Speaker 1: Welcome to Stuff to Blow Your Mind from how Stuff
Speaker 1: Works dot com. Hey you welcome to Stuff to Blow
Speaker 1: your Mind. My name is Robert Lamb and I'm Julie Douglas,
Speaker 1: and this week we're talking about vampires. Specifically, we're talking
Speaker 1: about vampire bats. But I feel like I have to
Speaker 1: to urge everyone, like, don't don't run away, because because
Speaker 1: on one hand, vampires, of course, as just is a
Speaker 1: is a whole. It's like bringing in all of the
Speaker 1: various fantasy elements. They're like, that's completely overblown, to the
Speaker 1: point that most people I think are getting, if not
Speaker 1: completely already forward with vampires, you know, we kind of
Speaker 1: know what to expand with it. And then with vampire bats,
Speaker 1: I don't want to, you know, discredit them either, but
Speaker 1: on a at a surface level, it's easy to say, oh, well,
Speaker 1: their bats and they drink blood from cows, no big deal.
Speaker 1: I've seen them on I've seen Attenborough talk about them
Speaker 1: on documentaries, and yes, they're they're neat, but I don't
Speaker 1: necessarily need to hear about them for an hour. But
Speaker 1: the thing is, we really start asking questions about the
Speaker 1: blood diet and about the vampiric lifestyle style and how
Speaker 1: that evolved really get into some crazy imaginative areas that
Speaker 1: that that that really blew my mind. Yeah, these guys
Speaker 1: are so interesting for for many many reasons. And we've
Speaker 1: talked about bats. I think we had a couple of
Speaker 1: bad episodes last year. Maybe we've talked about how um,
Speaker 1: we'll just we'll discuss a little bit about this, but
Speaker 1: we've talked about how they have rich social bonds and
Speaker 1: they are amazing creatures, and they have these these four limbs.
Speaker 1: If you look at their bodies, it's very easy to
Speaker 1: see the human hand and the human armbones replicated in
Speaker 1: that wingspan. That alone gives us this idea that there's
Speaker 1: so much to this mammal that's only flying mammal um
Speaker 1: that relates to us. And then there's the weirdness of
Speaker 1: the blood diet too. So let's let's launch into these
Speaker 1: guys because they're so amazing. Yeah, vampire bats. Now, bats
Speaker 1: exist in various places throughout the world. We have both
Speaker 1: both the Old World and the New World bats, the
Speaker 1: New World of course being the America's. But out of
Speaker 1: all these species and uh, and we're talking over a thousand,
Speaker 1: like five more or less different species of bats in
Speaker 1: the world, they make up a quarter of all mammal species,
Speaker 1: and yet vampire bats limited to three species currently, all
Speaker 1: three live in the New World in the America's ranging
Speaker 1: from Mexico to Brazil, Chile and argat Argentina. And there's
Speaker 1: a reason for that. Yes, we'll get into that in
Speaker 1: a little bit. But when we're talking about these three species,
Speaker 1: we were talking about does modest rotundus, diphilia eco data
Speaker 1: and Diningma's jungi and respectively, were talking about the common vampire,
Speaker 1: the hairy legged vampire, and the white winged vampire. Yes,
Speaker 1: and these are all three again their vampires their single bars.
Speaker 1: They live which in their obligates obligates samla single bars,
Speaker 1: meaning they live exclusively on blood. There are obligated to
Speaker 1: drink it. It's not just a situation of like, yeah,
Speaker 1: I eat blood, eat bugs and then I get a
Speaker 1: little blood here and there. No, they exist solely on blood.
Speaker 1: And as will discuss, like that's that's a hard road,
Speaker 1: like blood is not a great nutrient. Like if you
Speaker 1: had to choose one thing in the world to live upon,
Speaker 1: that's not a good choice. Like that's why you have
Speaker 1: that's really one of the reasons you have only three
Speaker 1: species out of these thousands of species of bats that
Speaker 1: do this. The rest are living on fruits or insects.
Speaker 1: And then here these these guys and gals, and they're
Speaker 1: depending upon blood. Yeah, in a pretty limited region if
Speaker 1: you look at it from a world perspective. Um, but
Speaker 1: let's look at the way these guys appear to us,
Speaker 1: because they're they're quite striking. Um. They have these pig
Speaker 1: like noses that if you ever look at angry birds
Speaker 1: and you see the pigs, they've got big gizmo ears, right,
Speaker 1: and um, they have a kind of a it's been
Speaker 1: described as a cleft on its chin which helps to
Speaker 1: channel the blood. And then of course these just razor
Speaker 1: sharp teeth. Yeah. And the and the nose you mentioned
Speaker 1: is all. They also have this this kind of nose
Speaker 1: leafing it's called, which almost kind of makes their nose
Speaker 1: looks like some sort of a fungus. Uh. And and
Speaker 1: you find these all in other bats as well, not
Speaker 1: just the vampire bats. But they give the the vampire
Speaker 1: about a very distinct appearance. And in fact, early naturalist thought,
Speaker 1: you know, I guess, based mostly on illustrations at this
Speaker 1: point that those leaves might be sharp, so their noses
Speaker 1: are kind of these these razor blades that they might
Speaker 1: be using to slice open their prey in order to
Speaker 1: drink the blood, which isn't so then the nose leaves
Speaker 1: have have to do with echolocation and also thermal location,
Speaker 1: not only seeing things with sight, but also detecting changes
Speaker 1: in temperature so they can see where that blood is
Speaker 1: to see where see where where to strike, and where
Speaker 1: to drink exactly. They actually it's sort of like an
Speaker 1: infrared system that can actually sense that heat. But um.
