Season 5: Episode 9

The Silent Type

Birds, frogs, dolphins, and humans—we're all big talkers. Turtles, on the other hand, are considered to be silent. Or are they? In this episode, we challenge what we know about some of our quieter planet mates.

Guests

Credits

Transcript

[00:00] INTRODUCTION

GABRIEL: Okay, so now I'm going to open the incubator where the eggs are. You can see one of them here.

AMY: Oh, yeah.

GABRIEL: You see?

AMY: Yeah, tucked under kind of like sawdust it looks like, in this box.

GABRIEL: And there's one that is about to hatch here.

AMY: Dr. Gabriel Jorgewich-Cohen and I are hovering over the eggs of some of the most endangered turtles in the world. Batagur baska is their Latin name, in English, they’re known as Northern River Terrapins. They’re native to southeast Asia, but these eggs are incubating in a turtle sanctuary in Graz, Austria.

GABRIEL: I don't want to disturb them too much….there's an egg.

AMY: There's an egg.

GABRIEL: There's another egg.

AMY: Many experts already consider Batagur baska functionally extinct in the wild. So these eggs we're looking at hold extremely precious cargo: little beings, about to be born in captivity, that could provide a crucial link in the chain of this once-ubiquitous species. Gabriel’s an evolutionary biologist who specializes in amphibians and reptiles. He's visiting this turtle sanctuary to do research, and I’m tagging along. Both us are holding microphones—mine is pointed at him, while he works on getting his set up in the nest.

AMY: OK, so you're putting a little —

GABRIEL: Now I'm going to put the microphone.

AMY: Right next to the egg.

GABRIEL: Yeah.

AMY: You're trying to capture the sound of that egg, that turtle as it comes out of that egg. And I assume you're not just interested in the sound of the egg cracking.

GABRIEL: No, I'm not interested at all in that.

AMY: So what are you listening for?

GABRIEL: I'm interested in understanding if they communicate through it.

AMY: Gabriel wants to know if these tiny little creatures, smaller than the palm of your hand and not yet out of the egg, might be talking. If you’re thinking: I didn’t know turtles could talk, you’re not alone. Until very recently, most species of turtles were described as mute. 

MUSIC

AMY: Welcome to Threshold, I'm Amy Martin, and as we learned in our last episode, around 250 million years ago, after the Earth went through the massive end-Permian extinction, mammals got small, stealthy, and social, while some new reptiles—including dinosaurs, eventually—came to dominate the planet. But turtles are also reptiles that emerged after that extinction, and with dinosaurs and mammals screeching and chattering around them, turtles explored the world quietly, and figured out how to live in fresh water, the oceans, and on land. Some turtle species have persisted relatively unchanged for tens of millions of years. But now, turtles are among the most endangered groups of animals in the world. Around 180 species are threatened with extinction. That’s almost half of all turtle species — a huge potential loss of animals that we really don’t know very well yet. Just in the last few years, Gabriel started recording the voice of every turtle he could find, and what he heard is helping to re-write the entire story of the evolution of acoustic communication. In this episode, we’re going to follow Gabriel’s journey of learning to listen to some of our quiet and most ancient neighbors.

THEME MUSIC

[04:15] SEGMENT A

AMY: OK, so just to set the scene here, let me tell you about this house in Austria, where I met up with Gabriel. It’s part of an international turtle conservation organization called Turtle Island. From the outside, it just looks like a house. Fairly big, but otherwise nondescript. Inside, however...

AMY: It's kind of like a magic funhouse full of turtles. Little ones, big ones. 

MUSIC

AMY: There's just turtles everywhere.

AMY: There are turtles in the hallways, turtles on the stairs. Turtles in buckets and boxes, in small aquariums and big pools. The living room and bedrooms that were once inhabited by an Austrian family are now homes for turtles from around the world, many of them endangered.

AMY: Three super cute little turtles on a log and there are others that are floating around amongst some cabbage.

AMY: And as I move through the house, taking it all in, one very simple fact hits me over the head: turtles are quiet. Once I step away from the big tanks, with noisy pumps pushing the water around, the house is nearly silent. Here I am, surrounded by hundreds of wild animals, and it sounds like this:

QUIET HOUSE

AMY: Imagine the difference if this was a sanctuary for monkeys or cockatoos or just about any other animal. Given how quiet they are, maybe it's not all that surprising that turtles have been mostly ignored in the story of the evolution of acoustic communication on our planet. But that’s changing, thanks to scientists like Gabriel Jorgewich-Cohen.

