Ologies with Alie Ward - Smologies #10: BODY HEAT with Shane Campbell-Staton

Episode Date: February 1, 2022

Bundle up for a smol, classroom-friendly episode with Princeton University evolutionary biologist and Thermophysiologist Dr. Shane Campbell-Staton. You’ll learn about everything from heat tolerance to frostbite, anti-freeze woodfrogs to icy alligators, why some people run hot, why your toes run cold, how a fever is like a honeybee, how geography influences our body composition, why mammoths are big, and why you should grab your hat before running out the door. Also: what counts as “balmy” in Alaska. Full, uncut, NSFW version of Thermophysiology plus research linksMore Smologies episodesHere is Dr. Campbell-Staton’s website and TwitterListen to his podcast The Biology of Super HeroesSponsors of OlogiesTranscripts and bleeped episodesBecome a patron of Ologies for as little as a buck a monthOlogiesMerch.com has hats, shirts, masks, totes!Follow @Ologies on Twitter and InstagramFollow @AlieWard on Twitter and InstagramSound editing by Zeke Thomas Rodrigues & Jarrett Sleeper of MindJam MediaSmologies theme song by Harold Malcolm

Oh, hey, it's a tangled pair of headphones you just found in your winter jacket pocket. It's Ali Ward. Hey, speaking of jackets, check in with your bod right now. Are you cold? Are you hot? How are your feet? Are they sweating? Is this too many questions?

Okay. Well, I'm back with another Smologies episode. I'm sure by now you know what a Smology is, right? Of course you do. However, the people that are just joining us, Smologies are these bite-sized kind of sampler episodes of our regular, entree-sized oligies episodes, but in a little digestible 20-30 minute format. Oh, and they're also G-rated, so they're kid and they're classroom friendly.

So we took out all the swears in the innuendos and we left them on the cutting board. We've probably taken this meal metaphor far enough, so let's get into it. So thermophysiology, here we go. Thermo in ancient Greek means hot, and physio is derived from the word for nature. So more specifically, physiology is the scientific study of functions and mechanisms in a living system like yours. So basically, how living things deal with and live with the heat or the cold. So this week's oligist is an evolutionary biologist who's an assistant professor in

the Ecology and Evolutionary Biology Department at Princeton University. He currently leads a research group on the evolution of wildlife in response to human activity and contemporary climate change. And he received his bachelor's in ecology and evolutionary biology from the University of Rochester and his PhD from a little place called Harvard in Organismic and Evolutionary Biology. And if that was not enough, he's also the co-host of a podcast called The Biology of Superheroes.

It's awesome. So in this small, small, small oligies episode, we cover all of your burning heat questions like, why do some people run hotter than others? Why do you sweat in your sleep? Maybe you specifically. How do animals regulate their body temperature? Why humans have adapted to all these different climates of the earth? And what is frostbite?

How an animal's mass influences its ability to disperse or conserve heat? And certain species of frog that, you ready? Creates its own internal antifreeze? No. Really? So we're going to cover it. We're also going to introduce you to your new favorite word. It's so much fun to say, poikilotherm, poikilotherm.

You're going to know what it means in a minute. Oh, also, you're basically kind of like a bear sort of. So let's give a warm, warm welcome to a science communicator, a podcast and TV host, and an evolutionary biologist and thermophysiologist, Dr. Shane Campbell Staten. How do mammals experience temperature? Oh, OK. So. It's exciting.

Yeah. So we're going to go in right now. I'm going in. When we're thinking about like the physiology, when we think about like thermophysiology, how animals experience temperature and how that temperature influences their function, their four major categories. OK. Here we go into a matrix of different combinations of body heat you can have if you weren't already

a hairy human. So the first difference is being ectothermic or endothermic. OK. All right. So being endothermic, you can, endothermic organisms can produce their own internal body heat. Endothermic organisms cannot. And then we have basically homeothermic versus poichelothermic.

Whoa. Yeah. That's a good word. I know. It is a good word. That is a scrabble word. It's a good podcast word. Yeah.

Poichelothermic. Yeah. I did not know this word poichelothermic. And yeah, I got you covered with the deaf. So a poichelotherm is an animal whose internal temperature varies considerably. It's all over the place as opposed to a homeotherm which maintains homeostasis and keeps the temperature pretty constant like you and me. So Shane explains how this is not just ectothermic and endothermic.

