From the Vault: Thirst, Part 3

the question of thirst. Now, if you remember, in the last episode, Rob we talked about the biology of thirst, anticipation of anticipation of the quenching of thirst. Because there's this interesting thing where after you drink a glass of water when you've been dehydrated, it takes some number of minutes, maybe on the order of tens of minutes before that water actually gets absorbed through the digestive system and ends up in the blood and makes a difference systemically throughout

the body. And yet you still feel that that thirst quinchiness after you have just the first glass of water. You're not continuously chugging for ten to twenty minutes at

least hopefully not. But to start off today, I wanted to come back to the question of how it is that the body detects, the anticipates the coming changes in your blood and your blood osmolality, which again is the concentration of dissolved substances like mineral salts in your body's water content, and how it anticipates those changes to provide you that delicious feeling of having your thirst quenched by

a glass of water. Now, in the previous episodes, we already talked about a few ways that the mouth in the throat might detect the introduction of water into the body and sort of sin signals to the brain saying hey, okay, you can put the thirst on hold for now, there are soon coming changes to the body's hydration levels. And one of the ideas we talked about was the possibility that temperature plays a role, because maybe there's some evidence that the power of water to cool the mouth and

throat sends quinching signals to the brain. And also there was some evidence that rodents were using sour taste receptors in the mouth to detect the presence of water. But Rob maybeing set me straight on this one. I don't think it was clear that triggering the sour taste receptors actually led to the quinching of thirst. Rather, it seemed to encourage more drinking behavior when the mouse was thirsty. Is that right? Yes, that's my understanding of these findings.

But I was actually reading about a few more studies on exactly this question of how thirst quinching happens. What is the mechanism that leads to these changes in the brain that tell you, aha, thou art now quinched. So the first thing I wanted to talk about was a study that I was reading about a New York Times article from twenty eighteen by Verny Greenwood called you get thirsty and drink? How does your brain signal you've had enough?

And this is referring to a paper that I think came up in passing in the previous episode, but it was by Vinnie Augustine at all in Nature in twenty eighteen called Hierarchical neural architecture underlying thirst regulation. And this research has been looking at exactly this question we just brought up, and they confirmed that, of course there is a complex of neurons in the brain that appear to

cease activity after a thirsty mouse drinks water. So there are some neurons that are apparently signaling that generating that thirst motivation state. But then when a rodent takes some water in through the mouth, those rons shut up, they go quiet. So this would be the neural mechanism to register quenching. But the question is what is the direct

mechanism that leads to the changes in those neurons. Now, this New York Times article summarizes the findings as explained by the first author on that paper, Vanite Augustine quote, Intriguingly, what these cells are responding to is not the presence of water itself, mister Augustine said. The researchers discovered that letting a mouse take big gulps of water would spur the neurons into action, but giving it water in gel form, which had to be chewed before it could be swallowed,

did not. Neither did providing water in tiny two second long SIPs, even when the animals consumed the same total amount of water. In fact, giving the mice oil to drink had just the same effect on the neurons as

gulping water. So that last part is a little gross, but based on this fine name, uh, it would kind of imply that a major mechanism leading these thirst neurons to to say, okay, thirst has been quenched would have something to do with like muscular movements in the throat, the kind of gulping that you do when you're guzzling down a bunch of water really fast. But technically maybe it doesn't even have to be water, it's just any

fluid that you're gulping. I mean, as humans, we don't I guess, drink a lot of just straight oil, but we do drink a lot of things that are that are to varying degrees removed from from from you know, from from just a neutral water. So this would make sense, right, But if you if you hydrate yourself in some other ways, so like the examples that you say, consuming water in gel form where you can't like gulp it down really that still hydrates you, but that apparently does not lead

to this immediate quinching signal in the brain. Similarly, with drinking water in very small isolated SIPs, I guess in those cases you would eventually hydrate your self and your thirst will eventually go away, but it will be more likely that your body has to just become systemically hydrated before the thirst goes away. It's not that sudden quinching

reward feeling. Now, there was an interesting detail offered here about reasons that the body might need to have this reaction where we turn off thirst very quickly after getting a drink, like why not just wait for your blood

osmolality to reach the ideal level. Well, in previous episodes, we talked about one reason for this, which is that you know, if you actually did have to wait for your body's water content to get all leveled out right before your thirst went away, you might you might like kill yourself drinking gallons and gallons of water because you know over the course of the tens of minutes that it takes for this change to take hold. But there's another reason, one of the authors of this paper brings up.

