This Dinosaur a Cannibal?

    • August 14, 2019
    • YouTube

    Paleontologists have spent the better part of two decades debating whether Coelophysis ate its own kind. It turns out, the evidence that scientists have had to study in order to answer that question includes some of the strangest and grossest fossils that any expert would ever get to see.

  • S2019E26 The Missing Link That Wasn’t

    • August 21, 2019
    • YouTube

    The myth of the Missing Link--the idea that there must be a specimen that partly resembles an ape but also partly resembles a modern human--is persistent. But the reality is that there is no missing link in our lineage, because that’s not how evolution works.

  • S2019E27 The Raptor That Made Us Rethink Dinosaurs

    • August 28, 2019
    • YouTube

    In 1964, a paleontologist named John Ostrom unearthed some fascinating fossils from the mudstone of Montana. Its discovery set the stage for what’s known today as the Dinosaur Renaissance, a total re-thinking of what we thought we knew about dinosaurs.

  • S2019E28 When Bats Took Flight

    • September 11, 2019
    • YouTube

    Bats pretty much appear in the fossil record as recognizable, full-on, flying bats. And they show up on all of the continents, except Antarctica, around the same time. So where did bats come from? And which of the many weird features that bats have, showed up first?

  • S2019E29 How Pterosaurs Got Their Wings

    • September 18, 2019
    • YouTube

    When pterosaurs first took flight, you could say that it marked the beginning of the end for the winged reptiles. Because, strangely enough, the power of flight -- and the changes that it led to -- may have ultimately led to their downfall.

  • S2019E30 When Giant Lemurs Ruled Madagascar

    • September 25, 2019
    • YouTube

    Just a few thousand years ago, the island of Madagascar was inhabited by giant lemurs. How did such a diverse group of primates evolve in the first place, and how did they help shape the unique environments of Madagascar? And how did they get winnowed down, leaving only their smaller relatives behind?

  • S2019E31 When Antarctica Was Green

    • October 3, 2019
    • YouTube

    Before the start of the Eocene Epoch about 56 million years ago--Antarctica was still joined to both Australia and South America. And it turns out that a lot of what we recognize about the southern hemisphere can be traced back to that time when Antarctica was green.

  • S2019E32 The (Ovi)Raptor That Paleontologists Got Wrong

    • October 16, 2019
    • YouTube

    Original Title: The Case of the Dinosaur Egg Thief Paleontologists found a small theropod dinosaur skull right on top of a nest of eggs that were believed to belong to a plant-eating dinosaur. Instead of being the nest robbers that they were originally thought to be, raptors like this one would reveal themselves to actually be caring parents.

  • S2019E33 When Hobbits Were Real

    • October 22, 2019
    • YouTube

    Its discoverers named it Homo floresiensis, but it’s often called “the hobbit” for its short stature and oddly proportioned feet. And it’s been at the center of a major controversy in the field ever since. Was it its own species? Or was it really just one of us? Or, could it even have descended from a whole lineage of hominins that we don’t even know about?

  • S2019E34 Were These Monsters Inspired by Fossils?

    • October 29, 2019
    • YouTube

    People have been discovering the traces and remains of prehistoric creatures for thousands of years. And they’ve also probably been telling stories about fantastic beasts since language became a thing. So, is it possible that the monsters that populate our myths and legends were influenced by the fossil record?

  • S2019E35 How We Domesticated Cats (Twice)

    • November 6, 2019
    • YouTube

    A 9,500 year old burial in Cyprus represents some of the oldest known evidence of human/cat companionships anywhere in the world. But when did this close relationship between humans and cats start? And how did humans help cats take over the world?

  • S2019E36 When Giant Hypercarnivores Prowled Africa

    • November 19, 2019
    • YouTube

    These hyaenodonts gave the world some of its largest terrestrial, carnivorous mammals ever known. And while these behemoths were the apex predators of their time, they were no match for a changing world.

  • S2019E37 Why Male Mammoths Lost the Game

    • November 26, 2019
    • YouTube

    Woolly mammoths, our favorite ice age proboscidean, disappeared from Europe and North America at the end of the last ice age, about 10,000 years ago. Today, we’ve teamed up with TierZoo to solve one of the mysteries about these charismatic megafauna: why do most remains of mammoths found in the fossil record turn out to be male?

  • S2019E38 The Forgotten Story of the Beardogs

    • December 12, 2019
    • YouTube

    Because of their strange combination of bear-like and dog-like traits, they’re sometimes confusingly called the beardogs. And even though you’ve never met one of these animals, the beardogs are key to understanding the history of an important branch of the mammal family tree.

  • S2019E39 The Fuzzy Origins of the Giant Panda

    • December 17, 2019
    • YouTube

    How does a bear -- which is a member of the order Carnivora -- evolve into an herbivore? Despite how it looks, nothing about the history of the giant panda is black and white.

Season 2020

  • S2020E01 That Time the Mediterranean Sea Disappeared

    • January 9, 2020
    • YouTube

    How could a body of water as big as the Mediterranean just...disappear? It would take decades and more than 1,000 research studies to even start to figure out the cause -- or causes -- of one of the greatest vanishing acts in Earth’s history.

  • S2020E02 The Neanderthals That Taught Us About Humanity

    • January 16, 2020
    • YouTube

    Throughout the first half of the 20th century, Neandertals were thought to have been…primitive. Unintelligent, hunched-over cavemen, for lack of a better word. But the discoveries made in that Iraqi cave provided some of the earliest clues that Neanderthals actually behaved -- and likely thought and felt -- a lot like we do.

  • S2020E03 The Giant Dinosaur That Was Missing a Body

    • January 28, 2020
    • YouTube

    From end to end, its forelimbs alone measured an incredible 2.4 meters long and were tipped with big, comma-shaped claws. But other than its bizarre arms, very little material from this dinosaur had been found: no skull, no feet, almost nothing that could give experts a fuller picture of what this dinosaur actually was.