Speaker 1: But what I love about the way they look and
Speaker 1: these depictions of them is they almost look like these
Speaker 1: fictional like medieval etchings or something or something that would
Speaker 1: come out of the mind of man, because they look
Speaker 1: so bizarre they do. They have this goblin the UH
Speaker 1: look to them, and it's right because you you look
Speaker 1: at the illustrations of fantastic goblins and whatnot and monsters
Speaker 1: and demons, and then you look at the bat, and
Speaker 1: then you have to know what comes first. You know,
Speaker 1: to what extent has the bat influenced our iconography of
Speaker 1: the monstrous? To what extent has the monstrous UH interpreted
Speaker 1: our interpretation of the bat, because for instance, the vampire thing,
Speaker 1: it really our understanding of the vampire bat is fairly recent. Uh.
Speaker 1: And again they're in there in the New World, they're
Speaker 1: in the Americas. But the idea of the vampire, of
Speaker 1: some sort of creature that sustains itself on blood, on
Speaker 1: human blood, especially, like, that's a very old idea that
Speaker 1: you find, uh, you know, back in even in the
Speaker 1: Hellenistic ages, and perhaps you know even earlier indeed. But
Speaker 1: let's let's get into some of their feeding habits, because
Speaker 1: this is really interesting stuff. In a study published in
Speaker 1: the journal BMC Biology, it was found that vampire bats
Speaker 1: of this species does modus rotundus by the way, if
Speaker 1: they were named rotundus at the time, because their stomachs
Speaker 1: looked appear to the people it is very very large
Speaker 1: to the researchers, um. But little did they know that
Speaker 1: the stomach was actually filled with blood at that moment,
Speaker 1: so that's why the stomach looked so rotund. But they
Speaker 1: found that these bats could recognize recorded human breathing sounds
Speaker 1: much better than human participants could. And vampire bats feed
Speaker 1: on the same prey, by the way, over several nights
Speaker 1: and the authors of the study proposed that the bats
Speaker 1: us breathing sounds to identify prey in the same way
Speaker 1: um humans use voice to recognize each other. So it's
Speaker 1: kind of it's interesting not only that they have the
Speaker 1: certain live stock in mind, but they can differentiate between
Speaker 1: that live stock based on their breathing patterns. And we've
Speaker 1: talked about this ability with bats before, this sort of
Speaker 1: zen like ability just to to take everything else in
Speaker 1: the background and have it sort of receeed and really
Speaker 1: hone in on the prey. Yeah, they're amazing creatures and
Speaker 1: and it's easy to focus on on all of this, uh,
Speaker 1: the alien aspects of the bat, because as we discussed
Speaker 1: in the previous podcast, it's it's it's almost impossible to
Speaker 1: put ourselves in that perspective and to imagine seeing the
Speaker 1: world as the bat sees the world. But they're also
Speaker 1: really social creatures. They typically gather in collegues about a
Speaker 1: hundred animals, but sometimes they meant living may live in
Speaker 1: a group of a thousand or more. And uh, incidentally,
Speaker 1: over that time, a hundred bat colony can drink the
Speaker 1: blood of twenty five cows. But but again, they're they're
Speaker 1: very social. You see actual um reciprocal altruism in vampire bats.
Speaker 1: You see, because this will discuss, it's essential with with
Speaker 1: a blood diet to to get that blood every night
Speaker 1: if possible. And if you go forty eight hours without
Speaker 1: blood as a vampire bat, you're starving yet your toast. Yeah,
Speaker 1: and so we we we see examples of the vampi
Speaker 1: of vampire bats bringing blood back and feeding the famished bats,
Speaker 1: the bats that haven't had enough to eat, and and
Speaker 1: looking after each other in this in this fashion. And
Speaker 1: that one of the theories here with this is that
Speaker 1: bats picked up this behavior, this kind of altruism, is
Speaker 1: looking after one another because in their habitats, as you
Speaker 1: see the horse die aways, you see the camel and
Speaker 1: the giant slop disappear from the continent, leaving them only uh,
Speaker 1: you know, much more limited food supplies. They had to
Speaker 1: do this in order to survive. Yeah, there's a kind
Speaker 1: of cooperation, just like among humans. Right. If you kind
Speaker 1: of help me out this time, I'll help you out
Speaker 1: next time. You know, you can't find a source of blood,
Speaker 1: right there, there's what I said yesterday, right exactly. Yeah,
Speaker 1: And there's they're they're even you know, there's some degree
Speaker 1: of of argument uh in this on this particular topic
Speaker 1: among bat researchers. But they may be able to weed
Speaker 1: out cheats. So if you're taking blood but not giving,
Speaker 1: then they're going to cut you off. Ah, that's interesting.
