Kleptotherms

0:28Hey, this is Radiolab. I'm Latif Nasser. seeking warmth. Sometimes they do it in obvious ways. Sometimes they do it in devious ways. We first aired this episode back in 2021, and you'll hear there are certain things about it that do feel very 2021. But there's also so much in here that feels timeless. Stories that I feel confident will stay relevant until the thermal death of the universe. Wait, you're listening. Okay. All right. Okay. You're listening to Radiolab. From WNYC.

1:10Rewind. Lou. Hey. How are you feeling? I mean, I feel fine. I think I still am like a dashed nasally. Hi there. It's Radiolab. I'm Lulu Miller here with senior correspondent Molly Webster. So can you humor me and close your eyes? Yes. Eyes closed in my closet. Okay. So now journey with me. Me and you are on a trip. We've got our backpacks and our hiking boots. Okay. And we come across this site, an archaeological dig, and they're like unearthing this ancient library. And we're like looking all around and you're over there and I don't know, you find like an old globe. And then we come across this book that's like covered in dust.

1:58and we blow the dust off. And the dust, like, it turns into, like, snowy, frosty snowflakes and little tiny flames. It's like... And then it says in silver letters, kleptotherms. And then we were like, ooh, what's, what, what? And we crack the book and it's like... And we open it. And there's five chapters. And we turn the page in the first chapter. There's just a picture of a snake in a coil. So we're going to start and read that chapter. Okay. So once upon a time, there was a bright blue snake in New Caledonia. It's bright blue and black. So it's just like striped. Is this real? This is real.

2:57Oh, this is one. Okay. Oh, it turns out this whole book is stored in the Library of Congress as nonfiction. Okay. So it's this blue and black snake. It looks kind of like beetlejuice. And it is a horrible thing. It's an amphibious sea snake. So it can live in the ocean and on land. And scientists have observed that it does this thing. They sneak into burrows, which are occupied by large tropical seabirds. This is Hans Iserman, a social scientist at the Université Grenoble Alps, who explained that the snake will slither deeper and deeper into the burrow toward the bird sneaking up. And then it just kind of hugs it.

3:43And they take advantage of the mass body heat in warming their own bodies. And are they not even eating those birds? They're just kind of like curling around them and sucking up their heat? That's essentially what they're doing, yes. Wow. There's just something so primal about the heat being more important even than the meat. Yeah. So this behavior is called kleptothermy. Kleptothermy. And what does that mean? Basically engaging in heat theft. Okay. You see it all throughout the animal kingdom. Really? Yeah. Seriously? Yeah. So like male garter snakes? They pretend to be female so that other males will try to mate with them.

4:21Like the friction of them trying to mate just warms them up? Yes. There's little dwarf caimans, which are kind of crocodile-y looking things that steal from termite nests. How do you cuddle up to a termite? I don't know. I think you just throw yourself upon the whole warm nestiness of all that bug heap. Wow. And us humans also engage in cleptothermia when we want to. That oh-so-sweet act of cuddling, or as the scientists call it, is, for at least one person involved, a theft. I remember reading about it a couple years ago, and I thought it was just fascinating. But if you think about it, it feeds into the same kind of equation.

5:03An equation biologists call the economy of action. It's very simple. Animals need to take in more energy than they exert. And one of the most expensive things that we do, particularly as mammals, is warming our bodies. And it turns out that of all the ways to keep our body warm, jumping up and down, finding a sunspot, eating something really fatty, getting our warmth from another creature is super efficient. It can decrease the cost of thermoregulation by up to about 60 or 70 percent. Wow. There are a lot of observational studies on this for many, many different animals. Rats, penguins, degus.

5:43Not only is their peripheral temperature higher, but also their base metabolic rate is much lower, meaning that they exert much less energy. To stay warm. Huh. And so Hans' idea is that because for so long, humans relied on getting warmth from one another to survive. Even 200 years ago, people would sleep with nine people in one bed to keep warm. Our sense of how chilly or warm we feel isn't just about air particles. It is being influenced by the people around us. Way more than we typically think. I think it's for most people, it's hard to imagine until you see it and then you can't unsee it.

6:34Which brings us to...

6:41Chapter 2.