GABRIEL: I was born with a passion. My mom says that my first word was mom, and my second was fish after I saw koi fish in a pond. My dad would buy me toys of cars and other things, and I would never be interested. Only animal toys.

AMY: Growing up in São Paulo, Brazil, Gabriel took a special interest in amphibians and reptiles. He was around 10 when he got his first pet turtle—the first of many, as it turned out. Two of the most recent ones were named…

GABRIEL: Hulk. And Homer.

AMY: (laughter) Like Simpson?

GABRIEL: Yeah. I thought that one was a bit stupid.

AMY: How does one turtle show its lack of intelligence? I'm curious.

GABRIEL: I don't know, maybe it was my own interpretation. Maybe I was the stupid one.

AMY: Hulk and Homer weren't big conversationalists, and that made sense to Gabriel, because he had been taught that although tortoises make sounds—a tortoise is a kind of turtle that lives exclusively on land—aquatic turtles were mute. But in 2012, when he was in the middle of earning his Bachelor's degree in biology, a team of scientists published some groundbreaking new research that changed what Gabriel thought was possible.

GABRIEL: They were one of the first people publishing a paper showing the one species of turtle was able to communicate with sounds.

AMY: That species was Podocnemis expansa (poh-dohk-NEH-mis ex-PAHN-sah), the Giant Amazon River Turtle. Like almost all aquatic turtles, females of this species dig nests on beaches and riverbanks when it's time for them to lay their eggs. They cover them with sand, and return to the water. Later, the baby turtles break out of their shells and dig up out of the nest, emerging into the world looking like miniature pancakes with legs. Then they have to find their way to water as quickly as they can, with hungry birds and other predators lurking everywhere. It’s a lot for a newborn turtle to handle right off the bat, and one of the ways they get through it is teaming up. In many species, turtle hatchlings coordinate the work of being born. Amazingly, some of them can actually control the speed of their own development in the egg. Then they hatch, scramble up through the sand, and run the gauntlet to the water together. 

GABRIEL: So they individually have less effort to dig out the nest. And also they have less chances of being eaten by a predator.

AMY: After earning his master’s degree, Gabriel took a trip into the Amazon with some of the scientists who had documented hatchling vocalizations to learn more about the role sound might play in this synchronized birthing process.

GABRIEL: They took me to a beach where the turtles were hatching, and I could actually hear them making sounds without the use of any equipment. And I thought that was super cool.

AMY: Turtles were supposedly silent, but here were these hatchlings, clearly making sounds, possibly to help them synchronize the daunting work of making it from the egg to the river. 

GABRIEL: And when I saw that it made me think—because I am a evolutionary biologist—what about those species that are in branches of the tree that are in between those that we already know they make sounds.

MUSIC

AMY: Lots of vertebrates were known to communicate vocally. Birds, frogs, dolphins, us...we're all big talkers. But not these aquatic turtles and a grab bag of other amphibians and reptiles. And based on that, it was thought that vocal communication had emerged multiple times, in multiple branches of the evolutionary tree. But as Gabriel stood there in the Amazon listening to the turtle hatchlings, he thought: what else have we gotten wrong here? If this species of turtle was using vocal communication, what other supposedly mute animals might have things to say?

GABRIEL: So I decided to try and record some of them. And I started with the turtles I had at home.

AMY: Gabriel came home from that trip eager to listen to Hulk and Homer. A former professor helped him rig up a hydrophone…

GABRIEL: And I started recording my animals, and...and they all made sounds.

AMY: He heard clicks, mostly. But also some bird-like sounds.

TURTLE NOISES

GABRIEL: But then I started questioning. Are those sounds made by the turtles, intentionally made by the turtles? Like, it could be that they are just scratching the floor. It could be that these sounds actually come from, I don't know, they're ambient sounds, and they're not actually coming from the turtles. And you're not sure.

TURTLE NOISES

AMY: So he kept recording his own pets and other turtles too.

GABRIEL: I was trying to record as many as I could. I was asking for access in zoos in Brazil and things like this.

AMY: He also continuously tweaked his process, eventually adding cameras to his set-up.

GABRIEL: So I could film the behavior that they were performing at the same time they were performing the sounds. And not only get to know for sure that they were producing those sounds, but also try to infer the meaning of them.