  • S2020E04 How South America Made the Marsupials

    • February 4, 2020
    • YouTube

    Throughout the Cenozoic Era -- the era we’re in now -- marsupials and their metatherian relatives flourished all over South America, filling all kinds of ecological niches and radiating into forms that still thrive on other continents.

  • S2020E05 A Short Tale About Diplodocus' Long Neck

    • February 11, 2020
    • YouTube

    Long necks gave sauropods a huge advantage when it came to food, but not in the way you think. And this benefit would allow them to become the biggest terrestrial animals of all time!

  • S2020E06 When the Rainforests Collapsed

    • February 19, 2020
    • YouTube

    The Carboniferous Rainforest Collapse set the stage for a takeover that would be a crucial turning point in the history of terrestrial animal life. If it weren’t for that time when the rainforests collapsed - in an extinction event that you probably haven’t heard of - our ancestors might never have made it out of the swamps.

  • S2020E07 How a Hot Planet Created the World's Biggest Snake

    • February 27, 2020
    • YouTube

    About 59 million years ago, the largest animal lurking in the ancient forests of Colombia by far was Titanoboa - the largest snake ever known. It’s only been in the past few years that we’ve put together the many pieces of this puzzling creature, but it turns out that the greatest snake that the world ever saw was made possible by a warming planet.

  • S2020E08 When the Sahara Was Green

    • March 10, 2020
    • YouTube

    The climate of the Sahara was completely different thousands of years ago. And we’re not talking about just a few years of extra rain. We’re talking about a climate that was so wet for so long that animals and humans alike made themselves at home in the middle of the Sahara.

  • S2020E09 When Penguins Went From The Sky To The Sea

    • March 18, 2020
    • YouTube

    Today, we think of penguins as small-ish, waddling, tuxedo-birds. But they evolved from a flying ancestor, were actual giants for millions of years, and some of them were even dressed a little more casually.

  • S2020E10 How the Egg Came First

    • March 25, 2020
    • YouTube

    The story of the egg spans millions of years, from the first vertebrates that dared to venture onto land to today’s mammals, including the platypus, and of course birds. Like chickens? We’re here to tell you: The egg came first.

  • S2020E11 How Dogs (Eventually) Became Our Best Friends

    • March 31, 2020
    • YouTube

    We’re still figuring out the details, but most scientists agree that it took thousands of years of interactions to develop our deep bond with dogs. When did they first become domesticated? Where did this happen? And what did the process look like, in terms of genetics and anatomy?

  • S2020E12 When a Billion Years Disappeared

    • April 15, 2020
    • YouTube

    In some places, the rocks below the Great Unconformity are about 1.2 billion years older than those above it. This missing chapter in Earth’s history might be linked to a fracturing supercontinent, out-of-control glaciers, and maybe the diversification of life itself.

  • S2020E13 The Risky Paleo Diets of Our Ancestors

    • April 22, 2020
    • YouTube

    We can track our history of eating just about anything back through the fossil record and see the impact it’s had on our evolution. Throughout time, part of the secret to our success as a species has been our early - and sometimes fatal - experimentation with food.

  • S2020E14 How the Andes Mountains Might Have Killed a Bunch of Whales

    • April 29, 2020
    • YouTube

    At a site known as Cerro Ballena or Whale Hill, there are more than 40 skeletons of marine mammals -- a graveyard of ocean life dating back 6.5 million to 9 million years ago, in the Late Miocene Epoch. But the identity of the killer that they finally settled on might surprise you.

  • S2020E15 How Plants Caused the First Mass Extinction

    • May 12, 2020
    • YouTube

    In the middle of the Cambrian, life on land was about to get a little more crowded. And those newcomers would end up changing the world. The arrival of plants on land would make the world colder, drain much of the oxygen out of the oceans and eventually, it would help cause a massive extinction event.

  • S2020E16 The Two Viruses That We’ve Had For Millions of Years

    • May 20, 2020
    • YouTube

    There’s one kind of herpesvirus that’s specific to one species of primate, and each virus split off from the herpesvirus family tree when the primate split off from its own tree. But of course, humans are a special kind of primate.

  • S2020E17 How We Identified One of Earth’s Earliest Animals

    • May 28, 2020
    • YouTube

    Scientists had no idea what type of organisms the life forms of the Ediacaran were—lichen, colonies of bacteria, fungi or something else. It turns out, the key to solving the puzzle of Precambrian life was a tiny bit of fossilized fat.

  • S2020E18 When Dinosaur Look-Alikes Ruled the Earth

    • June 9, 2020
    • YouTube

    There were a huge number of croc-like animals that flourished during the Triassic Period. Dinosaurs had just arrived on the scene but it was these animals that truly ruled the Earth, becoming both abundant and diverse.

  • S2020E19 The World Before Plate Tectonics

    • June 16, 2020
    • YouTube

    There was a time in Earth’s history that was so stable, geologists once called it the Boring Billion. But the fact is, this period was anything but boring. In fact, it set the stage for our modern version of plate tectonics - and probably for the rise of life as we know it.

  • S2020E20 When Dinosaurs Chilled in the Arctic

    • June 24, 2020
    • YouTube

    All told, the Arctic in the Cretaceous Period was a rough place to live, especially in winter. And yet, the fossils of many kinds of dinosaurs have been discovered there. So how were they able to survive in this harsh environment?

  • S2020E21 How the Walrus Got Its Tusks

    • July 7, 2020
    • YouTube

    The rise and fall of ancient walruses, and how modern ones got their tusks, is a story that spans almost 20 million years. And while there are parts of the story that we’re still trying to figure out, it looks like tusks didn’t have anything to do with how or what these animals ate.