That's in this Greenwood article in the Times quote. Aside from the specter of water intoxication, there are good reasons to drink only the minimum amount necessary when an animal lowers its head to drink, doctor Oka speculated, and that's doctor Yukioka. It's in quite a vulnerable position. Quote, if you double the time of ingestion, that should double the risk of being prey, he said, And I thought that

was interesting too. I mean, I think it is true that in the natural environment, as we brought up in the previous episode, going for water is often putting yourself in a vulnerable position, you know, maybe exposing yourself from hiding or shelter and sort of turning your attention away

from scanning your surroundings. Yeah. I mean in many cases too, they the access point of the water might not provide much in the way of cover for smaller animals, and then for larger animals there may be you know, bodily positions they have to get into to drink that put them in a greater state of vulnerability. Like I'm thinking of a draft for instance. Though draft, of course is already formidable animal U but but still there's a certain

awkwardness present when it actually has to drink water. Sorry, I just started thinking about game or fuel. Um, yeah, this is this, says. I have no research to back this up. They're just observational material for me. But I think everyone knows that I enjoy watching the squirrels, and we have a bird bath outside near our feeders, and the bird bath is positioned right up against the fence,

and the squirrels drink from that all the time. But I wonder how much I wonder how much of that is that they're able to drink from the bird bath while essentially remaining in a vertical position attached to the to the fence, like they don't have to, you know, go across a clearing. They have, I guess, pretty good cover for a squirrel. Those squirrels are bold in other ways that, you know, make you think that they're they're less concerned, or they're or they're in control of the

situation as far as potential predators go. So if you happen to have sitter squirrels and rover squirrels, your bird bath is positioned in such a way that even the sitter squirrels could could get to it. I guess so. But then, yeah, I don't know. I'd be interested to hear what anyone else out there has observed with their squirrels and drinking water from bird baths and other water sources. They seem to like one thing versus the other. I don't know. They certainly drink more water than my cat.

I'll give them that well. Anyway, there was another article from the very next year, also in the New York Times, also by Greenwood, covering follow up research from some of

the same scientists. So this was published May thirty first, twenty nineteen, just called the Neurobiology of Thirst, and this is summarizing a study published in twenty nineteen in the journal Neuron where the authors oh again the first author on this one was Vanite Augustine and it was called Temporally and spatially distinct thirst satiation Sig and the authors here found that the pleasure we get from drinking when

thirsty is once again not directly related to hydration. It is a reward pathway separated by both time and space from the body's hydration and osmolality monitoring mechanisms. And one of the major findings in this paper is that though drinking water is associated with a dopamine release, this is a typical signal that the brain is expecting a reward. Right. You know, things that you want, you want to get and feel good when you get them. That's often that

involves a dopamine release. But the feeling of reward in the brain here is apparently not tied to becoming hydrated after being dehydrated, but specifically to the act of drinking water through the mouth. So if you're dehydrated and then you suddenly receive water through an iv or even via a direct injection into the stomach, your thirst will eventually go away after your body adjusts to the new fluid levels, but you won't get that feeling of reward satisfaction or

the corresponding dopamine release. Those come specifically from the activity of drinking, the gulping of water through the mouth. And picking up on this, I was actually looking at one more paper that had an interesting finding. I wouldn't have

mentioned this. Other one was a little earlier. This was from twenty sixteen published in Nature called thirst neurons anticipate the homeostatic consequences of eating and drinking, And this is by Zimmerman at All And this study found, among other things, a dual track monitoring system for thirst management. So along

the lines we've already been talking about. It found that if you take mice and you give them some salt and make them thirsty, drinking water rapidly inhibits neurons in a region of the brain called the subfornical organ or SFO, and that leads to thirst quenching. And of course this

is before there's any notable change in blood osmolality. But it also found that if you take these thirsty mice and you give them very salty water and the opportunity to drink it, they will drink it, and initially they will gulp it down and it will inhibit the SFO neurons and apparently quench thirst just like the freshwater. But the quenching doesn't last for very long, and they write quote,

