Paul Rosolie: Jungle, Apex Predators, Aliens, Uncontacted Tribes, and God | Lex Fridman Podcast #429

Lex Fridman 0:00 Where are we right now, Paul?

Paul Rosolie 0:02 Lex, we are in the middle of nowhere.

Lex Fridman 0:05 (laughs) It's the Amazon jungle. There's vegetation, there's insects, there's all kinds of creatures. A million heartbeats, a million eyes. So, uh, really, where are we right now?

Paul Rosolie 0:16 We are in Peru, in a very remote part of the Western Amazon Basin, and because of the proximity of the Andean cloud forest, to the lowland tropical rainforests, we are in the most biodiverse part of planet Earth. There's more life per square acre, per square mile out here than there is anywhere else on Earth. Not just now, but in the entire fossil record.

Lex Fridman 0:40 The following is a conversation with Paul Rosolie. His second time on the podcast, but this time, we did the conversation deep in the Amazon jungle. I traveled there to hang out with Paul, and it turned out to be an adventure of a lifetime. I will post a video capturing some aspects of that adventure in a week or so. It included everything from getting lost in dense unexplored wilderness with no contact to the outside world to taking very high doses of ayahuasca, and much more. Paul, by the way, aside from being my good friend, is a naturalist, explorer, author, and is someone who has dedicated his life to protecting the rainforest. For this mission, he founded Jungle Keepers. You can help him if you go to junglekeepers.org. This trip, for me, was life-changing. It expanded my understanding of myself and of the beautiful world I'm fortunate to exist in, with all of you. So, I'm glad I went, and I'm glad I made it out alive. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description. And now, dear friends, here's Paul Rosolie.

Lex Fridman 2:07 I can't believe we're actually here.

Paul Rosolie 2:09 I can't believe you actually came.

Lex Fridman 2:10 And I can't believe you forced me to wear a suit.

Paul Rosolie 2:12 (laughs) That was the people's choice. Trust me.

Lex Fridman 2:15 All right. We've been through quite a lot over the last few days.

Paul Rosolie 2:20 We've been through a bit.

Lex Fridman 2:21 Let me ask you a ridiculous question. What are all the creatures right now, if they wanted to, could, uh, cause us harm?

Paul Rosolie 2:30 The thing is, the Amazon rainforest has been described as the greatest natural battlefield on Earth because there's more life here than anywhere else, which means that everything here is fighting for survival. The trees are fighting for sunlight. The animals are fighting for prey. Everybody's fighting for survival, and so everything that you see here, everything around us will be killed, eaten, digested, recycled at some point. The jungle is really just a giant churning machine of death, and life is kind of this moment of stasis, where you- you maintain this collection of cells in a particular DNA sequence and then- and then it gets digested again and recycled back, and renamed into everything. And, uh, so- so the things- the things in this forest, while they don't want to hurt us, there are things that are heavily defended because, for instance, a giant anteater needs claws to fight off a jaguar. A stingray needs a stinger on its tail, which is basically a serrated knife with venom on it, to deter anything that would hunt that stingray. Even the catfish have pectoral fins that have razor-long, steak knife-sized defense systems. Then you have, of course, the jaguars, the harpy eagles, the piranha, the candiru fish that can swim up a penis, lodge themselves inside. It's the Amazon rainforest. The thing is, as you've learned this week, nothing here wants to get us with the except for- exception of maybe mosquitoes. Every other animal just- just wants to eat and exist in peace. That's it.

Lex Fridman 3:57 But there is, each of those animals like you describe, have a kind of radius of defense.

Paul Rosolie 4:03 Yeah.

Lex Fridman 4:03 So if you accidentally step into its home-

Paul Rosolie 4:08 Yeah.

Lex Fridman 4:08 ... into that radius, it can cause harm.

Paul Rosolie 4:10 Or- or make him feel threatened.

Lex Fridman 4:12 Make him feel threatened. There is a defense mechanism that is activated.

Paul Rosolie 4:15 Some incredible defense mechanisms. I mean, you're talking about 17-foot black caiman, crocodiles that with significant size that could rip you in half. Anacondas, the largest

Paul Rosolie 4:25 snake on Earth. Bushmasters that can grow up to be 9 to, I think, even 11 feet long, and I've caught bushmasters that are thicker than my arms.

Lex Fridman 4:33 So for people who don't know, bushmasters, snakes, what are these things?

Paul Rosolie 4:36 These are vipers. It's the lar- I believe it's the largest viper on Earth.

Lex Fridman 4:40 Venomous?

Paul Rosolie 4:40 Extremely venomous with hinge teeth, tissue destroying venom. Like, if you get bitten by a bushmaster, they say you don't- you don't rush and try and save your own life. You try to savor what's around you. Look at- look at- look around at the world. Smoke your last cigarette, call your mom. That's it.

Lex Fridman 4:57 So that moment of stasis that is life is going to end abruptly when you interact with one of those?

Paul Rosolie 5:02 Yeah. I even have- even this- this seemingly-

Lex Fridman 5:07 Can I just pause at how incredibly beautiful it is? That you could just reach to your right and grab a piece of the jungle?

Paul Rosolie 5:13 (laughs) It's like- it's like a... Even this seemingly beautiful little fern. If you- if you go this way on the fern, you're fine. As soon as- ow... As soon as you go this way, there's invisible-

Lex Fridman 5:21 Yeah.

Paul Rosolie 5:21 ... little spikes on there, if you wanna...

Lex Fridman 5:25 Oh, I see.

Paul Rosolie 5:25 Yeah.

Lex Fridman 5:25 I feel it.

Paul Rosolie 5:25 See that? So, like, everything is defended. If you're driving on the road and you have your arm out the side or if you're on a motorcycle going through the jungle-

Lex Fridman 5:31 Yeah.

Paul Rosolie 5:32 ... and you get one of these, it'll just tear all the skin right off your body. It's kind of doing that to me now.

Lex Fridman 5:37 So what- what would you do? Like, we were going through the dense jungle yesterday, and you slide down the hill. Your foot slips, you're sliding down-

Paul Rosolie 5:46 Yeah.

Lex Fridman 5:46 ... and then you find yourself staring a couple feet away from a bushmaster snake. What are you doing? You're, for people who somehow don't know, are somebody who loves, admires snakes, who has met thousands of snakes, has worked with them, respects them, celebrates them. What would you do with a bushmaster snake?... face-to-face.

Paul Rosolie 6:08 Face-to-face, this has happened.

Lex Fridman 6:09 (laughs)

Paul Rosolie 6:09 Um (laughs) , I've been there.

Lex Fridman 6:11 It's nice.

Paul Rosolie 6:12 Um, I've come face-to-face with a bushmaster and... There's two things, there's two reactions that you might get. One is, if the bushmaster decides that it's vacation time, if it's sleeping, if he just had a meal, they'll come to the edges of trails or beneath a tree and they'll just circle up, little spiral, big spiral, big pile of snake on the trail, and they'll just sit there. And one time, there was a snake sitting on the side of a trail beneath a tree. For two weeks, this snake was just sitting there, resting, digesting his food out in the open, in the rain, in the sun, in the night. Didn't matter. You go near it, barely even crack a tongue. Now, the other option is that you get a bushmaster that's alert and hunting and out looking for something to eat, and they're ready to defend themselves. And so I once came across a bushmaster in the jungle at night, and this bushmaster turned its head towards me, looked at me, and made it very clear, "I'm gonna go this way." And so I did the natural thing that any snake enthusiast would do and I grabbed its tail. Now, 11 feet later, by the head, the snake turned around and just said, "If you wanna meet God, I can arrange the meeting. I will oblige." And I decided to let the bushmaster go.

Lex Fridman 7:18 Mm-hmm.

Paul Rosolie 7:18 And so, it's, it's like that with most animals. You know, a jaguar will turn and look at you and just remind you of how small you are.

Lex Fridman 7:24 Like, what did you see-

Paul Rosolie 7:25 And keep going.

Lex Fridman 7:25 ... in the snake's eyes? What, how did you sense that this is not the right, this is not, this is gonna be your end if you proceed?

Paul Rosolie 7:32 His readiness. I, I, I wanted to get him by the tail and show him to the people that were there and maybe work with the snake a little bit. As an 11-foot snake, he, the snake turned around and made it very clear, like, "Not today, pal. It's not gonna happen."

Lex Fridman 7:44 Is it in the eyes and the movement and the tension of the body? What-

Paul Rosolie 7:47 It was the movement, it was the m- movement and the S of the neck. It was, it was, it was-

Lex Fridman 7:50 There was just-

Paul Rosolie 7:50 ... as if you pushed me and I went, "Let's go. Make my day."

Lex Fridman 7:52 Yeah.

Paul Rosolie 7:53 Like, he just looked a little bit too-

Lex Fridman 7:55 Yeah (laughs) .

Paul Rosolie 7:55 ... too ready. He was like, "I love this."

Lex Fridman 7:57 (laughs) Okay. All right. So you know that-

Paul Rosolie 7:59 You just know, you just know, whereas, like, the snake you met last night...

Lex Fridman 8:03 Yeah, beautiful snake.

Paul Rosolie 8:04 Such a calm little thing, he just focuses on eating baby lizards and little snails and things. And that snake has no concept of defending itself. It has no way to defend itself. So even a, even something the size of a blue jay could just come and just p- p- pa- pa- peck that thing in the head and swallow it, and it's a helpless little snake.

Lex Fridman 8:19 Mm-hmm.

Paul Rosolie 8:19 So it's, it's really, it kinda depends on the animal. It depends on the mood you catch him in. Each one has a different temperament.

Lex Fridman 8:25 The grace of its movement was mesmerizing. Curious, almost. Maybe I'm anthropomorphizing, projecting onto it, but it was-

Paul Rosolie 8:32 The tongue flicking was a sign of curiosity. He was trying to figure out what was going on. He was like, "Why am I on this treadmill of human skin?" You know? They're just, just trying to get to the next thing, trying to get hidden, trying to get away from the light.

Lex Fridman 8:42 Also, the texture of the scales is really fascinating. I mean, it was my first-

Paul Rosolie 8:45 That's right.

Lex Fridman 8:45 ... the first snake I've ever touched. It's so interesting. It was just such a incredible system of muscles that are all interacting together to make that kind of movement work, and all the texture of its skin, of its scales. What, what do you love about snakes? From my first experience with a snake to all the thousands of experiences you had with snakes, what do you love about these creatures?

Paul Rosolie 9:07 I think it's... W- when you just spoke about it, it was, that's the first snake you've met, and it was a tiny little snake in the jungle, and you spoke about it with so much light in your eyes. And I think that because we've been programmed to be scared of snakes, there's something, there's something wondrous that happens in our brain, maybe, maybe it's just this, this, this joy of discovery that there's nothing to be scared of. And whether it's a rattlesnake that is dangerous and that you need to give distance to, but you look at it from a distance and you go, "Whoa," or it's a harmless little grass snake that you can pick up and enjoy and give to a child, it's, they're just these strange legless animals that just exist. You know, they don't even have eyelids. They're so different than us. They have a tongue that sense- s- senses the air. And they, to me, are so beautiful. And I've, I've, my whole life, been defending snakes from humans, and it's, it's, they seem misunderstood. I think they're incredibly beautiful. There's every color and variety of snakes. There's venomous snakes, there's tree snakes, there's huge crushing anacondas. It's just, of the 2,600 species of snakes that, that exist on Earth, there's just such beauty, such complexity, and such simplicity. They're just, they're just... To me, to me, I'm, I feel like, I feel like I'm, I am friend with snake, and, and they rely on me to protect them from my people.

Lex Fridman 10:26 (laughs) Friend with snake.

Paul Rosolie 10:28 Me friend snake.

Lex Fridman 10:29 Me friend snake. You said some of them are sometimes aggressive. Some of them are peaceful. Is this a mood thing, a personality thing, a species thing? Is it... What is it?

Paul Rosolie 10:39 So, the, as far as I know, there's only really two snakes on Earth that could be aggressive, 'cause aggression indicates, uh, uh, offense.

Lex Fridman 10:47 Mm-hmm.