Speaker 1: And they have seen that in captivity all of the
Speaker 1: bats will share a meal if if someone needs it,
Speaker 1: but in their natural habitat the adult males will not
Speaker 1: engage in this behavior the female as well. Of course,
Speaker 1: they also like to sniff each other as a greeting
Speaker 1: and they perform social grooming of one another, which is key.
Speaker 1: We'll be getting back to that in a minute. Yeah,
Speaker 1: And for their body size, vampire bats have one of
Speaker 1: the largest brains among bats. The neo cortex is about
Speaker 1: twice the average size of other bats. And as we
Speaker 1: know about the neo cortex and humans, it's really important
Speaker 1: in terms of social intelligence and social complexity. So it
Speaker 1: would make sense that um it is so very large.
Speaker 1: And if they have these very rich bonds with one another.
Speaker 1: And we have talked about this before and the other
Speaker 1: podcast about bad but a lot of the test to
Speaker 1: do with their communication, which is super nuanced. We know
Speaker 1: of course they can recognize each other's voices. We also
Speaker 1: know that bats share a common gene for communication called
Speaker 1: fox P two with us. And we also known, according
Speaker 1: to researcher Mere Jean Quinn Child and her colleagues at
Speaker 1: the University of Erlingen Nuremberg in Germany, that the younger
Speaker 1: great greater sack bats that the baby ones were observed
Speaker 1: stringing together screeches, barks, and hisses with no soccial context,
Speaker 1: essentially practicing language much like a toddler does when it babbles. Yeah,
Speaker 1: so again, you see a lot of parallels with humans.
Speaker 1: All right, So let's talk about evolution. Now, mostly we're
Speaker 1: interested in the evolution of of vampiresm of depending upon
Speaker 1: that blood diet. But but let's let's step it out
Speaker 1: a little, uh, a little more and think about the
Speaker 1: evolution of the bat itself. Bats and birds. Obviously they
Speaker 1: have a great deal in common. Both both are flying organisms,
Speaker 1: yet they're very different. In birds, we have the aviens
Speaker 1: emerging about a hundred and fifty million years ago during
Speaker 1: the Jurassic period, uh, and they go on from there
Speaker 1: to fly, swim, trott and borrow all over the world. Meanwhile, uh,
Speaker 1: the mammalion bat dates back between seventy hundred million years ago.
Speaker 1: But it's hard to say because even though they're one
Speaker 1: of the most diverse groups of mammals today, they're one
Speaker 1: of the least common groups in the fossil records. Uh.
Speaker 1: Part of this is that they have small light skeletons,
Speaker 1: they don't preserve all that well. And also, if you're
Speaker 1: residing in a tropical environment, as a lot of these
Speaker 1: these bats due today and and did historically, these are
Speaker 1: not environments where where dead things last long decomposition is yeah,
Speaker 1: things that it's breaking down, it's hot, it's moist, things
Speaker 1: are eating. Uh, so it's chance the chances of fossilization
Speaker 1: are reduced. Again. They're over a thousand different species of
Speaker 1: bats in the world. They make up a quarter of
Speaker 1: all mammal species. Uh. And among these we have the
Speaker 1: mega bats as opposed to the microbats. These are large
Speaker 1: bats found in the Old World tropical rainforests Australia, Asia,
Speaker 1: and Africa. The biggest bat in the world is the
Speaker 1: is the Malayan flying fox found in Asia. Waighs about
Speaker 1: two pounds and has a wingspan a fan of about
Speaker 1: six feet, and that's one of the fruit eaters. The
Speaker 1: smallest bat in the world is Kitty's hog nose bat,
Speaker 1: also called the bumblebee bat, and that's stuff found in
Speaker 1: Thai land in ways about two grams uh. It's about
Speaker 1: as much as a dime, by the way, and it
Speaker 1: has a six inch wingspan. So both the bat and
Speaker 1: the bird learned to fly in their own way. And
Speaker 1: there are other fascinating examples of their covergent evolution. Several
Speaker 1: dozen bat species and more than three hundred species of
Speaker 1: hummingbird evolved to resemble each other, both anatomically and behaviorally, uh,
Speaker 1: solely because they existed in similar environments and exploited a
Speaker 1: similar resource name lamely nectar. All right, this is the
Speaker 1: sugary liquid bribe of pollen producing plants. But those are
Speaker 1: the nectivores. And we're here to talk about bats with
Speaker 1: another highly specialized lifestyle for a liquid diet. And we're
Speaker 1: talking here, of course about the songlevores, the blood drinkers.
