Stuff You Should Know - Selects: How Extinction Works

Episode Date: November 1, 2025

Scientists believe that 99% of the estimated 50 billion species that have ever lived on Earth have disappeared through extinction. This is a natural process typically, but it can also be cataclysmic and it's becoming clear we are amid a massive one. Find out more with Josh and Chuck in this classic episode.See omnystudio.com/listener for privacy information.

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And this week I've selected our 2014 episode on Extinction. In this episode, we go over all the big extinctions and what probably caused them, including the one we're most likely in right now, which is probably caused by humans. And if you pay attention, you can start to notice a little glimmers, a little beginnings of what would become my side podcast, The End of the World with Josh Clark. And although we don't talk about any movies, I'm betting there's some glimmers of Chuck's long-running side podcast movie crush in here, too. Hope you enjoy this episode. It's a good one. Welcome to Stuff You Should Know, a production of IHeart Radio. Hey and welcome to the podcast. I'm Josh Clark.

There's Charles W. Chuckers Bryant. Jerry is over there. I almost said your last name, Jerry. How weird. And then today we have a fourth character in the studio with this Chuck. This is a scent. Yeah. Scent.

It's coming together to make like a tangible human being. So you are wearing petuli. Uh, not wearing. Well, you have petulia on you as a result of one of Emily's sugar scrubs, right? Yeah. Mama? Yeah. And it's loveyour mama.com?

Yeah. Okay. And then Jerry is contributing to that with an enchilada. So all of them combined, I would say there's an extra person in this seat right here. What kind of person is that? Just another person. Okay. A viable living organism.

One, that when we live, leave the studio will probably become extinct. That's a good one. Did you like that? Yeah. I've had that plan since probably two weeks ago. Nice. How are you doing, man?

I'm good. I've been thinking of Buster Rhymes all day. Why? Did he have a song about extinction? He had an album called The Extinction Level Event. Oh, yeah? Yeah. And that was in one of the songs.

That sounds super 90s. Well, it's Buster Rhymes. It has to be 90s. But I mean, even those words, extinction level event, people were worried about stuff because of, like, the turn of the millennium. You remember? X-Files is a huge hit. Sure. Deep Impact and Armageddon came out on the same day, basically.

And both were hits. Like, people were just nervous. Yeah. And as a result, Buster Rhymes was very popular. That's right. Although he's not anymore. He's still good, though. He hadn't been doing much.

no but his body of work oh sure yeah leaders in the new school and his early work with tribe called Quest oh yeah he guessed it on one of my favorite songs yeah

what's the scenario was that the one I think so I mean he was definitely on that one yeah but they that was the one also where I think yeah

he makes fun of people with saggy pants because it was so new right apparently Buster Rums wasn't down with it yet yeah which is pretty ironic

because he got hardcore into that. That was raw, raw like a dungeon dragon, right? Right, right. That was pretty awesome. It's a good song. Yeah. So, Extinction is clearly what we're talking about today. And I guess we should probably give a shout out to some of the extra reading material we picked up on.

There's a woman named Elizabeth Colbert or Colbert, depending on if you watch the Colbert rapport. Yeah. And she is basically a leading expert as far as journalists go on extinction. She wrote a book called The Sixth Extinction. That's a good article. Yeah, and she wrote an article in the New Yorker. She's a New Yorker journalist that was basically the predecessor to the book. You know how they do?

They're like, oh, I need an extra 20 grand, so I'll just write a synopsis of the book I'm writing. Yeah. And it's a good article, and we worked from that. There's another one from the New York Review of Books called They're Taking Over about the explosion of jellyfish. Yeah. On How Stuff Works, there's one that I wrote years back called Will We Soon Be Extinct? Yeah. And there's another How Stuff Works one that we've done an episode on called Why Is Biodiversity Important?

Yeah, and I found one in an I-09 for animals that we thought were extinct, but miraculously popped back up. Nice. Which is always a good story. Oh, yeah, it's a heartwarming story of triumph over adversity and coming back when everybody thought you were down. Yeah, some of them like... It's basically rocky. Hundreds of millions of years later even.

Yeah. It's crazy. Like the silicant? I think that's one. Was that the big fish? Mm-hmm. Yeah. They just caught that thing one day.

Yeah. And said, hey, wait a minute. Yeah. This thing's extinct. It's supposed to be. Exactly. We'll talk about how and why things fall off, but things do fall off. And it seems that there is a, that the whole thing is a very natural

process, extinctionist. But for a very long time, I guess scientists believed that God created all of the animals on earth, and that his will was too perfect, his creation was too divine, to even allow for extinction so because they were aware of the fossil record they rationalized these huge bones of animals they didn't see anywhere as we just haven't found them yet well yeah and this was all the way up and you know into the 19th century and some really smart people like thomas jefferson thought for instance when he sent lewis and clark out west that they might come across the great mastodon right he's like it's found to be out there somewhere guys so be careful but there were some other smarter people um like george cuvier in 1812 he was pretty ahead of his time in fact in 1812