6:51What's the picture? I'm wearing sweatpants, a long sleeve shirt. It's a guy in a jacket. It's probably one of my nicer shirts. I wanted to look nice even though it's only the radio. His name is John, and he's going to lead us to a different idea about how to get warm. Okay. Okay. Can you tell me a little bit about where you grew up? I grew up in the woods, in a house in the woods in Connecticut. Do you remember how the world felt to you as a kid? um like thinking back me and my sister would make paths through the woods there was a pond nearby and we would go frogging and I just remember playing with the hose getting water all over us and feeling free but as he started to get a little bit older when I was 13 or 14 things really started to change.

7:55I gained a lot of weight and everyone was like making fun of me. And I became very uncomfortable in my skin. Which, you know, happens to a lot of middle schoolers. But for John, it hit him harder. I was scared of looking at my own reflection. I almost thought I like was seeing a ghost. I would keep the lights off and keep a distance from the mirror. I didn't look at the mirror for like two or three years. And then once he hit college, I started hearing voices. And what were some of the kinds of things they might sort of be saying to you? Do this and do that. I got to walk in a certain fashion and they told me that I didn't deserve to eat.

8:53It was madness. And then I saw a doctor. Like, did you get a diagnosis then? Yeah. Schizoaffective. Which is not exactly schizophrenia, but has some of its symptoms. He prescribed me a drug, an antidepressant, and I had a really bad reaction to it. What happened? It really brought on those internal voices. Like I remember driving in the car, thinking everyone on the road was targeting me. So? I went off my meds. But this sense that people were out to get him just kept getting worse. I just remember everyone giving me a hard time. How did they give you a hard time? They would like give me dirty looks.

9:44They would pull schemes on me and mock me at times, maybe even. I remember my mom saying once, people aren't out to get you. And if you take your meds, then you'll realize that. So like, how sure are you that you were actually being mocked and actually being given dirty looks? and how much do you think that could have been something inside you seeing it that way? It could have been something inside me somewhat, but it's hard for me to believe that it was all me making it up. So he keeps just trying to muddle through. And at a certain point, John does something seemingly trivial. It's a nice warm day out, shorts and t-shirt kind of weather.

10:38and he puts on a winter hat. I got for Christmas one year. What color? It was gray. It's a comfort. And before he heads out the door, he rifles through his stuff and decides to also put on a hooded sweatshirt, hood up. And then he grabs a third layer. It was a jacket. And a fourth. Sweatpants. Until eventually he's all bundled up from head to toe. And he started going out. in the muggy heat of a Connecticut summer, wearing this little getup all the time. And people would say things like, What are you preparing for a wrestling match? Like trying to lose weight for a wrestling match? Right, right, like training in trash bags kind of thing.

11:26Yeah. And John is the first person to say, like, as he was putting on all these layers, he was falling into this trope. Like if you saw someone walking around in a ton of layers in the heat of summer, you're probably going to think something's up. Maybe keep a wide berth. I mean, when people see you wearing layers, what do you think they think about you? I think they're fearful. They fear me. Hello? Hello. And the thing is, while most people might step away when they see someone wearing layers, there were a few people all over the globe who decided to look closer. Am I audible? There you are. Sorry about that.

12:12This is Dr. Tathagata Mahintamani, a psychiatrist in India. Currently, I am in north-western part of India. Who, back when he was starting out as a psychiatrist in Rachi, started noticing that in the middle of summer, Every now and then, people with schizophrenia would walk into the hospital wearing tons of layers. Ladies were wearing multiple layers of saris and male patients were wearing multiple layers of shirts. And over in Melbourne, Australia. I was doing my first psychiatry rotation. Dr. Terence Chong was treating a patient with schizophrenia. I noticed at the time he was taking off layers and layers and layers of clothing.

12:54And this was in the haze of summer. There was a doctor in Memphis, Tennessee, who noticed the same thing. Wow. Yeah. And eventually it even got a fancy medical name. Redundant clothing. So the idea there is just, it's redundant. You don't need it. It's multiple. It's redundant. Redundant clothing. Yes. So a bunch of doctors were seeing this, but nobody really knew why. And some of the explanations were like, look, people with schizophrenia, some of them end up not having homes. They're living on the street. You have to keep your belongings on your back. So like you have you wear them all. Another thing might be evolution.