Paul Rosolie 10:47 And so, uh, a reticulated python has been documented as eating humans. Anacondas, although while it hasn't been publicized, they have eaten humans. Um, every single other snake, from boa constrictor to bushmasters to spitting cobra to grass snake to garter snake to everything else, every single other snake does not want to interact with you.

Lex Fridman 11:07 Mm-hmm.

Paul Rosolie 11:08 They have no interest. So, there's no such thing as an aggressive snake once you get outside of a- anaconda and reticulated python. Aggression could be trying to eat you. That's predation. But for every other snake, a rattlesnake, if it was there, would either go escape and hide itself or it would rattle its tail and tell us, "Don't come closer."

Lex Fridman 11:24 Mm-hmm.

Paul Rosolie 11:25 A cobra will hood up and begin to hiss and say, "Don't approach me. I'm asking you nicely-

Lex Fridman 11:30 Mm-hmm.

Paul Rosolie 11:30 ... not to mess with me." And most other snakes are fast or they stay in the trees or they're extremely camouflaged, but their whole MO is just, "Don't bother me."

Lex Fridman 11:38 Mm-hmm.

Paul Rosolie 11:38 "I don't wanna be seen. I don't wanna be messed with. In fact, all I wanna be, do is be left alone. And once in a while, I just wanna eat." And by the way, when you see a snake drink, your heart will break. It's like seeing... It's the only thing that's cuter than a puppy.

Lex Fridman 11:52 Mm-hmm.

Paul Rosolie 11:52 Like, watching a snake touch its mouth to water and just, you just see that, that little mouth going as they suck water in, and it's like-

Lex Fridman 11:59 Mm-hmm.

Paul Rosolie 11:59 It's just so adorable watching this scaled animal just be like, "I need water."

Lex Fridman 12:03 In a state of vuln- vulnerability.

Paul Rosolie 12:05 Yeah.

Lex Fridman 12:06 But bro, there's nothing cuter than a little puppy with a tongue like... (slurping sounds)

Paul Rosolie 12:10 A baby ball python.

Lex Fridman 12:11 All right. (laughs)

Paul Rosolie 12:11 A baby king cobra, man.

Lex Fridman 12:12 Does it take your word for it?

Paul Rosolie 12:13 Baby elephant.

Lex Fridman 12:14 All right. So what are they? They're like at a puddle and they just take it in?

Paul Rosolie 12:17 They can be at a puddle and they just take it in, or one time in India, I was with a snake rescuer and we found this nine-foot king cobra. This, this god of a snake. They're Ophiophagus hannah, is their Latin name, and they're, they're snake eaters. They're the king of the snakes. The largest venomous snake. And the people that cal- called the snake rescuer, 'cause that's a profession in India, um, you know, it had gotten into their kitchen or their backyard. And so we showed up and we got the snake. And the snake rescuer, he knew, he looked at the snake and he went, to me, he said, you know, "Why do you think this snake would go in a house?" And he was quizzing me, and I actually went, "You know, I don't know. Is it warm? Is it cold?" You know, like sometimes cats like to go on to, into the warm, warm cars in the winter. And he was like, "He's thirsty." He goes, "Watch this." He took a water bottle, poured it over the... Now the snake is standing up. The snake stands up three feet tall. This is a huge king cobra with a hood, terrifying snake to be around. He leans over to the snake and the snake is standing there trusting him. And he takes a water bottle and pours it onto the snake's nose, and the snake turns up its nose and just starts drinking from the water bottle. Human giving water to snake, big scary snake, but this human understood snake gets water, snake gets released in jungle, everybody's okay.

Lex Fridman 13:30 So sometimes the needs are simple. They just don't have the words to communicate them to us humans.

Paul Rosolie 13:36 Yeah.

Lex Fridman 13:37 And is it disinterest or is it fear? Almost like they don't notice us or is it where source, the unknown aspect of it, the uncertainty is a, is a source of danger?

Paul Rosolie 13:48 Well, animals live in a constant state of danger. Like if you look at that deer that we saw last night-

Lex Fridman 13:53 Yeah.

Paul Rosolie 13:53 ... it's stalking through the jungle wondering what's gonna eat it, wondering if this is the last moment it's gonna be alive. It's like the animals-

Lex Fridman 13:59 Mm-hmm.

Paul Rosolie 13:59 ... are constantly terrified of that this is their last moment.

Lex Fridman 14:02 Yeah, just for the listener, we were walking through the jungle late at night. So it's darkness except our headlamps on, and then all of a sudden, Paul stops. He says, "Shh." And he looks in the distance and he sees two eyes. He's... I think you thought, "Is that a jaguar or is that a deer?" And it was moving its head like this.

Paul Rosolie 14:22 Mm-hmm.

Lex Fridman 14:23 Like, uh, scared or maybe trying to figure, trying to localize itself, trying to figure out... (laughs)

Paul Rosolie 14:28 Trying to see around the...

Lex Fridman 14:29 You're doing the same to it. (laughs)

Paul Rosolie 14:30 Yeah.

Lex Fridman 14:30 The, the two of you like moving your head.

Paul Rosolie 14:32 Yeah.

Lex Fridman 14:33 And like deep into the jungle, like, I don't know, uh, it's pretty far away. Through the trees, you could still see it. It's fascinating.

Paul Rosolie 14:40 30 feet or so, yeah.

Lex Fridman 14:41 That's the thing to actually mention. I mean, the, with a headlamp, you see the reflection in their eyes. It's kind of incredible-

Paul Rosolie 14:47 Yes.

Lex Fridman 14:48 ... just to see a creature, to try to identify a creature by just the, the reflection from its eyes.

Paul Rosolie 14:52 Yeah. And so the cats, sometimes you'll get like a greenish or a bluish glow from the cats. The deer are usually white to orange. Caiman, orange. Nightjars, orange. Snakes can usually be like orange. Moths, um, spiders sparkle. And so you have all these different, as you walk through the jungle, you can see all these different eyes. And when something large looks at you, like that deer did-

Lex Fridman 15:14 Mm-hmm.

Paul Rosolie 15:15 ... your first thing is, "What animal is this that I am staring back at?" 'Cause through the light, you kinda get, you see the reflection off the, the bright light off the leaves, and I couldn't tell at first 'cause actually the, those big bright eyes-

Lex Fridman 15:28 Mm-hmm.

Paul Rosolie 15:28 ... it could've been an ocelot, it could've been a jaguar, it could've been a deer. And then when it did this movement, that's what the cats do. They try to see around-

Lex Fridman 15:35 Mm-hmm.

Paul Rosolie 15:35 ... your light. I thought maybe Lex Friedman's here, we're gonna get lucky. It's gonna be a jag right off trail.

Lex Fridman 15:40 (laughs) Your definition of lucky is a complicated one today.

Paul Rosolie 15:43 Yeah. (laughs)

Lex Fridman 15:44 It's a fascinating process when you see those two eyes trying to figure out what it is.

Paul Rosolie 15:48 Mm-hmm.

Lex Fridman 15:48 And it is trying to figure out what you are, that

Lex Fridman 15:51 process. Uh, let's talk about caiman.

Paul Rosolie 15:53 For sure.

Lex Fridman 15:53 We've seen a lot of different kinds of sizes. We've seen a baby one, a bigger one. Tell me about these, uh, 16-foot plus apex predators of the Amazon rainforest.

Paul Rosolie 16:03 The big bad black caiman, which is the largest reptilian predator in the Amazon except for the anaconda. They kind of both share that, that, that notch of apex predator. They were actually hunted to endangered species level in the '70s 'cause they're, they're leather, black scale leather. But they're coming back. They're coming back and they're huge and they're beautiful. And I was, I was walking near a lake and I never understood how big they could get except for I was walking near a lake last year, and I was following this stream. You know what it's like when you're following a little stream and there's just a little trickle of water? And all of a sudden, this river otter had been running the other direction on the tre- on the stream. River otter comes up to me, and I swear to God this animal looked at me and went, "Hey." And I went, "Hey." He like didn't expect to see me there.

Lex Fridman 16:48 (laughs)

Paul Rosolie 16:48 And he turned around. He like did a little spin.

Lex Fridman 16:50 Mm-hmm.

Paul Rosolie 16:50 Started running down the stream. Then he turned around and he, you could tell he was like, "Let's go." And I s... You know.

Lex Fridman 16:55 Mm-hmm.

Paul Rosolie 16:55 I'm not anthropomorphizing here. The animal was asking me to come with him.

Lex Fridman 16:58 Mm-hmm.

Paul Rosolie 16:59 So I followed the river otter down the stream. We started running down the stream and the river otter looks at me one more time and is like, "Yo." Jumps into the lake, and I'm like, "What does he want me to see?" Now in the lake, there's river otters doing dives and freaking out and going up and down and up and down and, and they're very excited. They're screaming, they're screeching. All of a sudden, and I've never seen anything like this except for in like Game of Thrones.

Lex Fridman 17:20 (laughs)

Paul Rosolie 17:21 This crock head comes flying out of the water.

Lex Fridman 17:24 Oh.

Paul Rosolie 17:24 All of the river otters were attacking this huge black caiman, 16 feet.

Lex Fridman 17:29 Wow.

Paul Rosolie 17:29 Head half the size of this table. And she was thrashing her tail around, creating these huge waves in the water.

Lex Fridman 17:35 Mm-hmm.

Paul Rosolie 17:35 Trying to catch an otter and they're so fast-

Lex Fridman 17:38 Yeah.

Paul Rosolie 17:38 ... that they were zipping around her, biting her, and then going around. And this otter, swear to God, interspecies, looked at me and went, "Watch this."

Lex Fridman 17:45 (laughs)

Paul Rosolie 17:45 "We're, we're fucking with this caiman."

Lex Fridman 17:47 Yeah.

Paul Rosolie 17:47 It was amazing. And I, for the first time, I got to stand there watching this incredible interspecies fight happening. They weren't trying to kill the caiman. They were just trying to mess with it.

Lex Fridman 17:56 Mm-hmm.

Paul Rosolie 17:56 And the caiman was doing his best to try and kill these otters. And they were just having a good time in that sick sort of hyper-intelligent animal, like wolf sort of way where they were just going, "You can't catch us."

Lex Fridman 18:07 Yeah, like intelligence and agility versus like raw power.

Paul Rosolie 18:10 Uh-huh.

Lex Fridman 18:11 And dominance. I mean, I got to handle-... some smaller caiman and just the power they had, you know, you scale that up to imagine what a 16-foot, even a 10-foot, any, any (laughs) kind of black caiman-

Paul Rosolie 18:25 Yeah.

Lex Fridman 18:25 ... the kind of power they deliver. Maybe can you talk to that? Like, the power they can generate with their tail, with their neck, with their jaw.

Paul Rosolie 18:33 Yeah. Alligators and caiman, and crocodiles have some of the strongest bite forces on earth. I think a saltwater crocodile wins as the strongest bite force on earth. And you got to hold about a f- what was it? A four-foot spectacle caiman?

Lex Fridman 18:48 Mm-hmm.

Paul Rosolie 18:49 And you got to feel, I mean, you're a black belt in jiu-jitsu. How do you, how do you compare the, the f- explosive force you felt from that animal compared to what a human can generate?

Lex Fridman 18:59 (laughs) It's, uh, it's difficult to describe in words. There's a lot of power. And we're talking about the power of the neck, like the... What is it? I mean, there's a lot... It can generate power all up and down the body. So, probably the tail is a monster.

Paul Rosolie 19:12 Mm-hmm.

Lex Fridman 19:13 But it just, just the neck and, you know, not, not to mention the, the power of the bite, that.

Paul Rosolie 19:19 (laughs)

Lex Fridman 19:20 And the speed, too.

Paul Rosolie 19:21 Mm-hmm.

Lex Fridman 19:21 Because, uh, the thing I saw and, and got to experience is, how still and calm, at least from my-

Paul Rosolie 19:27 Yeah.

Lex Fridman 19:27 ... amateur perspective, it seems calm, uh, still. And then from that sort of zero to 60, it can just-

Paul Rosolie 19:35 Oh.

Lex Fridman 19:35 ... just go wild.

Paul Rosolie 19:36 Just thrashing.