he was way ahead of his time because he published an essay called revolutions on the surface of the globe yeah and he kind of asserted that now things can go extinct and he called them a species produce lost species right and basically hypothesized that there have been cataclysmic events that have caused extinctions in so many words this is basically flew in the face of this that like not only was their extinction but there were there were huge events that caused it and so the the religious thinkers of the day said okay wait wait wait we can work with this because buddy what you're talking about is like noah's flood so you my friend just proved the bible correct using science yeah darwin wasn't on board though although he did believe in extinction he thought it was the only way it could

happen is the gradual extinction right that is also true and we'll talk about that as well and of course darwin is this huge hero of biology yeah so everybody's like well darwin's right about just about everything so literally until the 1990s darwin's view that extinction happens extremely slowly yeah slower than speciation events so ultimately you should always have more species new species coming up than you have going extinct yeah Until the 1990s, that's the way that it was, that's the way it seemed. Yeah. So, Chuck, like I said, all of this stayed around until 1991.

Yeah. And it was a result of, like, think about it. Think about how you think of mass extinctions now. You think of an asteroid hitting Earth, destroying everything. And it wasn't until 1991 that that view became widely accepted. And it was because of this dude named Alvarez. He was a geologist, I believe, Walter Alvarez. And in the 70s, he started studying this clay layer

that was basically in the fossil record right at the time the dinosaur suddenly died out. Right. And no one could quite explain what was going on here. They just knew that this must have happened gradually. So it must be a problem with the actual fossil record, not our way of thinking. Yeah, and there are plenty of problems with the fossil record,

which we'll get into as well. Right. But Walter Alvarez said, let me look at this in a little more detail. And he looked at the iridium and found that the iridium levels were off the charts, which shouldn't be because it's very, very rare. And we associate iridium on Earth as being brought here by, say, like an asteroid or whatever. Yeah, it's super abundant in asteroids. So all of a sudden this guy goes, oh, wait a minute, maybe we can explain this dying out of dinosaurs,

where the dinosaurs went 65 million years ago, by an asteroid. And that was in 1980 that they proposed this hypothesis, and they ran into a lot of resistance. And then finally, in 1991, a year after a crater was discovered under the Yucatan Peninsula in Mexico, they dated it and said, yeah, it just so happens that this crater was formed just at the moment the dinosaurs died out. So the Alvarez hypothesis is probably right, and extinction can happen on a mass sudden scale. scale, just as it can also happen on a very long-term scale, too. Yeah, that crater was 112 miles wide, so it fit the profile, and basically ended the Cretaceous period in the Mesozoic era, and for a while they called it the Cretaceous tertiary event, but now they call it the Cretaceous Paleogene event.

And did you notice that they... Right, they noticed that... Did you notice the Cretaceous, which is spelled with the C, is denoted with the C, is denoted with a K? Yeah, I did. Did you see why? It's just German. It's just a German translation for it. I figured it was something like that. Yeah. It was just bugging me. So now, we now believe, an asteroid brought us into the Cenozoic era that we enjoyed today.

Love the Cenozoic. It's pretty awesome. It's a good era. I mean, it's our era. Yeah. So you've got to love it. You got to love it. So, Chuck, like I said, the extinction can happen, and it does have. happen and it's a natural process um if you talk to people about extinction today though they say yeah we're kind of in a huge extinction event yeah and it makes sense i mean when you look at the

the our past they estimate maybe up to five billion species have lived on earth and more than 99% of those are gone and i love how the new yorker put it i think that there's an old joke that all of life on Earth today could be accounted for with a simple rounding error. Yeah. Like everything we know. So, yeah, we've lost 99% of things that have ever lived on this planet due to extinction. Right, which again is, like it has such a terrible connotation these days, extinction, extinction. But it happens naturally.

Apparently, what they've found from looking at the fossil record from studying life on Earth is that a species tends to have about a 10 million year lifespan. A speciation event occurs where it branches off from one species and produces an entirely new species, and that species, on average, will stick around for about 10 million years, and then something happens and it dies out, and other species take its place. This is the natural course of life from what we can tell. The thing is, it normally happens on a very slow time scale, like when it's what's called background extinction, right?

Yeah, the background rate is supposed to be between one and five species per year, but they think that now it could be like a hundred times that. I've seen up to a thousand times the normal rate, and I saw another study from 2014, so it's fresh. And it said that these researchers calculated the normal rates, and they found that there's between 0.03 and 0.13-15 extinct species per million species per year. that doesn't really mean much it means so much that it boggles the mind

you know like that's a really strange way of putting it but basically they're saying like for every million species on earth at any given point in time during a year as low as 0.023 species will die out

so in a year you shouldn't necessarily have that main species in current times though like you said between 100 and 1,000 times that rate is what we're seeing right now which is you could say alarming it is alarming uh the reason they don't have hard numbers on this stuff is because like we said uh it's a tough thing to study because the fossil record is well there's a lot of problems uh one is it's incomplete we don't really

know how many species there have been on earth since the beginning of earth it's just impossible to tell um fossils form under you know really specific condition so You may think something is gone because it has disappeared from the fossil record, but all that means is there wasn't a fossil. It doesn't necessarily mean it's gone. Right. So that's why things will pop back up. They'll think, hey, we haven't seen a fossil of this guy in 2,000 years.