Speaker 1: How did the blood drinkers evolve? Well, the first vampire
Speaker 1: bats emerged less than twenty six million years ago, according
Speaker 1: to genetic evidence, and they are closely related to insect
Speaker 1: eating bats that may have gorged on the parasites of
Speaker 1: prehistoric beasts. So if you've just feasted on a fat,
Speaker 1: juicy tick, let's say, then it's not too far of
Speaker 1: a walk in logic to see how some bats may
Speaker 1: have begun to have the taste for blood or to
Speaker 1: seek it out as as a mean source. Right, And
Speaker 1: we we see this to a certain degree in birds. Uh,
Speaker 1: there are birds that occasionally or even frequently feed on blood.
Speaker 1: Vampire finches of the Glagos Islands occasionally feed by drinking
Speaker 1: the blood of other birds. Meanwhile, there are plenty of
Speaker 1: birds that feed on picks and other parasites and large animals,
Speaker 1: you know, ox peckers and the like. They're eating the ticks,
Speaker 1: they're eating the fleas, whatever. And then if there's a
Speaker 1: little blood there from the host organism, they'll they'll go
Speaker 1: ahead and cross that line and have some of it
Speaker 1: as well. But there's little or no convergence between birds
Speaker 1: and bats when it comes to blood. When we're talking
Speaker 1: about obligate blood drinking, you don't see uh, any obligate
Speaker 1: blood drinking birds. Well, I think imagine the pigeons out there,
Speaker 1: so so central are these blood meals to the vampire
Speaker 1: bats that they actually have been missing around or modifying
Speaker 1: a plasma gen activator gene, which we haven't. Humans have it,
Speaker 1: and it protects against heart attack by producing proteins that
Speaker 1: bust up blood clots and they clear vessels. Um. But
Speaker 1: they actually have this, uh, this gene that they can
Speaker 1: activate in their saliva. And David Liberles, a geneticist at
Speaker 1: the University of Wyoming and Laramie, studied three species of
Speaker 1: vampire bouts and found this modification. And he found that
Speaker 1: two species that prey on lifestock acquired additional mutations that
Speaker 1: prevent these p A proteins from being silenced by natural inhibitor.
Speaker 1: So he says that's a process that humans and other
Speaker 1: mammals used to put a harness on blood clotting, but
Speaker 1: feeding on mammals, he says, is a key adaptation for that.
Speaker 1: So it's just further evidence that this is so important
Speaker 1: to them that they've been tinkering over time their genes
Speaker 1: say hey, we need to make this process more solid. Yeah,
Speaker 1: like thet a genetic level, they are completely committed to
Speaker 1: this blood diet and we're going to get into into
Speaker 1: some more aspects of this little more. But it's such
Speaker 1: a specialized diet that it demands a very specialized physiology.
Speaker 1: It's not. And that's something to keep in mind again
Speaker 1: when you think of of humanoid vampires, like, what would
Speaker 1: it take for a human? Could a human live on
Speaker 1: blood exclusively? No, a human couldn't. It would require a
Speaker 1: different species of humanoid exactly entirely. Yeah, you'd have to
Speaker 1: be a very tiny humanoid first of all. Um. But
Speaker 1: I did want a little side note here mentioned that
Speaker 1: the anticoagulating enzyme that they produce has been synthathesized by
Speaker 1: researchers and it is called draculin. Nice. It isn't that nice,
Speaker 1: And it's used in medication for strict victims to keep
Speaker 1: tissue damage and a minimum by keeping that blood flow
Speaker 1: to the tissues. Yeah, like we discussed when we were
Speaker 1: talking about leeches, I believe any animal that that depends
Speaker 1: on blood has to be kind of a hacker. And
Speaker 1: the and the the bat though it's hard to call
Speaker 1: about a parasite. You see people shying away from them
Speaker 1: as bat and calling them a carnivore, but still they
Speaker 1: have to be able to hack the blood. And so
Speaker 1: from a medical standpoint, as we try to figure out
Speaker 1: ways to hack the blood, we end up turning to
Speaker 1: the to the leeches, to the bats, the parasites of
Speaker 1: the world, to the blood drinkers of the world, and
Speaker 1: see how they do it. Um. You mentioned the evolution
Speaker 1: of the bat and the idea that they evolved from
Speaker 1: insect eating bats in prehistory, and I just wanted to
Speaker 1: run through UM that that that idea because it gave
Speaker 1: me some visual old, didn't it It did? And uh
Speaker 1: And specifically I was reading a fantastic book and you
Speaker 1: were reading this as well, by Bill Shoot called Dark Banquet,
Speaker 1: Blood and the Curious Lives of Blood Feeding Creatures. It's
Speaker 1: available on paperback, hardcover, and kindle, and it's it's really excellent,
Speaker 1: excellently written, great for just about any any reading level,
Speaker 1: in any science level. UM. But he really goes into
Speaker 1: this topic and I was. I really enjoyed it so
Speaker 1: much I wanted to hit the three uh or so