this initial decline was reversed after approximately one minute. This indicates that the rapid anticipatory response to drinking has at least two components, an immediate signal that tracks fluid ingestion and a delayed signal that reports on fluid tonicity, possibly generated by an esophageal or gastric osmo sensor. So if you put all of this together, it seems like you've got at least three different time dependent levels of sort

of the body's quinch watch. So you put them all together, and you've got one system that's like, are you gulping fluid? If you are, oh, that's very good, very good thou art quinched, But then there's a second system on a slight delay from that one, roughly one minute of delay in mice. It's like, wait a second, what exactly was that you were just gulping? Was that oil or was that super salty water? You know, what are you trying

to pull? And if it well, if it was not good fresh water, then it will cancel, cancel the quinch and return the thirst. And then finally I guess there's just the direct blood volume in osmolality monitoring, which is on a much greater delay than the other two. So, first of all, reminder, if anyone else, if anyone's interested in the whole drinking saltwater thing, we did a whole episode on drinking saltwater a while back. You should be

able to find that in the archives. Not a good idea was it was one of the main findings there. But the other thing, I think, and we've kind of we've kind of touched on this a little bit already, but you know, it would be in a steak to think of like, Okay, it's just you know, what's drinking water, water in water out, you know, even if you you then acknowledge, okay, well, you know, the levels have to

be just right. But it's it's more than that. It's not like organisms just one day we're like, hey, there's water we can drink that we should use this to our advantage. Now, like we are of water. So it's like water in am water evolved out of things in water, etc. So it's it makes sense that there would be a more complex relationship with multiple triggers that you know that

we're still trying to understand. Yeah, I mean, as we said at the very beginning, you you are the direct descendant of creatures that long ago lived in the ocean and all of your ancestors, just like you brought the ocean with you onto land. The ocean is now inside your skin. Yes. Oh, and before I wrap up, this last study I mentioned also documents interesting evidence for the the oral cooling mechanism of thirst quenching that I brought up in previous episode. So the authors here say that quote.

We found that a playing cold but not room temperature metal to the oral cavity of a wake thirsty mice was sufficient to rapidly inhibit SFO neurons. Thus, temperature dependent modulation of SFO neurons may explain the enigmatic connection between oral cooling and thirst, including why thirsty rodents will avidly lick cold metal, and humans report that sucking on ice

chips rapidly relieves thirst. That's interesting. I hadn't really thought about that with sucking on ice chips though, though obviously, I mean that's I think that's something we all do

if we have access to iced drinks. Of course, the thing with ice, of course, is that ice melts in your mouth as well and actually serves to hydrate you, right, but that the cooling effect of having the ice in the mouth may provide a level of thirst quenching sensation that goes beyond the actual amount of water you're taking

in from that ice. This gives me a great idea, so, showrunners and so forth, of the Witcher, if you're listening, I would love to see a scene where Henry Cavill's Witcher character share some wisdom and he's like, sometimes when when I'm thirsty, I just have a good lick of my sword takes care of you know. That'd be great, And you haven't seen there was just kind of licking is the blade of his sword. I'd never heard this before that apparently thirsty, thirsty rodents will lick cold metal.

But yeah, I had not seen it. Yeah, but it's good enough for mice, it's good enough for the witcher. I think all Garrold's just gonna that's that's how you cut your tongue, buddy, That's how you cut your tongue. Oh you know. It reminds me of brom Stoker's Dracula. We have that wonderful scene where Gary Oldman's elderly Dracula licks the blood from the straight razor. See, he was thirsty and he quenched the thirst. But also hopefully the blade was cold enough that that also had an fact.

I well, I guess after all these studies we looked at on the quenching mechanism, I'm wondering, so the two main different ones have emerged. One is the oral cooling mechanism and the other is the gulping mechanism. You know, the muscular movements in the throat is you're swallowing large amounts of water. And I guess I'm not sure if these two different explanations are competing or if they're complementary. Maybe they both play a role in regulating these thirst neurons.

In the SFO. I'm not sure. Now, given all the things we've discussed about the complexity of thirst, sensations, and water acquisition by various organisms, I thought it might be interesting to look at a couple of examples that, in different ways seem to hijack mechanisms of related to thirst and our relationship with water, not only ours, but also some other organisms for the benefit of a life form.