But here it is all of a sudden. And even if it has gone extinct, just where it stopped showing up in the fossil record doesn't mean, like you said, that's when it went extinct right then. It could have been millions of years later. Well, because then you're supposing that the last thing of that's true. species happen to make a fossil, which is just silly. And also it makes you wonder how many species have lived and died on Earth that just never showed up in the fossil record. Yeah, just weren't fossils at all.

Right. Yeah. Well, if it never crawled into amber or, you know, was buried by ash or something, that's luck. Or got trapped in brontosaurus poop. I don't know if that's good luck or bad luck. It's just, it is what it is. It's nature. So because of all these gaps in the fossil record, these researchers that love this topic tend to do a lot of math and a lot of speculating with algorithms and mathematical formulas to figure this stuff out.

Sure. And that's the only way to do it, really. It's to speculate with numbers. It also helps them define things like the minimum viable population, which if you go below that, then it's bad news for the species. it's the minimum amount you can have to still be considered to have a bright future. Right. As a thing. Or to just survive as a species, right?

Yeah, that's what I mean. Yeah. Dim future if you're not surviving. Yeah, math is pretty grim. It can be, in this case, for sure. So we'll talk about exactly what makes an extinction and then what makes up mass extinctions. But first, let's do a little breakage, huh? I live below a cult leader, and I fear I've angered her.

Well, wait a minute, Sophia. You know she's a cult leader. Well, Dakota, luckily it's I'm not afraid of a scary story week on the OK Storytime podcast, so you'll find out soon. This person writes, My neighbor has been blasting music every day and doing dirt rituals, and now my ceiling is collapsing. I try to report them, but things keep getting weirder. I think they may be part of a cult. Hold up, Sophia. A real-life cult? And what is a dirt ritual? No clue. But according to this person,

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with Cal Penn on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Stuff you should know. Okay, so Chuck, you've been talking about animals species going extinct and then showing up again, like the sealicant. Yeah, or at least disappearing from the record. But we as humans assume they were extinct. Like, again, the celacanth is this fish that they caught off the coast of South Africa. When did we talk about it?

Was it in this day in history? I don't remember. We definitely have hit on that, though. I think it was. Because it's huge, right? Yeah, it's a big, ugly fish. And it looks like an old dinosaur, but they thought it had died out like 50, 60 million years ago. Actually, way longer.

They thought it disappeared 400 million years ago. Even more impressive. Yeah. So then they caught one off the coast of South Africa in the 30s. Then they caught another one a couple decades later in Madagascar or Mauritius or something. And that made the celicant a Lazarus species. Yes. No, it hadn't really gone anywhere.

We just thought it did. So, we humans, having the most important perspective on the entire planet, possibly in the entire universe, it was a Lazarus species to us. Yeah, Lazarus from the Bible. Right. Raised from the dead. Yeah. Like the celiacanth. Again, with the biblical connotations with extinction.

Yeah. There's a lot at stake here. That's true. Another way something might disappear and you might think it's gone is if it actually evolves into a new species. That's called pseudo-extinction. and that's a great success story as well it is but it also I don't understand why that's not just a speciation event

I mean why is that pseudo-extinction why is that any different from regular extinction yeah maybe just because it's didn't die out but actually just changed and evolved those are two different things yeah it seems like a gray area to me yeah but for the most part

when an animal just disappeared years and we should say like even today we're still finding things that we thought were extinct yeah yeah was so-called lazarus species which goes to make the point we have no idea how many living species there are on the planet today yeah or have been it's all just a good guess it is using math yeah grim grim math but for the most part we understand that when a species goes away suddenly it went extinct and as we've been saying again and again extinction is kind of this natural process or it is a very natural process um and it typically results from a change in the habitat yeah of a species and it's inability to adapt so it dies out yeah uh competition with other

species um hunting by humans or perhaps the environment has been tainted uh by humans. Humans or a new bacteria or a new virus. The thing is, though, is so these big factors, habitat loss, competition with new species, hunting, and contaminants in the environment. Those are the big four reasons that something goes extinct, right? Yeah. Humans can and are responsible for all four of those. Yeah, and this is the extinction that happens over time, obviously.