MUSIC

AMY: And the more recordings he made, the clearer it became: the turtles were indeed intentionally producing sounds. These were not random body noises, but acoustic communication.

GABRIEL: Yeah, and when you start hearing those things, it's very exciting in one hand. But on the other hand, I wasn't super confident because this is something that's not known and you think, well, if I discovered this, someone would have discovered it before, right? Like, it's so stupid. I didn't do that much effort.

AMY: (laughter)

GABRIEL: And, in the end, in the end, they were actually making sounds, and no one knew.

TURTLE SOUNDS

AMY: Gabriel started working toward his PhD at the University of Zurich in Switzerland, and his quest began to change.

GABRIEL: At first, I wanted to have a good sampling so I could understand the evolution of acoustic communication in turtles. Once we realized that every single species we recorded were producing sounds, we decided to go further and check, all those species that have been historically considered to not not being able to produce any sounds.

AMY: This included some very ancient species, like—

GABRIEL: Tuatara, which is, lizard-like animal, but not quite, from New Zealand.

AMY: And some extremely unusual creatures.

GABRIEL: A caecilian, which is an amphibian related to salamanders and frogs. It's a strange limbless animal.

AMY: He also put a microphone in front of a lungfish, the modern version of a very early type of fish that started the whole vertebrate migration out of the sea. And in every instance, Gabriel got the same answer.

GABRIEL: Every single one was producing sounds.

AMY: Gabriel pulled some of his recordings up on his computer, so we could listen to them together. We started with the caecilian.

AMY: OK, let's listen to it.

CAECILIAN: (splat)

AMY: Let's hear that again!

CAECILIAN: (splat)

AMY: Yeah, what do you think that sounds like, Gabriel?

GABRIEL: Sounds like a beautiful bird in the morning, right?

AMY: laughter

GABRIEL: It sounds like a fart.

AMY: Sounds a lot like a fart. But it's coming from the front end of the caecilian, not the back end?

GABRIEL: Yeah.

AMY: So granted, these are not particularly beautiful sounds—at least not to us, maybe this is poetry to another tuatara. 

TUATARA

AMY: But the real point here is not the aesthetic values of these sounds but rather the fact that they’re happening at all. These creatures, previously defined as voiceless, are not silent. We just haven’t been good listeners. And it turns out they actually have important information to share about how acoustic communication has evolved throughout the whole tree of life.

TURTLE SOUNDS

GABRIEL: Before, the ability of communicating with sounds was thought to have evolved many different times. So, the sounds made by frogs were thought to be different evolutionary-wise from the sounds made by birds, and the ones made by mammals.

AMY: And that was because there was this missing gap where they assumed all these animals were mute. So then it would have had to have popped up in in frogs over here, and birds over there.

GABRIEL: That's right. Okay. Yeah, that's exactly it.

AMY: Okay. So then you started recording, and you're like, okay, all these turtles are making sounds. What about tuataras, what about the weird limbless guy whose name I forget already...

GABRIEL: Caecilians.

AMY: Caecilians. And you found they were all making sounds.

GABRIEL: Yeah.

AMY: And then that tells you…

GABRIEL: Exactly the opposite. They actually, they all have the same behavior that comes from one unique evolutionary origin.

AMY: That is so cool. I mean, that's like rewriting parts of our story of evolution. How old are you?

GABRIEL: I'm 31.

AMY: You're too damn young to discover something that big. I mean, that's a pretty big deal, isn't it? It seems like a big deal.

GABRIEL: I guess. I well, I guess so.

MUSIC

AMY: I'm just going ahead and say: it is a big deal. Gabriel's work shines a new light on how crucial acoustic communication is to life on Earth. Animals apparently started producing sounds for communication way, way back in time, in the common ancestor of amphibians, reptiles, birds and mammals.

GABRIEL: I'm talking about a common ancestor between all these land vertebrates.

AMY: And how far back would that common ancestor be?

GABRIEL: Over 400 million years.

AMY: Wow.

GABRIEL: This gave us a new interpretation of the origin of sound production or the communication with sounds in this group of animals. And I don't think it's because it's like a super complex finding, but just because no one tried.

MUSIC

AMY: We are descending into the basement of the turtle house, where...guess what? More turtles. It truly is turtles all the way down.

AMY: The basement is full of big tanks with pumps running nonstop to keep the water moving.

MADELEINE: Anybody see one, this big, brown with yellow splotches?