There's difference and thus a matrix. Do you know what I'm talking about? The matrix. So homeotherms are able to maintain a constant body temperature and poichelotherms have a fluctuating body temperature with respect to their external environment. For instance, you can have an endothermic poichelotherm. These are like mammals that hibernate. For animals that hibernate for really long periods of time like weeks or months, their

internal body temperature can actually drop to within about one degree Celsius of ambient temperature. What? Even though they have these internal mechanisms of producing heat. And this is an energy saving mechanism. So these endopoics, if you will, generate their own heat, but it can vary. Kind of like a house with a furnace, but they set the dial depending on what they need. Here is a list, bears, gophers, bats, groundhogs, just to name a few.

Ectothermic homeotherm is through behavioral thermoregulation. And basically this means paying really close attention to the micro-environments, like the micro-thermal environments that are available to you. So if you are a small lizard, for instance, and it gets really hot outside, again, because you're so small, you're going to gain heat really quickly because of that same volume to surface area issue, except if you move into the shade. So if you move into the shade at the right time and you stay there for long enough, you can actually maintain a steady body temperature, even though you're not producing internal body

heat. Oh, okay. Exactly. And then insects do it a whole different way. So things like bees are technically ectothermic homeotherms because they can actually use their flight muscles, they can decouple their flight muscles and vibrate them without moving their wings to generate heat. And why do some animals and humans have set body temperatures that they need to maintain

in order to live? Like why do humans have to be 98.6 and why do our dogs a different temperature and do mice in Montana have to be a different temperature than the ones in New Mexico? That's a great question. So generally speaking, you know, it's all about strategy, like evolutionary strategy and life history strategy. So mammals benefit from being warm all the time in the sense that, you know, I can get up and move regardless of, you know, what time of day it is, which means because I have

that high metabolism, you know, I can, you know, go run and, you know, and do like really high intensity activities for a pretty sustained period of time, much more so than if I was an ectotherm. But also on the flip side of that, it also means that I have to take in much more energy in order to fuel that internal furnace, right, that defines endotherms. So we have to be out grazing and hunting and finding food in order to have this like 24 hour open supermarket of body heat kind of. Yes.

All of that totally makes sense. Now if we want to keep this train moving, we got to fuel the engine. But geography also plays an important role, as Dr. Shane explains. And here he introduces us to Allen's rule on how geography can affect phenotypes, essentially the way that our genes express themselves and what we look like based on how near or far away an organism is from the equator or the Earth's geographical belt line. It's complicated because it is not just a function of size, behavior plays a really large role in this as well, right.

So we can say things like, you know, Allen's rule or Bergman's rule, which states that as you move farther north, you get generally larger animals, right, because larger animals are able to maintain internal temperatures better. Oh, I never would have thought about that. Like woolly mammoths were in Siberia and not just kicking it in Panama. Exactly. I never ever thought about that. But the largest mammal on the planet, the elephant, is like smack dab right at the equator.

Well, what the hell's up with that? Yeah. And, you know, so, but it's, you know, so size is is one parameter. But in order to get around the fact that they have so much volume to surface area, they've evolved the very special features that allow them to cool. And so if you're out on the savannah, or if you're in India, you know, a lot of times in the heat of the day, you'll see, well, one, you'll see the elephants are typically in the shade, but you'll also see them constantly fanning their ears, right, back and forth.

And if you look at their ears, they have these massive blood vessels that go out into their ears. And essentially it acts as a personalized air conditioner. So as they fan their, their, their ears that blood cools, and then that cool blood circulates back into their body and it helps them to stay cooler. What are some other crazy adaptations that you've seen to deal with extreme heat? So if we look within Africa, for instance, right, there are populations like right around the equator, it's very, it's very warm and gets like extremely hot during the day.

And in response, right, the body changes proportions again to sort of manipulate this volume to surface area. This is what we call Alan's rule. But Alan's rule states that in these warmer environments, animals, mammals specifically have a tendency to grow longer, narrower limbs, right? And by growing longer, narrower limbs, you sort of manipulate that volume dessert is like having up a little pipe, right, instead of like a big thick appendage by decreasing the volume with respect to that surface area, you can then dump heat really quickly to the

environment. Okay. All right. So if you look at a lot of Sub-Saharan African populations that occur right around the equator, the very tall, very thin phenotypes, but then as you move north into really high latitude environments, you know, look at populations like the Inuits, very different bill, right? They're sort of very sort of compact, so it prevents them from dumping heat, it allows them to retain heat in the face of the cold much more efficiently.

Cold. So cold. What are some other crazy adaptations that you've seen to deal with extreme heat? Ooh. Or cold. Okay. Okay. So I will go in on both.

