This Podcast Will Kill You - Ep 147 Tasmanian Devil Facial Tumor Disease: Sympathy for the Devil

Episode Date: July 30, 2024

Think of an infectious disease. What comes to mind? A viral infection like influenza? Or a bacterial illness like cholera? Maybe some of you thought of a fungal pathogen or a parasite. But how many of you thought of a cancer? In this episode, we explore the bizarre, stranger than fiction story of devil facial tumor disease (DFTD), a transmissible cancer that has devastated Tasmanian devil populations over the past few decades. And when we say transmissible cancer, we don’t mean a cancer caused by a virus - we mean the cancer itself is transmissible. How is that possible? What does it do to the devils? What are Tasmanian devils like? What role do they play in the ecosystem? What does the future hold for these adorable creatures? Tune in for a lively discussion all about these devils and their disease, featuring Dr. Rodrigo Hamede, Senior Lecturer at the University of Tasmania and DFTD expert. This episode will have you looking up pictures of baby devils, listening to their wide range of sounds, and rethinking the lines between contagious and non-contagious disease. See omnystudio.com/listener for privacy information.

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Terms and conditions apply. Visit blueapron.com slash terms for more information. I'm Amanda Knox, and in the new podcast, Doubt, the case of Lucy Letby, we unpack the story of an unimaginable tragedy that gripped the UK in 2023. But what if we didn't get the whole story? Evidence has been made to fit. The moment you look at the whole picture, the case collapsed. What if the truth was disguised by a story we chose to book?

Oh, my God, I think she might be innocent. Listen to Doubt, The Case of Lucy Letby on the Iheart Radio app, Apple Podcasts, or wherever you get your podcasts. I'm Clayton Eckerd. In 2022, I was the lead of ABC's The Bachelor. But here's the thing. Bachelor fans hated him. If I could press a button and rewind it all I would. That's when his life took a disturbing turn.

A one-night stand would end in a courtroom. The media is here. this case has gone viral. The dating contract. Agree to date me, but I'm also suing you. This is unlike anything I've ever seen before. I'm Stephanie Young. Listen to Love Trapped on the I Heart Radio app, Apple Podcasts,

or wherever you get your podcasts. My name is Rodrigo Ahmed, and I work at the University of Tasmania as a wildlife researcher. The first time that I saw a Tasmanian devil with facial tumor disease was actually 20 years ago in 2015. in a place called Bronte Park in the central highlands of Tasmania. It had massive tumors, and I was surprised to see how these animals could get on with their taflies with such large and disfiguring facial tumors. It was quite confronting because they're disfiguring tumors, and you can see how horrible this disease is.

And I had been working on my study site for about five years. This was in 2009, until I saw the first tumor regression. And I still remember that animal. It was a devil called Rattus Rattus. I microchipped her as a juvenile, and she had a very rodent-like expression. And I decided to call her Rattus for that reason. And then two years later, in May 2009, she contracted DFTD. And that happens a lot.

You see these animals in the pouch, and then you see. see them just dispersing and then suddenly, and sadly, you see them with tumors. So I took biopsies of her tumor and let it go, as we do with disease animals. And then three months later, in August 2009, we caught an animal in one of our surveys. And as we do, we transfer animals from the traps into Hesian sac so we can handle them and collect our samples and collect our data. And the first thing we do when an animal is in a sack is to scan. for a microchip to see whether we caught them in the past or not.

We can refer to our database and look for samples that we may have taken in the past, their productive status of females and other metadata. So when we realized that it was rattice, we got everything ready for collecting our samples. I remember telling my research assistant to take the tumor biopsy kit, the blood sample kit, so we could just re-sample this tumor again. And when I exposed her face, I was perplexed because there was no tumor. So my first thought was that we got the microchip wrong.

And that was another animal. So I asked my assistant to check the number. And we repeated this number to each other at least a dozen times. I remember scanning the microchip over and over again in disbelief. And she actually had a scar above her eye as well. And she looked like ratters. So I knew it was her. So there was no doubt it was the same animal, and somehow that tumor had disappeared.

There was only a small scar where that tumor used to be three months ago. And I knew this was something important. I was extremely happy. I remember just being absolutely jubilous with happiness seeing this animal, not having this tumor anymore. But I knew it was a sort of a game changer. Until then, this disease was inevitably fatal, 100% mortality. So this was the first evidence that somehow some animals could recover from this cancer. And over the following years, we found more cases of tumor regressions, interestingly, mostly in females.

And these changed the direction of our research. It was sort of a parallel shift to understand these disease from an evolutionary perspective. And as a result, our long-term conservation strategies also changed. And it was also a trigger for investigating how mechanisms against life, cancer arise and evolve in nature because these things usually happen in experimental settings when animals are manipulated with treatment is undertaken. So this was an incredible opportunity to study the big picture of evolution and cancer in a natural setting. What an amazing story. I loved it so much. So much. Like how cool would that have been? How amazing and also hopeful to be.

like, oh, there is, like, this doesn't have to end this way. I know. But it's hope. I'm still hopeful. Yeah, me too. Dr. Hamide, thank you so much for sharing that story with us. And we are also so excited that we get to chat with Dr. Hemete later in this episode about many different things, about DFTD, which we'll get into what that is. But first, hi, I'm Aaron Welsh. And I'm Aaron And this is, this podcast will kill you. And today we're talking about Tasmanian devils and their facial tumors, aka devil facial tumor disease, which maybe a lot of people have absolutely never heard of and it's going to be a really exciting opportunity to learn about something unbelievably fascinating. Truly, truly. I mean, do you remember when you first learned about this? Yes, it was at, I think,

an EEID conference. Yes. Yes. I really think it was like in the, it was the one in Santa Barbara, I think, maybe. Or Athens, I don't know. Either way, I remember being like, wait, what? Transmissible cancer, because that's what this disease is. It is. And I misremembered it because I thought that it was viral. And so I like got to relearn this for this episode. And I will never stop thinking about this because it is Tasmanian devil facial tumor disease, everyone who is listening, is a transmissible cancer, meaning it is a cancer that moves from Tasmanian devil to Tasmanian devil. We're going to get into so much detail. We are so lucky that we got to chat with Dr. Hamide, who is on literally every single paper that has ever. been written about this disease on every side of it, from the evolution to the behavior of

these devils. Like, every paper, I'm not kidding. We got to chat with such an expert. Oh, my gosh, this is going to be such a fun episode. It's such a fun episode. And I think also, just to not lose sight of the subject of the episode, are the devils themselves, which, Aaron, I am in love. I know you are. I love them so, so much. I keep watching videos. of them, like the little babies. I just, I can't. It's, they're amazing. I'm really excited. I'm really excited. They're very, very, very cute. Yeah, they are. But first. But first, it's quarantine time. It is. What are we drinking this week? We're drinking with the devil. Yeah, perfect. And, okay, so I will admit to searching for Australian cocktails. I didn't know if they were like,

specific cocktails or cocktails specific to Australia. And so what came up on my searches was something called a lemon lime bitters, which is really delicious. It has lemonade, lime cordial, and bitters. And for this to make it a quarantini, we'll add vodka. And if you want to keep it a placebo Rita, omit the vodka. Fantastic. And we'll post the full recipe for that quarantini as well as the non-alcoholic placebo-rida on our website, this podcast will kill you.com, and all of our social media channels. If you're not following us on social media, what are you waiting for? There's some great stuff there. We're doing reals. We're on TikTok. Stuff like that. It's good. But also, we have a website, which you should also check out, where we've got stuff like transcripts.