  • S2020E22 The Story of the Dino Stampede

    • July 16, 2020
    • YouTube

    To try to solve the puzzle of Lark Quarry, experts have turned to a special subfield of paleontology -- paleoichnology, or the study of trace fossils -- to reconstruct exactly what happened on that spot, on that day, nearly 100,000 millennia ago.

  • S2020E23 The Biggest Frog that Ever Lived

    • July 23, 2020
    • YouTube

    Untangling the origins of Beelzebufo -- the giant frog that lived alongside the dinosaurs -- turns out to be one of the most bedeviling problems in the history of amphibians.

  • S2020E24 The Dinosaur Who Was Buried at Sea

    • August 5, 2020
    • YouTube

    Paleontologists have been studying these dinosaurs since the 1830s, but nobody had ever found a specimen like Borealopelta before. The key to all of this exceptional preservation was where ended up after it died and how it got there.

  • S2020E25 How We Figured Out Fermentation

    • August 13, 2020
    • YouTube

    Thanks to a recent adaptation, instead of getting sick from the boozy, fermented fruits, one of our primate ancestors could digest them safely, and get more calories at the same time. This new superpower would open up a whole new nutritional landscape for us: fermented foods.

  • S2020E26 The Oddest Couple in the Fossil Record

    • August 20, 2020
    • YouTube

    To figure out how Thrinaxodon and Broomistega became entombed together, scientists looked at the burrow itself, along with their fossilized bones. And it looks like their luck ran out, when a behavior that usually would’ve helped them survive just didn’t work.

  • S2020E27 How Ancient Art Captured Australian Megafauna

    • September 2, 2020
    • YouTube

    Beneath layers of rock art are drawings of animals SO strange that, for a long time, some anthropologists thought they could only have been imagined. But what if these animals really had existed, after all?

  • S2020E28 The Sea Monster from the Andes

    • September 10, 2020
    • YouTube

    In 1977, a farmer was plowing his field on a plateau high in the Andes mountains when he stumbled upon a giant fossilized skeleton. How did this giant marine reptile end up high in the Andes Mountains?

  • S2020E29 When Rodents Had Horns

    • September 15, 2020
    • YouTube

    These odd rodents belong to a genus known as Ceratogaulus, but they’re more commonly called horned gophers, because, you guessed it, they had horns. And it turns out the horns probably had a purpose - one that rodents would likely benefit from today.

  • S2020E30 The First and Last North American Primates

    • September 30, 2020
    • YouTube

    Early primates not only lived in North America -- our primate family tree actually originated here! So what happened to those early relatives of ours?

  • S2020E31 How Plants Became Carnivores

    • October 7, 2020
    • YouTube

    How and why does botanical carnivory keep evolving? It turns out that when any of the basic things that most plants need aren’t there, some plants can adapt in unexpected ways to make sure they thrive.

  • S2020E32 How Ankylosaurs Got Their Clubs

    • October 13, 2020
    • YouTube

    While clubs are practically synonymous with ankylosaurs, we’ve only started to get to the bottom of how they worked and how this unusual anatomy developed in the first place.

  • S2020E33 Why Do Things Keep Evolving Into Crabs?

    • October 28, 2020
    • YouTube

    For some reason, animals keep evolving into things that look like crabs, independently, over and over again. What is it about the crab’s form that makes it so evolutionarily successful that non-crabs are apparently jealous of it?

  • S2020E34 How Plankton Created A Bizarre Giant of the Seas

    • November 10, 2020
    • YouTube

    At more than 2 meters long, Aegirocassis was not only the biggest radiodont ever, but it also may have been the biggest animal in the Early Ordovician. This bizarre marine giant may have only been possible, thanks to a major revolution among some of the tiniest organisms in the world.

  • S2020E35 The Rise and Fall of the Tallest Mammal to Walk the Earth

    • November 19, 2020
    • YouTube

    It arose from rhino ancestors that were a lot smaller, but Paraceratherium would take a different evolutionary path. Believe it or not, it actually became so big that it probably got close to what scientists think might be the actual upper limit for a land mammal.

  • S2020E36 How Humans Lost Their Fur

    • December 2, 2020
    • YouTube

    We’re the only primate without a coat of thick fur. It turns out that this small change in our appearance has had huge consequences for our ability to regulate our body temperature, and ultimately, it helped shape the evolution of our entire lineage.

  • S2020E37 When Lizards Took Over the World

    • December 9, 2020
    • YouTube

    Lizards are incredibly widespread and diverse but it took them a long time to get to where they are now. Because they used to face some pretty stiff competition from a group of lizard look-alikes.

  • S2020E38 When the Earth Suddenly Stopped Warming

    • December 17, 2020
    • YouTube

    For decades, scientists have been studying the cause of the Younger Dryas, and trying to figure out if something like it could happen again. And it turns out that what caused this event is the subject of a heated debate.

  • S2020E39 The Triassic Reptile With "Two Faces"

    • December 22, 2020
    • YouTube

    Figuring out what this creature’s face actually looked like would take paleontologists years. But understanding this weird animal can help us shine a light on at least one way for ecosystems to bounce back from even the worst mass extinction.

Season 2021

  • S2021E01 What Happened to the World's Biggest Beaver?

    • January 13, 2021

    It’s important to us that you understand how big this beaver was. Just like modern beavers, it was semiaquatic -- it lived both on the land and in the water. The difference is that today’s beavers do a pretty special thing - one that the giant beaver probably didn’t, or couldn’t, do.

  • S2021E02 The Reign of the Hell Ants

    • January 21, 2021

    This ancient species had the same six legs and segmented body that we’d recognize from an ant today. But it also had a huge, scythe-like jaw and a horn coming out of its head. This bizarre predator belonged to a group known as “hell ants.” But they’re gone now, and we’re still trying to figure out why.