13:33A lack of motivation. So basically the person maybe forgot to take the last layer off. Yes, yes. Another explanation is just this generalized erratic. I'm confused. So I have on all these clothes. I mean, there were all kinds of different explanations. Can you just describe why you crave the layers? I think it's a way of shielding myself from the world. Like, I feel the world is harsh. It's hard. It's hard for me to completely put a finger on it because I was just doing what felt natural. And Dr. Maheen Tamani, after seeing enough people walk through his door wearing layers in the heat, seemingly comfortable, wanted to figure out if something else was going on.

14:23So he got a group of people with schizophrenia, some of whom wore layers and some of whom didn't. And he just ran all these tests. He did like cognitive tests and psych tests and physiological tests and basically long, long, long, long, long story short. What he found was that the people in layers had something different going on with their blood. First of all, their blood pressure was dropping way lower on certain tests. And when he analyzed blood samples, he found that their T3 and T4 levels were lower. And what does that really mean? Like, what does that mean? So, free T3 and free T4s are very reliable markers of temperature regulation.

15:05Temperature regulation? Yes, with cold intolerance. Like you just get cold quicker? Yes. Okay. You feel cold quicker. Wait, so they're actually, they may have layers on because they are actually physically colder. I asked him almost exactly that. Is your idea that they are actually wearing the layers to feel warmer? It is our findings.

15:38and our ideas are based on our findings. He says the evidence suggests that they are wearing layers for the same reason you or I wear layers when we go out into the winter. Their body is telling them they feel colder. Now, back in Connecticut, John didn't know any of this. He just knew that the more he tried to stay warm by bundling, the more it pushed people away. It was a really difficult time for me. And things finally got so bad that he goes back to the doctor and this time is in fact diagnosed with... Paranoid schizophrenia. And he's prescribed a different medication. I immediately noticed less up and down, less craziness.

16:22I noticed myself getting better by the day. And the world seemed to be getting a little better too, a little gentler. And I felt people liked me. And he started loosening up, literally taking off his hat. Yeah. His jacket. Well. Or one of them. It was winter and I would wear like a tank top under a winter jacket. And that was it. And he started to embrace his diagnosis. I read about how people with schizophrenic disorders oftentimes think divergently. and a link to creativity. And he would tell people about it. Like one time he went to go buy cigarettes and the guy behind the counter thought he looked a little young.

17:12And I said something like, schizophrenic people tend to look young, which I don't know if it's even true, but I was very proud. I wasn't very proud, but I was like I had some pride.

17:30And then one day, about 30 miles away from where he lives...

17:56For an instant, they worried the shooter had been John. It was really hurtful. It was like I would never do anything like that. I definitely stopped having that pride towards my diagnosis. He stopped taking his medication. I felt a lot more gloom and doom, and I started to slip real quickly. Into this chilly spiral where without his meds, the world started to seem colder, which Dr. Maheen Tamani explained can be this unfortunate part of the disease that the longer you go it alone, it can have what's called a neurotoxic effect. Our neurotoxic effect on the brain, loss of brain function, and also there is structural brain damage also there.

18:46As the time progresses, the patients with schizophrenia often, you know, drifts. So as John was drifting, the world started seeming even colder. Thinking everyone was targeting me. So he'd layer up, which itself would make the world oftentimes be colder. There was a woman walking and she just gave me the dirtiest look I've ever seen in my life. And I said to her, what is it, the winter clothes that I'm wearing that makes you dislike me? And she immediately called the police. And then it's like one more layer. Another layer. Wow. Wow. At the end of our study, we also thought that this might be a window.

19:40You know, this kind of redundant clothing might be a window through which we can peep towards something really, really broken down. Dr. Maheen Tamani found that the thing that the people who were wearing layers all had in common was that compared to the controls, they were the ones who had been going it alone. without treatment for longer. That's really wild that you could just look out and like see that from the outside. Yeah. Which made me start to wonder, is it almost like humans have within them like this visual signal for like, I'm really lost. I might not even know how to ask for help, but here is a signal.

20:28That's pretty. I mean, I put the idea to Dr. Raheem Tavani and he was like, I am not in a position to answer this, but this is a wonderful and intriguing question. Yeah, but I also put it to John. Is there anything to that or am I like overly projecting an idea? No, I think you're you could be on to something. I think there could be like a cry for help through layers. And he told me a story about one time when someone seemed to read it that way.