We've got show notes for our episodes, which have all of the sources that we use. We've got links to merch, links to music by Bloodmobile, links. to our Bookshop.org affiliate account, our Goodreads list. We've got a contact us form. We've got a firsthand account form. So if you're like, hey, I want you to do this because I have this, whatever I have experience with this, send us your thoughts. We love it. It's a great website. Check it out. This podcast, okay, you dot com. You can find a lot. Erin, let's get started. Let's just take a break and then get into it, yeah? Okay. Let's do it. Dinner shows up every night, whether you're prepared for it or not. And with

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free shipping with code this podcast 50. Terms and conditions apply. Visit blue apron.com slash terms for more information. Anyone who works long hours knows the routine. Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keefe's Hand's hand cream is such a relief. It's a concentrated hand cream that is specifically designed to relieve extremely dry, cracked hands caused by constant hand washing and harsh conditions. Working hands creates a protective layer on the skin that locks in moisture. It's non-greasy, unscented, and absorbs quickly. A little goes a long way. Moisturization that lasts up to 48 hours. It's made for people whose hands take a beating at work, from health care and food service to salon, lab, and caregiving

environments. It's been relied on for decades by people who wash their hands constantly or work in harsh conditions because it actually works. O'Keefs is my hand cream of choice in these dry Colorado winters when it feels like my skin is always on the verge of cracking. It keeps them soft and smooth, no matter how harsh it is outside. We're offering our listeners 15% off their first order of O'Keefs. Just visit O'Keef's company.com slash this podcast and code this podcast at checkout. I'm Clayton Eckerd, and in 2022, I was the lead of ABC's The Bachelor. Unfortunately, it didn't go according to plan. He became the first Bachelor to ever have his final Rose rejected.

The internet turned on him. If I could press a button and rewind it all I would. But what happened to Clayton after the show made even bigger headlines. It began as a one-night stand and ended in a courtroom, with Clayton at the center of a very strange paternity scandal. media is here. This case has gone viral. The dating contract. Agree to date me, but I'm also suing you. Please search for it. This is unlike anything I've ever seen before.

I'm Stephanie Young. This is Love Trapped. This season, an epic battle of he said she said, and the search for accountability in a sea of lies. Listen to Love Trapped on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. So Tasmanian Devil, or sarcofilis heresii. Do you want to know the etymology of that? Of course I do. Okay, hold on one second. Okay, got it.

So sarcophilis means flesh-loving. Of course it does. And heresiae is just one of the dudes who wrote one of the first descriptions about some dude. Tasmanian devils. Flesh-loving. Flesh-loving. Harris is flesh-loving animal.

animals. They are truly adorable. They're carnivorous marsupial mammals native to Tasmania. And Aaron, that's where I literally end my description of these little bugs, because I know that you're going to talk in a lot more detail about how cute they are and how awesome they are in their natural history. I'm going to focus on the topic at hand, which is the thing that is rapidly, rapidly decimating Tasmania devil populations across their native range. And that is devil facial tumor disease or DFTD. We have covered Aaron a lot of weird stuff on this podcast, but I think that this might be one of the weirdest. I mean, I think just the phrase transmissible cancer is really difficult to wrap your head around.

It is. And it's, I don't want to say terrifying, because I don't think that that's the right word, but it is fascinating in a way that really gets at, questions of like immunology and evolution that just are kind of mind-boggling. And like, what is a cancer? What is a parasite? Like, it really kind of makes you question these categories that we have. So let's like keep going. So DFTD, it is a cancer. It's a highly fatal cancer. And cancers are proliferations of cells, usually somatic cells, so body cells that mutate in a way, that causes uncontrolled and abnormal cellular proliferation. We've covered a number of other cancers on the podcast before. Devil facial tumor disease is a highly fatal cancer that causes tumors,

as you can probably guess, on the face, it's in its name, of Tasmanian Devils. But this isn't something that just happens because of an environmental exposure or something like smoking or any of the things that you might think of that cause or are associated with cancers in humans. Devil facial tumor disease is a cancer that is transmitted from one devil to the next and has rapidly spread across the entire geographic range of Tasmanian devils and is nearly 100% fatal. So let's get into a little bit more detail about this transmissible cancer. Listeners who especially listen to this podcast a lot might think when I say transmissible cancer that this is something like HPV, right?

HPV related cancers or even hepatitis C that causes cancer or EBV which can cause cancer. Any of these are transmissible viruses that we know cause DNA mutations that lead to cancer. That's not what this is. in devil facial tumor disease, it is actual cancer cells themselves that are transmitted from devil to devil as what is called an allograph, which essentially just means cells that come from someone else's body. How? How?

How? So the how that this gets transmitted devil to devil is usually through biting. And this biting happens during a variety of devil's social interactions. Also, I just have to take a minute because I just have to keep saying devil, and it feels so weird to just... I know that's what these are called, but... But these devils engage in a lot of behaviors that include biting, both, like, because they're fighting each other or because they're mating. Like, there's a lot of biting, apparently. You're going to talk more about it, Aaron, that happens.

and you might say, okay, so this is kind of like rabies where a sick animal bites and then transmits this cancer cells to another animal. But no, it gets weirder because it seems to be that the animals most likely

to contract this cancer are the ones who are doing the biting. So it's thought that it's more likely animals biting into the tumors on the faces of infected animals that then end up contracting this disease, this cancer. I have so many questions. I know. I know.

I still have so many questions, too. But what that also means is that it tends to be, and there's some data to support this, that it's the most fit individuals, the ones who are either the most aggressive or who are the most reproductively fit, who are actually more likely to get these cancers, which, from an evolutionary perspective is just fascinating because of how fatal this cancer tends to be. Right. And altogether, the idea of these cancer cells being transmitted from one animal to another directly is really, really novel. There's only one other known cancer that is transmitted from creature to creature, I guess.

And that's called canine transmissible venereal tumor, or CTVT. This is a tumor that's found in domestic dogs, and it's massively different than DFTD because it's not fatal. In most dogs, it's usually eventually suppressed by that dog's own immune system. Which maybe it once was fatal. Oh, my gosh. I did not go deep evolution on CTVT, but. Well, and I think that there are also other transmissible cancers in invertebrates. but for vertebrates, it's like super limited. Interesting.

Yeah, just a handful, just a couple, really, a few. Erin, I don't think that I've ever thought about cancers in invertebrate. Well, because the immune system is so different. So it's, yeah, I don't know. Oh, that's fascinating. Oh, my gosh. Now I just feel like I need to do a lot more research, but there do exist cases, case reports of cancers that are being spread person to person during pregnancy

to the fetus or after things like bone marrow or other solid organ transplants. But this is where things get really, really interesting is that even in those exceptionally rare circumstances, most of the time, like two-thirds of the time when a cancer is found to have arisen in a transplanted organ or arisen in a person who then has an organ trillance plant or something like that, most of the time, two-thirds of the time, this cancer doesn't end up progressing because that person's own immune system is able to fight it off. In devil facial tumor disease, on the other hand, it's almost the exact opposite. Almost every single animal who contracts this disease will die from it. And often within six to 12 months of the first signs of tumor development. This is an

incredibly fatal disease. And we're going to talk a lot more about the ecological effects that this has had across the range of Tasmanian devils, not just for the devils themselves, but also for the entire ecosystem because they are a keystone species. But what does this mean for this cancer. Why is it that these cancer cells, which were thought to have arisen in a female Tasmanian devil back in the 90s, in a Schwann cell? Okay. Now, a Schwann cell is, because I'm going to ask. A swan cell is a type of peripheral nervous system cell. So we have Schwant cells. Vertebrates have Schwant cells. And these are cells that are involved in repair mechanisms and also in some degree to our immune response, but of our nervous system in the periphery.