So on the cold side of things, there are a lot of animals who have developed extreme adaptations and the sort of subfield of thermobiology that specializes in those cold adaptations is called cryobiology. Oh, okay. And almost the most extreme, for instance, if you were in North Carolina, I'm not sure if you've seen the recent pictures, but people were freaking out because, you know, the lakes were freezing solid in North Carolina, and when you look at the lakes, every once in a while, you see like a little snout, right, that's stuck in, you know, like kind of poking

up in the ice. Who's snout was it? And that snout was connected to an American alligator. Oh, geez Louise. And the alligator, you know, it's stuck in the ice, but they're able to deal with that really cold situation for a pretty long period of time. There are some species that can actually freeze solid for months at a time and then thaw out and go on about their business.

So animals like the wood frog, for instance, so wood frogs, when they begin to freeze, they undergo a lot of significant physiological changes, right? So they begin to pump glycogen out of their livers into their bloodstream. So it's like basically sugar. And they also dump urea into their bloodstream, which we typically try to get rid of through peeing. Yeah, usually that's something you don't, you want to off board there. Exactly.

But this combination of, you know, sugar and urea essentially acts as an antifreeze, right? So they can super cool without the formation of ice crystals. Ice crystals are typically, like that is the thing that is most dangerous about cold temperatures, because when water crystallizes, essentially it turns into little daggers that start stabbing and ripping apart cells. And you know, so when you, you know, when you get like, like severe frostbite or you're in your, you know, toes turn black and fall off, it's because in large part because of crystal damage.

What? Frostbite is water crystal damage? The very water we love that keeps us alive just does a heel turn when it turns cold and tries to take out our extremities. So let me hand you a hot tip. Keep your gloves close, people. Oh, speaking of hot, what about extreme heat? For hot temperatures, obviously there are animals all around the planet that have evolved

to live in extremely hot environments. So for instance, in desert environments, right? And there's some, you know, behaviors that evolved that are, you know, kind of, kind of funny, right? There are, there's a lizard species, for instance, that lives in deserts that, you know, at the heat of the day in order for them to survive, they essentially rotate picking up their, their feet. You know, they pick up two at a time and they just keep, you know, it's like, if you were

to walk out on asphalt barefoot and you do that thing where you hop back and forth, it's essentially what, like how they get by. Oh, because they get so fancy. Yeah. I know. They're like very, like, prancy little. Yeah. I think they're adorable.

Look at you. So fancy. All right. The lightning round of Patreon questions is right around the corner, but I wanted to take a moment to acknowledge that a portion of the ad revenue every week is donated to a cause of theologist's choosing. And Shane shows the Environmental Defense Fund, which is a non-profit. It's guided by science and economics, and it tackles urgent threats with practical solutions.

And they have a staff of 700 scientists, economists, policy experts, and other professional grown-ups from around the world, and they're committed to bipartisan environmentalism. Lots of great scientists getting stuff done for us. And that donation was made possible by sponsors of the show. Okay. Back to your Patreon questions. And wow. So many of you were all on the same page.

So many people asked the same questions, and I'm just going to read through their names because I kind of categorize them. Okay. Okay. Megan Younce, Sarah Clark, Anna Thompson, and Ashley Kelly all kind of want to know, can people have different set body temperatures, or is it total BS when someone says that they run hot and someone else runs cold? No.

There is variation in average body temperatures. Oh. Yeah. Okay. A human being should be 98.6 degrees. That means that there's just like any bell curve. That's the top of the bell curve. Yeah.

Yeah. I think most humans typically fluctuate between like 97 and 98.5 or 99. Areologists who studies Mars, who is on the show Jennifer Booze and Suki Hali both wants to know, what's the point of fevers? Oh, what's the point of fevers? Why do we get them? So again, so the point of fevers is more or less the same point of the Japanese bee heat balls.

See? See? These small angies episodes are all connected. So we have things that are attacking our body, and by generating a fever, we're hedge betting. We're betting that we are more heat tolerant than the things that are invading our body. Man, so if you have a fever, you should keep it up? No.

Not necessarily. First of all, you should see a doctor is what you should do. And not a PhD. You should see a medical doctor, not a thermophysiologist. Do not just tweet at Shane. No. Don't tweet at me. Go see a doctor.

I don't have anything for you over here. Don't at me. But that's why you're getting it is just cooking the bugs. Yeah. Yeah. But yeah, at the same time, if you have, you know, if you maintain a fever for a really long time, it can actually have extremely detrimental effects. Yes.