21:26I think she was wearing a t-shirt and short jean, jorts. Jorts, the old lady jorts. Yeah. I said, hey, how are you? I was probably not talking that clearly and making much sense either. And she asked me if I would sit down and have lunch with her. I took a bite or two from my grilled cheese sandwich. I almost felt I didn't deserve that food. and I said to her, I think I'm going to feed the rest of the birds. And she said to me, don't feed the birds, just eat your food. But then I ultimately fed the birds. She went aw, like feeling empathy towards me. Yeah. Did you feel a little bit better after that?

22:19Yeah, I did feel better. He eventually felt so relaxed. He slipped off his sandals and he put his feet on the sand and he just walked home barefoot. Yeah.

22:51Okay, so turning the page. Chapter three. Picture two people playing a game sort of like catch. The cyberball experiment. Okay. So Hans, our researcher from earlier, told me about this study he did where he had people playing this game called Cyberball. And the way it works is that you enter the game and two other computer players invite you to start tossing a ball around with them. Foop, foop, foop, foop. Okay. And then at a certain point, they just suddenly start rejecting you. You're not part of this ball game anymore. They just suddenly start excluding you and won't throw you, pass you the ball.

23:30And in... That's terrible. Yeah. And so like in that, people rate the room temperature as colder. But then what he did was he snuck onto their fingers a little digital thermometer. With Velcro on it was just a bunch of sensors with a wire sticking out of it. And he found that their peripheral skin temperature, their skin temperature dropped in that condition when they were excluded. Yeah. And so it's like you perceive it as colder and your skin actually gets a little colder. Oh, wow. I mean, to see it reflected on the skin felt like such a leap from emotion or feeling or thought to physical reality.

24:12What was it like for you to find that result? I think in the beginning it was stunning to find it. I mean, I think that's also why we repeated the experiment. But it also opened up the door for kind of trying to figure out what else was there.

24:32What else was there after the break?

24:45This is Lulu, Radiolab, back here with senior correspondent Molly Webster. Should we go back to the book? Yeah. Nice. Chapter four here, right? Chapter four. The picture's pretty groovy. It's like a thermometer, and it's broken, and mercury is spilling out of it like blood.

25:10And I want to take chapter four. Hell yeah. You're welcome. Thank you for letting us in. Because I've been thinking about this a lot lately. Like for all of us right now, our core body temperatures, that basic temperature that our body is working at, has become a literal passport back into society. It's kind of a rainy day, so it might be a little bit light. So I went to a bar in Brooklyn where, like any other bar in the city right now, there are people at the front of the bar with the gun. Temperature gun. The temperature gun. Zapping everybody who shows up. Honey and Scott have got it under control.

25:48Deciding if people can come in and out of the door. Oh, like the new bouncer of temperature. Exactly. We got a 96.1. And this is happening. Before I go to work every morning. Basically everywhere. I have to take my temperature and text it to the school nurse. So here we go. We actually put a call out to our listeners, had people send us little recordings. Walking up to get my temperature tested. As they headed to work. Arriving in Mask Sound in East Rutherford, New Jersey. Or to the grocery store. I'm at my supermarket. I'm about to go take the temperature. Dropping their kids off at school. Okay, Joey, let's take your temperature so you can go into school.

26:25Stop if your temp reads above 99.4. This is how we decide now whether or not it's okay to be around other people. Normal temperature. You are free to pass. Thank you. Good to go. See you, buddy. Now, we did not get anybody who is in the sort of uh-oh range, but what you do hear in the tape... 97.5. And what I saw in the bar... 95.5. 96. 96.3. Is a pretty surprising range of numbers. 97.5. 97.2 degrees. 96.4. 98.5. 95.2. That's not right. 94.6. Little chilly, but low is better than high. I mean, there were temperatures from maybe 92 all the way up to 98. That's six whole degrees. Okay, so what are these guns?

27:15They don't work. Yeah. What is that? There was just a study out that says the temperature guns read like two to three degrees cooler than you actually are, which is troubling in its own right. But the thing that really hit me is that the spread of supposedly healthy people sort of flies in the face of that bedrock of human health, that golden number, 98.6. Yes, the golden number of like what a human body should be. Except it's kind of a con. A con? Sort of. Let me just explain first where it comes from. Okay. So the story of 98.6 starts in the 1800s, as all good science stories do. Yep. So in the late 19th century, you get the introduction of thermometers into medical practice.