So not our central nervous system, but along our nerves and things like that. So this is a cancer that originated in one female and has since spread as like a clonal aggregate, this cell. Certainly it has evolved, it has changed, it has mutated as cancers are wont to do. But the widespread of this devil facial tumor disease can be traced back to this single cell. Why is it that in these devils this can be transmitted so easily? How is it able to infiltrate and then make a new cancer home in all of these other devils? That is a huge immunologic question because it doesn't happen in so many other animals, right? One of the big thoughts as to how this happens is that this cancer down regulates the immune response.

And that's something that we see a lot of other pathogens do as well. We've talked about it a number of times on this podcast. But in the case of devil facial tumor disease, it seems like there's specifically one class of immune cells called MHC Class 1. It's really one type of protein. This is antigen presenting proteins that help induce antibody responses. So it's part of that here let me present these four. peptides or these foreign proteins, and then your body mounts an immune response against these proteins. That whole class of immune response is downregulated in these cancer cells.

I can see that, but how did that first happen? Because I would imagine that in that first female, where this cancer had first arisen, it was self. It was self. It was self-sales. It was a cancer, the same way that normal cancers develop. Right. And then now with every subsequent Tasmanian devil that has been infected, it is a non-self. So like to override that, how did that get overridden? And then this is a question that like is a broader and probably rhetorical question. But like the fact that this is so rare and not only that, but as we'll get into, there's a second one. Right. brings up the question of how much of it is the cancer, characteristics of this cancer,

versus how much of it is characteristics of the Tasmanian devil? And then, because, like, what does this tell us for other transmissible cancers in wildlife populations, and humans, in livestock, and, like, everything? Right. And what does it teach us about even bigger picture, the immune response in general and our immune response to cancers in general, regardless of whether or not they're transmissible? But you bring up a really good point, Aaron, because they're, has been a big suggestion that part of the reason that this cancer, and now we see that there is a second DFT2,

which was first reported in 2015, and thought to have come from a male Tasmanian devil initially. This cancer, which is a separate cancer, but essentially the same, causes the same kind of tumors. It's also nearly 100% fatal, but has been much more limited so far in its geographic range. So one of the suggestions, and there's some evidence for this, is that the devils themselves are different than a lot of other mammals,

in that they have very low genetic diversity, especially specifically in some of these immune regulatory regions, including this MHC-1 region. So there's some thought that maybe it's because the MHC is so similar across all of these different Tasmanian devils that the fact that this particular cancer down-regulates that response, Even though it is different non-self cancer cells, the devil's immune system don't recognize it as such, and so they don't mount a huge immune response to it.

But skin allografts, like moved from devil to devil, are rejected among devils. So it really doesn't entirely explain how this cancer can be so transmissible. To get even more interesting, I did say that this cancer is considered nearly 100%. percent fetal. And you heard a little bit of that in our firsthand account that it's not always. And there is evidence, even in natural populations, that regression is possible. Why? And how? That is a question that we still don't know. Is it certain genetic characteristics of particular devils that make them more resistant to this cancer? There is evidence of antibody response that can be mounted, both in like lab populations, but also in these natural populations where devils,

individuals have mounted an immune response and have kind of regressed their own cancer spontaneously. But it's not clear if this is because of genetic characteristics that make those individual devils able to fight off that cancer, or if there have been mutations in the cancer themselves, in the cancer cells that make them able to regress or essentially make them less fatal, which, again, from an evolutionary perspective, from the point of view of the cancer, if you extinct your entire population, you also go extinct as a cancer. Right. So there's just so many things about this that are really interesting and fascinating.

And we don't have full answers to them. It's like very much open questions still. Mm-hmm. Mm-hmm. Yeah, I think it brings to mind so many. questions about strategies. Yeah. What are the different outcomes that could possibly happen in terms of complete resistance in terms of tolerance, in terms of the cancers and sort of their evolutionary pressures for high virulence, low virulence, all of these things. And then to throw a wrench into

things, the competition. So yeah, it's with the other cancer. So it's a complete jump. bag of fascinating questions that we have just like, you know, the tiniest sprinkle of answers to. And it's so interesting, too, to even kind of, like we kind of mentioned, conceptualize this as a cancer because there are some papers who will say, well, at this point, these cells that are being transmitted from devil to devil are acting like a parasite, right? They are reliant on a host to be able to continue to reproduce and to grow. And they are non-self. So there's some really interesting kind of discussion as to, is this now, like, should we

consider this a parasite? Is that different than considering it a cancer? And it's more like philosophical and a little bit pedantic, but it's fascinating, too, from an evolutionary perspective. So these cancers are nearly 100% fatal. Right. How does that happen? Like, what do these devils die of?

Yeah. Great question. So let's talk about what this disease actually looks like. So as the name suggests, and as I said, this cancer causes the formation of tumors. The tumors are all over the face of these devils, and they can become very, very large. And they're soft tissue tumors that are very, like cancer tumors in general are not normal cells. And so they don't grow, like these are not skin cells that are growing just like skin lumps. These are very dysregulated cells growing these massive soft tissue tumors.

They can grow really large, they can ulcerate and kind of open up, which can lead to secondary infections of these kind of open wounds. But they can cause death in the devils in a number of different ways. One is that they can grow so large that they block the airway, making it difficult for the devil to breathe. They can grow so large that they make it difficult or impossible to eat. and so then these animals die of starvation, or because it's a cancer, they also can metastasize to any and all other organs and then cause organ failure and death from organ failure.

So it really is a terrible, terrible, very disfiguring and very, very fatal cancer. And at this point, there is no treatment for this cancer. First, it would be exceptionally difficult to treat for cancer a lot of wild animals, right? It's very difficult to even treat humans for cancers. It's extensive. It takes a very long time. But right now we also don't have any treatment for this particular cancer. There is a lot of work being done to produce a vaccine.

Because a vaccine to be able to prevent the transmission of this transmissible cancer is plausible, right? Because we know that in the cases where these populations or where these individuals have been able to cause tumor regression, that an antibody response is possible to kind of fight off this cancer. So theoretically, it would then be possible to prevent it. Thus far, there still isn't a vaccine, but it's at least something that is like theoretically possible and that people are really working on. What's the incubation period? That's a really good question. I don't actually know, because what I don't know is whether you can fully tell if a devil is going to develop tumors before the tumors arise. But the time from first tumor growth, like when you first

are able to see those tumors to death is usually a matter of months. Right. Yeah, and I still have a lot of open questions too, like knowing that the transmission tends to be from biting and we think more likely from the devils who bite into tumors, rather than just the devils who have tumors doing the biting, means that they're getting exposed from actually getting their teeth into that tissue of the tumor. But then where are the tumor cells going? Are they going directly into the bloodstream? Are they traveling through the lymphatics? How are they getting there? Where are they attaching? Where do they first start to develop a tumor? Is it wherever that devil happened to have a little cut? And so that's where the cell's in. There are so many open questions still about this cancer and not just the transmission,

like so many questions about it. Yeah. But that's what I know thus far about the biology and the kind of pathophysiology of this transmissible cancer. It's so bizarre and fascinating that like I feel like I'm still wrapping my head around it. I know. Well, to that end, Aaron, Can you tell us a little bit about these Tasmanian devils? Who they are, where they came from, how important they are, and why we need to care. I certainly can. Let's take a quick break, and I'll get into it. Anyone who works long hours knows the routine.

Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keeffe's working hands hand cream is such a relief. It's a concentrated hand cream that is specifically designed, to relieve extremely dry, cracked hands caused by constant hand washing and harsh conditions. Working hands creates a protective layer on the skin that locks in moisture. It's non-greasy, unscented, and absorbs quickly. A little goes a long way. Moisturization that lasts up to 48 hours. It's made for people whose hands take a beating at work, from health care and food service to

salon, lab, and caregiving environments. It's been relied on for decades by people who wash their hands constantly or work in harsh conditions because it actually works. O'Keefs is my hand cream of choice in these dry Colorado winters when it feels like my skin is always on the verge of cracking. It keeps them soft and smooth no matter how harsh it is outside. We're offering our listeners 15% off their first order of O'Keefs. Just visit O'Keef's company.com slash this podcast and code this podcast at checkout. I'm Clayton Eckerd, and in 2022, I was the lead of ABC's The Bachelor.

Unfortunately, it didn't go according to plan. He became the first bachelor to ever have his final rose rejected. The internet turned on him. If I could press a button and rewind it all I would. But what happened to Clayton after the show made even bigger headlines. It began as a one-night stand and ended in a courtroom with Clayton at the center of a very strange paternity scandal. The media is here. This case has gone viral.

The dating contract. Agree to date me, but I'm also suing you. Please search for it. This is unlike anything I've ever seen before. I'm Stephanie Young. This is Love Trapped. This season, an epic battle of He Said She Said, and the search for accountability in a sea of lies. Listen to Love Trapped on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

In 2023, a story gripped the UK, evoking horror and disbelief. leave. The nurse who should have been in charge of caring for tiny babies is now the most prolific child killer in modern British history. Everyone thought they knew how it ended. A verdict, a villain, a nurse named Lucy Lettby. Lucy Lettby has been found guilty. But what if we didn't get the whole story? The moment you look at the whole picture, the case collapses. I'm Amanda Knox, and in the new podcast, doubt the case of Lucy Lettby, we follow the evidence and hear the from the people that lived it, to ask what really happened when the world decided who Lucy Lettby was. No voicing of any skepticism or doubt. It'll cause so much harm at every single level of the British

establishment of this is wrong. Listen to Doubt, the case of Lucy Lettby on the Iheart Radio app, Apple Podcasts, or wherever you get your podcasts. Now that we know everything that's going on with devil facial tumor disease. Yeah, right. Okay, well, we know more than we did at the beginning of this episode. Now I kind of want to zoom out a bit to get to know these devils themselves. Where do they get their name? What do they look like? What do they eat? What's their reputation? And is it based in truth, in lies, or in a mix of the two? And then after getting better acquainted with the Devils is when I want to get into some of their history over the 20th century leading up to the first official recognition of devil facial tumor disease. In short, Tasmanian devils are marsupial

carnivores about a couple of feet long. They're covered in black fur with white stripes around like their neck and their bum and whose existence is severely threatened by this transmissible cancer. And then getting into more details now. How can I start any other way than with a quote? These animals were very common on our first settling at Hobart Town, and were particularly destructive to poultry, etc. They, however, furnished the convicts with a fresh meal, and the taste was said to be not unlike veal. They are easily procured by setting a trap in the most unfrequented parts of the woods, baited with raw flesh, all kinds of which they eat indiscriminately and voraciously. They also, it is probable, prey on dead fish,

etc., as their tracks are frequently found on the sands of the seashore. In a state of confinement, they appear to be untamably savage, biting severely and uttering at the same time a low, yelling growl. They frequently sat on their hind parts and used their forepaws to convey food to their mouths. The muscles of their jaws were very strong as they cracked the largest bones with ease asunder, and many of their actions, as well as their gait, strikingly resembled those of the bear. Its vulgar name is the native devil, end quote. You can just picture how cute it is. It's like, don't put me in a cage. And so this actually comes from one of the earliest descriptions of a Tasmanian devil by a European, George Harris,

hence Horaceae. Yep. So this is from 1806. He's the namesake of the species name. So you might think, based on this quote, that Tasmanian devils are big, fearsome, vicious beasts that leave a path of destruction and carcasses in their wake. Like, lock your doors and arm yourselves against their deadly attacks. But you'd be wrong. I mean, some people probably would tell you to lock or at least close your doors because they might come in and grab like a few blankets or clothes or clothes off the line or pillows to cozy up their dens. Do they do that? I love that so much. I know. I love when animals make themselves cozy, Aaron. Or maybe they'll steal a pair of sunglasses to consume in their entirety.

Oh, no, that doesn't sound like a good plan. No, I mean, you know, it doesn't seem to be that bad as far as I can tell. And we'll get there. But Tasmanian devils don't attack humans. They're more likely to run away from you unless they're trapped or threatened. And also, no self-respecting devil is going to be leaving carcassizabeth. behind. They're going to be devouring those. Every last bit of flesh and sinew and bone. They're incredibly, incredibly, like, I think one of the most powerful jaws on, like, for any carnivore,

enabling them to leave no trace. That's amazing. They are, after all, predator scavengers who eat as much as they can when they can get it. 40% of their body weight per meal, apparently, every two to three days. Wow. Yeah. That is a high metabolism. And even if this means taking a nap inside the carcass between meals, as they are known to do. So they'll be like there's a dead cow, they'll eat a bunch, they'll get really full, they'll nap because they can't. Brew into the cow and take a nap. And they'll take a little nap. Oh, that's a little horrific, though. I love it. It's very one of the Star Wars episodes. Good job.

Yeah, thank you. I'm impressed with you, Aaron. It's been like 20 years since I've seen them, but I remember that part vividly. But this scavenger role that they play is actually really helpful as an ecosystem function. They clean up dead carcasses of livestock. They break up the sheep tapeworm cycle. They reduce blowflies. And they cut down on stench.

You know, I think that a lot of the times when it comes to character, charismatic endangered species, we tend to be like, oh, they're so cute, they're so cool, look at what they do. This is like how horrible would it be to lose this species? And like all of that is valid. But I think that sometimes what we also need to remember too is the role in the ecosystem is so profound and interconnected that it's not just about saving, you know, a adorable marsupial. It's also saving the function of the ecosystem as a whole. And yeah, because I feel like we could be like, get rid of all the ticks. But, you know, I would agree with that in part, but yeah. No. But like, there's, there's a bigger picture for all of these things. Anyway, in addition to being

scavengers, devils are also predators, mostly like the ambush type, and their preferred prey is apparently wombats. They're not, like, quite fast enough to catch rabbits. Unfortunately, see our maximatosis and RHDB episodes. And I think that they're not quite fast enough either to reliably catch wallabies, like adult wallabies, maybe babies, or sick ones. They have been recorded running in fast bursts, so one clocked in at 35 kilometers per hour for about 300 meters. But usually they're more endurance type,

and they run 10 to 12 kilometer per hour for hours. They can do that. Wow. Yeah. But they'll eat pretty much anything. So this is from a list of facts about the Tasmanian devil in an article by Nick Mooney titled The Devil You Know. So these are some of the things that have been found in devil scats.

Quote. Part of a woolen sock. A wallaby foot complete with snare. Part of a dog or cat collar. 27 whole echidna quills. stock ear tags and rubber lamb docking rings, the head of a tiger snake, aluminum foil, plastic, and styrofoam, a ring off of a bird's leg, half a pencil, leather jacket, a fish spine, a boobook owl foot, cigarette butt, part of a stilo pot scraper. And this person also mentioned that they also had

part of a leather boot and the knee of a pair of fat-stained jeans eaten after being left outside a tent, not with me in them, end quote. Oh, wow. Yeah. That's like more than a goat. I know. I was just thinking how it's like a goat. Yeah. Wow. Yeah. It's pretty incredible. And their poops are evidently quite big for their size. So 15 centimeters are about six inches long on average. And this is like, you know, these are not that big. Yeah. A six inch poop? Like, what's our diameter we talk in?