Speaker 1: hypotheses that he mentions. Now, the first hypothesis is, again,
Speaker 1: we have these proto vampire bats and they're feeding on
Speaker 1: blood in gorge ectoparasites found on large prehistoric animals. So
Speaker 1: think of all those crazy prehistoric animals that we covered
Speaker 1: in the past. Or you send pictures of um and there,
Speaker 1: and there of course loaded with parasites, big old ticks,
Speaker 1: big old fleas, other things that are gorging on the blood. Yeah,
Speaker 1: it's a feast. And you're a bat, you're you're you
Speaker 1: eat insects, and it's a world in which the insects
Speaker 1: are are the available prey. And here is a large
Speaker 1: animal and it's crawling with these things. So you're you're
Speaker 1: gonna you're gonna eat those, right, You're gonna eat those
Speaker 1: big blood gorge ticks and whatnot. And so that the
Speaker 1: idea here is that they're dining on those and over
Speaker 1: time they crossed the line, you know, they start drinking
Speaker 1: some blood from the host, and then they reached the
Speaker 1: point where they're living exclusively on the blood of the
Speaker 1: host animal and ignoring all of those ticks and fleets. Now,
Speaker 1: this is supported by the fact as a theory, as
Speaker 1: a hypothesis, rather that bats are insectivore. So we know
Speaker 1: that that prehistoric bats would have been eating insects, and
Speaker 1: there are anecdotal reports of vampire bats praying on vampire moths. Now,
Speaker 1: just that's gonna come as a surprise for a lot
Speaker 1: of you, because yes, there is a vampire moth um
Speaker 1: blood on blood here, yeah, and you'll find him in Malaysia,
Speaker 1: you'll find him in Thailand. You're all southern Europe and
Speaker 1: and so there. Again, there's anecdotal evidence that vampire bats
Speaker 1: have preyed on blood engorged insects, So take that point.
Speaker 1: It's another scenario that lends support to this idea. Is
Speaker 1: the whole grimming thing, right, you had pointed that out.
Speaker 1: That's that's important socially that you sit there and groom
Speaker 1: each other. So that would be an opportunity to pick
Speaker 1: out some nice, juicy morsels, right, That's so that could
Speaker 1: lend some support to it. And I said that it
Speaker 1: was a sort of short walk in logic to say
Speaker 1: you would cross over. But that's also a little simplistic, right,
Speaker 1: because that's like saying that if you had to be
Speaker 1: a cannibal in this very dire situation as a human being,
Speaker 1: that once you had that, you might go cannibal for
Speaker 1: the rest of your life, right right. Yeah. We find
Speaker 1: it increasingly when you try and apply some sort of
Speaker 1: mathematical model for evolution, if you fall into this trap here,
Speaker 1: because it's not a situation able X plus y equals
Speaker 1: z here so it must be the same here, and
Speaker 1: it gets gets complex anyway, Um that expert brock Fenton
Speaker 1: disagrees with this, uh, this theory that we've been discussing,
Speaker 1: and he argues on some three points. Number one, ectoparasites
Speaker 1: are small, Like even if we're talking about a prehistoric animal,
Speaker 1: it's it's still gonna have small parasites. It's not like
Speaker 1: the giant elephant head giant ticks. So let's take like
Speaker 1: thousands of these things. Yeah, you still a lot of them,
Speaker 1: and it's gonna be difficult to act. The ectoparasites are
Speaker 1: difficult to find on other animals, and vampire bats are
Speaker 1: restricted to a very slim portion of the Americans. And
Speaker 1: so part of his argument is, if this was really
Speaker 1: how things were gonna go down, why didn't it go
Speaker 1: down like this in other places? So he presents hypothesis
Speaker 1: number two, the idea that proto vampire bats fed on
Speaker 1: insects and larva crawling around the gaping wounds of large
Speaker 1: prehistoric mammals. So, which is another wondrously grotesque image to
Speaker 1: imagine a giant prehistoric creature. It's, you know, it's shambling
Speaker 1: through the forest. Maybe it's something that attacked it, had
Speaker 1: got into a fight, or it just ripped itself on
Speaker 1: some thorns, just got this bleeding hole. So what happens
Speaker 1: to a bleeding hole on an animal? Insects come for it, right,
Speaker 1: things start laying their squirming larvae in there, and uh.
Speaker 1: And so a bat might come and say, well, hey,
Speaker 1: I want to hang out where all these delicious insects
Speaker 1: are hanging out. And then they end up inevitably drinking
Speaker 1: from that font as well, which again is kind of
Speaker 1: too easy to walk here. Yeah. Shoot. In his book Counters,
Speaker 1: he says that the scenario requires large wound sits on
Speaker 1: a regular basis um and uh. And also, as we're
Speaker 1: gonna get into a little later, vampire invertebrate blood is
Speaker 1: water and protein. There's no fat, so vampire bats can't
Speaker 1: store it as fat like non blood drinking bats store
Speaker 1: away their their their food. Uh. They need to feed
Speaker 1: and consume fifty of their body weight and blood each night.