Lex Fridman 19:39 And then there's also a decision it makes in that split second whether, uh, as it thrashes, is it going to kinda bite you on the way or not?

Paul Rosolie 19:48 Hmm. And that's where, that's where of the four species of caiman that we have here, you see differences in their personalities as a species.

Lex Fridman 19:56 (laughs) Yeah.

Paul Rosolie 19:56 And so you can like, just like, you know, like generally golden retrievers are viewed as a, as a friendly dog. Generally, not every single one of them, but as a rule. Spectacle caiman puppies. You released one in the river and it did nothing.

Lex Fridman 20:11 Mm-hmm.

Paul Rosolie 20:11 Didn't bite one of your fingers. It just swam away.

Lex Fridman 20:13 Mm-hmm.

Paul Rosolie 20:15 We dropped one in the river. And what did it do? It chose peace. Now, I had a smooth-fronted caiman a few weeks ago, and this was probably about a three and a half footer. Not big enough to kill you, but very much big enough to grab one of your fingers and just shake it off your body, just death roll it right off. And as I was being careful... Totally different caiman than the one that you got to see. This one has spikes coming off it. They're like, like, like leftover dinosaurs. It's like they evolved during the dinosaur times and never changed. They have spikes and bony plates and all kinds of strange growths that you don't see on the other smoother caiman. And I tried to release this one without getting bitten and I threw it into the stream, gently into the water. Just went, "Whack," and tried to pull my hands back. And as I pulled my hand back, this caiman, in the air, turned around and just tried to give me one parting blow and just got one tooth whack, right to the bone of my finger.

Lex Fridman 21:04 Mm-hmm.

Paul Rosolie 21:04 And, uh, uh, bone injury feels different than a skin injury. So, your in- instantly, "Ah." And it just reminds you of that's a caiman with a head this big.

Lex Fridman 21:13 Mm-hmm.

Paul Rosolie 21:14 And it hurt. And I know that it could have taken off my finger. Now, if you scale that up to a black caiman, it's, it's rib crushing. It's, it's zebra head removing size, you know, just, just meat destroying. It's (laughs) it's incredible. It's n- nature's metal sort of, you know, just raw power.

Lex Fridman 21:32 So, what's the, the, the biggest croc you've been able to handle?

Paul Rosolie 21:36 We were doing caiman surveys for years, and we would go out at night. And you wanna figure out what are the populations of black caiman, spectacle caiman, smooth-fronted caiman, dwarf caiman. And the only way to see which caiman you're dealing with is to catch it. 'Cause a lot of times you get up close with your light and you can see the eyes at night, but you can't quite see what species it is. For instance, this past few months, we found two baby black caiman on the river, which is unprecedented here. We haven't seen that in decades. So, it's important that we monitor our croc population. So, I started catching small ones. Um, in Mother of God, I write about the first one that me and JJ caught together, which was probably a little bigger than this table. And, uh, probably mid-20s bravado and competition with other young males of my species led to me trying to go as big as I could.

Lex Fridman 22:25 Mm-hmm.

Paul Rosolie 22:26 And I jumped on a spectacle caiman that was slightly longer than I am. And I'm 5'9". So, I, I jumped on this probably six-foot croc, and quickly realized that my hands couldn't get around its neck, and my legs were wrapped around the base of its tail. And the thrash was so intense, that as it took me to one side, I barely had enough time to realize what was happening before it beat me against the ground. My headlamp came off, so now I'm blind, in the dark, laying in a river, in the Amazon rainforest-

Lex Fridman 22:57 Mm-hmm.

Paul Rosolie 22:57 ... hugging a six-foot crocodile. And I went, "JJ!" (laughs)

Lex Fridman 23:03 (laughs)

Paul Rosolie 23:03 As I always do. But I, in that moment, before I even let go, I knew I couldn't let go of the croc, because if I let go of the croc, I thought she was gonna destroy my face. So, I said, "Okay, now I'm stuck here. If I just stay here, I can't release her. I need help." But I was like, "I'm never, ever, ever, ever gonna try and solo catch a croc this big again." And I was like, "This is, this is..." I knew in that moment, I was like, "This is good enough."

Lex Fridman 23:22 So, anything longer than you-

Paul Rosolie 23:24 Yeah.

Lex Fridman 23:24 ... you don't have control of the tail. You don't have-

Paul Rosolie 23:25 Yeah.

Lex Fridman 23:25 You have barely control of anything, really.

Paul Rosolie 23:27 Yeah, and that's a spectacle caiman.

Lex Fridman 23:28 Yeah.

Paul Rosolie 23:28 A black caiman is a, is a whole other order of magnitude there. It's like saying like, oh, you know, I play- I was play-fighting with my golden retriever versus I was play-fighting with like, you know, uh, what, what's the biggest, scariest dog you could think of? The s- the, the dog from Sandlot, a giant gorilla dog thing, like a, like a malamute. Something (laughs) , something huge. What are they called? Mastiffs.

Lex Fridman 23:48 Yeah, mastiffs.

Paul Rosolie 23:50 Mastiffs.

Lex Fridman 23:50 I mean, you mentioned dinosaurs. What, w- what do you admire about black caiman? What... They've been here for a very, very long time. There's something prehistoric about their appearance, about their way of being, about their presence in this jungle.

Paul Rosolie 24:03 With crocodiles, you're looking at this, this mega survivor. They're in a class with sharks where it's like, they've been here so long.

Lex Fridman 24:11 Mm-hmm.

Paul Rosolie 24:11 When you talk about multiple extinctions, you talk about the sixth extinction. Earth's going through all this stuff. The crocodiles and the cockroaches have seen it all before. They're like, "Man, we remember what that comet looked like," and they're not impressed.

Lex Fridman 24:24 Yeah, they have this, they carry this wisdom-

Paul Rosolie 24:26 Yeah.

Lex Fridman 24:26 ... in their power.

Paul Rosolie 24:27 Yeah.

Lex Fridman 24:28 In the simplicity of their power, they carry the wisdom.

Paul Rosolie 24:30 Yeah.... and they're just sitting there in the streams and they don't care. And even if there was a nuclear holocaust, you know that there would just be some croc sitting there dead-eyed in that stagnant water-

Lex Fridman 24:39 (laughs)

Paul Rosolie 24:39 ... waiting for the life to regenerate so they could eat again.

Lex Fridman 24:42 It's gonna be the remaining humans versus the crocs and the cockroaches. And the cockroaches are just background noise.

Paul Rosolie 24:49 Yeah, they'll always be there. Sons of bitches.

Lex Fridman 24:53 You know, we were talking about individual black caiman, and caiman, and different species-

Paul Rosolie 24:56 Mm-hmm.

Lex Fridman 24:56 ... of caiman, but whene- whenever they're together and you see multiple eyes, which I've gotten to experience, i- it's quite a feeling. There's just multiple eyes looking back at you.

Paul Rosolie 25:06 Mm-hmm.

Lex Fridman 25:07 (Laughs) Of course, for you, that's, uh, immediate excitement. (laughs) You immediately go towards that. You wanna see, you want to explore it, maybe catch them, analyze what the species is, all that kind of stuff.

Paul Rosolie 25:19 Yeah.

Lex Fridman 25:20 Wh- what's ... C- can you just describe that feeling when, when they're together and they're looking at you? So, head above water, eyes reflecting the light?

Paul Rosolie 25:28 Yeah. So the other night, Lex and I were in the river with JJ, surviving a thunderstorm. We're in the rain and we had covered our, covered our equipment with our boats. And the only thing that we could do was get in the, in the river to keep ourselves dry. And so we were in the river at night, in the dark, no stars, just a little bit of canopy silhouetted with all this rain coming down. It was such a din, you could hardly hear anything. And all the way downriver, I just see this caiman eye in my headlamp light.

Lex Fridman 25:59 Mm-hmm.

Paul Rosolie 26:00 And I started walking towards it, because I was like, "This is even better. We can catch a caiman while we're in this thunderstorm in the Amazon River." And, uh, when JJ went, "Paul, it's too far." JJ very rarely, very rarely ... Like, he'll, he'll make a suggestion. Like, he'll usually go like, "Maybe it's far."

Lex Fridman 26:20 (laughs)

Paul Rosolie 26:20 But in that situation, deep in the wilderness, unknown caiman size, he went, "Paul, it's too far."

Lex Fridman 26:26 Mm-hmm.

Paul Rosolie 26:26 "Don't leave the three of us right now."

Lex Fridman 26:29 Yeah.

Paul Rosolie 26:29 We were too far out to take risks.

Lex Fridman 26:31 Yeah.

Paul Rosolie 26:31 We're too far out to be walking along the riverbed at night because then ... You know, right here at the research station, if you step on a stingray, you get Evaced. Out where we went? Uh, nothing. So, so for me, seeing those eyes, I think I've become so comfortable with so many of these animals that I, I may have crossed into the territory where I feel, I feel so comfortable with s- with many of these animals that they just don't worry me anymore.

Lex Fridman 26:56 Mm-hmm.

Paul Rosolie 26:56 I mean, you were ... I, I, I looked at you in a raft while you had a sizeable, probably about 12-foot black caiman right next to your raft.

Lex Fridman 27:04 Mm-hmm.

Paul Rosolie 27:04 I watched its head go under-

Lex Fridman 27:06 Bubbles, bubbles.

Paul Rosolie 27:06 The bubbles, it was all coming up right next to your raft as he, he was just moving along the bottom of the river-

Lex Fridman 27:10 Mm-hmm, mm-hmm.

Paul Rosolie 27:10 ... 'cause he looked at me, went under, and then my raft passed and yours came over him.

Lex Fridman 27:14 Uh-huh.

Paul Rosolie 27:14 So, now I'm looking back and your raft is going over this black caiman. And I'm going, "I'm not worried at all."

Lex Fridman 27:21 Mm-hmm.

Paul Rosolie 27:21 I was not worried. I was not worried that the caiman would freak out. I was not worried that he would try to attack you. I knew 100% that caiman just wanted us to go so you could go back to eating fish.

Lex Fridman 27:31 Yeah.

Paul Rosolie 27:32 That's it.

Lex Fridman 27:32 Man, it's humbling. It's humbling these giant creatures. And especially at night like you were talking about. And for me, it's both scary, but ... and just beautiful when the head goes under.

Paul Rosolie 27:45 Hmm.

Lex Fridman 27:46 'Cause, like, underwater it's their domain, so anything can happen. So, what is it doing that it's, its head is going under? It could be bored, it could be hungry, looking for some fish. It could be maybe wanting to come closer to you to investigate, maybe you have some food around you. Maybe it's an old friend of yours and just wants to say hi. I don't know.

Paul Rosolie 28:06 I have a few on the river, old friends.

Lex Fridman 28:07 Okay.

Paul Rosolie 28:08 Um, no, th- when we see their heads go under, it's just ... They're just getting out of the way. We're, we're shining a light at them and they're going, "Why is there a light at night? I'm uncomfortable." Head under. So these caiman ... Again, you think of it as this big, aggressive animal, but I don't know anybody that's been eaten by a black caiman. And the, the smaller species, smooth-fronted caiman, dwarf caiman, spectacle caiman, they're not gonna eat anybo- ... Again, at the worst, if you were doing something inappropriate with a caiman, like (laughs) you jumped on it and were trying to, to do research and, and it bit your hand, it could take your hand off. But that's the only time. I've been walking down the river and stepped on a caiman, and the caiman just swims away. And so in my mind, caiman are just these ... They're peaceful dragons that sit on the side of the river.

Lex Fridman 28:51 Mm-hmm.

Paul Rosolie 28:51 And so to me, they are my friends, and I worry about them because two months ago we were coming upriver and on one of the beaches was a beautiful, about five-foot black caiman with a big machete cut right through the head. The whole caiman was wasted, nothing was eaten, but the caiman was dead.

Lex Fridman 29:11 What do you think that was?

Paul Rosolie 29:13 Curious humans.

Lex Fridman 29:15 Just committing violence?

Paul Rosolie 29:17 Yeah. Just loggers, people who aren't from this part of the Amazon, because a local person would either eat the animal or not mess with it.

Lex Fridman 29:25 Hm.