I don't, so that I don't know. I did see a couple of pictures, but it didn't, I couldn't get a scale. There was no banana for scale or whatever. I mean, they're chewing out parts of boots. Like, you can identify something as a part of a boot. That's a chunk. I know. I mean, their digestive systems must be.

What is their microbiome? What is their microbiome? Questions. Unanswered questions. Talk about low priority for right now, I think. But the size of their poops has apparently, according to this book I read, helped to encourage the belief that thylacines are still out there. And they also poop in communal latrines, which is somewhat unusual for carnivores. I think hyenas do it. And maybe honey badgers do it? I'm not sure. But it does make potty training for wildlife

rehabbers really easy. Because they're like, and this is your body. poop in this one hole. Yeah. And before I forget, I do want to shout out, I meant to do this at the top of my section. I want to shout out the book that I read for this episode, which was so great. I really enjoyed it. It is called Tasmanian Devil, a unique and threatened animal by David Owen and David Pemberton, two Davids, The Davids. But I really enjoyed it. It was a great book. And so that's where the vast majority the bulk of this information comes from. I love it. Anyway, okay, back to the devils. In terms of size, Tasmanian devils aren't huge beasts at all. Tasmanian devils are the largest living marsupial carnivore, and that's a title that they claimed when the thylacin, aka Tasmanian

tiger, went extinct in the 20th century, the early 20th century. Okay. Adult male devils top in at 8 to 10 kilograms, so 18 to 22 pounds. And adult females are around 5 to 7 kilograms or 11 to 16 pounds. Take me a little kitty cat. I know, I know. Yeah, they are about 570 millimeters or 650 millimeters long, so it's like 1.9 to 2.1 feet long, roughly, and around 30 centimeters or 12 inches tall at the shoulder. Does, like, a small cat, like smaller than a cat? I was thinking like doxen, like a small dog, yeah. Okay.

I'm mostly more around dogs than I am around cats. That's fair. But yeah, I feel like a cat dog is like, yeah, similar. Bigger than a chihuahua. Bigger than a chihuahua, smaller than a beagle. Okay. Depending on the beagle. Like a puppy beagle.

Yeah. So I said dachshin size, but they're, I think, a little bit taller, and they have a much bigger head. Like their head is comically huge. I love it. And it's to accommodate their powerful jaws. And then they have this stiff, thick tail where they store their fat. Like that's where their fat is stored in their tail. It's a fatty tail? Yeah. Yeah. Interesting. We're rubbing our hands trying to feel it in the air. And they kind of, I feel like in some ways, so they resemble like a Wolverine, if you know what a Wolverine looks like, but they're a little bit They're smaller than Wolverines, and they're less, yeah, there are vibes.

Wolverine Honeybadger vibes. Right, right, right, right. And like those, they also have long claws, which are great for digging or holding on to prey or climbing, which they do when they're young, as several, like, zoos who had young found out out later on. They were like, oh, this fencing is not sufficient for the babies, yeah. But Tasmanian Devils, of course, don't start out small to medium dog-sized. after a short but intense breeding season, about three weeks long, where males will sometimes

hold females in dens and not let them leave for days at a time, it's like it can be a very violent from our perspective mating situation. Lots of transmission of this cancer. Exactly. Yeah, exactly. After this, a female will give birth after an 18 to 21 day pregnancy. As marsupials, they are born as teeny tiny, little nuggets, each about the size of a split pea or grain of rice. Oh my God, so tiny. So tiny. Like smaller than half of your pinky nail. Four could fit on a quarter. There was a picture in the book. It was so, I was like, what is that? Oh my gosh. Amazing. And then they crawl their whole way up to get into the little pouch? Yep. So a female will give birth to about 20 to 40 babies or joys. I've also seen

them called Imps, but only a few will survive. She only has four teats. Oh, okay. Ooh, gosh, brutal competition. Yeah, it's very interesting. It's very interesting. Just reproductive strategies, man, you know. Joey's are dependent on mom for about nine months, at the end of which is basically breeding season again. Okay. After they wean, they lead a pretty solo lifestyle, not territorial but covering a large area, fully mature at the age of two, and their lifespan, even before devil facial tumor disease, DFTD, it wasn't much longer than five years, like rarely six. As they're doing their solo traveling, they're aided by a great sense of smell and whiskers all over their head, which helps them sense movement at night. And like I mentioned,

they're covered in mostly black fur with a few white markings around their chest and rump, and their ears are mostly hairless, and I think it's to help them regulate their temperature. So their ears look like pink or red in the sun. It's very cute. I just really need to see pictures of this while you're... Yes, please, please look them up. They are amazing. And also, if I feel like so many of us have this image of Tasmanian devils from the cartoon, Taz, the Warner Brothers Looney Tunes. Yeah. In my eyes, there's like nothing alike. And I just am so baffled. Now I need to look up with that. Oh, my God.

Do your little bottom teeth? Yes. Oh, they're kind of dweeby. Yes, they are. I know. I love them. Tasmini devil cartoon. Now I have to remind myself what he looks like. Oh, yeah, no, that's not even a little bit close. No, right? How weird. I don't understand it. Well, Looney Tunes. Looney Tunes. I mean, well, speaking of Looney Tunes or Warner Brothers specifically, the company trademarked the name Tasmanian Devil. And so aside from Warner Brothers and one fishing lure company in Tasmania that got an

exception, no one can use the name Tasmanian Devil on branding or products. So is that why this is called Devil Facial Tumor Disease and not Tasmanian Devil Facial Tumor. I don't know. I mean, but I know that like it's just, it is that kind of blew me away from like, this is, can you trademark an animal name that doesn't seem like you should be able to do that? You know, unless. Yeah. Who knows?

Yep. But speaking of names, how did this cute dog bear looking thing get the name devil? Look at it laying down. It's so cute. So cute. Have you looked at babies? Oh, no. I want to see babies.

to see the babies. Ooh, this is one eating. That's, that's gross. Okay, keep going. Okay, so how did it get the name devil? One idea is their feeding tendencies, as you just saw the picture of one and went, ooh, gross. So first is just the association with flies around carcasses. So Beelzebub is is also surrounded by flies, hence the nickname Beelzebub's pup. Oh. And then there's the behavior. Devils will often feed in groups drawn to the carcassab. by the loud cries of those who are already there, which is another contender, the noises, by the way, for their name. I'll get back to that in a second.

But as researchers later learned, there's actually order, a hierarchy where certain devils will get their fill and then they'll relinquish the carcass to the rest, not stand guard over it as some other species will do. That being said, the noises that devils can make are varied, to put it mildly, and have been described as otherworldly. If you were to ask me, I would probably say Nasgul-like.

Ooh, okay. Yeah, and I'm going to play a sample for you here. Oh, good. Okay, okay. It's really good. It's wild, and that's just one example. If you go on YouTube, there are videos where there is, like, the full gamut of snorts and barks and growls and screams and shrieks. It's wonderful. I love it. I love it. And so one story goes that when Europeans first landed on Tasmania,

they assumed that it was part of the Australian mainland, which they were already familiar with. And so they also assumed that they knew all of the wildlife that they might encounter. But then at night, as they lay in their tents, they heard the shrieks and screams of a mysterious creature and thought this must be the devil or a devil. Oh, that's a good story. Because Tasmanian Devils are now only, as the name indicates, found on Tasmania, an island state of Australia a couple hundred kilometers to the south of the mainland, and which separated from the mainland around 12,000 years ago. Okay. Devils used to be on the mainland, but when extinct there, along with the Thylacine, around 3,000 years ago, give or take, was before Europeans arrived, which was in the early 17th century. So it's unclear exactly why they went extinct, but it could be due to changes in climate, like the land becoming more arid and thus supporting fewer prey or competition from dingoes.