Speaker 1: So you need to be able to find if you're
Speaker 1: depending upon wounds, uh, surrounded by insects, you've gotta be
Speaker 1: able to find those wounds surrounded by insects on a
Speaker 1: regular basis basis, and also echolocation is gonna be useless
Speaker 1: in finding these animals. Um It's it's just that there
Speaker 1: are a number of holes in this argument as well. Now,
Speaker 1: a third hypothesis here is something called the arboreal feeding hypothesis,
Speaker 1: and it really focuses on carnivorous members of the neotropical
Speaker 1: bat family Philisto muda i found in South America where
Speaker 1: formerly there had been vast forests which were then replaced
Speaker 1: by grasslands. So what does that mean. That means that
Speaker 1: all of a sudden you have very small little islands
Speaker 1: of forest area, and you have a lot of big
Speaker 1: mammals taking refuge in these trees, sleeping in them at night,
Speaker 1: and so all of a sudden you've got a population
Speaker 1: of one tree that might be hosting many different hosts
Speaker 1: um as opposed to being spread out through the forest.
Speaker 1: And this is an opportunity for vampire bats. So what
Speaker 1: you're talking about here is a bunch of animals like
Speaker 1: sloth taking refuge in these trees, falling asleep, and then
Speaker 1: these vampire bats, who are so stealthy by the way,
Speaker 1: sneaking up and just saying well you don't mind if
Speaker 1: I do, and taking their blood samples there, and then
Speaker 1: of course this would encourage that behavior over and again
Speaker 1: as an adaptation in this scenario. Because if you've got
Speaker 1: that loss of habitat, and all of a sudden you've
Speaker 1: got these mammals congregated in the trees, well that makes
Speaker 1: easy pickings. So which hypothesis is true? Well, the answer
Speaker 1: still open to debate. Uh. That you know, it's possible.
Speaker 1: As with a lot of things, it's more of a
Speaker 1: combination of these ideas as opposed to one distinct idea.
Speaker 1: And uh, and we have to remember that it's it's
Speaker 1: it's it's difficult to avoid falling into the trap of
Speaker 1: thinking of evolution as this clockwork predictable scenario. Again, if
Speaker 1: it's X here, then it's X there. Uh. If we
Speaker 1: turn back the clock and did it again, everything would
Speaker 1: come back to the same place that we get the
Speaker 1: same results. And that's that's likely not how it goes.
Speaker 1: Um For whatever reason, a single group of New World
Speaker 1: leaf nose bats evolved as the only vertebrate obligate sangle bores.
Speaker 1: And it's pretty amazing. All Right, we're gonna take a
Speaker 1: quick break. When we get back, we're gonna talk more
Speaker 1: about the hard knock life and uh blood letting. All right,
Speaker 1: we're back. Let's talk about these vampire bouts because if
Speaker 1: you made it this far in the Vampire About Territory,
Speaker 1: you're about to get this serious blood payoff. Because this
Speaker 1: is fascinating stuff. And uh, maybe we should start this
Speaker 1: section as like, you imagine you are the vampire bout,
Speaker 1: dear listener. Yeah, I imagine that you have sort of
Speaker 1: gone down this uh almost evolution. I wouldn't almost say
Speaker 1: an evolutionary dead end, but you've you've gone down far
Speaker 1: enough that you're you're in this very niche area and
Speaker 1: there's no there's no turning back. It's like that line
Speaker 1: in Macbeth where Shakespeare says, you know, if I've waited
Speaker 1: that the main character says, I've waded through blood so
Speaker 1: far that if I were to turn back, it would
Speaker 1: be just as much work to keep going. And that's
Speaker 1: where the vampire bad is. It's a hard knock life
Speaker 1: that the vampire back has evolved into, but there's no
Speaker 1: turning and turning back at least not anytime soon, that's right.
Speaker 1: So you are stuck with this blood diet and the
Speaker 1: bad news here is again and We've talked about it before.
Speaker 1: Blood just doesn't have much to it in terms of nutrients.
Speaker 1: In fact, a percent of it is water. So what
Speaker 1: do you have to do Every night? You must go
Speaker 1: out and hunt and lap up of your body weight.
Speaker 1: And this is this is a hard thing to do
Speaker 1: because you can't store any fat that it might have
Speaker 1: because it doesn't have any fats. So you every night
Speaker 1: are obligated to go out. You can't sleep it off,
Speaker 1: you know. You Also you can't hybrid it. You can't
Speaker 1: build up stores for later. You're there's no uh, there's
Speaker 1: no preparing for the winter. If winter comes, you're you're
Speaker 1: gone if you can't get blood. So and that's why
Speaker 1: we see these three species of vampire bats living in
Speaker 1: tropical areas. They cannot knack it in areas that have
Speaker 1: cold climates. So that's right, you cannot hack the cold weather.
Speaker 1: You have to take advantage of these areas that have
Speaker 1: warmer web other and you must be really wildly. So
Speaker 1: it's not just like, hey, I gotta go out and
Speaker 1: get some blood. No, you're gonna be the best at
Speaker 1: getting blood. Is any blood getting mammal is gonna get. Yeah,
Speaker 1: you've got to use your stealth to the highest degree
Speaker 1: because you need to prey on sweeping animals. You need
Speaker 1: to not wake them up while you're drinking their blood.