Paul Rosolie 29:25 Like, Pico would never kill a caiman for no reason because it doesn't make any sense. So, these are clearly people who aren't from the region, which usually means loggers, 'cause they've come from somewhere else. They're doing a job here and they ... They're just cleaning their pots in the river at night and they see eyes come near them because the caiman probably smells fish, and then they just whack 'cause they wanna see it. And they're just curious monkeys on a beach. And again, me friend of caiman. I protect from my type.

Lex Fridman 29:51 That said, you know, you, uh, protect your friends and you analyze and study your friends. But sometimes y- ... Friends can have a bit of a misunderstanding, and if you have a bit of a misunderstanding with a black caiman, I feel like just a bit-

Paul Rosolie 30:06 Big one.

Lex Fridman 30:06 ... of a misunderstanding could lead to a, uh, bone-crushing situation.

Paul Rosolie 30:12 But not for a little five-foot caiman.

Lex Fridman 30:14 Sure.

Paul Rosolie 30:15 And I think that's incredibly speciesist of you.

Lex Fridman 30:18 About humans or about caiman?

Paul Rosolie 30:20 (laughs)

Lex Fridman 30:21 (laughs) Hey.

Paul Rosolie 30:21 No, I'm saying, like, all my friends do the same thing. They go, "You swim in the Amazon rainfor-" ... You know, "You swim in that river?" And I go, "Yes, every day." We ... You know, backflips into the river.

Lex Fridman 30:30 Mm-hmm.

Paul Rosolie 30:30 We've been swimming in the river how many times?

Lex Fridman 30:32 Yeah.

Paul Rosolie 30:32 With the piranha and the stingray and the candiru and the caiman and the anacondas, all of it in the river with us-

Lex Fridman 30:38 Mm-hmm.

Paul Rosolie 30:40 ... and we just do it. And what's that for you? So, what- what allows you to doing that- to do that, knowing and having researched all the different things that can kill you, which I feel like most of them are in the river.

Lex Fridman 30:49 Mm-hmm.

Paul Rosolie 30:50 What allows you to just get in there with us?

Lex Fridman 30:53 Well, I think it's something about you, where you become like this portal through which it's possible to see nature as not threatening but beautiful. And so, in that, you kinda, naturally by hanging out with you, I get to see the beauty of it.

Paul Rosolie 31:08 Yeah.

Lex Fridman 31:09 Uh, there is danger out there. But the danger is part of it. Just like the- there's a lot of danger in the city, there's danger in life. There's a lot of ways to get hurt emotionally, physically. There's a lot of ways to die in the stupidest of ways.

Paul Rosolie 31:20 Yeah.

Lex Fridman 31:20 We went on an expedition through the forest. Just twisting your ankle, breaking your foot, um, getting a bite from a thing that gets infected. It's- there's a lot of ways to die and get hurt in the stupidest of ways, in a non-dramatic, caiman eating you alive kind of way.

Paul Rosolie 31:37 Yeah. It- it- it strikes me as unfair because humans, we're still in our minds, so- so programmed to worry about that predator, that predator, that predator. What predator? We've killed everything. Black caimans are coming off the endangered species list. We exterminated wolves from North America. I actually heard a suburban lady one time tell her son, "Watch out. Foxes will get you."

Lex Fridman 31:59 Mm-hmm.

Paul Rosolie 32:00 Foxes.

Lex Fridman 32:01 Yeah.

Paul Rosolie 32:02 They eat baby rabbits and mice.

Lex Fridman 32:05 Well, in the case of apex predators, I think when people say dangerous animals, they really are talking about just the power of the animal. And the black caiman have a lot of power.

Paul Rosolie 32:16 A lot of power.

Lex Fridman 32:18 And it's- it's almost just a way to celebrate the power of the animal.

Paul Rosolie 32:21 Sure. And if it's in celebration, then I'm all for it because my God is that powerful. Like, the waves of- of- of fury that you saw, like when that tail... I mean, you saw- you saw the tail of the spec-

Lex Fridman 32:30 Yeah.

Paul Rosolie 32:31 That perfect amazing thing with all those interlocking scales that works-

Lex Fridman 32:34 Yeah.

Paul Rosolie 32:34 ... so it's like a perfect creation of engineering. And then- and then when you have one that's this thick, and all of a sudden that thing is moving with all the acceleration of that power, whoa. The volume of water, the sound that comes out of their throat.

Lex Fridman 32:48 Mm-hmm.

Paul Rosolie 32:49 They're such- they're dragons.

Lex Fridman 32:51 Mm-hmm. We talked about the scales of the snake, but like, the caiman, just the way it felt-

Paul Rosolie 32:55 Yeah.

Lex Fridman 32:56 ... was, um, incredible. Just the armor, the texture of it was so cool.

Paul Rosolie 33:01 Yeah.

Lex Fridman 33:02 I don't know, like the- the- the bottom of the caiman has a certain kind of texture. And it just all feels like power, but also all feels like designed really well. It's like- it's like exploring through touch like a World War II tank or something like that. Just-

Paul Rosolie 33:17 Yeah.

Lex Fridman 33:17 ... it's the engineering that went into this thing-

Paul Rosolie 33:19 Yeah.

Lex Fridman 33:20 ... that like, the mechanism of evolution that created a thing that could survive for such a long time is just like incredible. This is a work of art. The po- you know, the defense mechanisms, the power of it, the damage it can do, uh, how effective it is as a hunter, all of that, all- you could feel that in- just by touching it.

Paul Rosolie 33:42 Do you ever see the- the mashup where they put side by side the image of, I think it's a falcon in flight next to a stealth bomber, and they're almost the exact same design? It's incredible, like that.

Lex Fridman 33:54 W- what's the equivalent for- for a croc? (laughs)

Paul Rosolie 33:57 (laughs) Like he said, maybe a tank.

Lex Fridman 33:58 Maybe a tank.

Paul Rosolie 33:59 Like, ... but then more like an armadillo, turtle.

Lex Fridman 34:00 Yeah.

Paul Rosolie 34:01 I don't know.

Lex Fridman 34:01 Like hippos and...

Paul Rosolie 34:02 Yeah, there may not be a- a mach- a machine- a war machine equivalent of a crocodile. It'd have to have like a big jaw element to it.

Lex Fridman 34:11 Yeah, in the water, I mean, we- we talked also about hippos. Those are interesting creatures from all the way across the world, just monsters.

Paul Rosolie 34:18 Yeah.

Lex Fridman 34:19 Hippos and rhinos. Hippos are bigger usually, or rhinos are bigger.

Paul Rosolie 34:23 Rhinos.

Lex Fridman 34:24 Yeah.

Paul Rosolie 34:24 Rhinos is the- after elephants is the largest, white rhinos.

Lex Fridman 34:28 They can be terrifying, too. Again, when you step into the defense.

Paul Rosolie 34:31 Absolutely, but I have to tell you, after being around so many rhinos-

Lex Fridman 34:35 You have friends- you have friend rhino-

Paul Rosolie 34:36 ... I have rhino friends.

Lex Fridman 34:37 Yeah.

Paul Rosolie 34:37 Black and white rhinos.

Lex Fridman 34:39 Yep.

Paul Rosolie 34:39 And, uh, they're all sweethearts.

Lex Fridman 34:42 Awesome.

Paul Rosolie 34:42 And I mean- I mean sweethearts. And I mean when you look at a rhino, it's like a living dinosaur. I know it's a mammal, but somehow it screams dinosaur 'cause it seems like Pleistocenic and- and-

Lex Fridman 34:52 It is.

Paul Rosolie 34:52 ... and from another age with the giant horn. And they're so much bigger than you think. Like, they're minivan-sized animals. Like you're- you're- we're not taller than they are. A- at the shoulder, and they have this strange shaped head and the huge horn. And they sit there eating grass all day. So if a rhino is dangerous to a human, it's because the rhino is going, "Don't hurt me."

Lex Fridman 35:13 Yeah.

Paul Rosolie 35:13 "Don't hurt me. Don't- don't hurt my baby." And then they're like, "You know what? I'll just kill you. It'd be easier 'cause you're scaring me right now."

Lex Fridman 35:17 Yeah.

Paul Rosolie 35:17 "You're too close to that rhino."

Lex Fridman 35:19 Yeah.

Paul Rosolie 35:20 And so, like there again, I just think it's funny 'cause humans were so quickly to go, "Which snakes are aggressive?" There are no aggressive snakes. You know, rhinos can be dangerous, eh, if provoked. Otherwise, they're peaceful, fat grass unicorns.

Lex Fridman 35:34 (laughs)

Paul Rosolie 35:34 You know, like they're- they're really pretty calm.

Lex Fridman 35:37 (laughs) Yeah.

Paul Rosolie 35:37 Then we had these incredible giant animals and the largest animals on our planet, the black caiman, the rhinos, the elephants, all the big beautiful stuff is becoming less and less.

Lex Fridman 35:48 Yeah.

Paul Rosolie 35:48 And it almost reminds me, like in Game of Thrones, they're like, yeah, they're- in the beginning they're like, "Yeah, there used to be dragons." And it was like this memory. And it's like, yeah, we used to have mammoths. And we- we used to have stellar sea cows that were 16 feet long, manatees, and it's- there are things we used to have, the Caspian tiger that only went extinct in the '90s, our lifetimes. And it's- that- that's mind-blowing to me. That's- that- that has haunted me since I'm a child. I remember learning about extinction and I went, "Wait, you're telling me that..." I remember being a kid and going, "By the time I grow up, you're saying that, uh, gorillas could be gone?"

Lex Fridman 36:24 Mm-hmm.

Paul Rosolie 36:24 "Elephants could be gone? And because we're doing it?" And then I- I just- that- I re- I remember- I remember looking at the- the night light being blurry 'cause I was crying. I was so upset. And, oh, and it was Lonesome George, that turtle, the Galapagos tortoise where there was one left.

Lex Fridman 36:39 Yeah.

Paul Rosolie 36:39 And they said, "If we just- if we just had a female-"... he could live. And I, as a 6, 7, 8-year-old, that destroyed me.

Lex Fridman 36:46 We're all just trying to get laid, including that turtle.

Paul Rosolie 36:48 Including that turtle, for a few hundred years.

Lex Fridman 36:51 (laughs)

Paul Rosolie 36:53 Dude.

Lex Fridman 36:53 So, for young people out there, you're thinking-

Paul Rosolie 36:54 Yeah.

Lex Fridman 36:54 ... of having trouble, think about that turtle.

Paul Rosolie 36:56 Think about that turtle.

Lex Fridman 36:58 (laughs)

Paul Rosolie 36:58 Yeah. You know there's a turtle that Darwin and Steve Irwin both owned?

Lex Fridman 37:01 Yeah, yeah.

Paul Rosolie 37:02 Yeah.

Lex Fridman 37:02 Heard about that turtle.

Paul Rosolie 37:03 Hmm.

Lex Fridman 37:03 Man, they live a long time.

Paul Rosolie 37:05 Yeah.

Lex Fridman 37:05 They've seen things.

Paul Rosolie 37:07 They've seen things that, there's a, there's a great, like, internet joke where they're like, they're like accusing him of, like, being, uh, incongruous with modern times.

Lex Fridman 37:15 Mm-hmm.

Paul Rosolie 37:15 They're like, "He did nothing to stop slavery."

Lex Fridman 37:17 (laughs)

Paul Rosolie 37:17 "He didn't fight in World War II." Like (laughs) .

Lex Fridman 37:20 He canceled the turtle.

Paul Rosolie 37:22 Yeah, he canceled the turtle.

Lex Fridman 37:22 Oh, shit.

Paul Rosolie 37:23 (laughs)

Lex Fridman 37:23 What a world we live in.

Lex Fridman 37:25 So, it's interesting, you mentioned black caiman and, uh, anacondas are both apex predators.

Paul Rosolie 37:32 Mm-hmm.

Lex Fridman 37:32 So, it seems like the reason they can exist in similar environments is 'cause they feed on slightly different things. How's it possible for them to co-exist? I read that anacondas can eat caiman but not black caiman. How often do they come in conflict?

Paul Rosolie 37:49 So, anacondas and caiman occupy the exact same niche.