Not a big asteroid hit in the planet. No, but it can happen pretty quickly. and this is a Tracy Wilson joint and in the introduction she mentions the stellar sea cow which was an Arctic resident it was a big old manatee

basically yeah and they were first described by Arctic explorers in 1741 by 1768 they were extinct so it can't happen on a pretty rapid scale especially when you introduce

humans yeah and it you know It has a domino effect, too, because we talked about, and everyone knows about the dangers of losing bees, it's not just like, oh, well, there are no more bees. That's going to affect pollination and plants, and those plants are being fed on by other animals, and it tends to have a snowball effect. Like, for example, at the end of the last ice age, mammals, small mammals started to go extinct, and because of that, large animals started to go extinct because they like to eat the small animals. Exactly, which is the answer to the question. and why is biodiversity important? Well, because ecosystems thrive and survive on a wide number of species

that exist pretty much naturally in balance. Yeah. You know, a pretty good example of that stuff falling out of balance is the passenger pigeon. You familiar? Yeah, they're trying to de-extinct that thing. Yeah, you want to talk about de-extinction? Yeah, well, de-extinction is exactly what it sounds like.

It is sort of Jurassic Parky. It is, in 2003, some scientists revived the Burkardo, Bucardo, and that's a Spanish mountain goat, and they did it just sort of like Jurassic Park from DNA that was frozen in time. Unfortunately, although it did work initially, the DNA only survived a matter of minutes, but they did count as a de-extinction. I think there was a live birth that survived a few minutes. wasn't it yeah the animal itself only survived a few minutes though right it was like I should not be that's true and I mean they basically said it's happening now and we have the

capabilities and we may not be able to bring the woolly mammoth back but we might be able to bring back something kind of close right so and that raises in this article that you sent just this moral question like should we be doing this just because we can does that mean we should. And so, like, if you bring back an animal that has been extinct for so long that its habitat is now gone. Yeah, where are they going to live? Exactly.

Where are you going to put it? A zoo? That doesn't seem like a good reason to bring an animal back so we could put it in a zoo. Yeah, and just, like, maybe this is my opinion here, which we don't do a lot of, but it seems like concentrating on the problems we face now with the extinction rates is something that we should concentrate on, not bringing back the woolly mammoth. Right. And that also kind of dovetails with a point that if we have this ability and routinely exercise it,

we may be less inclined to protect the stuff we have now. If we're like, well, it's important enough, we'll just genetically re-engineer it and bring it back later. Yeah, I think in the CNN article, they liken it to just thinking we have an undo button on the world. Control Z. Yeah, no good. No. And it's funny because the author doesn't realize that Control Z works outside of Microsoft Word. too.

He specifically mentioned Control Z and Microsoft Word. Oh, Word specifically? Microsoft Word, he said it. Yeah, that's a little weird. He could be a shill, and he was just working it in.

Maybe. You know? Well, on Max, though, it's not control. Maybe he dismissed Microsoft and awkwardly put in Word. Maybe. Or maybe that's the only program he knows. Maybe.

You know? How do I work this? So you were saying that they're trying to bring back the passenger pigeon, right? Yeah. So the passenger pigeon is this really neat example of what happens when you have a lack of biodiversity. Yeah. There were when European settlers came to the New World, apparently like one out of every four birds in North America was a passenger pigeon. A quarter of the entire bird population was passenger pigeons.

It's a lot of pigeons. That has a ton of pigeons. There are so many that you could just shoot into like a flock and you would kill a couple hundred. Literally, there were that many. The thing is, if you read 1493 or 1491, I can't remember which one it is, but both are excellent books by Charles C. Mann. He talks about the passenger pigeon and how they've recently realized that there were so many passenger pigeons because a century before, one of their great predators, the Native American, had been wiped out by disease

that had been introduced to the continent about a century before that. So by the time the Europeans got here and really started to settle and encounter the passenger pigeon, they were like, God, look at all these pigeons and didn't realize that the pigeon population had exploded because their natural predator had died off. Right.

And so we, in turn, hunted them into existence. extinction. So because of one near extinction, another species was allowed to thrive and explode. And then that, when they were faced with their predator again, humans, they were eventually wiped out and went extinct. Yeah, the American buffalo, we almost hunted them out of existence. Yeah, or not for Ted Turner. Yeah, we tried our best to. They were just shooting those things for fun at one point. Man, that's disgusting. It is disgusting. You hear about the trains just going through the west. and just shooting out the windows at the Buffalo for no reason. Yeah, and doing nothing, just leaving them there to rot. Unbelievable. Remember, we did an episode on the Buffalo. That was a good one. So sad.

No, it was good. Well, it was sad, too, though. Oh, gotcha. So if you want to talk about extinction-level events, that's a whole different deal. You want to talk bust or rhymes. That's not a slow, gradual extinction. That is some big thing that happens that wipes out a lot of, living things all at once and um they estimate there's been more than 20 of these in the history

of the world but um five of them they call them the big five right for a reason for good reason and we'll just go through those kind of quickly now uh the ordo vician extinction it's about 490 million years ago and that wiped out about half of all animal families and the reason it wiped out about half was because at the time most of the stuff on earth still lived in the the sea, glaciers formed at this time, lowering sea levels, which meant that animals that lived in a certain depth of the sea, usually toward the surface, lost their habitat. Boiled? Yeah.