Not the life form that is that is potentially thirsty, but a life form that is that is hijacking that organism, such as a parasite or a virus. Oh. Interesting. So the first one I want to mention here is is one that definitely affects humans, and that is rabies. Now, I imagine I think everyone has heard of rabies. If not, buckle in because I'm gonna share a little bit. Though. This is obviously a topic that you know, we could really bust out if we wanted to and give a

full episode treatment. But even if you're just vaguely familiar with rabies, uh, you know, you might not grasp the full danger and horror of this particular zoonotic viral disease. I think a while back, I've read at least somebody making the case that rabies is a contender for like the worst disease known. Yeah, it is pretty horrifying and for a lot of people in um in the world, particularly and let's let's say United States, you're lucky enough

to live largely removed from it. I think that the US is sometimes class of classified as being free of canine rabies. Now, there are still cases of canine rabies that pop up, and there are deaths that occur, but not at the same rate as other parts of the world where the problem has not been contained as well. So it's rabies is caused by the virus Lisa virus,

which essentially means rage poison. It's named for the Greek goddess Lissa, the goddess of rage, fury and rabies, the daughter of Nicks, sprung from the blood of Lauranus, and she pops up in different tales, like for instance, at the urging of Hera, she inflicts madness on Heracles, and in some tellings she's also involved in the punishment of the hunter Acteon, who's torn apart by his own mad hunting dogs, and in memory Serves. There are some interesting

treatments of the this latter tale in art. Yeah, I think he looked at a god or something to that effect. You know, you don't have to do much to get to torn apart by dogs when you're dealing with the Greek pantheon. Yeah. I don't remember all the details, but I think he makes Artemis angry for some reason, and then he's a hunter. But then he's transformed into the quarry, like he's transformed into a stag or something, and then his own hunting dogs hunt atch. Right, there's some transformation

involved there as well. So humans have been exposed to rabies for a very long time. It's um. It's thought that it probably originated in old world bats and especially flourished during the heyday of of dog domestication. So it is, you know, it is. It is definitely tied to the

canine world. According to the History of Rabies in the Western Hemisphere by Velasco Villa at All, published in Anti Viral Research, the earliest record of a disease affecting humans that's consistent with rabies and associated with dogs is found in the Eshnuna cuneiform law tablets in ancient Mesopotamia dating back to the eighteenth through nineteenth centuries BC. Wow, Yeah, and I believe memories served it. It concerns like laws concerning dogs biting people, like if you you have a

dog and it bites somebody. And of course we have other references to either cases that seem like they could be rabies, or we feel pretty strongly are referring to rabies. Aristotle wrote seemed to have wrote of it in three thirty BC. Quote dogs suffer from the madness. This causes them to become very irritable, and all animals they bite

become diseased. Democratus and Hippocrates also wrote of it as well, and there are comparisons to raging dogs in the Iliad that it seems like maybe you're less certain that this is referring, because of course a dog can rage. I guess it doesn't have to be rabid. But there are also mentions of the dog star Ryan exerting a malignant influence on human health, and rabies is just a terrible disease, especially when you really get into what it can do to an organism and what it can do to a

human being. Today, it's vaccine preventable, and the vaccines keep improving, but once clinical symptoms appear, it is one fatal According to the World Health Organization, in ninety nine percent of cases, domestic dogs are responsible for spreading it to humans. Again, in the United States, it is effectively we're effectively canine rabies free, though you will still find cases that occur and deaths that occur, so it's it's still possible, but it is largely under control. In other parts of the

world it's not the case. And so you know, this is all great reminder why it is important to get your dog a rabies vaccine and to also get yourself immunized if you come into contact with the disease, right, and that time is very important there, right, Yeah, so that the incubation period for rabies is typically two to three months, but may vary from one week to a year. And I think it depends on like the viral load and you know, being introduced into your body and some

other factors. And then there are two forms of the disease that are possible in humans. So once you know this virus is in your system, one version is paralytic rabies. This only occurs in about twenty percent of cases, and it consists of gradual muscle paralyzation, coma, and death. It's often misdiagnosed, but again, like twenty percent of cases, this

is what occurs. The other, however, is the the the incarnation of rabies that certainly brings to mind these ideas of strange curses from the gods, you know, the really horrible stuff, and that's furious rabies. Symptoms here include hyperactivity, excitable behavior, hydrophobia, the fear of water, and sometimes aerophobia as well, fear of drafts of fresh air or you know, blasts of air, that sort of thing. And death occurs