Lex Fridman 37:53 Mm-hmm.

Paul Rosolie 37:53 And they're born at almost the exact same size. And, unlike most species, they don't have, sort of, a size range that they're confined to.

Lex Fridman 38:01 Mm-hmm.

Paul Rosolie 38:02 They start at this big. Baby caiman are this big. Baby anacondas are a little longer, but they're, they're thinner and they don't have legs. So, it's the same thing in, in terms of mass. And they're all in the streams, or at the edges of lakes or swamps. And so the baby anacondas eat the baby caiman. Baby caiman can't really take down an anaconda. They're, they're going for little insects and fish. They, they have quite a small mouth. So, they, again, it's in their interest to hide from everything. A bird, a heron can eat a baby caiman, pop it back.

Lex Fridman 38:33 Mm-hmm.

Paul Rosolie 38:34 And so they have to survive. But the anaconda and the caiman kinda, kinda joust as they grow.

Lex Fridman 38:38 Mm-hmm. Can you actually explain how the anaconda would take down a, a caiman? Like, would it first, uh, use constriction and then eat it? Or what, what's the method- methodology?

Paul Rosolie 38:48 Yeah, so anacondas have a, kind of a, I don't know, like a three-point constriction system where their first thing is anchor.

Lex Fridman 38:55 Mm-hmm.

Paul Rosolie 38:56 Something like jiu-jitsu. So, the first thing is latch on to you.

Lex Fridman 38:59 I like how I'm writing this down, like, "All right."

Paul Rosolie 39:01 Yes.

Lex Fridman 39:02 "This is jiu-jitsu, like, uh, masterclass here."

Paul Rosolie 39:04 (laughs) This is for when you're wrestling an anaconda, just in case.

Lex Fridman 39:08 (laughs)

Paul Rosolie 39:09 (laughs)

Lex Fridman 39:09 And you'll be like the coach on the sidelines screaming, "Run it up."

Paul Rosolie 39:11 You got it, Lex.

Lex Fridman 39:13 (laughs) Yeah. Uh-

Paul Rosolie 39:14 Don't let him take the back.

Lex Fridman 39:16 Yeah (laughs) .

Paul Rosolie 39:17 All right, so, so one time, me and JJ were following a herd of collared peccary and JJ's teaching me tracking. So, we're following, you know, the, the hoof prints through the mud, and we're doing this, and I'm talking about no backpacks, just machetes, bare feet, running through the jungle. And we come to this stream and JJ's like, "I think we missed them. You know, I think they went." And I'm like, "No, no, no. They went here, look." And not 'cause I'm a great tracker, 'cause I can see hun- you know, a few dozen footprints, hundreds of individual footprints right there, and I'm going, "No, no, they just crossed here." And JJ was like, "You know what? We're not gonna get eyes on them today." He was like, "It's okay." He's like, "We did good. We followed them for a long time." And I was like, "Cool." And then I was trying to gauge, like, "Can I drink this stream?" And I see a colpa. And a colpa is a salt deposit where animals come to, to feed, 'cause sodium is a, is, is a deficiency that most herbivores have here. And all of a sudden, I just hear, like the sound of a wet stick snapping, just that bone crunch. And I look down and there's about a 16-foot anaconda wrapped around a freshly killed peccary-

Lex Fridman 40:18 Mm-hmm.

Paul Rosolie 40:18 ... wild boar. And what this anaconda had done was, as the, all the pigs were going across the stream, the anaconda had grabbed it by the jaw-

Lex Fridman 40:28 Mm-hmm.

Paul Rosolie 40:28 ... swiped the legs, wrapped around it, bent it in half, and then crushed its ribs. And that's what the anaconda do, whether it's to mammals, to caiman, it's all the same thing. It's grab on. They have six rows of backwards facing teeth.

Lex Fridman 40:44 Mm-hmm.

Paul Rosolie 40:44 So, once they hit you, they're never gonna come off. You actually have to go deeper in bef- and then open before you can come out.

Lex Fridman 40:50 Mm-hmm.

Paul Rosolie 40:51 All those backward facing teeth. So, they have an incredible anchor system. And then they use their weight to pull you down to hell, to pull you down into that water, wrap around you, and then start breaking you.

Lex Fridman 41:02 Mm-hmm.

Paul Rosolie 41:02 And every breath you take, you go (gasps) and you, you're up against a barrier.

Lex Fridman 41:06 Mm-hmm.

Paul Rosolie 41:07 And then when you (exhales) , when you exhale, they go a little tighter and you're never gonna get that space back. Your lungs are never going to expand again. And I know this because I've been in that crush-

Lex Fridman 41:16 Mm-hmm.

Paul Rosolie 41:16 ... before JJ pulled me out of it. And so this pig, the anaconda had gotten it, and as the pig was thrashing and the anaconda was wrapping around, it had bent it in half.

Lex Fridman 41:24 Mm-hmm.

Paul Rosolie 41:24 And I just heard those vertebrae going.

Lex Fridman 41:26 Yeah.

Paul Rosolie 41:26 And so for a caiman, it's the same thing. They just grab and they wrap around it, and then they have to crush it until there's no response. They'll wait an hour. They'll wait a long time until there's no response from the animal. They'll overpower it. Then they'll, then they'll reposition, probably yawn a little bit, sh- open their jaw, and then start forcing that entire... Now, here's the crazy thing, is that an anaconda has stomach acid capable of digesting an entire crocodile-

Lex Fridman 41:53 Mm-hmm.

Paul Rosolie 41:54 ... where nothing comes out the other side.

Lex Fridman 41:55 Mm-hmm.

Paul Rosolie 41:56 And when you see how thick the bony plate of a crocodile skull is, that that can go in the mouth and nothing comes out the other side. That's insane. And so it always made me wonder, on a chemistry level, how you can have such incredible acid in the stomach that doesn't harm the anaconda itself. And someone said the mucus-

Lex Fridman 42:14 Anybody's able to digest... Oh, it's some kind of mucus. Oh, oh, the mu-

Paul Rosolie 42:17 The mucus...

Lex Fridman 42:17 There's lot... Oh, interesting.

Paul Rosolie 42:19 Yeah.

Lex Fridman 42:19 There's levels of protection from the anaconda itself. But it seems like the anaconda's such a simple system as an organism-

Paul Rosolie 42:25 I know but-

Lex Fridman 42:26 Like, that simplicity taken at scale, it could just do the, can swallow a caiman and digest it slowly.

Paul Rosolie 42:33 I know, but my question was how, how on earth is it physically possible to have this hellish bile that can digest anything?

Lex Fridman 42:40 Mm-hmm.

Paul Rosolie 42:41 Even something as, as, as horrendous as a, as a caiman scales and bones and all the hardest shit in nature.... and then not hurt the snake itself. And I had a chemist explain to me that it's probably some sort of mucus system that, that lines the stomach and, and neutralizes the acid and keeps it floating in there. But my God-

Lex Fridman 42:59 Yeah.

Paul Rosolie 42:59 ... that must be powerful stuff.

Lex Fridman 43:01 So, what does it feel like being crushed, choked by a a anaconda?

Paul Rosolie 43:08 Uh, I th- you... When an anaconda is wrapped around you, and you, you find yourself in, in the, in the shocking realization that these could be your last moments breathing, you are confronted with the vast disparity in power. That there is so much power in these animals, so much crushing, deliberate, reptilian, ancient power that doesn't care. They're just trying to get you to stop. They just want you to stop ticking, and there's nothing you can do. And there's... I find it very awe-inspiring when I encounter that kind of power. When you... Even if it's that you see, you know, you see a dog run. You know, you, you ever try and outrun a dog?

Lex Fridman 43:49 Mm-hmm.

Paul Rosolie 43:49 And they just zip by you, and you go, "Wow." You know? Or you see a horse kick, and you go, "Oh, my God. If that, if that hoof hit anyone's head, it'd knock 'em three states over." And it's like, it's like there, there is muscular power that is so far, that ex- like you said, that explosive-

Lex Fridman 44:04 Mm-hmm.

Paul Rosolie 44:05 ... that we, we dream of doing it. Like imagine if like a, a Muay Thai p- kickboxer could, could harness that sort of caiman power-

Lex Fridman 44:11 Mm-hmm.

Paul Rosolie 44:11 ... that smash. Um, and so it's, it's just awe-inspiring. I think it's really, really impressive what animals can do. And we're, we're all, you know, we're all the same sorta makeup for the most part, all the mammals. You know, we all have... Our skele- skeletons look so similar. We all have like... You know, if you look at like a kangaroo's biceps-

Lex Fridman 44:28 Mm-hmm.

Paul Rosolie 44:28 ... and chest, it looks so much like a, like a, like a, a man's. And if... Same thing goes for a bear, or you ever see a naked chimp? There's like-

Lex Fridman 44:35 Have I?

Paul Rosolie 44:35 ... chimps with alopecia.

Lex Fridman 44:38 Oh, shit.

Paul Rosolie 44:38 And so it l- looks-

Lex Fridman 44:39 Oh, they're shredded. Yeah, yeah.

Paul Rosolie 44:40 It looks like a bodybuilder.

Lex Fridman 44:41 Yeah, yeah, yeah.

Paul Rosolie 44:41 Like it's got cuts and huge, huge everything. Like it's got pecs, and they got that face that's just like-

Lex Fridman 44:48 Yeah.

Paul Rosolie 44:49 ... "Just let me in."

Lex Fridman 44:50 "What now?" (laughs)

Paul Rosolie 44:51 (laughs) Yeah. "Where's your wallet?"

Lex Fridman 44:52 Yeah, "Do something." (laughs) But yeah, but there's a, a specialization of a lifetime of doing damage to the world, and using those muscles-

Paul Rosolie 45:02 Yeah.

Lex Fridman 45:02 ... it just makes you, makes you just that much more powerful than most humans. 'Cause humans, I guess, have m- more brain, so they get lazy. They start puzzle-solving versus, you know, using the biceps directly.

Paul Rosolie 45:17 Well, yes and no. And I have this question, okay? So, I, uh, y- you know, that whole you-are-what-you-eat thing. Now, we one time here had two chickens.

Lex Fridman 45:24 Mm-hmm.

Paul Rosolie 45:24 Now, one of them was a wild chicken, like from the farm.

Lex Fridman 45:27 Mm-hmm.

Paul Rosolie 45:27 Had walked around its whole life finding insects. And the other chicken was like factory-raised.

Lex Fridman 45:32 Mm-hmm.

Paul Rosolie 45:33 And so, we cut the heads off of both of 'em-

Lex Fridman 45:35 Mm-hmm.

Paul Rosolie 45:35 ... started getting ready to cook 'em. Now, the factory-raised chicken was like a much higher percentage of fat-

Lex Fridman 45:41 Mm-hmm.

Paul Rosolie 45:42 ... had less muscle on its body, was softer tissue, a, a lighter color. The farm-raised chicken had darker, more sinewy muscles-

Lex Fridman 45:51 Mm-hmm.

Paul Rosolie 45:51 ... less fat, was clearly a better-made machine. And so my question is, is that what's happening with us? You know, like if you go see a Sherpa who's been walking his whole life-

Lex Fridman 46:02 Mm-hmm.

Paul Rosolie 46:02 ... and pulling, you know, and walking behind musk oxes and lifting things up mountains and breathing clean air and not being in the city, versus someone that's just been chowing down at IHOP-

Lex Fridman 46:11 Mm-hmm.

Paul Rosolie 46:12 ... for 40 years and never getting off the couch. Like I imagine it's the same thing, that you, you become what you eat.

Lex Fridman 46:19 Yeah, I mean like, you and I, we're like half-dead running up a mountain. Meanwhile, there's a grandma just like walking, and she's been walking that road, and she's just built different. (laughs)

Paul Rosolie 46:29 (laughs) With her alpaca on her shoulders.

Lex Fridman 46:32 With her baby. She's just... (laughs) They're, they're just built different, when you, when you apply your body in a physical way your whole life.