AMY: I see a much bigger one.

MADELEINE: Yeah, that's the baska.

AMY: Madeleine Wheatley is a scientist who works at Turtle Island. She's waiting until a female Batagur baska swims close by, and then reaches into the tank and pulls her out. For a moment, the three of us stand around this turtle, admiring her glistening shell and her cute little piggy snout. Then Madeleine puts her into a different tank, with a male of the same species.

SPLASH

AMY: Big turtle delivery.

MADELEINE: whoop!

AMY: We step away to give the couple some space and I ask Gabriel to explain what he's up to here.

GABRIEL: I just set up a hydrophone inside of the tank of the couple. Because I want to get the sounds that they make when they are together. So these two individuals were in separate pools, and now they are together in the male is interested in the female. And I expect that he makes, like, courtship sounds.

AMY: Can you imitate what a courtship sound might look sound like?

GABRIEL: No no no, this species has never been recorded before. So I have no clue.

AMY: Just like with fish, and treehoppers, and naked mole-rats, we know next to nothing about the acoustic lives of most turtles. 

GABRIEL: Like, I'm, I'm in the Middle Ages of turtle acoustic research.

AMY: Gabriel did end up capturing sounds from this highly endangered Northern River Terrapin—and he was the first person ever to do so. 

BATAGUR BASKA 

AMY: Here’s the voice of another critically endangered river turtle, Tortuga Blanca, from Central America.

TORTUGA BLANCA

AMY: And here’s what the world’s most endangered sea turtle sounds like, known as a Kemp’s Ridley.

KEMP’S RIDLEY

GABRIEL: So far, what I did was to check if turtles are making sounds. I just needed an answer, yes or no. But now I want to understand how they use those sounds and what is the diversity of sounds that they produce and things like this. And of course, this is limited because I'm doing it in captivity, but it's a first step and later on I can or other people can start recording them in the wild as well.

AMY: But only if they still exist in the wild, or can be successfully reintroduced. We could very well lose the voices of these and many other turtles, just as we've begun to listen to them. They’re getting hit from all directions by habitat loss, over-consumption, destructive fishing practices, and climate change. And when Gabriel headed out into the field, it became clear that the science he wants to do is also tangled up in these human dramas. We’re following him into the Amazon after this short break.

Break

[20:44] SEGMENT B

GABRIEL: This is day one in the Amazon journey. We are at the airport in Sao Paulo..(AIRPORT NOISE) about to go to Manaus.

MUSIC

AMY: Welcome back to Threshold, I’m Amy Martin, and this, as you know, is Gabriel Jorgewich-Cohen. Before the break, we were focused on Gabriel’s research and discoveries; his scientific output. The rest of this episode is about process: what it actually takes to do science like this. I wasn’t able to travel with Gabriel into the Amazon, but he took me with him via voice memo.

GABRIEL: Today's our first day in Manaus. We arrived here, around 2 a.m.

AMY: Manaus is the biggest city in the Amazon, and it’s where Gabriel organizes his field work. His destination is the Trombetas River Biological Reserve, a protected portion of the rainforest near Brazil’s northern border. Giant Amazon River Turtles thrive in this area. That’s the same species that Gabriel had seen—and heard—years before. On this trip, he’s aiming to collect a lot more recordings from both adults and hatchlings. But first he has to get there.

GABRIEL: And the way there is a bit complicated with several different boats that we have to take, and I'm a bit lost at the moment. It's a bit stressful, but at the same time, I'm very excited about what we're going to see.

AMY: The Amazon region is one of the most biodiverse and critically important ecosystems on the planet. It functions like an enormous lung for the Earth, with billions of trees breathing in carbon dioxide and exhaling oxygen on a mass scale. Although it’s less than one percent of the surface of the Earth, it’s home to around 10 percent of all known plants and vertebrate animals, and likely many more that we haven't yet discovered. An area of the forest half the size of a New York City block has more species of trees than the entire continent of Europe. And then there are the millions of insects and other invertebrates that live in the rainforest, including thousands of different kinds of butterflies. Industry and agriculture are eating away at the forest, but huge swathes of it are still roadless. That’s part of what makes it so mind-blowingly diverse, and so challenging to access.

GABRIEL: Today's Tuesday and we are finally, after two weeks in Manaus, traveling to Oriximiná by boat, where we’re going to get another boat to Porto Trombetas, where we’re going to get another boat to the base. So I'm excited about it, and it's good to be in the boat, finally.