Some people have suggested that overhunting by indigenous Australians drove down numbers, but that idea does not seem to be well supported. Okay. Okay. So hopefully by this point, I've convinced you that the ferocious, deadly, dangerous reputation that followed Tasmanian Devils around for centuries is largely unfavorable. unless you're a wombat. This rebranding of the Devils, like one chapter of the book that I read about them, was titled From Antichrist to Ambassador, which I thought was great. This rebranding is relatively recent, beginning around the second half of the 20th century or so, although there was still some animosity, like even up until the devil facial tumor disease.

Yeah. From the time that Europeans arrived in Tasmania, Devils were firmly on the do not want list. Trapping, poisoning, hunting any way that these devils could be eliminated was a good way. They were blamed for killing livestock, eating animals out of snares, attacking children, causing general mayhem, escape devil, if you will. To give you an idea of the animosity poured over these creatures, I'm going to read you a couple of quotes from author and artist Louisa Anne Meredith from 1880. Quote, if anyone desires to see a blacker uglier, more savage and more untamable beast than our devil, he must be difficult to please.

That's my opinion. We hunt them down or set traps or dig pitfalls. Any and every way we can to destroy them, we do. Why one winter, some years ago, one of Papa's shepherds caught nearly 150, end quote. Isn't that wild? Yeah. And this is like their native rain. Like, y'all went there.

I know. Okay? Yeah, I know. And this sentiment is polar opposite of what Mary Roberts, who is a wealthy socialite who opened a zoo near Hobart, wrote just a few years after the one I just read, quote, many visitors from the Commonwealth have heard such exaggerated accounts of the ferocity and ugliness of the Tasmanian devil that they sometimes express surprise when they see them act so lively, sprightly, and excited running out to my call. I have derived much pleasure from

studying the habits and disposition of the Tasmanian devils and have found that they respond to kindness and certainly show affection and pleasure when I approach them. Others who do not know or understand them may think of them as they like, but I, who love them, will always regard them as first favorites." End quote. I love that. It's so cute. Unfortunately, this appreciation for devils was relatively rare, and trapping, hunting, poisoning continued until the mid-20th century. And that's when people started to go, guys, like, look what just happened to the thylacine. Are we really going to do this to the Tasmanian devil too?

So then with protections put into place and the devil being used to draw tourists to Tasmania, populations rebounded. And by the 1960s and into the 1970s, they had climbed. to such a degree that some people complained that they were a plague, like a plague of Tasmanian Devils. But then in 1996, things began to change, or at least that's when people started to notice the change. That year, Dutch wildlife photographer Christo Barr's was working in northeastern Tasmania near Mount William when he spotted a group of devils and naturally photographed them. But there was something very odd about this particular set of devils.

Sometimes he would come across older devils with facial wounds or scars, torn ears, that sort of thing. But this was on a whole other level. These devils had extreme facial growths, lumps and lesions. Devils are no stranger to cancer, apparently. In fact, it was known to be a major cause of mortality among the animals, but those cancers were internal. And so this photographer showed these photos around to researchers who were justifiably alarmed and had no idea what could be going on. Before these photos were taken, there had been a couple of mentions of devils with facial tumors, like one in 1984 and one in 1993, but nothing as extreme as this and nothing really suggesting a pattern. And around the same time as these pictures were taken, anecdotal reports of drops in devil populations were coming out of the same area.

where those photos were taken, where devil concentrations had previously been among the highest. Farmers were reporting that dead cows or sheep were just laying there, uneaten. Previously, the devils would have made really fast work of the carcass. So what was happening? Within a few years, researchers identified the disease as a transmissible cancer, one that was rapidly spreading throughout devil populations. And initially there was this question of whether this cancer was an old re-emerging disease, maybe one that had previously cycled through Devils and contributed to past population declines,

which we actually have very little data on to even say that there were clear boom and bust cycles. Like I read that the first dissertation about Tasmanian Devils was published in 1991. And so I think that there's been, yeah, there have been like over the years it was sort of not very much, research and then within the past few decades, there's been a lot, a lot. Interesting. Huh. And while there are apparently some devil skulls from the 1800s that seem to have formations similar to those caused by the cancer, more recent genetic analysis revealed that the first

strain of the cancer, DFT1, emerged sometime in 1986, roughly, plus or minus. With the second strain, DFT2, emerging seemingly indefty-one, emerging seemingly indiftonable. independently in 2011. Within a few years of those 1996 photos, researchers began seeing the cancer pop up hundreds of kilometers away, suggesting that the disease was rapidly spreading throughout the population. By 2005, half of Tasmania was affected, with no signs of slowing. In 2009, the Tasmanian devil was officially listed as endangered, and research ramped up on understanding what this cancer was, how it was spreading, and especially how we might be able to control it. While this disease may no longer pose the existential threat it once was to Tasmanian

Devils, it still is very much up in the air what the near future will look like for these devils whose populations have declined 60 to 70%. To have any hope at stopping this decline and working towards recovery means integrating knowledge from across so many different fields, from evolution to vaccines, behavioral ecology, to conservation strategies, cancer biology, and beyond. And we are so excited to be able to talk with someone who has expert knowledge in so many of these aspects, as evidenced by the fact that, like, literally, like you said, on, he's on so many of these papers. Like everyone that I read. Let's take a quick break here and then we'll chat with Dr. Rodrigo Hamede, senior lecturer at the University of Tasmania.

Well, my name is Rodrigo Hamele. I'm a disease psychologist here at the University of Tasmania. I've been investigating Tasmania Devils for 20 years now. I came to Tasmania 25 years ago as an enthusiast, Bush Walker and wildlife lover. my background was in arts and music, so I wasn't a scientist in those years. But I came with the expectation to see a Tasmanian devil in the wild. Tasmania has a lot of resemblance with Patagonia.

They're both called Juana relics. So I was always interested in Tasmania. And I became so enchanted by these amazing creatures that I decided to have a career past change and study science and here I am 20 years later still. working with them. That's incredible. Well, thank you so much for chatting with me today. I can't wait to chat more about Tasmanian devils and get your expert knowledge about this incredibly fascinating animal and this unique and deadly disease that is threatening its existence. So far in this episode,

we've covered some of the biology of this transmissible cancer, like how it's spread, the tumors that it causes, and we've also discussed the devils themselves, their natural history, what charming little creatures they are. I am completely in love. And also we talked about when people first observed devils infected with this deadly transmissible cancer. Since those early observations, how have devil populations been affected throughout Tasmania? And have there also been downstream effects on the ecosystems where they're one of the top

predators? Yes, so the disease was first observed by a wildlife photographer from Netherlands called Cristobar's in 1996. Molecular work that we've done now suggested the disease was present in the late 1980s. But that was the first time in 1996 that we saw a devil with massive tumours. We didn't know this was a transmissible cancer. We just saw this poor devil has some weird malformations in the face. It was in the next following three to four years. We didn't know. that in the eastern part of Tasmania, more devil starting to look with these tumors. And then a few years later, we realized this was a transmissible cancer. Since then, we have lost two-thirds of the world devil population because they're endemic

to Tasmania, so that's the only place where they occur. And of course, Tasmanian devil's being an apex predator has a very important role in the ecosystem of our island, Tasmania. and that decline has had a lot of cascading ecological effects in other communities. We've seen an increase in some mesopredators. One of them is the Eastern Quo, areas where I used to trap like my long-term study site that I've been investigating for almost 20 years for the first seven or eight years we never saw an Eastern Quill.

And now we get there was a bycatch, and 80 or 90% of our traps are Eastern Qualls, and only a handful of animals are devils. Sadly, we've also seen an increase in feral cats, which is the biggest conservation threat that Tasmania and Australia has. It is a horrible thing because there's nothing we can do about it. It's out of control. And of course, less competition from a nervous predator means more space and more ecological niche for feral cats.