Precisely. And cells generally speaking. Ooh. Don't poach yourself. Okay. Don't do that. But at least you know why it happens. And then a few people had a question about their partners having different heat tolerances

than them. Bethany G says, why are women so much colder in office buildings than men? She says, generally speaking, Cassie Flint asked the same question, disclaimer, sorry for the sweeping gender generalization, but why do men seem to be walking heaters? Kelly Meeker also asked this. So did Bethany G and Anna Thompson. So if I had to make a guess at this, I would say it has to do with body size on average. On average, men have a tendency to be larger than women.

It's like sexual size, dimorphism. What that means is that they have more volume to surface area, which then means that they can retain heat more efficiently than smaller bodied individuals. Of course, this is regardless of gender, it's just a property of size, but because there are different distributions of size for men and women, on average it can create that shift. So tinier people are not just bigger winers. They're actually colder. So listen to us sometimes if you're short and cold.

They physiologically have to work harder to keep their heat. Yes. Because as a person who is shorter and has been freezing and worn fingerless gloves in an office building in August, I understand that very much. So side note, if your temperature feels all wonky, you can thank your glands. So the hypothalamus acts as a thermostat. It helps your body adjust to whatever your heat needs are. And typically when you're asleep, your temperature drops to its lowest point a few hours before

you wake up, which kind of keeps you comfortably snoozing. Now, if you're sweating a bunch, it could be hormonal changes that are messing with your hypothalamus or a sudden plummet in blood sugar if you kind of went a little hard on the desserts. Also, if you're always freezing and you feel tired and sluggish, you may want to have your own one-on-one allergies episode with an endocrinologist to chat about thyroid levels. Another symptom of that, having freezing hands and feet, which I know for a fact some of you do.

A lot of people had questions about extremities in parts of the body, like Jocelyn Vincent, Marisa Brewer, Mariko Shin, Miig, Megan Yountz, Heather Hutchinson, Rodovacaria, Heather Wills, Azrael King, and Moritz Latuske all kind of asked, why are feet freezing while the rest of our body is warm? Why are our hands cold? What is happening with different parts of bodies? So this phenomenon is called regional heterothermy. Oh, these are great times.

So thermal physiology has some awesome terms. I do like that part about being a thermal physiologist. And essentially what happens is your body has priorities, and your core is the top priority. So if you're in a cold environment and you need to preserve heat, the first thing that your body, or one of the first things that your body does is it shunts blood away from your extremities in order to preserve it at your core because the same thing would happen as I talked about with the elephants, right? When they're, as they pump blood out, it cools and then it returns.

But if you're in a cold environment and you're pumping blood to your extremities and it cools and comes back, then your internal body temperature begins to plummet much quicker. So your feet get cold and your hands get cold so that your heart and lungs and liver and all that good stuff can stay warm. Because we got to keep that, that all those organs pumping. Oh, yeah. But we can lose a hand, we'll be fine. Yeah.

Right? Yeah, but also at the same time, you notice that, you know, if you're out in the cold, like your head is always steaming, even though it's technically an extremity, that's because that's where the moneymaker is at the brain. Do we lose a lot of heat from our heads? Yes. Oh my God, okay. Let me find who asked this again.

Claudius and others asked, I've heard it's an urban myth that we lose most of our body heat in your head. Time to have an expert be the judge, they say. So it's not an urban legend for multiple reasons. One, because typically when we wear clothes, our head is least likely to be covered. So just as a product, we would lose most of the heat by way of our head because the rest of us is insulated. The other thing is that this regional heterothermia doesn't really apply to your head because

your body will do pretty much anything to keep your brain functioning. So you will continue to pump blood to your head, which means that you're continually supplying warmth to your entire head and your face, except for your lips and all the cartilaginous places, right? Your lips and nose and ears get really- Purple? Yeah, exactly. Well, they get purple on you, not so much on me because of the melanin.

We definitely need a dermatology or skin episode all about melanin. Am I right? I am. Now, can you simply beat the heat? Does the cold grow old? You know, I once went to Alaska in April and I witnessed human beings wearing short sleeves in 45 degrees. We're all the same species, so what is happening?

How can they deal with that? I'd be so cold. So many people, Carla Fiacco, Todd McLaren, Michael Pascura, Joshua Kuhn, Alina Tanabe, and Kitty Boyd all want to know about acclimation. Over time, does the body adapt to climate? And as a person who lives in Southern California that gets very cold everywhere else, and as you've just moved here, just wait till it happens to you, you'll start getting weaker and weaker.