in these cases within a few days due to cardiac arrest. Now, I gotta admit I've always heard rabies described as or associated with this idea of hydrophobia, which obviously, yeah, that means fear of water, but I never knew exactly what

to make of that, Like what does that mean in practice? Yeah, because it's you know, when you start thinking about like the things that a viral infection does, like you know, to what extent is it about prolonging that virus or or or you know, achieving something, and it's um you know, in its cycle, and as you look into it, it's it's really quite interesting. So again, this is the really

horrible fate the furious rabies. If one comes down with this person's behavior and mood is drastically altered, anxiety, hallucinations, confusion, paranoia, terror, and they tend to experience both a profound thirst and a severe inability to quench that thirst. So what does all this mean? Well, keep in mind that saliva is

central to rabies transmission. You know, if you think of you just hear the words rabid dog, the image that probably comes to mind is that of a dog frothing at the mouth, right, with frothing saliva right, And it's generally understood that I guess the saliva is what transmits the disease. Like if you are bitten by a dog that has rabies or by an animal that has rabies, the saliva will transmit it to your blood. Is that a real route of transmission? Yes, that is the primary

route of transmission. Bites and scratches are are the most common ways that it is just transmitted. There are other ways, you know, basically any infected fluid could do it, but those are uncommon compared to bites and scratches, especially when you're you know, think of a dog, think of think of even you know, a bat or any other organism that would carry rabies. The bite is the thing, and it's steered in these cases by you know, enhanced aggression

and altered behavior. And seemingly, you know, the mouth is primed to transmit the virus by excess infectious frothing saliva. Okay, so much in the same way that respiratory viruses that are spread by aerosols or droplets might tend to cause the infected person to cough or sneeze in order to

further spread themselves to other people. Uh, this disease that is spread often by saliva into blood through bites, Uh, it would tend to cause the infected animal to froth in the mouth with a lot of infectious saliva and to be irritable or or aggressive in ways that would lead to biting. Right, And that brings us back to this question of hydrophobia. Like, then then for what reason, you know, seemingly, like what role does does the fear and does this carror at the idea of water have

to do with anything? So in humans this peers to manifest as a kind of panic that sets in when presented with water and difficulty in or inability to drink, like attempts to drink may result in spasms. There is some clinical footage you can find online of individuals that have been diagnosed with rabies attempting to drink water, and I do not, I do not very disturbing footage, so I don't recommend seeking it out. But if you find yourself in need of of of the visuals for this, uh,

there there is some documentation online. I believe a case in Vietnam is typically typically cited here. Now, does the difficulty with drinking water when someone is infected with rabies usually have something to do with difficulty in muscle control, for like swallowing through neurological routes. Yes, yes, definitely so.

And the insidious nature of all this, though, is that since the individual is prohibited from drinking water by the infection, or at least the drinking water becomes excruciatingly difficult, saliva production increases. You have hypersalivation, and they can't swallow the excess saliva, and that's and they can't wash away this excess frau thing saliva. So, in other words, it primes the victim's mouth to be this potent transmitter of the virus, especially through a bite. So it's um. Yeah, it has

a real insidious quality to it. But as as horrible as rabies is. Again, fortunately there are vaccines that exist, right, yes, So again all a great reminder get your pet vaccinated for rabies. And if you come into contact with a with an animal that has rabies or may have had rabies, you definitely need to go to a doctor. They can take care of it. You don't want this, this, this is not an illness you want running its course. Yeah, thank now. I wanted to share another example though that

seems to go or potentially goes in the opposite direction. Uh. Rabies inhibits thirst and and and alters thirst in that direction. But if we look to to to the world of the horsehair worm, we see something that that may possibly be involved in generating excessive thirst in the host. So uh, this would have to do with parasitoid worms from the phylum Nematomorphah. They're known as horsehair worms because they're threadlike round worms that resemble the hair of a horse's tail

or maine. Now, some people may have seen these before. These are creatures that you'll sometimes fine living free in a puddle or stream. I think I saw one once like this while while walking on my mom's property. But you can also see them occasionally burst out of the body of a cricket, mantis, beetle, or other host organism,