Maybe. Yeah. Or were brought down to the level where their predators like to hang out and were eaten en masse. But that accounted for that extinction, which is kind of rare because, as you'll see, when we're talking about the big five or mass extinctions in general, it's very difficult to pinpoint exactly what happened. So that's one of the rare ones that were, like, pretty sure this is why all of these, all this life went extinct all of a sudden. Yeah, and one reason is difficult is because it was almost 500 million years ago.

That's another reason. It's kind of tough here in 2014. Number two, if you like Letterman. Number two on the top five extinction. The late Devonian extinction, they're still debating about that. And about a quarter of the marine families. And by the way, we should mention when they research these things, they home in on. and family and genera in the big classification group.

Right. They don't say like, oh, look at these kingdoms that have disappeared or these phylum. They go down to the smaller levels. Right. And family and genus are just above species as far as the taxonomy is concerned. Exactly. So what I say, about half of the Marine genera, and that was 360 million years ago. Right.

No idea what caused that one. No idea. At least you and I have no. Yeah, I don't think they care about that one too much. The Permian Triassic extinction, this is a pretty big one. This is the biggest one ever. This is the one they call The Great Dying, right? I think so.

I've seen estimates of as much as 95 to 96% of all life died off during this extinction event. In this article, it says 85% of Marine genera and 70% of land species when extinct. And that was 250 million years ago. There's a lot of people who have different ideas about what did it, but they think it's possible as volcanic activity, creating acid rain. Yeah. That's a big one. That possibly happened more than once. Was that the one where, I don't know, I think that was the,

the KPG event was the one where they think they're not exactly how it happened, but they may have been just broiled. Isn't that awesome? Broiled on the face of the earth? Yeah. Which would have happened pretty quickly, too, actually. And I think that one is because they think it may have burst through the atmosphere, right? Yeah, so...

It just rained hot debris everywhere. That's the one that got rid of the dinosaurs, 65 million years ago. What is it called, the K-P-G? Yeah, the C-Pyceous paleogene event now. And that's the one where they are pretty sure that an asteroid hit Central America. Yeah. And sent all of this rock, like basically vaporized rock, away from Earth

with so much force that this stuff made it out of the atmosphere and then started to come back down and as it did it generated thermal heat enough to bring the broil down

on Earth yeah and that's the one of two sub explanations the other is that the old familiar ash basically kept photosynthesis from it like it blacked out the sun

yeah like a nuclear winter yeah yeah pretty nuts though but we We skipped number four, for no good reason. The end Triassic extinction killed about 20% of marine families, about half of Marine genera, and that was 200 million years ago. Yeah.

And again, like, with a mass extinction, there's no real definition for it, I found. I was looking to see, okay, who's the body that says, like, okay, a mass extinction event took place? It's, again, the fossil record is incomplete enough, and we're making guess. and mathematical guesses, but still guesses, to the extent that we don't have a real definition for what constitutes a mass extinction. But those five were so massive that there's virtually no debate whatsoever that those account for mass extinction events.

It's kind of like you know it when you see it kind of thing. But there's no agreement on how fast... Like pornography? Pretty much. Yeah. There's no agreement on how... fast it has to happen or how widespread it has to happen but typically it's like a large percentage of all of the animals alive yeah something like 20% say of all living animal species not just animals animal species just die off yeah um and it's worldwide that's another that seems to be another um factor in defining a mass extinction yeah like how wide spread yeah sure so um these events were pretty big yeah and one of the um i think think one of the researchers in the article you sent made a pretty good point that the current mass extinction that we're in now, which we're going to talk about in depth here in a minute, he said, these are way more dangerous because in the event of an asteroid, let's say, while it might really suck, it's one bad event. And right afterward, the world starts to try and recoup. It may take a million years, but it tries its best to start reforming life and get going again. Where in now, there's no stress relief. just a constant there's no recuperation because it's not over right or the recuperation will come but

we won't be around to see it because it the the breaking point will be us wiping ourselves out by wiping out the biodiversity who and there is a kind of this whole moralistic thing to the idea of extinction this there's this whole human guilt but if you just kind of take a step back and look at mass extinction um intellectually it's It doesn't wipe out life. It just changes everything. Right. So for one species, it might be a boom time.

For everybody else, it's a dying off time. But it's all in your perspective. Well, yeah, this beautiful Earth that we know and love now isn't anything like it was 100 million years ago. Exactly. And there's not necessarily a set level or a baseline that Earth is supposed to be at. Right, because nature doesn't care. Right. And nature's not like, oh, we got all these people here now, and things seem pretty modern, and they got smartphones, so maybe we should just protect this version.

Yeah. They're like, what, what was the cycle every what, 10 million years? For a species. For a species, okay. That's a lifespan of a species on average. So basically every, what, 10,000? 10 million. 10 million years, the Earth just doesn't care.

No, the point is, for a species, its lifespan is 10 million years, and the Earth is not caring every. day of that. Yeah. It doesn't care. It's just stumbling toward the next event, basically. Exactly.