Paul Rosolie 46:39 Yeah. Like you can't replicate that. Like, like just like that chimp has those mu- from constantly moving through the canopy, constantly using those arms. Just like if you ev- you know, if you see an Olympic athlete or you hug Rogan- (laughs)

Lex Fridman 46:54 (laughs) They're exactly the same.

Paul Rosolie 46:55 ... you just go, "What? Why is there so much muscle here?" (laughs)

Lex Fridman 46:59 (laughs) That's exactly what I, uh, what I feel like when you give him a hug.

Paul Rosolie 47:02 (laughs)

Lex Fridman 47:02 This is, this is definitely a chimp-

Paul Rosolie 47:04 (laughs)

Lex Fridman 47:04 ... of some sort. How, how does that, uh, just, just that, the, the constriction of the anaconda-

Paul Rosolie 47:10 Mm-hmm.

Lex Fridman 47:11 ... just the, the f- the feeling of that, as... Are they doing that based on insu- instinct, or is there some brain stuff going on? Like, is this just like a basic procedure that they're doing? I- and they just-

Paul Rosolie 47:26 Yeah.

Lex Fridman 47:26 ... really don't give a damn? They're not like thinking, "Oh, well, this is this kind of species who tastes good"? Or is it just a mechanism, just start activating and you can't stop it?

Paul Rosolie 47:37 With an anaconda, I really think it's the second one.

Lex Fridman 47:40 Yeah.

Paul Rosolie 47:40 I do think that they're impressive and beautiful and incredibly arcane.

Lex Fridman 47:45 Yeah.

Paul Rosolie 47:45 I think they're a very simple system, a very ancient system. And I think that once you, once you hit predation mode, it's going down, no matter what. This stupid mosquito, I'm going like this, and every time, he just flies around my hand, like I'm a big slow giant, "Whoo." And he just goes around my hand, and then he goes back to the same spot like... And I'm like, "No," and then he comes right back to the same spot. It's like, it's like he's just going, "Fuck you. Fuck you."

Lex Fridman 48:10 Now, here's the question. If the mosquito is stupid and you can't catch it, what does that make you?

Paul Rosolie 48:14 Fucking stupid. Dude, I flicked a wasp off me the other day. It flew back like 12 feet, and it, in the air, corrected, and then flew back at my face.

Lex Fridman 48:22 Yeah.

Paul Rosolie 48:22 It made so many correc- like calculations and corrections, and decided to come back and let me know about it. And I was like, "Shoot."

Lex Fridman 48:29 That wasp probably went back to the nest, said-

Paul Rosolie 48:31 Yo.

Lex Fridman 48:31 ... "Guess what happened today?"

Paul Rosolie 48:32 "This bitch-ass kid from Brooklyn tried to flick me, and I showed him what's up."

Lex Fridman 48:35 (laughs)

Paul Rosolie 48:35 "I had him running."

Lex Fridman 48:36 They had a good chuckle on that one. Uh, yeah, you actually mentioned to me, uh, just on the topic of anacondas, that you've been, uh, participating in a lot of scientific work o- on, on the topic. So, like really, in everything you've been doing here-You are celebrating the animals, you're respecting the animals, you're protecting the animals, but you're also excited about studying the animals in their-

Paul Rosolie 49:01 Mm-hmm.

Lex Fridman 49:02 ... environment. So, you've, you're actually a co-author on a, on a paper, uh, on a couple of papers, but one of them is, uh, on anacondas and, uh, studying green anaconda hunting patterns. What's that about?

Paul Rosolie 49:13 So, um, the lead authors of that paper, Pat Champagne and Carter Payne, uh, friends of mine, and what we started noticing, for me, began at that story I told you where we were coming across the stream and we saw the anaconda had, had, had been positioned just below a culpa. And then other people began noticing that anacondas seemed to always be beneath these culpas, where mammals were gonna be coming. And that, that contrasted with what we knew about anacondas, 'cause what we understood about anacondas were that they're purely ambush predators and they don't pursue their prey. But what we began finding out here, and Pat led the process of... Amazing scientist, he w- worked with Acadia University for a long time, worked with us for a long time, and, and he, he was one of the first to put a transmitter in an anaconda right around here, and we were able to see their movements.

Lex Fridman 50:09 Mm-hmm.

Paul Rosolie 50:10 And that's what these papers are showing-

Lex Fridman 50:11 That's awesome.

Paul Rosolie 50:11 ... is that they actually do pursue their prey, they do move up and down using the streams as corridors through the forest. They actually do pursue their prey, they actually do seek out food. So, I mean, think about it, it's a, it's a giant anaconda. Obviously, it's not... It can't just sit in one spot. It has to put some work into it, and so they're using scent and they're using communication to use the streams. So you could be walking in the forest in a very shallow stream-

Lex Fridman 50:35 Mm-hmm.

Paul Rosolie 50:35 ... and see a sizable anaconda looking for a meal.

Lex Fridman 50:38 So, in the shallow stream, it moves not just in the water, but in the sand.

Paul Rosolie 50:44 Yeah.

Lex Fridman 50:44 So it's li- it, it also likes t- so, so to burrow a little bit?

Paul Rosolie 50:47 They burrow quite a bit, and so these large snakes operate subterranean more than we think.

Lex Fridman 50:55 Interesting.

Paul Rosolie 50:56 Like, there's times that you'll go with a tracker, you go with a telemetry set, and it'll say, "Do-do-do-do-do-do-do-do-do." Like, we'll be over the snake. The snake's underground. The snake has found either a recess under the sides of the stream, you saw it last night-

Lex Fridman 51:08 Mm-hmm.

Paul Rosolie 51:08 ... where all the fish have, have their holes under the side-

Lex Fridman 51:12 Mm-hmm.

Paul Rosolie 51:13 ... of the stream. There was a, there was a six-foot dwarf caiman right in the stream-

Lex Fridman 51:16 Mm-hmm.

Paul Rosolie 51:17 ... right where we were standing.

Lex Fridman 51:18 Mm-hmm.

Paul Rosolie 51:18 He had his cave. He goes under there. They know. They have their system.

Lex Fridman 51:22 Yeah. We walked by it.

Paul Rosolie 51:24 We walked by it, and he stuck his head out 'cause he thought we'd gone and then we turned around, and I just got a glimpse of him 'cause I was in the front of the line and he just went, "Dunk," right back into his cave.

Lex Fridman 51:34 Mm-hmm.

Paul Rosolie 51:34 "You, you guys are not gonna touch me." And so yeah, with the anacondas, it's been really exciting and, uh, in 2014, JJ and me and Mohsin and Pat and Lee, we all, we ended up catching what at the time was the record for Eunectes marinus scientifically measured. It was 18'6", 220 pounds, one of the largest female anacondas on record. And since that time, these guys have been continuing to study the species, continuing to just, again, just add a little bit by little bit to the knowledge we have of the species. And studying green anacondas in lowland tropical rainforest, you've seen how hard it is to, to move, to operate, to navigate in this environment. And so when you think of the fact that in order to learn anything about this species, you have to spend vast amounts of time first locating them and then finding out a way to keep tabs on them, 'cause even if you get lucky enough to see an anaconda by the edge of a p- a stream, to, to be able to observe it over time, to learn its habits or to put a radio transmitter on it or to take any sort of valuable information from the experience is almost impossible. And so a lot of the stuff that I wrote about in Mother of God, us jumping on anacondas and trying to catch them, and at first it just seemed like something we were doing to lear- to, to just try and see them, but it ended up being that we were wildly trying to figure out methodology that would have scientific implications later on-

Lex Fridman 53:03 Mm-hmm.

Paul Rosolie 53:03 ... because now it's allowing us to try and find the largest anacondas. And people used to say, "There's no way there's 25-foot, 27-foot..." Well, there was just that video of the guy swimming with the 20-foot anaconda.

Lex Fridman 53:14 Mm-hmm.

Paul Rosolie 53:14 And so now as we keep going, I'm going, "Well, maybe through drone identification, we could find where the largest anacondas are sitting on top of floating vegetation." And even then, how do we restrain them so that we could measure them and prove this to the world? It's sort of a side quest, but...

Lex Fridman 53:31 So, by doing these kinds of studies, you figure out w- how they move about the world, what motivates them in terms of when they hunt-

Paul Rosolie 53:38 Mm-hmm.

Lex Fridman 53:38 ... where they hide in the world as the sizes of the anaconda change, so all of that. That's, that's, those are scientific studies.

Paul Rosolie 53:45 Yeah. I mean, look, there's so much that we don't know about this forest. We don't know what medicines are in this forest. We don't know... With a lot of the 1,500... There's something like 4,000 species of butterflies in the Amazon rainforest, and of the 1,500 species that are here in this region, all of them have a larval stage, caterpillars, right?

Lex Fridman 54:04 Mm-hmm.

Paul Rosolie 54:04 And each of the caterpillars has a specific host plant that they need to, need to eat in order to become a successful butterfly, to enter the next life sig- cycle. And for most of the species that fill the butterfly book, we don't know what those interactions are. I recently got to see a, uh, a, the white witch, which is a huge moth. It's, it's one of the l- it's, it's one of the two largest moths in the world. It's the largest moth by wingspan.

Lex Fridman 54:28 Wow.

Paul Rosolie 54:29 Huge. It looks like a bird.

Lex Fridman 54:30 Mm-hmm.

Paul Rosolie 54:31 Big white moth. We still... I believe, I believe that we still don't know what the caterpillar looks like. It's 2024. We have iPhones and penis-shaped rocket ships. Like-

Lex Fridman 54:43 Yeah.

Paul Rosolie 54:43 ... we don't know where that moth starts its life.

Lex Fridman 54:45 Yeah.

Paul Rosolie 54:46 We still haven't figured that out.

Lex Fridman 54:47 By the way, the rocket ships are shaped that way for efficiency purposes, not because they want it to look, make it look like a penis. Speaking of which, I've ran across a lot of penis trees while exploring-

Paul Rosolie 54:57 Have you?

Lex Fridman 54:58 ... and they make me ver-I, this... I know it's not just a figment of my imagination.

Paul Rosolie 55:02 (laughs)

Lex Fridman 55:02 I'm pretty sure they're real. In fact, you explained it to me, and they, they make me very uncomfortable.

Paul Rosolie 55:06 (laughs)

Lex Fridman 55:06 'Cause there's just a lot of penises hanging off of a tree.

Paul Rosolie 55:09 Yes.

Lex Fridman 55:10 I don't know what the purpose is.

Paul Rosolie 55:11 Um-

Lex Fridman 55:12 I don't know who they're supposed to attract, but it certainly makes... (laughs) But certainly, Paul, like, uh, uh, really enjoys them.

Paul Rosolie 55:18 Yeah.

Lex Fridman 55:19 Uh-

Paul Rosolie 55:19 Yeah, well, clearly, you've, you've done some, some research-

Lex Fridman 55:22 You, you... (laughs)

Paul Rosolie 55:22 ... and you've noticed a lot of them. I haven't even seen them.

Lex Fridman 55:24 There was, there was, (laughs) there was a time when I almost fell, and to catch my balance, I had to grab one of the penises of the penis tree, and-

Paul Rosolie 55:30 Yeah.

Lex Fridman 55:31 ... unforgettable. Uh, anaconda. The biggest, baddest anaconda in the Amazon versus the biggest, baddest black caiman. 'Cause you mentioned there are like... There's a race. If there's a fight that's UFC in a cage, who wins underwater?

Paul Rosolie 55:44 This is the biggest and the baddest.

Lex Fridman 55:46 The biggest and the baddest that you have... can imagine given all the studies you've done of the two animals' species.

Paul Rosolie 55:53 Biggest and the baddest. So you're talking about an 18-foot, several hundred pound black caiman versus a 26-foot, 350-pound anaconda.

Lex Fridman 56:03 Yeah.

Paul Rosolie 56:05 I think it's a... It's a... It's a death stalemate.

Lex Fridman 56:07 Mm-hmm.

Paul Rosolie 56:07 I think the caiman slams the anaconda, bites onto it, the anaconda wraps the caiman, and then they both thrash around until they both kill each other. 'Cause I think the-

Lex Fridman 56:14 Oh, yeah.

Paul Rosolie 56:14 ... the caiman will tear him up so bad.