  • S2021E03 The Pandemic That Lasted 15 Million Years

    • January 28, 2021
    • YouTube

    Our DNA holds evidence of a huge, ancient pandemic, one that touched many different species, spanned the globe, and lasted for more than 15 million years.

  • S2021E04 When We First Talked

    • February 11, 2021
    • YouTube

    The evolution of our ability to speak is its own epic saga and it’s worth pausing to appreciate that. It’s taken several million years to get to this moment where we can tell you about how it took several million years for us to get here.

  • S2021E05 The Return of Giant Skin-Shell Sea Turtles

    • February 17, 2021
    • YouTube

    The biggest turtle ever described wasn’t an ancestor of today’s leatherback turtles or any other living sea turtles. But it looks like there are some things about being a giant, skin-shelled sea turtle that just work, no matter where, or when, you lived.

  • S2021E06 The Genes We Lost Along the Way

    • February 24, 2021
    • YouTube

    Our DNA holds thousands of dead genes and we’ve only just begun to unravel their stories. But one thing is already clear: we’re not just defined by the genes that we’ve gained over the course of our evolution, but also by the genes that we’ve lost along the way.

  • S2021E07 Our Bizarre, Possibly Venomous, Relative

    • March 10, 2021
    • YouTube

    It's possible Euchambersia possessed venom about 20 million years before the first lizards and over 150 million years before the first snakes evolved. We’ve teamed up Sarah Suta from Bizarre Beasts to explore the story of venomous mammals, both living and extinct.

  • S2021E08 How Worm Holes Ended Wormworld

    • March 18, 2021
    • YouTube

    Elongated tubes, flat ribbons, and other “worm-like” body plans were so varied and abundant that a part of the Ediacaran is sometimes known as Wormworld. But in the end, the ancient Wormworld was ended by the actions of its very own worms.

  • S2021E09 How Humans Became (Mostly) Right-Handed

    • March 24, 2021
    • YouTube

    No other placental mammal that we know of prefers one side of the body so consistently, not even our closest primate relatives. But being right-handed may have deep evolutionary roots in our lineage. And yet, being a leftie does seem to come with some unexpected advantages.

  • S2021E10 How Chilis Got Spicy (and Why We Love the Burn)

    • April 7, 2021
    • YouTube

    Today, chilis are the most widely cultivated spice crop in the world - grown everywhere from their native home in the Americas to Europe, Africa, and Asia. But how and why did chilis evolve this weird, fiery trick in the first place? And why did we learn to love that spicy burn?

  • S2021E11 How To Survive the Little Ice Age

    • April 20, 2021
    • YouTube

    Nunalleq, a village in what’s today southwest Alaska, seemed to have thrived during the Little Ice Age. How did this village manage to survive and prosper during this time period? And what caused this period of climate change in the first place?

  • S2021E12 When Crocs Thrived in the Seas

    • April 29, 2021
    • YouTube

    While dinosaurs were dominating the land, the metriorhynchids were thriving in the seas. But taking that plunge wasn’t easy because it takes a very special set of traits to fully dedicate yourself to life at sea.

  • S2021E13 When Trees Took Over the World

    • May 12, 2021
    • YouTube

    420 million years ago, the forest floor of what's now New York was covered with a plant that didn’t look like a tree at all, except its roots were made of wood. Instead of looking up to learn about the evolution of trees, it turns out paleobotanists should’ve been looking down all along.

  • S2021E14 How Weasels Got Skinny

    • May 20, 2021
    • YouTube

    Weasels have an extreme body plan that may push the boundaries of what’s metabolically possible. So when and how did this happen? Why'd the weasels get so skinny?

  • S2021E15 Where Are All The Squid Fossils?

    • June 3, 2021
    • YouTube

    It might surprise you but cephalopods have a pretty good fossil record, with one major exception. If squids were swimming around in the same oceans as their closest cousins, where did all the squids go?

  • S2021E16 Did These Giant Sloths Poop Themselves to Death?

    • July 14, 2021
    • YouTube

    At Tanque Loma, at least 22 giant ground sloths in the genus Eremotherium met their end. Of the five hypotheses that researchers proposed for what killed the sloths, the best supported one right now is that they died surrounded by their own poop.

  • S2021E17 The Traits That Spawned the Age of Mammals

    • July 21, 2021
    • YouTube

    Lots of the traits we think of as defining us as mammals show up pretty early, during the time of the dinosaurs. And, in some cases, they show up a lot earlier and in things that weren’t mammals at all.

  • S2021E18 The Island of the Last Surviving Mammoths

    • July 29, 2021
    • YouTube

    The Wrangel Island mammoths would end up being the final survivors of a once-widespread genus. In their final years, after having thrived in many parts of the world for millions of years, the very last mammoths that ever lived experienced what’s known as a mutational meltdown.

  • S2021E19 Where Are All the Medium-Sized Dinosaurs?

    • August 12, 2021
    • YouTube

    The remains of medium-sized predatory dinosaurs are pretty rare in places where giant predators like T. rex existed. Which is weird, because that’s just not how ecosystems work today.

  • S2021E20 How the Starfish Got Its Arms

    • August 24, 2021
    • YouTube

    The story of how the starfish got its arms reminds us that even animals that might be familiar to us today can have incredibly deep histories - ones that stretch back almost half a billion years.

  • S2021E21 The Creature That Stumped Darwin

    • September 1, 2021
    • YouTube

    Toxodon was one of the last members of a lineage that vanished 11,000 years ago after thriving in isolation for millions of years. And its fossils would inspire a revolutionary thinker to tackle a bigger mystery than Toxodon itself: evolution.

  • S2021E22 How Pollination Got Going Twice

    • September 16, 2021
    • YouTube

    The world of the Jurassic was a lot like ours - similar interactions between plants and insects were happening, but the players have changed over time. Because it looks like pollination by insects actually got going twice.