They're also interestingly changing the peak of their activity patterns. Previously in areas with high devil densities, the peak of activity patterns was during the day in the absence of high densities of devils now they shift in their activity patterns during the night. And of course, most of our wildlife is nocturnal, so there's much more opportunities for predation. We've seen behavioral changes in some pre-species where they're much more relaxed. And so the ecological role of devils is sort of in some areas absent. Changes in parasitic communities, of course, because being scavengers, there's a lot of parasites. There's a lot of things that a lot of people don't care, but some of us do care about.

Above these things, carrying availability, the biomass of food in Tasmania, it's amazing. There's so much wildlife and they're scavengers, so they act as ecological recyclers, killing up all that carrion. So this increasing carryings also result in increasing other carrion figures like Forest Ravens. And lastly, but not the least, changes in humans. Believe it or not, when I started working, a lot of farmers had negative thoughts about Tasmanian Devils because every now and then they would lose a lamb during lemon season. The general public also didn't have this special relationship we have now with

Tasmanian devils. They're quite important. Most farmers now are seeing that the carcass dumps where all these animals are put, they were cleaned in a couple of weeks. And now they're rotten, causing some diseases to emerge, fly strike disease and other things. So now they're seeing in the absence of devils, they're seeing how important they are. And I must say the entire community, the entire Tasmanian community now is a lot more apathetic of our beloved avid predator than 20 years ago.

Beyond the dramatic impact on Tasmanian devil population numbers overall, and as well as these cascading ecosystem effects that you discussed, has this cancer or have these cancers also led to any life history or behavioral changes in the Tasmanian devils themselves? Indeed, it has. And when you think about it, diseases that affect fitness usually end up altering some of these evolutionary processes in their host. When you have a disease that is almost 100% lethal in such a short period of time, the pressure is immense. So the evolutionary response we've seen into Spanian Devils is incredible fast evolution. These things are ought to happen over centuries or thousands of years. But, you know, we've seen it as little as four to six generations.

that's eight to 12 years. Perhaps the most important and immediate one is precocial breeding. So devils reach sexual maturity in the second year of their lives and now in chronically affected populations, some females, not all, but some females are able to breed in their first year, which is astonishing because that shouldn't happen. So this is driven by the availability of resources. In the lack of high devil abundances, there's a lot more resources.

the females can grow much faster and they can reach that minimum critical size to breed in the first year. There's also less competition by other adult females in the population because most populations affected by the disease are comprised of young animals. And that gives more scope for these one year of females to breed and manage to put a litter in the next generation before they succumb to the disease because when they made, they contract the disease. So it's sort of a vicious circle in a sense. but it has caused at least populations to become stable below carrying capacity, but stable because they can still breed in the first year. We've seen also behavioral changes in behaviors associated with transmission risk. You would think that a disease that is transmitted by aggressive behavior,

there would be a selection for shy phenotypes, for animals that are less aggressive to have more opportunities for breeding because they're not contracting the disease, and those genes would be passed into the next generation. So you would expect that devils will become less aggressive, aggressive. But of course, the trade-off of that is that aggressive behavior is associated with mate acquisition. And so there is a bit of a trade of there. But we have seen changes in animals that are sub-battels where they didn't use to bite each other very much, particularly

severe bite wounds. And now they're increasing the proportion of severe bite wounds. In the absence of these aggressive animals, they've overtaken that role of the older animals in the population. And we've also seen sickness behavior, the behavior of those animals that are infected as the disease progressed, become less and less isolated from their social network. And that is perhaps something good for avoiding transmission in lower population densities. These animals are less likely to infect others later in the disease progression. So most transmissions might happen during the early stages of the disease when their effect of the cancer has not made them less likely to interact with other individuals.

And perhaps the most important one is the evolution of resilient mechanisms to cancer, the one that we were discussing before. Changes in allele frequencies in genes that are associated with cancer and immune function in humans have occurred, as I said before, in as little as four to six double generations that eight to 12 years. Tolerance to cancer is also something that we have seen. So now animals are surviving at least up to two years, but almost 50% more time. And when they're infected, they survive for much longer than, you know, eight or ten generations.

ago. The interesting thing is that tolerance is good for the cancer too, because animals living longer infectious with these massive tumours. I mean, I've seen animals that have tumors of the size of four tennis balls, you know, like there's half of the face as a tumor, and they're just hanging about. And that's good for the disease because it's increasing his basic reflective number. It's increasing his magic R number that we all learned with COVID. So these animals surviving longer with the disease is a thing good for them, and it's also a thing good for the cancer. And some of them are resistant diseases and not just tolerating it, but, you know, causing tumor regressions. And what we don't know is true resistance is the ones

that are getting infected, but they don't develop tumors because we don't have a preclinical test. So we don't know if the animals infected unless they have tumors. So there might be a proportion of animals that are challenged with this cancer and they're not developing tumors, but unfortunately we don't know that. We do know that a small proportion can show tumors and then create an immune response and cure themselves from cancer, which is quite interesting and quite exciting. Getting into that a little bit more, are there ecological or behavioral characteristics of Tasmanian devils? You mentioned aggression and social networks. How does that sort of contribute to the spread of this cancer, both in terms of the Tasmanian devils themselves, but also

external factors like habitat fragmentation, anything that influences these dynamics of transmission? Yeah, the big one is mating season. So under lower densities, there's less likelihood of these animals encountering each other. But we've done a fair bit of work with social networks using a marvelous technology called proximity sensing radicolors, which interact with each other at pre-programmed distance. So in the same way, we did social networks with COVID and humans who can do this with just million devils. And it's fantastic because it's 24 hours a day, seven days a week data. So we know that there's a peak of interactions during the mating.

season. We know that a lot of these bite wounds that come up in animals are the result of both male guarding and copulation, which is quite aggressive. And that even at low densities means that these animals will encounter with each other and then they will maintain the disease under low population density. So mating season and aggressive behavior is the big driver of transmission for this disease. Age structure is another one because populations are now biased. towards one and two-year-olds, the rules live up to five, six years maximum in the world. If you go to any chronically disease population,

90% of the population will be composed of one and two-year-olds. And they're breeding once or twice and before succumbed to the disease, because when they mate is when they're most likely to contract the disease. So that's fuel for the epidemic. In terms of fragmentation, devils have overlapping home ranges, and they have home ranges about 12 square kilometers. So the way the disease moves in areas with high density is much faster than in areas with

lower density, of course. But the distribution of range of Tasmanian Devils has been now entirely affected by the FD. So there's only some pockets in the West Coast or in the South Waste that are unaffected, but it's not prime habitat. So we could say that, you know, the entire distribution of Tasmanian Devils, the original range is affected by the FD. In the last decade, a second strain of transmissible cancer, DFT2, has emerged seemingly independently. What does its emergence tell us about infection dynamics or where these cancers originated or about the devils themselves? Like, is this just something that happens to them or they're more susceptible to this? Yeah, this is so interesting.

This is always, I use an analogy story with the lottery with my students. when they ask me about these. I say, imagine if you just want to have a great holiday and you buy one lottery ticket and you win it. And you win lots of money. You have a wonderful life. And 20 years later, you run out of money and you decide to buy another lottery ticket.