very much like a xenomorph. Oh, now, maybe I was seeing something else, but I know I've seen video of something that was like a long, thin worm that was just gradually spooling out of a cricket sexoskeleton to just and it just kept spooling and spooling and spooling, almost like the clown car where you know, fifty clowns get out of a Volkswagen. But it's a worm that seems bigger than the cricket it was inside, yes, and it's

it's crazy to watch. I have a very vivid memory of being in a junior high band environment and there was a cricket on the floor and somebody in a neighboring section was grossed out by the presence of the cricket, and so they stopped it. And then once they had stomped the cricket, this horsehair worm began emerging from the cricket, which of course only further grows out the individual who'd stopped the cricket. So there's kind of there's some sort

of weird, horrific justice in that. Like if you think the crickets grows, will just wait till you see what the encore is. Surely it helped that in band practice that day you were playing Carmena barana. Yeah, if only so. The interesting thing here is that the adults of this species, in these these organisms, they are free living in the water, but the larva are parasitic and grow to adulthood inside the body of an insect. So I think you can

all imagine how this probably goes down. A male and male horsehair worms mate and damp soil and fresh water, and then the female lays millions of the eggs. These eggs hatch and the tiny larvae insist on vegetation near the water's edge. And then what happens while a cricket or some other suitable host drops by, it ends up eating that larva one way or another, either either the you know, like a cricket is eating the grass, or like a mantis is going to eat the larva itself.

And so what happens then is a like a cricket comes along and it eats the grass that has this larva on it, or if it's a carnivorous mantis, well then it eats a cricket that has already been infected by the larva. In either case, the larva winds up inside of another organism, the cyst dissolves, and then the juvenile worm escapes, bores through the gut wall, and starts absorbing nutrients from the host organism. This worm has a move fast and things philosophy. It is a It is

a disruptor of the internal organs of its host. Right, And at this point, it's kind of it's kind of like you can imagine it like a stowaway in the hold of a ship. You know, it's it's rummaging around, it's eating some of the stored food supplies, maybe eating the occasional crew member on that ship and minute and otherwise also damaging the ship. But it doesn't need If you're a stowaway human stow and a ship, what do

you want to do? You want to get to a port somewhere, right and uh, And likewise, with this worm, it needs to get to water or damp soil in order to continue its life cycle. Now, if if something happens to the cricket. If it's gets stomped in on the floor of a middle school band room, it's going to escape. It's going to you know, abandoned ship, but it needs to get to damp soil or fresh water.

So it may be moving fast and breaking things, but it's going to try to do so in such a way that it ends up at a certain place when when the whole thing goes to put right, it needs to steer the host in the right direction. And so this is where we get that bit of parasitic hijacking in action um or at least that's that's one hypothesis of exactly what's going on. That the worm instills a crazed thirst in the host so that it seeks out water.

That's sometimes referred to as the thirst hypothesis. An alternate hypothesis states of the worm simply waits till the host finds water on its own, and then it jumps out. And it's my understanding that we're really not one hundred percent sure what happens. That there's some some interesting evidence for both both hypotheses. Ed Young and a twenty fourteen Ted talk um mentioned that there's research that indicates that this may occur because the organism releases proteins that alter

the crickets brain functionality. So and there does seem to be some sort of of It seems like there is a strong case to be made some sort of hijacking is taking place, and if that's occurring, it may be pushing the animal towards water via thirst. Okay, so I guess that would mean you might be able to notice this if you had a place where a bunch of insects were getting infected by this parasite, they would be showing a lot of drinking behavior, a lot of water

drinking behavior, right. But then again, yeah, there's also the other argument. Well, it's just it's waiting until the water is until it's drinking. Even even that, that would be pretty impressive because it's that like, how does the how does the worm know what's going on inside the darkness of the cricket or the darkness of the mantis that enables the stowaway to know that there is water or

damp soil close at hand. But I was looking at some of the papers that discussed this, there was a this is of course, this is a much older paper now but there was a two thousand and one study published in the German journal zoo Logisha and Zeiger that says that the thirst hypothesis has been supported by observation of quote unquote suicidal behavior by infected mantis is in southern France that would seemingly jump into the water and