  • S2021E23 How a Supervolcano Ignited an Evolutionary Debate

    • September 23, 2021
    • YouTube

    The Toba supervolcano was the biggest explosive eruption of the last 2.5 million years. And humans were around to see it, or at least feel its effects! But what were those effects?

  • S2021E24 How a Mass Extinction Event Created the Amazon

    • September 29, 2021
    • YouTube

    The Amazon rainforest of South America is a paradise for flowering plants. But long ago, the landscape that we now think of as the Amazon looked very different. And would you believe that the entire revolution of the Amazon began with just one day?

  • S2021E25 When Mammals Only Went Out At Night

    • October 7, 2021
    • YouTube

    For decades, scientists believed dinosaurs were diurnal and tiny mammals were nocturnal. But as researchers have uncovered more mammalian fossils and studied the biology of different dinosaur species, they’ve found some surprising results.

  • S2021E26 How Ancient Whales May Have Changed the Deep Ocean

    • October 21, 2021
    • YouTube

    It looks like the evolution of ocean-going whales like Borealodon may have affected communities found in the deep ocean, like the ones found around geothermal vents. And it turns out that when a whale dies, that’s just the beginning of the story.

  • S2021E27 How Dinosaurs Coupled Up

    • October 28, 2021
    • YouTube

    Dinosaur mating behavior has been the subject of a lot of speculation, but what can we actually say about it from the fossil record?

  • S2021E28 When It Was Too Hot for Leaves

    • November 17, 2021
    • YouTube

    Plants first made their way onto land at least 470 million years ago but for their first 80 million years, leaves as we know them today didn’t exist. What held them back?

  • S2021E29 Why The Paleo Diet Couldn't Save The Neanderthals

    • December 2, 2021
    • YouTube

    These relatives of ours lived in Eurasia for more than 300,000 years. They were expert toolmakers, using materials like stone, wood, and animal bone. They were also skilled hunters and foragers, and may even have created cave art. So what caused the decline and disappearance of their population? Well, in a way...it could’ve been us. But maybe not in the way you might’ve heard.

  • S2021E30 The Fossil Record In Your Mouth

    • December 9, 2021
    • YouTube

    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.

  • S2021E31 When Pterosaurs Walked

    • December 16, 2021
    • YouTube

    If you know one thing about pterosaurs, it’s that they’re flyers. And while pterosaurs may be well-known for their domination of the skies in the Mesozoic Era, they didn’t live their entire lives in the air. So how did we figure this out? And what were they like when they finally came down?

  • SPECIAL 0x7 Sharks nearly went extinct 19 million years ago

    • March 2, 2022

Season 2022

  • S2022E01 How Our Deadliest Parasite Turned to the Dark Side

    • January 11, 2022
    • YouTube

    Around 10,000 years ago, somewhere in Africa, a microscopic parasite made a huge leap. With a little help from a mosquito, it left its animal host - probably a gorilla - and found its way to a new host: us.

  • S2022E02 Primates vs Snakes (An Evolutionary Arms Race)

    • January 19, 2022
    • YouTube

    The Snake Detection Hypothesis proposes that the ability to quickly spot and avoid snakes is deeply embedded in primates, including us - an evolutionary consequence of the danger snakes have posed to us over millions of years.

  • S2022E03 How the Rise of Social Insects Shrunk These Dinosaurs

    • January 27, 2022
    • YouTube

    We often think of dinosaurs as either preying on other dinos or mammals, or as plant-eaters -- but in ecosystems today, those aren’t the only two options. So why would we expect dinosaurs to have only been carnivores or herbivores, with the occasional omnivore thrown in the mix?

  • S2022E04 How Vertebrates Got Teeth... And Lost Them Again

    • February 8, 2022
    • YouTube

    As revolutionary as teeth were, they would go on to disappear in some groups of vertebrates. But why?

  • S2022E05 How Horses Went From Food To Friends

    • February 16, 2022
    • YouTube

    Do our modern horses descend from just one domesticated population, or did it happen many times, in many places? Answering these questions has been tricky, as we’ve needed to bring together evidence from art, archaeology, and ancient DNA…Because, as it turns out, the history of humans and horses has been a pretty wild ride.

  • S2022E06 Why We Only Have Ten Toes (It's a Long Story)

    • February 23, 2022
    • YouTube

    Today, all mammals from humans to bats have five fingers or fewer. Yes, even whales, whose finger bones are hidden in their fins. Birds have four or fewer and amphibians get the best of both worlds, often having four digits on their “hands” and five on their “feet.” But no species of vertebrates have more than five digits, let alone eight!

  • S2022E07 When a Giant Pterosaur Ruled the European Islands

    • March 15, 2022
    • YouTube

    The ecological niche of apex predators was empty on Hateg Island, waiting to be occupied by something large, mobile, and powerful enough to fill it.

  • S2022E08 The Sudden Rise of the First Colossal Animal

    • March 22, 2022
    • YouTube

    A truly enormous ichthyosaur around the size of a modern sperm whale, reached its size within just a few million years of taking to the water - a blink of an eye in evolutionary time.

  • S2022E09 The Extreme Hyenas That Didn't Last

    • March 29, 2022
    • YouTube

    Hyenas weren’t always able to eat bones. In fact, only a few million years ago, they lived very different lives.

  • S2022E10 How the Smallest Animal Got So Simple

    • April 13, 2022
    • YouTube

    We tend to think that evolution only goes in one direction— toward getting bigger and more advanced. But that’s not always the case. This tiny, simple animal, the Myxozoans, (yes, animal!) evolved from something bigger and more complex.

  • S2022E11 Why Sour May Be The Oldest Taste

    • April 20, 2022
    • YouTube

    While sour taste's original purpose was to warn vertebrates of danger, in a few animal groups, including us, its role has reversed. The taste of danger became something it was dangerous for us to avoid.