Imagine winning it again. Those are the odds of having two transmissible cancers in 20 years in the same species. These things don't happen, right? There's three transmissible cancers in anthropology in vertebrates and 16 invertebrates in muscles. But this is not coincidence. In the early 1990s, Patient Zero was a female

and developed this cancer that somehow managed to evade the immune system and become transmissible. In 2014, Patient Zero was a male that had a cancer. Same story. It looks the same. It's completely different, but it looks exactly the same, managed to evade the immune system. So this is telling me at least and a few of our colleagues

using the most parsimonious explanation that these animals may have a particular system susceptibility to these malignancies. And in fact, I would argue that this is not the second transmissible cancer that they've experienced through their evolutionary history. If they had two in 20 years, I would think that maybe this is not number two, this is number 12, or something like that. And they've managed to recover from them. So they may have, during the evolutionary history, figured it out how to overcome cancer. When I say figured it out, I mean, figuratively, of course. And this is quite important because transmissible cancers, there's this theory about the perfect storm theory

for transmissible cancers that, you know, a number of coincidences, both in the tumor and the house must coincide for these transmissible cancers to emerge. And the theory is that they are much more common than what we think, but they don't, they're not sustaining populations because not all these coincidence happens. So they might emerge, but they die out. Somehow just many devils are proving that, you know, transmissible cancers can be sustaining populations. and I think it's a fantastic story to learn a little bit more about cancer. We tend to forget that cancer is half a billion years old. It's a disease that is thought to have appeared with the transition of unicellularity to

multicellularity. And we have evolved over millions of years mechanisms to avoid horizontal transmission and cancer dies when the host dies. So these two cancers are fantastic opportunity, sadly as it is, to learn that a little bit more about the evolutionary trajectory of cancer cells in nature. And now, not only that, but also to learn about competition dynamics between these two cancers. Because the pressures that the devils are facing now are not the same that they faced 20 years ago. They are in a much lower abundance of hosts, so there's less scope for mutations and transmission

events. There's pressure for these two cancers to outcompete each other, short and latent period, faster tumor growth rates. are these evolutionary responses to the first cancer transferable to the second one? There's a lot of things we need to start figuring out now. When a new wildlife disease emerges, conservation is the top priority. Like, do what we can right now to save the animals while we figure the rest of this question out. What are some of the conservation efforts that have been employed for Tasmanian devil populations?

And what are some of the challenges associated with conservation? We've changed a little bit our conservation strategies in the last few years. When this disease first emerged and we thought that, you know, devil's words were just declining in a matter of two or three years after disease arrival significantly. So we were in panic mode and our conservation strategies was to avoid extinction. And therefore, we created when I say we, I'm talking now about Tasmania, not myself. Don't want to seem to presumptuous about that.

This is all our work. Lettersmanian government had this mission to create insurance populations, both in Tasmania and in Australia, mainland zoos, so captive insurance populations, to preserve the genetic diversity of the species and to ensure that we had a stock of animals if things were dire towards extinction. We also did a fantastic translocation to an island called Mariah Island,

where there's now abundance of too many devils now. on the island. Of course, free of disease, they were all sourced from captive institutions and on the basis of genetic diversity. It is a wild insurance population. Now, several generations have been born in the world, and we know that they're free of disease, because the diseases won't get there.

But I think the biggest conservation strategy that we have switched from managing for extension to managing for evolution, these days, is no longer an extinction-threatening disease. It has depleted devil populations by two-thirds. It has not allowed devil recovery yet, but we have not seen any local extinction in any particular area almost 30 years after this disease because of these evolutionary responses. So now we're starting to think, do we need to trade of genetic rescue with evolutionary rescue? Is it more important to have devils that are adapted and have the genes to become more resilient to this disease?

and trade that off for maximum genitive diversity. One of the things that we were doing in the past was reintroductions from captive populations back into the world to boost those numbers. And I don't think that was a good idea because one of them is going to fuel epidemics, it's going to fuel transmission because more susceptible are added to the population,

but also because if these animals that have never been exposed to the FD mixed with the genotypes that are being selectively adapted, to cope with the disease, we might dilute that evolutionary response. So we are in a bit of a conundrum now to think how we need to manage this disease in the long term, because it seems like the situation is the disease is not going to go anywhere, right? It's here to stay for the foreseeable future. Devils are not going extinct either. So we need to start thinking about much more innovative solutions to make sure that our conservation strategies are long term and not short term. And speaking of innovative solutions, what do you see as the most important next steps

or the steps that you would most like to see in this field of DFTD research? Well, we need to start using modern genomic tools to try to manage this population in the long term. We've realized that these tumors regressions, these devils that had tumor regressions have the expression of certain genes that devils that didn't have tumor regressions had. So we've isolated a few genes that have a role in cancer in humans as well and that are related with these tumor regression. So we need to model long-term evolutionary dynamics and possibly co-evolutionary dynamics between devils and tumors. We need to understand whether these selective mechanisms for cancer resistance are heritable. That's very important, particularly to manage their genetic stock of insurance populations.

and if they are heritable and they are present in these chronically affected populations, we need to make sure they're taking into account when managing the insurance populations. I think one of the biggest challenges we have at the moment is particularly to understand how this is going to pan out in the next 10 to 20 years. These evolutionary dynamics we've seen might be transient. We need to realize that we're still dealing with a disease early in its own. evolutionary stages. We tend to think, well, we've been working in this disease for 20 years, you know, like we've been working with us many devils for so long. That's only 10 generations.

And when you put things in the evolutionary board, you may think, okay, things are just starting. So we need to be very careful about what we do now and make sure that whatever we're doing now, we have tested that is proven to be not detrimental into the future. So at least we have the benefit of time now. We're not like 10 or 15 years ago. We thought devils are going to go extinct. We need to do things rapidly. And we're translating our research, our cancer research, our genomic research, with co-evolutionary models. We're working with oncologists, with cancer labs around the world. A lot of experts in cancer in humans are quite interested in our study system because it's a fantastic study system to see how cancer operate in nature

and hopefully make a difference for the next generation of kids in Tasmania, that are not Tasmania and devils, and make sure that we can pass the way to recovery. It seems like the devils are doing that themselves. They may need a bit of help from us once we understand how these residual mechanisms operate, and hopefully we'll have devils and facial tumors in the foreseeable future. That was incredible. I still, I want to know so much more, Erin.

I know, I know, me too, me too. Thank you so, so much, Dr. Hamide, for sitting down with us and for talking us through all of this. And for all of your incredible work. Like, this is just, wow. What a joy. Thank you, thank you, thank you. Well, I think at this point, all that is remaining is sources, yeah? Yeah, so that everyone can keep learning more about these inquiries.

incredible devils and this fascinating, fascinating disease. I will shout out again the great book that I read titled Tasmanian Devil, a unique and threatened animal by the Davids, David Owen, and David Pemberton. I hope they're okay with me saying the Davids. And there are a couple of papers that I'll post. I had so many papers, so many papers to go through. I think some of the ones that were really great for. like big picture of this disease. One of them was a 2006 paper by Hawkins at all, which is kind of one of

the big papers that often gets cited about this disease. There's a few really detailed ones on the immunology of this disease, one by SIDL at All from 2013, titled Reversible Epigenetic Down Regulation of MHC Molecules. It's a really good one. Lots of detail there. And honestly, There's so, so many other papers. We post the list of sources from this episode and every single one of our episodes on our website, This Podcast Will Kill You.com under the episodes tab. A big thank you to Bloodmobile for providing the music for this episode and all of our episodes. Thank you to Tom Brifogel and Leanna Squillachi for the incredible audio mixing.

Thank you to exactly right. And thank you to you, listeners. We hope that you had fun with this episode and learned a lot. and have a little bit more love for Tasmanian Devils. Yeah, who wants to meet us in Tasmania? Yeah. Yeah. That would be fun.

For real. It's going to field trip. Yeah. And a special thank you, as always, to our wonderful, fantastic, generous patrons. We appreciate your support so very much. So much. Thank you. Well, until next time, wash your hands. You filthy animals.

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