GABRIEL: Today's Wednesday, 3 p.m. We just arrived at Oriximiná. We are getting closer.

GABRIEL: Today's Thursday, it’s now almost 10 p.m., and we just arrived at the base. We finally got here, it took forever. And now we have everything we need. And we can start to work tomorrow. 

NIGHTIME SOUNDS FROM NEAR THE BASE

AMY: People are part of the Amazon too, and they have been for thousands of years. Around 400 Indigenous groups live in the region speaking at least 300 distinct languages—and there were probably twice that many languages spoken here before Europeans arrived.

GABRIEL: People at the base are really nice. We feel welcomed. The turtles already started laying eggs, so there are couple of nests at the beach, and they're going to be laying eggs for nearly a month now. And there's lots of work to do. And yeah, it's exciting to finally be here.

MUSIC + AMBI: GABRIEL IN CANOE, THUNDER

AMY: The Amazon is full of life because it’s full of water. It’s essentially a giant network of streams and rivers all flowing into the namesake main stem, running west to east across the top of the continent. Years ago I visited different parts of this region and I’ll never forget how the sky would open up and unleash torrents of water repeatedly throughout the day. Another strong memory is how loud the Amazon was. Everything seemed to be singing and calling and humming and chirping and growling and buzzing at once, day and night. And that’s what the recordings Gabriel made sounded like too.

GABRIEL: The place is beautiful. We see many animals. We saw, like a giant otter the other day. River dolphins. Monkeys everywhere. A lot of birds. A lot of caimans. Lot of turtles. It's a beautiful place.

GABRIEL: We have been at the base for 3 or 4 days now. A lot of work going on here and not a lot of sleep. We spent the last night at the riverbank with the people that live here and take care of the turtles. And there were many, many turtles. We only saw them from far away. And, it was an interesting experience to sleep at the beach. There were many birds there and also many howling monkeys.

HOWLER MONKEYS

GABRIEL: They say that sometimes there are jaguars there. And we slept there on top of the sand. So it was… it was fun. It was fun.

GABRIEL: But it's so hot. So hot. And we are sweating all the time, and it's really, really tiring. There are also vampire bats here. We're a bit afraid of them because we don't have any protections, and it's impossible to sleep inside of the house. So I'm going to try to get a net to avoid being bitten and getting rabies.

AMY: He did end up hearing a jaguar one night while he was sleeping at the beach.

GABRIEL: That's not something you hear every day. And that was awesome. And I have some recordings of it. If you're interested, I do have it.

JAGUAR

MUSIC

AMY: Giant Amazon River Turtles live up to their name. They weigh in at up to 65 kilograms, or around 145 pounds. Gabriel has arrived just as the turtle mothers are starting to climb up out of the water, dig deep holes in the sand with their feet, and deposit their eggs.

GABRIEL: So we're going to see a lot of activity, so we can see their behaviors, and we can record their sounds, which now I plan to do both underwater and in air, and also inside the nests. So it's pretty exciting.

AMY: And he told me multiple times that there was no way he could do his research here without the assistance of the people who live in the community closest to the base. He told me more on a phone call one day.

GABRIEL: Just so you understand the context a little bit. The place we are at is a base from the wildlife services and this is a national park. So it's a protected area and this is all on one side of the river. On the other side of the river is all Quilombola territory. Quilombola, I think I told you before, it's a name we use to refer to people that were brought to Brazil as slaves, and they ran from slavery into the jungle and created communities. And they are in these communities until today. So now the wildlife services hire these people to help protecting the target species. In this case, it's the Giant River Turtle. And they do all the surveillance, they care for the eggs, things like this.

AMY: Quilombola people were living inside the Trombetas Biological Reserve when it was founded in 1979. Some of them were forcibly removed, a process that created tensions that are still alive today. But many Quilombola people now work with wildlife officials and researchers like Gabriel.

GABRIEL: We talk a lot. We spend a lot of time together at the base, we have meals together. We play football. We sit down and chat. Also, they tell us what we can do, we cannot do, or what we shouldn't do for our own safety, or for the safety of the animals, for example. They support us in setting up the equipment. They're very important for the success of the whole operation.

JOEL (in Portuguese): Well, first of all, I am the natural son of the river, since I was born I have been here. In 2016 I had the opportunity…

GABRIEL (translating): He said that he's a natural son of the river.