  • S2022E12 The Ancient Human Species With A Missing Body

    • April 27, 2022
    • YouTube

    Only a handful of Denisovan fossils have been identified. In the absence of actual body fossils, it’s impossible for us to reconstruct their morphology, right?

  • S2022E13 When Ants Domesticated Fungi

    • May 10, 2022
    • YouTube

    While we’ve been farming for around 10,000 to 12,000 years, the ancestors of ants have been doing it for around 60 million years. So when, and how, and why did ants start … farming?

  • S2022E14 The Curious Case of the Cave Lion

    • May 17, 2022
    • YouTube

    A mysterious, large feline roamed Eurasia during the last ice age. Its fossils have been found across the continent, and it’s been the subject of ancient artwork. So what exactly were these big cats?

  • S2022E15 Is This The Oldest Dad In The Fossil Record?

    • May 26, 2022
    • YouTube

    Fossil evidence suggests Diictodon used burrows to breed, and that a parent stayed behind to feed and protect their young. And the parent that stayed behind? It might’ve been the male.

  • S2022E16 How To Build A Woolly Mammoth (But Should We?)

    • June 8, 2022
    • YouTube

    In the quest to understand how evolution basically built the woolly mammoth, we may have found the blueprints for building them ourselves.

  • S2022E17 Something Has Been Making This Mark For 500 Million Years

    • June 15, 2022
    • YouTube

    Paleodictyon, a hexagonal-patterned fossil, is a bit of a mystery. We don’t even know if it’s a trace fossil, or the organism itself. So… what could it be?

  • S2022E18 Giant Viruses Blur The Line Between Alive and Not

    • June 29, 2022
    • YouTube

    In 2003, microbiologists made a huge discovery. One that would force us to reconsider a lot of what we thought we knew about the evolution of microbial life: giant viruses.

  • S2022E19 When Giant Millipedes Reigned

    • July 13, 2022
    • YouTube

    This giant millipede was the largest known invertebrate to ever live on land. So how did it get so big??

  • S2022E20 How Plate Tectonics Transformed Los Angeles

    • July 21, 2022
    • YouTube

    Despite the profound changes we’ve made here in recent history, the epic saga of Los Angeles' natural history is still visible - and even striking - if you know where and how to look for it.

  • S2022E21 Why Does Caffeine Exist?

    • July 28, 2022
    • YouTube

    Today, billions of people around the world start their day with caffeine. But how and why did the ability to produce this molecule independently evolve in multiple, distantly-related lineages of flowering plants, again and again?

  • S2022E22 Did An Ancient Pathogen Reshape Our Cells?

    • August 11, 2022
    • YouTube

    There is one - and only one - group of mammals that doesn’t have alpha-gal: the catarrhine primates, which are the monkeys of Africa and Asia, the apes, and us.

  • S2022E23 How Whale Evolution Kind Of Sucked

    • August 18, 2022
    • YouTube

    Mystacodon is the earliest known mysticete, the group that, today, we call the baleen whales. But if this was a baleen whale, where was its baleen? Where did baleen come from? And how did it live without it?

  • S2022E24 The Fungi That Turned Ants Into Zombies

    • August 23, 2022
    • YouTube

    This fungus was actually manipulating ants’ movements, forcing them to do something they’d never ordinarily do, something strange, yet specific…

  • S2022E25 Where Did Water Come From?

    • September 27, 2022
    • YouTube

    Mercury, Venus, and Mars are all super low on water – so where did ours come from and why do we have so much of it? We think our water came from a few unlikely sources: meteorites, space dust, and even the sun.

  • S2022E26 Our Ancient Relative That Said 'No Thanks' To Life On Land

    • October 4, 2022
    • YouTube

    Around the time that some of our fishapod relatives were crawling out of the water, others were turning around and diving right back in.

  • S2022E27 Darwin Missed An Example of Evolution Right Under His Nose

    • October 18, 2022
    • YouTube

    Charles Darwin encountered a tiny fox-like creature during his famous voyage but instead of discovering its fascinating evolutionary story, he just knocked it on the head with his geology hammer.

  • S2022E28 Are We All Actually Archaea?

    • October 25, 2022
    • YouTube

  • S2022E29 How Plate Tectonics Gave Us Seahorses

    • November 8, 2022
    • YouTube

  • S2022E30 We Met Neandertals Way Earlier Than We Thought

    • November 16, 2022
    • YouTube

  • S2022E31 Thylacoleo Is The Missing Australian Apex Predator

    • December 6, 2022
    • YouTube

    In Australia, evolution built a family of deadly predators by taking a group of cute, harmless herbivores and turning them murderous.

  • S2022E32 How Did Lucy Live and Die?

    • December 14, 2022
    • YouTube

    Did our most famous fossil ancestor, Lucy, die by falling out of a tall tree? The answer is part of a decades-long debate over how, exactly, our ancestors transitioned from life in the trees to life on the ground.

  • SPECIAL 0x8 Dire wolves aren’t wolves at all

    • March 3, 2022

Season 2023

  • S2023E01 These Creatures Were Darwin's Greatest Enemy

    • January 10, 2023
    • YouTube

    They may not look like much, but beneath that shell lies an evolutionary mystery - one that stumped the biggest names in natural history for over a hundred years.

  • S2023E02 When Ancient People Changed Their Own DNA

    • January 19, 2023
    • YouTube

    Thanks to our ability to develop and share complex learned behaviors across generations - a thing we sometimes call culture - we have become the ultimate niche builders.

  • S2023E03 The Neandertal Burial That Taught Us About Humanity

    • January 31, 2023
    • YouTube

    If we can see ourselves in the way our ancient cousins dealt with death…what else could we have in common?

  • S2023E04 These Fossils Were Supposed To Be Impossible

    • February 7, 2023
    • YouTube

    Hidden in rocks once thought too old to contain complex life we may have found the animal kingdom’s oldest known predator.