That will one day probably happen. The thing is, is all of this is not to say that humans are off the hook. All evidence that's coming in now is

showing that we are doing a lot to speed up extinction events and create a mass extinction so much so that the big five is possibly the big six.

And we may be in the very beginning stages of the six one and we'll talk about that right after this. I live below a cult leader, and I fear I've angered her. Well, wait a minute, Sophia. How do you know she's a cult leader?

Well, Dakota, luckily it's I'm not afraid of a scary story week on the OK Storytime podcast, so you'll find out soon. This person writes, My neighbor's been blasting music every day and doing dirt rituals, and now my ceiling is collapsing. I try to report them, but things keep getting weirder. I think they may be part of a cult. Hold up, Sophia. A real-life cult? And what is a dirt ritual? No clue. But according to this person, contractors are tearing down the patio to find out what's going on with her ceiling and her neighbors are not happy. Well, she needs to report them ASAP. She did. And now they've been confronting her in really creepy

ways all the time. So do we find out if this person survives their neighborhood cults? or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple podcasts, or wherever you get your podcasts. Here we go. Hey, I'm Cal Penn. And on my new podcast, Here We go again. We'll take today's trends and headlines and ask, why does history keep repeating itself? You may know me as the second hottest actor from the Harold and Kumar movies, but I'm also an author, a White House staffer, and as of like 15 seconds ago, a podcast host. Along the way, I've made some friends who are experts in science, politics, and pop culture. And each week, one of them will be joining me to answer my burning questions.

Like, are we heading towards another financial crash like in 08? Is non-monogamy back in style? And how come there's never a gate ready for your flight when it lands like two minutes early? We've got guests like Pete Buttigieg, Stacey Abrams, Lili Singh, and Bill Nye. When you start weaponizing outer space, things can potentially, go really wrong. Look, the world can seem pretty scary right now, because it is. But my goal here is for you to listen and feel a little better about the future.

Listen and subscribe to here we go again with Cal Penn on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. The Crying Wolf Podcast is the story of two men bound by injustice, of a city haunted by its secrets, and the quest for redemption, no matter of it. the price. White victim, female, pretty, wealthy, black defendant. Chicago, a white woman's murder, a black man behind bars for a crime he didn't commit. I got 90 years for killing somebody I have never seen. He says the police are his friends and then that's it. They turn on it. A corrupt detective. How he was interrogated the techniques. That's crazy. A snitch and a life stolen.

They got the wrong guy. But on the inside, Lee Harris finds an ally in his sally, Robert, who swears to tell the truth about what happened to Lee and free his friend. And if you're with me, your goal to, I'll take care of you. I'm going to be with you. You stuck with me for life. Listen to the Crying Wolf podcast, starting on October 22nd, on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. So Chuckers, we've been talking about mass extinction events.

There's a big five, and a lot of people are saying, no, there's six, and the six one is human-caused. So much so that geologists are proposing that we call our current epoch the Anthropocene. Because humans are having such an impact on Earth that they imagine, 10,000 years from now, geologists will be able to look and point to this layer and say, here's where humans started. Yeah, let's get in the Wayback Machine Oh, yeah Let's crank this baby up Does it have enough kerosene? Oh, it's got enough kerosene, buddy

Because we're going back about 50,000 years Oh, you got enough? Okay, I'm going to bring a spare kit And we're going to go to Australia even Because it's just nice down there And what I see around me Are these huge wombat-like things That are as big as hippos

Huge And I see a tortoise over there That's the size of a VW beetle And this little, weird short-faced kangaroo and he's 10 feet tall 10 foot tall kangaroo look at the size of that thing and everything is crazy but um let's just unpack here and let's start propagating you and me okay i'm going to make a spear just for safety all right and it sounds like i needed to fend you off too and you know what it's weird things are starting to disappear around us as we grow and as we

expand and uh and seen that's nice can we get out of out of here because that 10-foot tall kangaroo's eyeing us. Well, not anymore, buddy. He's dead. Oh, wow. Wow. Because they believe, a lot of people think that around 50,000 years ago, when humans started expanding their footprint, there was a very inconvenient correlation with species dying out as we spread about the earth. Yeah. this sixth mass extinction

I apologize for not being able to say sixth correctly but there's a huge debate and it's still it's not settled both sides are like we're right another one is like we're right the thing is both sides agree like yeah

we're in the midst of a sixth mass extinction and isn't that what matters but is it human caused or is the result of climate change and just because it's the result of climate change doesn't mean that if you take the trail back far enough, it isn't necessarily human cause. But these are the two debates. So one is the theory of overkill, which is the one you were just describing. Yeah, and that was describing Australia 50,000 years ago.