then immediately outcomes the worm. So that would be a case where yeah, like the mantis is not just going to the water, it is to drink and then it bursts out. It's actually jumping in. It's it's it's giving up the ghost. So but I guess with that you still would have to ask your question, at what point is there some hijacking of behavior. Was it the seeking the water to begin with or was it something that

kicked in when the creature was close to water. So we're not sure exactly you know which way way to go on this as far as I understand based on the research I was looking at. But it seems like either way you're getting into these interesting Um you're getting into the relationship between the host organism and water. You know something about its uh it's bodily awareness of water or the thirst or desire to be in close proximity to water, and of course that is ultimately what the

parasite wants as well. Right, So the parasite either needs a mechanism of making the host to go drink water or knowing when the host is drinking water. Right. Oh, in case anybody's worried, it's my understanding that occasionally humans end up ingesting these things, But I don't think there's ever been any evidence or anything to support the idea that they're capable of hijacking human behavior. Again, if that is indeed what's happening in the case of crickets and mantises, well,

what happens when humans do ingest them. It's just kind of gross. They could like bombit them up. I was looking. There were two Japanese cases reported in twenty twelve due to the accidental ingestation of infected insects. I think in these cases that this has occurred via the consumption of vegetables that had those insisted larvae on them. You're in it a Some vegetables seem like they'd be a lot better at hiding a little stowaways than others. Oh yeah,

I have this consistent problem with broccoli. I love broccoli. I love cooking with it. But I a number of times I've been like giving it a rinse before I cook it or something, and then I'm like, oh, there's just a bug up in the up in the tree limbs there. It's hiding out in a little fork in

the in the florets. That's true. I mean, I guess the it's kind of a this kind of the thing about broccoli, right, is that the thing that makes it so delicious, that's it's so great to cook because you get you know, all the oil or the seasoning, it ends up just getting embedded there in all the little mooks and crannies. It also means they are all these additional places that I guess something could potentially hide, or you could just end up with some dirt or grid

in there. Maybe I'm just getting my broccoli from really buggy sources. I don't know. Sometimes I get like CSA broccoli, that's it's it's really nice, good stuff, but there's just like a there's just a big old bug in there, just just like tarantulas crawling out of it through your kitchen and stuff. Almost. I mean, it's all just a good reminder, you know, wash your vegetables everybody, even if you're not sure they need it. You know, you give

them a once over? Why not? Right, you'll feel better about it, especially if you're if you're listening to this episode whilst cooking. All right, we're gonna go ahead and close out Thirst Part three. What do you think, Joe? Do you think we'll be back with Thirst four colon Thirst for Knowledge the Return of Jack Thirst. Yes, yes, yes,

we will be back. I'm sure of it. Yeah, like this Thursday back this Thirst today back, Yes Thursday, this Thursday, Thirst Part four, Thirst for More Knowledge, the final chapter on the final chapter only on Stuff to Blow Your Mind or some other topic. I don't know. We'll see I guess all right. In the meantime, if you would like to check out other episodes of Stuff to Blow your Mind, you know where to find them. They're in the Stuff to Blow your Mind podcast feed every Tuesday

and Thursday. You can find it wherever you get your podcasts. You can also go to Stuff to Blow your Mind dot com and that will shoot you over to the iheartlisting for this show. I think there's a there's a Yeah, there is a link to our t shirt store there if you just want to pick up some sort of stuff to Blow your Mind related design on a shirt or a sticker. M We actually have a we maybe getting some new ones in the weeks and months ahead. And I know there are some some designs by listeners

that I that I've added in recent months. So there's a leshy t shirt in there, there's a there's a kind of psychedelic looking mushroom in there. And let's see what's the other one. Oh yeah, there's the Pandora's box shirt. Those are all wonderful designs, So check those out if you want to um. Pretty fun. And let's see what else. Oh yeah. Tuesday and Thursday Corps episodes, Wednesday's Artifact, Monday's

Listener Mail. Friday is Weird House Cinema. That's our time to set aside most serious matters and just talk about a strange film, huge things. As always to our excellent audio producer Seth Nicholas Johnson. If you would like to get in touch with us with feedback on this episode or any other, to suggest a topic for the future, just to say hello, you can email us out contact and Stuff to Blow your Mind dot com. Stuff to

Blow Your Mind is production of iHeartRadio. For more podcasts from my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you're listening to your favorite shows.