  • S2023E05 The Mystery Of The Mashed-Up Dinosaurs

    • February 14, 2023
    • YouTube

    How the therizinosaurs lived and evolved ended up being just as weird as their mixed-up anatomy.

  • S2023E06 How a Mass Extinction Changed Our Brains

    • March 1, 2023
    • YouTube

    During one of the most pivotal moments in our evolutionary story our brains actually shrank relative to our bodies.

  • S2023E07 That Time the American West Blew Up

    • March 7, 2023
    • YouTube

    How is it possible to have cataclysmic eruptions without any real cataclysm?

  • S2023E08 Does Our "Junk" DNA Make Us Human?

    • March 16, 2023
    • YouTube

    In the search for the genes that make us human, some of the most important answers were hiding not in the genes themselves, but in what was once considered genomic junk.

  • S2023E09 Nautiloids Thrived For 500 Million Years Until These Guys Appeared

    • March 28, 2023

    Around 30 million years ago, a new group of predators began to push nautiloids from their former global range into a single remaining refuge. But who were these predators?

  • S2023E10 The Real Story Of The Dodo Bird's (Current) Extinction

    • April 4, 2023
    • YouTube

    What’s the real story of the dodo? How did such a unique bird even evolve in the first place? And are we really responsible for its extinction?

  • S2023E11 How (Some) Plants Survived The K-Pg Extinction

    • April 13, 2023
    • YouTube

    Perhaps for plants in times of great stress and ecological upheaval, the more DNA the better.

  • S2023E12 It's Becoming Very Clear That Birds Are Not Normal

    • April 25, 2023
    • YouTube

    A new discovery raises an important question: from an evolutionary perspective, who really has the stranger wings?

  • S2023E13 The Invisible Barrier Keeping Two Worlds Apart

    • May 2, 2023
    • YouTube

    In between two of the islands of Indonesia, there’s an ancient line that is both real and…not real.

  • S2023E14 A Natural History of Mars

    • May 9, 2023
    • YouTube

    While Earth’s natural history has been playing out over the last few billion years, another epic planetary saga has also been unfolding right next door.

  • S2023E15 We've Had The Giraffe's Neck All Wrong

    • August 1, 2023
    • YouTube

    How and why the giraffe's neck emerged in the first place has been a mystery that generations of biologists have argued over – one that has made us reconsider our understanding of how evolution actually works over and over again.

  • S2023E16 We Helped Make Mosquitoes A Problem

    • August 15, 2023
    • YouTube

    Around 6,000 years ago, in the Sahel region of Africa, a lone female mosquito buzzed through the lush, green savannah. She couldn’t know it, but the planet itself was about to change in ways that would see her descendants evolve to live very different lives. A sudden ecological shift would force them to go from living in forests and feeding on a range of animals to specializing on just one single species: us.

  • S2023E17 Did a Tsunami Swallow Part of Europe?

    • August 29, 2023
    • YouTube

    What happened to the piece of prime prehistoric real estate known as Doggerland? While a massive megatsunami might have drowned it for good, the underlying reason that it now lies under the sea may have actually been the same thing that made it so great in the first place.

  • S2023E18 That Time The Ocean Lost (Almost) All Its Oxygen

    • September 12, 2023
    • YouTube

    Original Title: How a Volcanic Eruption Almost Suffocated the Ocean This is the story of how our planet rescued itself from extreme conditions in the Cretaceous Period, at the cost of essentially suffocating the oceans for half-a-million years.

  • S2023E19 This Is An Ant World, We're Just Living In It

    • September 26, 2023
    • YouTube

    How did ants take over the world? Well, it looks like they didn’t achieve world domination all by themselves. They may have just been riding the wave of a totally different evolutionary explosion.

  • S2023E20 Are Giant Animals Inevitable?

    • October 24, 2023
    • YouTube

  • S2023E21 When Did We Stop Being Naked?

    • November 9, 2023
    • YouTube

    Of course, the ancient Egyptians were probably not the first people to ever wear clothing, but we haven’t found any clothes older than the Tarkhan Dress. So how can we figure out when we first started wearing clothes? Well, it turns out that some of our best evidence for clothing in the past comes from a pretty unlikely - and kinda gross - place.

  • S2023E22 The Secret Extinctions Of The Silurian Period

    • November 21, 2023
    • YouTube

  • S2023E23 Beans & Bees (Not Bats) Gave Us Butterflies

    • December 5, 2023
    • YouTube

  • S2023E24 Why Only Earth Has Fire

    • December 19, 2023
    • YouTube

Season 2024

  • S2024E01 How Ancient Microbes Rode Bug Bits Out to Sea

    • January 9, 2024
    • YouTube

    Tiny exoskeleton fragments may have allowed some of the most important microbes in the planet’s history to set sail out into the open ocean and change the world forever.

  • S2024E02 Our Most Mysterious Extinct Cousins

    • January 23, 2024
    • YouTube

  • S2024E03 Animals Might Be Much Older Than We Thought

    • February 6, 2024
    • YouTube

    What are animal-like fossils doing in rocks a billion years old, and what does that mean for our understanding of their evolution and geologic time itself? Turns out, there might've been a long, slow-burning fuse that ultimately ignited the Cambrian Explosion.

  • S2024E04 Why Is It So Hard to Tell the Sex of a Dinosaur?

    • February 20, 2024
    • YouTube

    While we think we know a lot about dinosaurs – like how they moved and what they ate – for a long time, we haven’t been able to ID one seemingly basic thing about their biology...

  • S2024E05 How Snake Venom Sparked An Evolutionary Arms Race

    • March 5, 2024
    • YouTube

    For some, the rise and spread of venomous elapids was just another challenge to adapt to. For others, it was a catastrophe of almost apocalyptic proportions. And we humans are no exception, because it seems that when elapids slithered onto the ecological scene, not even our ancestors were safe…

  • S2024E06 When Did We Start Practicing Medicine?