If we want to get back in the Wayback Machine and go to North America 11,000 years ago, three quarters of our largest animals started to die out, like the mastodon and the woolly mammoth and the giant beaver, saber tooth tiger and not coincidentally probably that's right around the time where we first walked over the bearing land bridge and set up shop here in north america yeah the thing is is you can also say well that kind of gives or takes a few thousand years and yeah you can that's definitely stretchable but it's just not been proven so it there is a huge correlation between the spread of humans and the death of what are called megafauna huge land animals yeah and they say that that theory of overkill says that we came a

long with our smart little toolkits, which included like spearheads and arrows and axes and clubs and domesticated dogs after a certain point in time. Sure. And overhunted either these huge, like, hippo-sized marsupials. Yeah. Or we hunted things that were slightly smaller that the huge hipposized marsupials ate. Either way, we contributed directly to their mass extinction. Yeah.

Yeah, and they think generally that overhunting isn't, the very least, it's not the sole cause because you probably just can't hunt enough the amount of people that we had, especially in a place like Australia, which wasn't super heavily founded. You know, it wasn't like 10 million people moved to Australia overnight, you know? Right. So they say overhunting is probably not the sole cause, but maybe a factor. But other things humans did, like maybe in Australia they started burning shrubs. to clear land and maybe those shrubs were eaten by certain species and then that caused that domino effect again another um the other camp that basically says no it's climate change and it's fairly natural other people might say it's human cause climate change but for the most part if you are a

climate change extinction proponent you're probably just believe that this is a natural process that the earth is undergoing and humans didn't have enough of an impact early on to account for the loss of a lot of these species. Yeah. This one study pointed to a place called Sahul, which was Australia, New Guinea, and Tasmania all joined together in this megacotinent. That was a crazy place. It was several tens of thousands of years ago.

And they were saying that by the time humans arrived in Sahul or Australia, most of the megaphone was already gone. It was gone as a result of climate change. And there's no evidence that we had a toolkit capable of killing these animals. um you know at this time yeah true so the debate still rages on yeah and you know there's been several ice ages that didn't make things go extinct right so people point to that as maybe uh another counter argument yeah but the researchers you sent along did this uh pretty cool thing they did the first global analysis um of mapping large animals during this period 132 000 to a thousand years ago right and it was

the first time they were able to really get a fine point on this geographical variation in the species loss and they did find that a hundred and seventy-seven species of large mammals disappeared during that period where we were starting to spread out as a species right and which apparently is as it's put in this article a massive loss yeah and they said you know they they expect these kind of things to happen on an island like if you go to hawaii or uh you know any island, they say that survival is the exception when humans invade an island. Exactly. But to happen

on like a continent, it's pretty amazing to think about the human impact. Still an island? Well, yeah, I guess it's a good point. But the jury is still out, though, on exactly what's causing this. Most scientists agree that we are

in a mass extinction event, and it's happening pretty quickly. something like I think a third of all coral reefs are in danger of extinction a third of amphibians I believe yeah and a quarter of all mammals and an eighth of all birds are all classified as threatened with extinction and this is happening around the world so it's fitting the criteria for a mass extinction yeah they're basically chalking up to the pace of human expansion and you know if you

consider that farming and logging and building roads and buildings and most of the world's waterways have been diverted or damned at this point or manipulated somehow. Only 2% of rivers in the United States run unimpeded. 2%. Everything else has been altered in some way. Chemical plants affecting CO2 in the atmosphere, it's having an effect. And the CO2 actually in the atmosphere is having another effect called ocean acidification,

which has been described as global warming. as more and more CO2 gets released in the atmosphere, the oceans scramble to keep up by absorbing more and more. Yeah. And it stores some of that by turning some of it into acid, which lowers the pH of the ocean, which is making the ocean unfit for a lot of life. But to kind of demonstrate how mass extinction is bad for one species,

but great for another, jellyfish populations are booming. Oh, really? So probably... Because they like the lower pH? Yeah. They like it more acidic, and they are like seriously starting to cause some real problems,

and we're just seeing the beginning of this. So it's entirely possible that the next thousand years we'll see the rise of the jellyfish as the rest of life on Earth starts to die off. Well, here's a staggering stat. The drop in ocean pH levels that have occurred in the past 50 years they think might exceed what has happened

in the past previous 50 years. million years. Wow. So in the past 50 years, they've changed the, basically changed the chemical makeup of the ocean more than the past 50 million. And speaking of 50 years, apparently in the next 50 years, an estimated half, half of all species on Earth could be extinct. It sucks, man.

I want to see a sloth as big as an elephant. Hey, get into de-extinction. Well, here, um... You just saw when we were in... We were in Sahul. Well, yeah, it was nice. But I wanted to come in the way back machine and bring it to Atlanta. No, I don't think that's a good idea, man.