Do we adapt that quickly? So yeah, so individuals can acclimate to temperatures. Okay. So again, I study this mostly in reptiles, in reptiles and ectotherms, we call it heat hardening. Okay. So essentially, when you're exposed to a hot temperature for an extended period of time, you become more adept at functioning at high temperatures and vice versa.

So this is acclimation or phenotypic plasticity, where you have one genome that can produce multiple phenotypes depending on its interaction with the environment. Some of you wanted to know how weight loss or gain might affect your ability to adapt to the elements. Is this Allen's rule at work? What's happening? And then Armando and Mae both said that they recently lost a lot of weight and they're constantly cold.

Does weighing less affect body heat? Weighing less does affect body heat, again, because of this volume to surface area. And but also, fat generally speaking, does also acts as an insulator. So if you think a lot of mammals that occur in polar climates, so things like polar bears, walruses, seals that can live in really cold waters, they have blubber, which is fat. Okay. It's time to get a little sci-fi and discuss putting yourself on ice. Kind of like a mac and cheese leftover dinner that you're going to enjoy next month.

Heat it back up and poof, you're good to go. Only it's you and your body. It's spooky, but it's very fascinating. Okay. Cryogenics. Sonja Karolepavik and Azrael King want to know, is cryogenic freezing in any way realistic or possible? So it depends on what you mean.

I'm always reluctant to say anything is impossible, but it's highly improbable. If you're talking about cryogenic freezing, so this is actually a really active area of research when it comes to things like organ transplants and extending the longevity of transplants and how long they can survive outside of the body. So actually a lot of this work that is being done on animals like the wood frog, if you have an animal that is able to do this for an extended period of time and have properly functioning organs, it's a good place to go to find solutions to being able to freeze an organ solid and then revive it and still have it be able to function.

So I do think that is a possibility and essentially we just need to really know more about the physiology of this process and how it plays out in nature. But in terms of like freezing heads and reviving people, improbable I will say, highly improbable. So improbable, but not impossible. So maybe there is a chance scientists are hot on the trail of this research. Now why do you do what you do? I asked Dr. Shane Campbell-Staten. What is the best thing about being a thermophysiologist?

Oh, oh my God, how much time do you have? Yeah, so it's definitely the animals, right? So, I mean, certainly being a thermophysiologist, I mean, I think this applies to pretty much any scientist, but the idea of like waking up in the morning and you know that your day is going to be spent trying to answer questions that have never been answered before and may have never been asked before, there's like just something so deeply satisfying about that. Deeply satisfying indeed.

So a quick review. Let's recap. We learned that there is a matrix for how animals experience temperature. There's ectothermic versus endothermic and homeothermic versus our new favorite word, poculothermic, and that Alan's rule applies to mammals, including humans that in warmer climates grow longer, thinner limbs in order to dump heat and survive. And then conversely, in colder climates and higher latitudes, you'll find compact, stockier builds in mammals, allowing them to retain their heat.

Smaller people are generally colder and have to work harder to retain heat. Also your glands act kind of like a thermostat and your feetsies get cold because of regional heterothermy or essentially the concept that your body prioritizes some parts over others. And wood frogs are cooler than us. Literally they are cooler than us. Also it's improbable but not impossible to cryogenically freeze your body and then reanimate it in the future. Still working on that.

Put a pin in it. So find out more about Dr. Shane Campbell-Stayton at CampbellStayton.com. He's also on Twitter at Campbell-Stayton and I will link all of this in the show notes including his podcast, The Biology of Superheroes. He's also on Instagram at Shane.Campbell-Stayton. So thank you Dr. Shane, you're the best and thank you for tuning in, any new smallgites. These fresh, clean little episodes are out about every two weeks and they are safe for all ages including classrooms.

We cut out all my swears and we keep them in the full thermophysiology episode. It's got way more details and adult content. Also a lot more info on Dr. Shane's journey that's all available on alleyward.com or in the show notes that will link you to the full episode. There's also a list of credits for this episode in the show notes since we like to keep things nice and short and small around here. And if you listen to the end, you know, I give you a piece of advice and this week it's that sometimes when we feel mad, we're mad because we're scared.

So next time you're mad, maybe sit down and ask yourself, am I scared or something right now? And if so, what is it? And tell someone so that they can help you. It's okay if that happens. Grownups go through that too all the time because sometimes emotions can be confusing unless you sit down and ask yourself, what am I really feeling? And right now I'm feeling happy and grateful that you listened to the end and we'll be

back soon. Until then, Smologites, bye-bye. Grownups. Grownups.