    • March 19, 2024
    • YouTube

    When did practicing medicine - in its varied, complex forms (from sharing medicinal plants to the earliest surgeries) - become something that we actually started doing? While it’s a hard question to answer, it’s possible that our tendency to heal one another might have been with us for even longer than we've been human.

  • S2024E07 What Will Earth Be Like 300 Million Years From Now?

    • April 2, 2024
    • YouTube

    We spend a lot of time here on Eons looking backwards into deep time, visiting ancient chapters of our planet’s history. But this time, we’re taking a look towards the deep future. After all, the story is far from over.

  • S2024E08 The Hazy Evolution of Cannabis

    • April 16, 2024
    • YouTube

    How did such a strange plant like cannabis come to be in the first place? When and where did we first domesticate it? And why oh why does it get us high?

  • S2024E09 There's No Single Cradle of Humankind

    • April 30, 2024
    • YouTube

    It would take decades for paleontologists to realize that maybe there wasn’t just one so-called "cradle of humankind," and realize that maybe they’d been asking the wrong question all along.

  • S2024E10 How Sponges Beat The First Mass Extinction

    • May 14, 2024
    • YouTube

  • S2024E11 When The Atlantic Ripped Open A Supercontinent

    • May 28, 2024
    • YouTube

    While the eruptions of the volcanoes along the Mid-Atlantic Ridge usually don't trouble us, their birth was once responsible for ripping a supercontinent apart and creating the Atlantic Ocean that we know today.

  • S2024E12 When India Was An Island

    • August 6, 2024
    • YouTube

    We need to talk about the biggest break-up of all-time: the break-up of the supercontinent Pangea, and how, ultimately, when India smashed back into Asia, it traded one form of evolutionary isolation for another.

  • S2024E13 The Mystery of South America's False Horses

    • August 20, 2024
    • YouTube

    How did the "false horse," Thoatherium, and its relatives survive when their hoofed legs seemed to be adapted for an ecosystem that wouldn't exist for another 12 million years?

  • S2024E14 What Was The First Beverage?

    • September 3, 2024
    • YouTube

    When exactly did we start drinking other things, and why? To find out, we have to look at the world’s oldest beverages – which might not be what you expect.

  • S2024E15 How The Elephant Got Its Trunk

    • September 10, 2024
    • YouTube

    Long-jawed proboscideans were doing pretty well for themselves. That is, until they were all rapidly replaced with proboscideans with long, flexible trunks instead: mammoths, mastodons, and our modern elephants.What suddenly made long jaws such a liability? Well it looks like we can thank a changing climate for the evolution of the elephant’s trunk.

  • S2024E16 When Earth "Ate" A Planet

    • September 25, 2024
    • YouTube

    Where did our unique moon come from? It turns out that lunar rocks brought back by Apollo astronauts are a clue, pointing to the origin of our closest cosmic companion, an origin even stranger than you might imagine…

  • S2024E17 How the Himalayas Changed the World

    • October 8, 2024
    • YouTube

    The rise of the Himalayas affected more than just the immediate area. Turns out, we may have them to thank for everything from the rise of giant flightless birds in Madagascar; to the disappearance of plants from Antarctica; to the expansion of the great grasslands of North America, and more.

  • S2024E18 The Dinosaurs That Evolution Forgot

    • October 22, 2024
    • YouTube

    Where are all the east coast dinosaurs? Why don’t we find famous species like Triceratops in Central Park? Turns out, evolution and geology came together to make the east coast into an ancient lost world of weird dinosaurs.

  • S2024E19 What Happened To The Other Mesozoic Mammals?

    • November 5, 2024
    • YouTube

    In 2003, a fossil belonging to a mammaliaform was discovered in an ancient lakebed in what's now China. It was an almost complete skeleton the size of a platypus, a find that complicated the history of mammaliaforms. It painted a picture of their explosive diversification, their mysterious disappearance, and how our own ancestors might have survived thanks to a leg up from some leafy allies…

  • S2024E20 How Animals Got Butts

    • November 19, 2024
    • YouTube

    While the evolution of the butthole was a major breakthrough in animal development, its story might actually end with redefining what it means to have a butthole at all.

Additional Specials

  • SPECIAL 0x1 A Quick Introduction to Eons

    • June 22, 2017
    • YouTube

    Join hosts Hank Green, Kallie Moore, and Blake de Pastino as they take you on a journey through the history of life on Earth. From the dawn of life in the Archaean Eon through the Mesozoic Era — the so-called “Age of Dinosaurs” -- right up to the end of the most recent Ice Age. The evolutionary history of mammals including humans and other modern species is explored with these amazing paleontology experts.

  • SPECIAL 0x2 Eons Livestream Q&A

    • January 8, 2018
    • YouTube

  • SPECIAL 0x3 Eons Is Evolving! Join Us on Patreon!

    • June 18, 2018
    • YouTube

  • SPECIAL 0x4 Eons 1-Year Birthday Livestream!!!!

    • June 26, 2018
    • YouTube

  • SPECIAL 0x6 Fossil Feud: Eons vs SciShow!

    • October 13, 2021
    • YouTube

    You’ve heard of Family Feud… but how about Fossil Feud? Join us for a National Fossil Day livestream to watch the Eons team compete against some of our friends from SciShow! Gabriel-Philip Santos from the Alf Museum of Paleontology will be our host. Kallie Moore, Blake de Pastino and Michelle Barboza-Ramirez will be up against SciShow's Sarah Suta, Stefan Chin, and Savannah Geary. Let’s see which team will be crowned the Champions of Deep Time! Thank you to our Patrons for submitting the questions we are using, and thank you to all of you who answered our survey a few weeks ago to get the top answers!