Lex Fridman 56:16 And the caiman's not gonna let go. He's just gonna get by-

Paul Rosolie 56:18 Caiman's never gonna let go, but then he's gonna, he's gonna realize that he's, he's also being constricted, so then he's gonna stop, and he's gonna, he's gonna keep slamming down on that anaconda.

Lex Fridman 56:26 Mm-hmm.

Paul Rosolie 56:26 And the anaconda's just gonna keep constricting. But if the caiman can do enough damage before the ana... It's... Again, it's almost like a striker versus a jiu-jitsu.

Lex Fridman 56:33 Mm-hmm. Yeah.

Paul Rosolie 56:34 You know? If you can get enough elbows in before they lock you.

Lex Fridman 56:37 How fast is the constriction? So it's pretty slow.

Paul Rosolie 56:39 It's, it's... No. It's, it's incredibly... It's, uh, it's incredibly quick. So it's, it's, it's you take... You see... You take the back and get me in a chokehold-

Lex Fridman 56:46 Yeah.

Paul Rosolie 56:47 It's that. It's-

Lex Fridman 56:48 Hmm.

Paul Rosolie 56:48 I have maybe 30 seconds, maybe on the upward side, if you haven't cinched it under my, under my throat. But if you've gotten good position, it's over.

Lex Fridman 56:57 Is there any way to unwrap the choke, undo the choke-

Paul Rosolie 56:59 No.

Lex Fridman 56:59 ... to finally escape the choke?

Paul Rosolie 56:59 Not unless you have outside help. Unless you have, you know-

Lex Fridman 57:01 So-

Paul Rosolie 57:01 ... another human or another 10 humans coming to unwrap the tail and help you.

Lex Fridman 57:05 So-

Paul Rosolie 57:05 But for an animal, like if a deer gets hit by an anaconda, there's no way. They don't stand a chance.

Lex Fridman 57:11 So the, the, the, the black caiman would bite somewhere, somewhere close to the head, and then-

Paul Rosolie 57:17 Yeah. ... and just try-

Lex Fridman 57:18 Yeah.

Paul Rosolie 57:18 ... to hold on and thrash? Yeah. I don't, I don't think a large black caiman... Here's the thing. Every fishermen knows this, that like the biggest fish, they're smart.

Lex Fridman 57:27 Yeah.

Paul Rosolie 57:27 And more importantly, they're shrewd. They're careful. A huge black caiman that's 16 feet long isn't gonna be messing with a big anaconda. Like they, they, they'll... They won't, they won't cross paths because while they, uh, technically occupy the same type of environment, that black caiman's gonna have this deep spot in a lake, and that anaconda's gonna have found this floating forest like sort of black stream backwater where it's gonna be. And they'll have made that their home for decades, and they'll already have cleaned out the competition. So maybe if there was a flood, and they got pushed together, then they, they could have some sort of a showdown but almost more certainly is that when they get to that size, that caiman, at any sign of danger, boom, right under the water. Just, you know... It's almost like... It's like even if you... What do you learn when you're a black belt? You know, a str- what, what, what do you do with a street fight? You still run away.

Lex Fridman 58:18 Mm-hmm.

Paul Rosolie 58:19 There's no reason for a street fight. And I think the animals really understand that. Y- there's no, there's no reason for this.

Lex Fridman 58:25 So like a giant anaconda and a giant black caiman, they will... They could probably even co-exist in the same environment just knowing-

Paul Rosolie 58:33 Mm-hmm.

Lex Fridman 58:33 ... using the wisdom to avoid the fight. Like why?

Paul Rosolie 58:35 Mm-hmm, yeah. Or they would have a big showdown, and one of them would either die or have to leave. They would have a territorial dispute.

Lex Fridman 58:41 Yeah.

Paul Rosolie 58:42 Yeah.

Lex Fridman 58:42 With- without killing either of them?

Paul Rosolie 58:45 Yeah. I don't... Dude, na- nature.

Lex Fridman 58:47 Nature is

Narrator 58:48 Yeah.

Paul Rosolie 58:49 ... could happen. One of the things that me and Pat wrote up was that I saw a yellow-tailed crepo, which is like a six-foot rat snake, eating an Oxyrhipus millenogenys, which is the, the, the red snake that we found-

Lex Fridman 59:00 Mm-hmm.

Paul Rosolie 59:00 ... last night. And just no one had ever... In scientific literature, we'd never seen a, a crepo eating an Oxyrhipus before. And so I just had the observation in the field, I sent it to Pat Champagne. Pat writes it up, paper. And so it's like, it's this really cool... That's a really cool system 'cause we're just out here all the time. You end up seeing things. JJ's dad saw an anaconda eating a tapir. Tapir is the size of a cow.

Lex Fridman 59:23 Yeah, I know.

Paul Rosolie 59:24 And it's... That guy didn't lie, you know?

Lex Fridman 59:26 Yeah.

Paul Rosolie 59:26 And some people, you trust your sources on that. He, he saw enough stuff, he didn't need to make up stories.

Lex Fridman 59:31 Mm-hmm.

Paul Rosolie 59:31 And you know how you... You know what I love now is when you go to s- when you ask people... When we were going up the mountain with Jimmy.

Lex Fridman 59:36 Yeah.

Paul Rosolie 59:38 JJ said to him... He goes, "Have you ever seen a puma up here in the mountains?"

Lex Fridman 59:42 Mm-hmm.

Paul Rosolie 59:42 And Jimmy goes, "They're up here." And J- J- JJ went, "No, no. Have you seen it?" And Jimmy went, "No, never seen one." And, you know, how most people go, "Yeah, yeah, yeah, I've seen it"?

Lex Fridman 59:52 Mm-hmm.

Paul Rosolie 59:53 That makes me trust a person when they admit, "No, I haven't seen it."

Lex Fridman 59:58 "They're up here. I haven't seen it." And-

Paul Rosolie 1:00:00 Yeah.

Lex Fridman 1:00:00 ... Jimmy's been living there his whole life.

Paul Rosolie 1:00:03 His whole life.

Lex Fridman 1:00:05 There's pumas in the mountains?

Paul Rosolie 1:00:06 You know, mountain lions, pumas-

Lex Fridman 1:00:08 Damn.

Paul Rosolie 1:00:08 ... whatever the... You know, there's all different names for them. They're distributed from, I think, from Alaska down through Argentina. That's... They're everywhere. It's an extremely successful species.

Lex Fridman 1:00:17 Mm-hmm.

Paul Rosolie 1:00:17 From deserts to high mountains. Everything.

Lex Fridman 1:00:21 I think you're saying pumas have a, have a curiosity, have a way about them where they like explore, uh, like follow-

Paul Rosolie 1:00:30 Yeah.

Lex Fridman 1:00:30 ... people. Like just to kind of figure out like, uh... Just out of curiosity, versus like as opposed to causing harm or hunting and that kind of stuff, like what is this about?

Paul Rosolie 1:00:40 I think it's based in predatory instincts. But I also think there is a playfulness to higher intelligence animals that you don't see in lower intelligence animals. And so something like a rabbit, for instance, you're never gonna see a rabbit come in to check you out. Or a... You just would... You just...

Lex Fridman 1:00:56 Yeah.

Paul Rosolie 1:00:56 You can't even think of it like that. Like a rabbit's just gonna either eat or run away. There's really two settings.

Lex Fridman 1:01:01 Mm-hmm.

Paul Rosolie 1:01:02 When you think of something like a river, giant river otter-... or a tayra, which is a, they call it manco here. It's a, it's a huge arboreal weasel. And they'll come check you out. I woke up at my house the other day, and there was a tayra climbing up the side of the house, and he was looking down at me sleeping.

Lex Fridman 1:01:21 Hmm.

Paul Rosolie 1:01:21 And it's like, "He came to check me out." Like, it's like they're smart enough and they're brave enough.

Lex Fridman 1:01:26 Mm-hmm.

Paul Rosolie 1:01:26 Here's the important thing. They know that they can fend for themselves.

Lex Fridman 1:01:29 Mm-hmm.

Paul Rosolie 1:01:29 They can fight, they can climb, they can run. And so they're like, "Let me... I'm curious."

Lex Fridman 1:01:34 Mm-hmm.

Paul Rosolie 1:01:34 "I got time, let me check this out."

Lex Fridman 1:01:35 Yeah, they're gathering information. I wonder how complex and sophisticated their wo- world model is. Like, how they're integrating all the information about the environment, like where all the different trees are, where all the-

Paul Rosolie 1:01:46 Hmm.

Lex Fridman 1:01:46 ... different nests of the different insects are, what the different creatures are, their bite size, all that kinda stuff. I'm s- I'm sure they don't have enough, you know, storage up there to like keep all that, but they probably keep the important stuff. Base- You know, so they sort of integrate the experiences they have into like what is dangerous, what is tasty, all that kind of stuff.

Paul Rosolie 1:02:07 Hmm. I think it's more complex than we realize. You go back to that Friends de Waal book, Are We Smart Enough to Know How Smart Animals Are?, there's so many incredible examples of controlled studies where the re- researchers weren't understanding how to shed being so insurmountably human and understand that there are other types of intelligence.

Lex Fridman 1:02:31 Wow.

Paul Rosolie 1:02:31 And whether that's elephants or cats... So big cats for instance, we just saw a camera trap video-

Lex Fridman 1:02:37 Mm-hmm.

Paul Rosolie 1:02:37 ... from last night-

Lex Fridman 1:02:39 Yeah.

Paul Rosolie 1:02:39 ... where you see one of our workers walk down the trail, and then five minutes later, a cat behind him.

Lex Fridman 1:02:45 Mm-hmm. By the way, we were walking just exactly the same area, also exact same time, yeah.

Paul Rosolie 1:02:50 Yeah.

Lex Fridman 1:02:50 Yeah.

Paul Rosolie 1:02:50 So we're out there, and there's deer, and there's cats-

Lex Fridman 1:02:53 Yeah.

Paul Rosolie 1:02:53 ... and there's a jaguar, and there's a puma-

Lex Fridman 1:02:54 Yeah.

Paul Rosolie 1:02:54 ... and there's all these animals out there.

Lex Fridman 1:02:56 Mm-hmm.

Paul Rosolie 1:02:57 And we're out in the night, in the inky black night, in this ocean of darkness beneath the trees-

Lex Fridman 1:03:01 Mm-hmm.

Paul Rosolie 1:03:01 ... and we're just exploring and getting to see everything, and there's all these little eyes and heartbeats. I love the jungle at night, man. It's the most exciting thing.

Lex Fridman 1:03:07 You know one of the things you do when you turn off the headlamp-

Paul Rosolie 1:03:09 Yeah.

Lex Fridman 1:03:09 ... complete darkness-

Paul Rosolie 1:03:11 Yeah.

Lex Fridman 1:03:11 ... all around you. And just the sounds.

Paul Rosolie 1:03:14 Everything you hear, the cicadas, the birds, they're all screaming about sex-

Lex Fridman 1:03:20 Yeah.

Paul Rosolie 1:03:20 ... all the time, so they're just trying to get laid.

Lex Fridman 1:03:22 Yeah.

Paul Rosolie 1:03:22 So all of them are making mating calls. Now, the trick is to make your mating call without attracting a predator.

Lex Fridman 1:03:27 Yeah.

Paul Rosolie 1:03:28 But at night, what, what, what amazes me is that for us, it's so... From the, from the caveman logic of it's hard to make fire here, it's hard to even light a fire here, to having this, this, this incredible beam of, of, of e- You know, all of a sudden we can look at the jungle-

Lex Fridman 1:03:49 Mm-hmm.

Paul Rosolie 1:03:51 ... and walk through that darkness, then we're seeing the frogs on those leaves, and the snakes moving through the undergrowth, and the deer sneaking through the shadows. It's like, it's almost as supernatural as skydiving. It's a strange thing to be able to do that technology allows us to do. We're doing something really complex, and we're walking on trails that have been cleared for us-

Lex Fridman 1:04:11 Mm-hmm.

Paul Rosolie 1:04:11 ... that we've planned out. And so walking through the jungle at night, you just get this freak show of, of, of biodiversity, and I'm, I'm addicted to it. I truly love it.