AMY: Joel Pires is one of the Quilombola people helping Gabriel with his research. I talked to him on the phone with Gabriel serving as the translator.

GABRIEL: So he was born here and his life was always associated to the river and to wildlife. And although he works for the wildlife services for three years where he's getting more of a scientific knowledge about the animals, he always had, like, a tight relationship with nature and he was always interacting and observing them.

AMY: I asked Joel how much sound is a part of that tight relationship he has with the forest.

JOEL: Let's say that we know how to identify all the sounds of animals here in our river….

GABRIEL: He says that the sounds of animals are really important for them, that they can recognize every species here just based on the sound, they don't need to see anything. They know where the animals are, and what are the animals producing these sounds. And then I asked if they answered the animals, and then he said, yeah, we can make the noise as well, and communicate with the animal and then I asked him, why would you communicate with the animal? And then he laughed and said, just to test my abilities.

JOEL: (....just to test my abilities)

AMY: Does he remember as a child being taught to listen as part of just keeping himself safe in the forest?

JOEL: So, as we have the habit of walking in the woods, we have a kind of alert sound to always look for attention and observe. And we have a little bird…

GABRIEL: When you're walking in the jungle and you hear the sound of a bird, the bird is called uirapuru, that bird is known to signal predators, and other animals also recognize the call of this bird. So he knows that when the bird is singing, there's always something more ferocious than him.

AMY: This is what the uirapuru sounds like.

UIRAPURU: recorded by Felipe Arantes

AMY: It’s English name is the Musician Wren.

UIRAPURU

AMY: Gabriel says for Quilombola people, the jungle is home—a space they are as intimately familiar with and comfortable in as I am in my living room. And of course, I would notice if someone came into my house and left something new in it. And it’s the same if Gabriel wants to set up a recorder in the jungle and leave it running. He says people will spot it right away.

GABRIEL: We don't know the ways of people here. There are things that they see I cannot see. So if I want to set up something and I want it to be hidden so no one will touch it, it has to be such a great camouflage that it's really hard for me to get it back later. So they have to camouflage it with me and teach me how to do it. 

MUSIC

GABRIEL: Today is October 6th, the recordings are going well. The turtles are aggregated and laying their eggs. Most of the nights you can find turtles at the beach. Around, I don't know, let's say 100 turtles a night, maybe 50. Something between the those numbers. Although things are going well with the recordings we have experienced some issues with the environment because there are several people trying to eat the  turtles and catch their eggs.

AMY: People have eaten turtles and their eggs in the Amazon at a sustainable scale for thousands of years. But European colonization brought an entirely different kind of turtle hunting into the rainforest. The story is reminiscent of what happened to bison and whales—in the 1800s, millions of animals were captured and killed. Their bodies sold for meat, their skins and shells used in everything from combs to tambourines. Oil made from turtle eggs was used to light lamps in quickly-growing cities. Today, Giant Amazon River turtles are a protected species. But smuggling them and their eggs is still big business here, and the lines between that sort of turtle hunting and subsistence consumption are not well-defined or easily enforced. Mix in conservation and research efforts, drought and deforestation, and you have a recipe for conflict.

GABRIEL: So the rangers at the park are struggling, trying to protect them. But the area is way too large for these people to take care of every single turtle and all the extension of the park. And the tactics that the hunters use are sometimes very mean. They have, set fire to an area of the park, and the rangers have to go there to get rid of the fire and protect the jungle.

AMY: And while the rangers are busy putting out fires, the hunters zero in on the beaches where the turtles are gathering to lay their eggs.

GABRIEL: And they catch them, and they're very large animals, so it’s hard to transport them. So they catch them, they put them inside of the jungle, and make sure that they are unable to move. They use ropes, and I don't know what else. And then they keep catching the turtles, and once they have a large number of them, they just put them in a boat and leave at night to sell them at markets, or at people's houses, or something like that. So it's tough and you have to be careful. People bear guns. You don't want to find them in the middle of the jungle because they want to protect their hunt and they know it's illegal. So we have to be careful with that. But, yeah, you have to deal with the circumstances. This is part of the job, I guess. And, I'm here to study everything, I guess. So, this is also part of it. All right.