Speaker 1: And you can't exert a tremendous amount of effort and
Speaker 1: energy finding your prey because again you're you're you're on
Speaker 1: a very tight budget here. You have to eat every night,
Speaker 1: and you can't spend too much energy because you can't
Speaker 1: store that much energy. So you can't go on long
Speaker 1: drawn old hunts covering you know, vast miles of of area.
Speaker 1: You have to you have to really hone in. You
Speaker 1: gotta make it work, and you've got to You've gotta
Speaker 1: get defeating, that's right. And so as a result, you
Speaker 1: have this exquisitely sensitive heat detecting molecule covering nerve ending
Speaker 1: on your nose, and this allows you to detect infrared
Speaker 1: heat that is just beaming from areas on a livestock's
Speaker 1: body and and that that's sort of like the the
Speaker 1: area that you know you're going to hone in on,
Speaker 1: because as you said, you don't have tons of energy here.
Speaker 1: You gotta be fast. Yeah, you gotta go right for
Speaker 1: the vein. There's no just crawling around on it's romp
Speaker 1: until you find an area that's that's that's right. You
Speaker 1: can't feel it out, you gotta see it. You gotta
Speaker 1: focus in on it, and luckily the vampire back can
Speaker 1: douce that. Yeah, and these guys that mostly attack from ground,
Speaker 1: though sometimes it's from the trees, but they can actually run.
Speaker 1: It's only like two point five miles per hour or something,
Speaker 1: but still that's pretty fast, and that they think. The
Speaker 1: reason for that, researchers think, uh, is because if they're
Speaker 1: around something like a horse or a cow, it's easy
Speaker 1: to get trampled upon, So you gotta get out of
Speaker 1: their fashion. Good people to hop away. But it's pretty
Speaker 1: amazing to see them running, all right. See you land
Speaker 1: next to the cow. You hit the ground running more
Speaker 1: or less than you you you scamper up there right
Speaker 1: to the place that that hot spot that you've you've
Speaker 1: seen with your your your fantastic heat vision. And this
Speaker 1: is where you're gonna feed. What do you do? Well,
Speaker 1: first thing you do is you lick that area where
Speaker 1: where you're gonna apply the incision the saliva anticoagulants. Yes,
Speaker 1: because the saliva here is key and is really amazing
Speaker 1: to quote Bill Shoot from his book Dark Banquet, the
Speaker 1: process actually consists of a maddening cascade of chemical reactions
Speaker 1: that must occur before clot forms. Because again, you're making
Speaker 1: when you make your incision now with your your sharp teeth,
Speaker 1: you're making a very small wound. You're not just you know,
Speaker 1: you're not making this enormous font from which to drink.
Speaker 1: You're making something that giving its own devices, given the
Speaker 1: body's own defenses, this would normally close up in a
Speaker 1: couple of minutes. This is not You're not just you know,
Speaker 1: opening a jugular here and dancing around the fountain. You're
Speaker 1: creating a small wound, but anticoagulants in the blood prevented
Speaker 1: from clotting, allowing you to feed there for the amount
Speaker 1: of time necessary to get that full meal. Yeah, in
Speaker 1: this case about minutes. And if you think about their incisors,
Speaker 1: they are knife sharp um. In fact, Bruce Patterson, a
Speaker 1: zoologists at Field Museum in Chicago, says, you can actually
Speaker 1: cut yourself handling a bat skull in a museum. They're
Speaker 1: that sharp. Because again we're talking about efficiency here, getting
Speaker 1: in and getting in quick, and their tongues also get
Speaker 1: into the game here because they contain a specialized groove
Speaker 1: that allows a blood meal to flow via capillary action.
Speaker 1: So they do not suck, they slurp, They lap up,
Speaker 1: which is another thing to keep in mind because again
Speaker 1: it's it's a small wound. It's not going to be
Speaker 1: held open by suction. And uh and to your point
Speaker 1: about the teeth, that's another aspect of this too, is
Speaker 1: that it's such a small cut in with such a
Speaker 1: sharp knife you barely feel it while you're sleeping. UM.
Speaker 1: In his book, Bill Shoot talks about an encounter with
Speaker 1: a bat and a hen that had him reeling. And
Speaker 1: I love this, you know what I'm talking about. So
Speaker 1: I was thinking about this. Not only does the bat
Speaker 1: have data from UM from the infrared molecule and data
Speaker 1: from the breathing pattern of the livestock, but also has
Speaker 1: been observing it and perhaps taking those observations and passing
Speaker 1: them down among its young and so on and so forth.