Lex Fridman 1:04:20 Except for the times over the last few days when we walked on, through jungle without a trail.

Paul Rosolie 1:04:27 Yeah, that's different.

Lex Fridman 1:04:27 And that's just a different experience.

Paul Rosolie 1:04:29 Well, how would you categorize? If somebody said, "Lex, I think I'm gonna go for a hike through the jungle, not on the trail."

Lex Fridman 1:04:36 Yeah.

Paul Rosolie 1:04:36 What would you tell 'em?

Lex Fridman 1:04:38 Every step is really hard work. Every step is a puzzle, every step is, uh, full of possibility of hurting yourself in a multitude of ways. You just... A wasp nest under a leaf-

Paul Rosolie 1:04:52 Hmm.

Lex Fridman 1:04:53 ... uh, a hole under a leaf on the ground where if you step in it you're gonna break a knee, ankle, leg, and going to, uh, not be able to move for a long time. Uh, there's all kinds of ants that can hurt you a little or it can hurt you a lot. Uh, bullet ants. There's snakes and spiders. And, uh... Oh, my favorite that I've gotten to know intimately, uh, is different plants with different d- defensive mechanisms, one of which is it just spikes, so it's sharp. You have, I don't know if you brought it, but there's a (laughs) -

Paul Rosolie 1:05:33 I didn't bring it.

Lex Fridman 1:05:34 (laughs) .

Paul Rosolie 1:05:34 I didn't bring it. Where's my club?

Lex Fridman 1:05:36 There's a, there's a, uh, there's an epic club with the spikes. But there's so many trees that have spikes on them. Sometimes they're obvious spikes, sometimes less than obvious spikes. And you know, it could be just an innocent... As you take a step through a dense jungle, it could be an innocent placing of a hand on that tree that could just completely transform your experience, your life, by penetrating your hand with like 20, 30, 40, 50 spikes-

Paul Rosolie 1:06:04 Yeah.

Lex Fridman 1:06:04 ... and just changing everything. That's just a completely different experience than going o- on a trail where you, where you're observer of the jungle versus the participant of it. And-

Paul Rosolie 1:06:14 Yeah.

Lex Fridman 1:06:15 And it truly is extreme hard work to take every single step.

Paul Rosolie 1:06:20 Now, just think about this. I think scientifically, 'cause people like to summarize, people like to get really, really, uh, sorta cavalier with our scientific progress and they go, "You know, we've already explored the Amazon." It's like, well, have we? Because in between each tributary is, you know, let's say just between some of them, let's just say 100 miles of f- of unbroken forest. Who's explored that?

Lex Fridman 1:06:40 Yeah.

Paul Rosolie 1:06:40 Maybe some of the tribes have been there. Maybe. Some areas they haven't been. Now, when you're talking about scientists, whether they're indigenous scientists, Western scientists, whatever, so many of the areas in this jungle that is the size of the continental US still have not been accessed. And the places where people are doing research... See, I've been down here long enough. I see all the PhDs come down here and they all go to the same few research stations.

Lex Fridman 1:07:06 Mm-hmm.

Paul Rosolie 1:07:06 They're safe, they have a bed. If you get heli-dropped into the middle of the jungle, in the deepest most remote parts, you're gonna find micro-ecosystems, you're gonna see little species variations, you're gonna see a, a type of flower that JJ's never seen before, like what happened the other day.... as you start walking through new patches of forest, you start finding new species, and everything here changes. You just go a little bit upriver and the animals you see differ. You go on this side of the river versus on the north side of the river, there's two other species of primates there that don't exist here, and that's in the mammal paper that we did-

Lex Fridman 1:07:38 Mm-hmm.

Paul Rosolie 1:07:38 ... with the, the emperor tamarins, and the pygmy marmosets that the rangers

Paul Rosolie 1:07:42 found.

Lex Fridman 1:07:42 Yeah. The, the mammal papers, looking at the diversity of life in this one region of the Amazon, what kinda... Can, can you talk, talk more about that paper? Mammal diversity along the Las Piedras River?

Paul Rosolie 1:07:57 Once again, the mammal paper, Pat Champagne, the prodigy, um, he was sort of leading on this with a bunch of other scientists who have worked in the region, including Holly O'Donnell out of Oxford. Uh, myself, I really just made a few observations. The Jungle Keepers Rangers got featured because they're the ones that spotted a pygmy marmoset that had previously been unrecorded on the river.

Lex Fridman 1:08:18 Mm-hmm.

Paul Rosolie 1:08:19 I got to, I got to contribute because I had, I had the only photograph that I believe anyone has of an emperor tamarin on this river. It's the first proof of emperor tamarin on this river, and that's exciting. It's exciting because, um, you know, you'll... You can post, post a picture or share a scientific observation or write about something, and then what happens is you get these, these, like, couch experts, these armchair experts who, who will come and say, you know, "No. No, you don't get blue and yellow macaws there. I can tell from my bird book, it says they're not there." And they'll tell you you're wrong, you know. "No, you don't get woolly monkeys there or, or emperor tamarins." It's like-

Lex Fridman 1:08:56 Yeah.

Paul Rosolie 1:08:56 ... but, but we, but we have proof. And so we're coming together to try and add to that knowledge.

Lex Fridman 1:09:01 My general sort of amateur experience of the species I've encountered here is like, this should not exist. Whatever this is, (laughs) this is not real. (laughs) This is CGI. (laughs) Like, what? Just the colors, the weirdness. I mean, there's, uh, I think I called it the, the Paris Hilton, uh, caterpillar-

Paul Rosolie 1:09:20 Yeah.

Lex Fridman 1:09:20 ... because it's like fur... It looks like a-

Paul Rosolie 1:09:21 (laughs)

Lex Fridman 1:09:21 ... one of those little-

Paul Rosolie 1:09:22 It sounds like Paris Hilton's dog.

Lex Fridman 1:09:23 Like, yeah, yeah. It, it's like really furry and it's transparent and, and, and sort of... It's transparent. All you see is this white beautiful fur and it's just like this caterpillar. It doesn't, doesn't look real.

Paul Rosolie 1:09:34 Yeah.

Lex Fridman 1:09:34 Do you think there's species... Like, how many species have we not discovered? And is there species that are like extremely badass that we haven't discovered yet?

Paul Rosolie 1:09:43 If you look up how many trees are in the Amazon rainforest, it's something in the order of 400 billion trees. There's something like 70 to 80,000 species of plants, individual types of plants here, 1,500 species of trees. It's, it's so vast that it, it, it, it's comparable, like the, the scale is like only comparable to the universe in terms of stars and galaxies and, and, and, and for the sheer immensity of it. And so we're, we're, we're describing new species every year. And just walking on the trail at night, you and I have seen, you know, you see a tiny little spider hidden in a crevice-

Lex Fridman 1:10:30 Mm-hmm.

Paul Rosolie 1:10:31 ... and has the scientific eye ever seen that spider before? Has it been documented? Do we know anything about its life cycle? There's still so much that's here that is completely unknown.

Lex Fridman 1:10:41 Mm-hmm.

Paul Rosolie 1:10:41 You know, we have pictures of all these butterflies. Somebody went out with a butterfly net and caught these butterflies, took a picture of it, gave it a name, put it in a bu- a butterfly book-

Lex Fridman 1:10:48 Mm-hmm.

Paul Rosolie 1:10:48 ... but what, what do we know? What host plant do they use for their caterpillars? What's their geographical range? What, what do we actually know? Not that much. So are there creatures out here that haven't been described? Absolutely.

Lex Fridman 1:11:00 And some of them could be extremely effective, uh, predators in a niche environment.

Paul Rosolie 1:11:06 Yeah, absolutely.

Lex Fridman 1:11:07 Mm-hmm.

Paul Rosolie 1:11:07 I mean, certainly, certainly in the canopy. 50% of life in a rainforest is in the canopy, and we've had very limited access to the canopy for all of history. You know, if you wanted to get up into the rainforest canopy, you basically have to climb a vine-

Lex Fridman 1:11:21 Mm-hmm.

Paul Rosolie 1:11:21 ... or what scientists... When I was a kid I always used to see them with like the slingshots or the bow and arrows, they would, they would shoot a, a piece of paracord over a branch, pull the rope up and then, you know, do the ascension thing. And then you're up in this tree getting swarmed by sweat bees, getting stung by wasps, you're trying to do science up there in that environment-

Lex Fridman 1:11:39 Mm-hmm.

Paul Rosolie 1:11:39 ... it's incredibly hostile. And so having canopy platforms... I actually met a guy at a French film festival who had used hot air balloons-

Lex Fridman 1:11:48 Mm-hmm.

Paul Rosolie 1:11:49 ... to float over the canopy of the Amazon and then lay these big nets over the, over the broccoli of the, of the trees-

Lex Fridman 1:11:55 Mm-hmm.

Paul Rosolie 1:11:56 ... and the nets were dense enough that humans could walk on the nets and then reach through and pull cactuses and lizards and snakes, whatever, just take specimens from the canopy. That's how difficult it is that, that scientists have resorted to using hot air balloons.

Lex Fridman 1:12:09 Mm-hmm.

Paul Rosolie 1:12:10 And so having a tree house, having canopy platforms, having... It's, it's starting to get, there's starting to be more and more access to the rainforest canopy, and so we're beginning to log more data, you know. We've even observed in our tree house, which is supposed to be the tallest in the world, we're seeing lizards that we don't see on the ground-

Lex Fridman 1:12:28 Mm-hmm.

Paul Rosolie 1:12:28 ... lizards that have never been documented on this sp- on this river. Like we're seeing snakes where they're saying, "We saw this snake inside a crevice on that tree in the strangler fig and we don't know what it is."

Lex Fridman 1:12:37 Mm-hmm.

Paul Rosolie 1:12:39 It's just people haven't been up there.

Lex Fridman 1:12:41 And that's where a lot of the monkeys are? That's where-

Paul Rosolie 1:12:44 Yeah.

Lex Fridman 1:12:44 ... there's just a lot of dynamic life up there?

Paul Rosolie 1:12:47 Yeah. I mean, you, when you wake up in the canopy in the morning in the Amazon rainforest, as soon as that, the darkness lifts, as soon as that purple comes in the east in the morning-

Lex Fridman 1:12:58 Mm-hmm.

Paul Rosolie 1:12:58 ... the howler monkeys start up.

Lex Fridman 1:12:59 Yeah.

Paul Rosolie 1:13:00 And then the parrots start up-

Lex Fridman 1:13:01 Yeah.

Paul Rosolie 1:13:01 ... and then the tinamous start going, and then the macaws start going, and pretty soon everybody's going, and the spider monkey groups are all calling to each other-

Lex Fridman 1:13:07 Mm-hmm.

Paul Rosolie 1:13:07 ... and it's just the whole dawn chorus starts and it's so exciting.

Lex Fridman 1:13:10 So you're saying when they're screaming, it's usually about sex?

Paul Rosolie 1:13:13 Sex or territory, usually, for-

Lex Fridman 1:13:15 Mm-hmm. Sex and violence.

Paul Rosolie 1:13:17 Sex-

Lex Fridman 1:13:17 Or implied violence, or it's the threat of violence.

Paul Rosolie 1:13:19 Implied violence. Yeah. I mean, howler monkeys in the morning, they're letting other groups know, "This is where we're at."

Lex Fridman 1:13:23 Yeah.

Paul Rosolie 1:13:23 "We're gonna be foraging over here. You better stay away." And so it's, it's a little bit respectful as well. There is order in the chaos.

Lex Fridman 1:13:30 So just speaking of screaming, macaws are like these beautiful creatures. They are...... uh, lifelong partners.

Paul Rosolie 1:13:38 Mm-hmm.

Lex Fridman 1:13:38 They stick together, so there's-

Paul Rosolie 1:13:39 Monogamous.

Lex Fridman 1:13:39 ... you often see just, they're monogamous, so you see two of them together. But when they communicate, their love language seems to be s- very loud screaming.

Paul Rosolie 1:13:47 Yeah.

Lex Fridman 1:13:47 (laughs) What, what do you learn about relationships from macaws?

Paul Rosolie 1:13:52 That, that it can be loud and