AMY: Poaching is only one of many things threatening the turtles here. The Trombetas area is home to Brazil’s largest bauxite mine—that’s a rock that often holds a lot of aluminum—and a major logging project was recently approved. The turtles and the local people are caught in between all of these forces of change, not only in the Trombetas area but throughout the Amazon. And it’s happening within the context of the overarching megathreat: a quickly changing climate. The entire Amazon region has experienced devastating drought for several years. Rivers are heating up and drying out, causing mass die-offs of fish and endangered river dolphins. Joel says that in recent years, the impacts of climate change have been impossible to miss.

GABRIEL (translating for JOEL): For the turtles specifically, it was really bad because the success rate for the hatchlings was very very low so they lost many of the nests and eggs. And also for the adults this is not good because they don't like to show themselves and because the water level was so so low, there were not very deep parts of the river anymore, so the animals were stressed, that delayed laying, and he could see from the behaviors of the adults that they were not happy, that they were stressed.

AMY: And he says the drought brings stress to people, too. In the Amazon, rivers are highways—they are how people move from place to place. So when they dry up, it’s like shutting down the interstate.

GABRIEL: So they get stuck because there's no more water, so they cannot pass.

AMY: The Madeira River, the biggest tributary of the Amazon, dropped to just 48 centimeters in September of 2024. That’s 18 inches of water in a river that’s normally around 10 feet deep. All of this makes it harder and harder for people in the Amazon to survive solely on what the forest provides. Working with wildlife officials and scientists can provide some income, but like Gabriel said, it can also be dangerous. But for Joel the risks are worth it. He says he’s excited about the research they’re doing, and he’s proud to be on the team working to keep the animals safe.

JOEL (in Portuguese): It really is the turtles. The turtles have a great importance for us here. And that's why I say, today I feel happy to work in their protection.
GABRIEL: They are very important for the community. And he mentioned the importance to focus on the conservation of the species. So it's there for the next generations. They don't want them to disappear, so they can keep being an important species for the community in the future.

AMY: Is there anything that he really wants people to know that I haven't asked?

JOEL: Yes, we have a very beautiful environment here, very beautiful, our landscapes are very beautiful…

GABRIEL: The thing that he would like people from outside to know is that the environment here is beautiful. They have so many things to see, and he thinks that people from outside would like to visit and get to know the things that they know here. And he thinks that's important because they have many people here that are specialized in many fields, but they don't have a lot of opportunity and having people visiting would create opportunity for them to work.

JOEL: Well, we have the hope of keeping it, because we are Quilombo, right? So we always expect that we continue.

GABRIEL: He hopes that they are able to keep their land and their traditions. And they get the respect for their ways, so it remains untouched in the future.

JOEL: Keep with our traditions, the Quilombolas. Keep our forest. This is a hope.

MUSIC

GABRIEL: Hello, Amy. This is Friday, 13th of October, and we are still recording turtles here. They are now about to finish the laying season. Last night there were around three animals only. So I expect to stay here for one more week or maybe ten days, something like this, and then go back to Manaus and I don't know how it's going to be because there have been several burnings of the forest, and I hear that Manaus is covered by smoke, so not the most welcoming environment. And also there is a huge drought here in the Amazon, and many of the rivers are gone. So I don't know if the boat can go through all the way back to Manaus from here. So we might be stuck as well. Let's see. 

AMY: Gabriel did get back to Manaus, where he was able to start processing the recordings he’d made in the open air, under water, and inside nests, as the little hatchlings worked their way out of the eggs and sand.

HATCHLINGS IN NEST

AMY: These are voices of Giant Amazon River turtles, before they get giant. Exactly how many of these turtles there are, and how well they’re holding up against all of the threats they face, isn’t clear. As with so many other turtle species, and so many of our planet-mates in general, we need more information. 

AMY: More science. More scientists. More collaborations between local people and researchers. More watching. More learning. More listening.

Credits

This episode of Threshold was written, reported, and produced by me, Amy Martin, with help from Erika Janik and Sam Moore. Music by Todd Sickafoose. Post-production by Alan Douches. Fact checking by Sam Moore. Special thanks to the staff at Turtle Island in Graz, Austria, and to Gabriel Jorgewich-Cohen for the use of his scientific recordings, for documenting his field work via voice memo, and for serving as a translator for the interview with Joel Pires. You can find his website in the show notes for this episode. The recording uirapuru, or musician wren, was made by Felipe Arantes, and shared through the website Xeno Canto dot com. This show is made by Auricle Productions, a non-profit organization powered by listener donations. You can find more about our show at thresholdpodcast.org.

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