That thing looked like it would go berserk. And finally, unless you have anything else. I don't think so. I'm looking at everything. We have a few highlights of extinct animals that have been rediscovered, which is not the same thing as being re-engineered. What was this, an I-09 article? Yeah, this is I-09, and some of those are pretty good. the Bermuda Petrel and disappeared they thought in the 1600s but rediscovered in

1951 there's about 180 of those alive today let me see here what else is good well we also we already talked about the Celicamp the Cuban Solondon solynodon excuse me discovered in 1861 has only been caught 37 times in the history of the world in 1970 they thought it was extinct it's like a weird rat like species but then they found one in the 70s and then another one in 2003 huh so like welcome back cuban solenadon so it was like caught during the 70s and then during the period of the 70s revival in the early 2000s that's right nice uh Gilbert's poturu man these have weird names that's why they went extinct because you couldn't say sloth you know that we should save the uh the what

In 1841, this is a rabbit-sized marsupial in Australia, and it last appeared in 1879, and they thought, well, this thing's gone. Up until 1994, came back out and poked his head around and got caught in a few traps, but currently less than 100 of those in the world. So those are just a few of the 10, and there's more than 10, obviously. But it's always a good story. Sure it is. Heartwarming. We think this thing's dead. It's like, yeah, welcome back to the mass extinction.

Yeah, exactly. It's still going on. If you want to know more about extinction, you should read each and every one of the articles we cited. And you can also read this article on How StuffWorks.com by typing extinction into the handy search bar. And since I said that, it's time for listener mail. I'm going to call this police interrogation follow-up. Okay. From Matt Pope.

A. in Victoria, British Columbia. All right. Thank you to Vancouver, by the way, for two great shows. After our great shows in Toronto. Yeah. Thanks to Toronto and Vancouver. Very supportive people. And boy, that second crowd in Vancouver was drunk and rowdy.

Yeah, right. Hey, guys, just listened to police interrogation. I thought I'd share a couple of quick personal stories that illustrate the pitfalls of relying on nonverbal cues to see if someone's guilty. I've never been in trouble with the law myself, but several years ago I witnessed a crime. Called 911 to report it.

Cops nab the perpetrator, and a few days later asked me to come down to provide a witness statement. When I arrived, an officer led me into a tiny room that was every bit as bleak as the ones you see on TV. It was a weird experience. Even though I wasn't accused of a crime and the cop was polite and is questioning the interrogation room setting and the power differential between the uniform cop with a gun and my unarmed self made me feel really nervous. I started sweating.

My voice shook. And if you had been watching my body language through the one-way mirror, you would have thought I was guilty. Wow. And he was just a witness. Yeah. The second story is very similar. every year our local courthouse has a public event where they give tours and put on a mock trial

and actually hang someone. Kidding. I made up that part. That was pretty good, too. It's supposed to be educational and fun. My father is a lawyer, and one year asked me I'd like to play the defendant in the trial. I'm no actor, but I said, sure, my character was accused of a minor drug offense,

and I went through the whole ordeal being on trial and testifying my own defense. I'll spare you the details, but afterward my mom said, wow, you looked really guilty up there. I hope you never actually are on trial for anything because they'll lock you up and throw away the key. I learned from these situations the very act of treating someone like a criminal can make him appear guilty. Yeah. It reminds me of the Stanford Prison Study that we've talked about.

And there's a Psychology is Nuts about that. Psychology is Nuts video on our YouTube channel about the Stanford Prison Experiment. Yeah, that's a good one. You should check that out. I hope you guys never have to find out the hard way. You'll react to police interrogation if you do. I hope you find a good lawyer. That is from Matt Pope, once again, in Victoria, BC. Well, thanks a lot, Matt.

That's kooky about your town doing mock trials and stuff like that. Yeah, and like hanging a guy? Yeah. Crazy. He said it's fun. The only thing that's okay about it is they make the guy look like Hitler. Right. So it's like hanging Hitler every year, which everybody can get behind.

Yeah, they call it the Hitler hang. If you want to send us an email that Chuck feels the need to make up stuff about, You can send us an email to StuffPodcast at iHeartRadio.com. Stuff you should know is a production of IHeartRadio. For more podcasts to My Heart Radio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. I live below a cult leader, and I fear I've angered her. Wait a minute, Sophia.

How do you know she's a cult leader? Well, Dakota, luckily it's I'm not afraid of a scary story week on the OK Storytime podcast, so we'll find out soon. This person writes, my neighbor has been blasting music every day and doing dirt rituals, and now my ceiling is collapsing. I try to report them, but things keep getting weirder. I think they might be part of a cult. Hold up, a real-life cult? And what is a dirt ritual? No clue, Dakota.

To find out how it ends, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Chicago, a white woman's murder, a black man behind bars, for a crime he didn't commit. 90 years of killing somebody I have never seen. The Crying Wolf podcast is the story of a corrupt detective, two men bound by injustice, and the quest for redemption, no matter the price. Listen to the Crying Wolf podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hey, I'm Cal Penn, and on my new podcast, here we go again, we'll take today's trends and headlines and ask, why does history keep repeating itself? Each week, I'm calling up my friends, like Bill Nye, Lilly Singh, and Pete Buttigieg

to talk about everything from the space race to movie remakes to psychedelics. Put another way, are you high? Look, the world can seem pretty scary right now. But my goal here is for you to listen and feel a little better about the future. Listen and subscribe to here we go again with Cal Penn on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. This is an IHeart podcast.