Speaker 1: And what I mean is that Bill Shoot saw this
Speaker 1: bat sidle up to a hen. Thought the hen was
Speaker 1: going to be like, no way getaway, but it did not,
Speaker 1: because the bat then went and cuddled up to the
Speaker 1: hen right at this area it's called UM I think
Speaker 1: it's called a brood patch. It's where chicks will go
Speaker 1: because there's more heat and more capillaries that are congregated there,
Speaker 1: so there's more heat available. So essentially, this bat is
Speaker 1: mimicking a chick and cozing up with the hen. And
Speaker 1: what he said is that he saw the hen like
Speaker 1: visibly looked to be relaxed and then settled down, and
Speaker 1: then the bat kind of burrowed down a little bit more,
Speaker 1: and a couple of minutes later he saw evidence of
Speaker 1: that blood from underneath the hen where that bat had
Speaker 1: been suckling a the vein. I mean, I think it's
Speaker 1: amazing that essentially said hello, hen, I know I look
Speaker 1: like a bat, but really I'm a sweet little chick
Speaker 1: who just needs a little warmth. That is amazing. Now
Speaker 1: you mentioned the tongue earlier, and the tongue is also
Speaker 1: really key here. Again, the bat is not sucking the blood.
Speaker 1: It's it's lapping the blood. But but lapping. It's easy
Speaker 1: to just say, oh, lapping and just sort of have
Speaker 1: this loose idea in your mind of a dog or
Speaker 1: a cat lapping up the milk or water, which even that, incidentally,
Speaker 1: if you slow it down and look at the video
Speaker 1: is a far more complicated process than we than we
Speaker 1: give the credit. With the bat, you have this piston
Speaker 1: like motion of the tongue and it causes the blood
Speaker 1: to flow along a pair of grooves on the bottom
Speaker 1: of the tug and into the mouth through that cleft
Speaker 1: in the lower lip that we mentioned earlier. So you
Speaker 1: have to imagine that again. It's like this piston action
Speaker 1: of the tongue just and you get this flow going
Speaker 1: out of the wound into the bat's mouth. Yeah, we're
Speaker 1: talking about a tablespoon when it's all um done. But again,
Speaker 1: that's half of the bat's body weight. So after it
Speaker 1: leaves the tongue, it goes into the esophagus and down
Speaker 1: into the stomach, which is richly lined with blood vessels
Speaker 1: that absorb that water and that shunts it straight to
Speaker 1: the kidneys before it actually goes to the intestines. So
Speaker 1: that something is really important here because it is absorbing
Speaker 1: all of that water. But the reason is is because
Speaker 1: they have to work fast, these bats in terms of
Speaker 1: digesting and expelling this stuff from their systems. Yeah, again,
Speaker 1: they're loading up on blood and they have to be
Speaker 1: ready to escape at a moment's notice, you know that
Speaker 1: cow might wake up, uh anything at any time, and
Speaker 1: you're gonna have to get away. You're gonna have to
Speaker 1: then fly away. And you cannot be weighted down with
Speaker 1: all of this waterway because again we're talking about just
Speaker 1: just consuming you know, half your body weight and food
Speaker 1: and you're and you're gonna have that that stomach just
Speaker 1: filled with water. So you've got to get rid of it.
Speaker 1: And that's why you have this rapid uh removed oval
Speaker 1: of the water, shut it through the kidneys. And then
Speaker 1: the bat vampire bat is urinating as it's feeding, Like
Speaker 1: shortly after it starts feeding, it starts urinating because it's
Speaker 1: it has to prepare for takeoff. Yeah, to add insult
Speaker 1: to injury here, and it avoids soiling itself by extending
Speaker 1: one hind limb sideways and downward. So it's like, I'm
Speaker 1: not gonna get on any on me, but hey, you
Speaker 1: sorry about that. And it's also an interesting scenario when
Speaker 1: you start thinking about about the urine itself and it
Speaker 1: has to the urine that the bat is pumping out
Speaker 1: is getting increasingly concentrated as it goes. Because part of
Speaker 1: the whole deal with our urine. Of course, we're getting
Speaker 1: rid of these toxic aspects of our meal and uh,
Speaker 1: and that's what the bat is doing as well. But
Speaker 1: it's doing in such a such a such a fast
Speaker 1: process at play here that you just have the concentration
Speaker 1: of the urine is just building up and building up
Speaker 1: the more that it urinates. And you get into this
Speaker 1: interesting area here too, where despite the fact that the
Speaker 1: vampire bat has this this liquid diet, and despite the
Speaker 1: fact that it lives in the tropics exclusively, it lives
Speaker 1: in its own kind of personal physiological desert, there's always
Speaker 1: this risk of dehydration because it has to get rid
Speaker 1: of so much of the water that it consumes through
Speaker 1: its meals. That that that that again factors into the
Speaker 1: economy of the vampire bat. It can't it can't live
Speaker 1: in a place where it's any kind of dryness, because
Speaker 1: it does it it's living, it's living with such a
Speaker 1: slim margin um between it's it's it's life and complete dehydration. Yeah,
Speaker 1: that's a that's a really complex balancing game there, And
Speaker 1: I think it speaks again to this idea, or at
Speaker 1: least in my head, that they almants feel like they're
Speaker 1: cursed in a sense like in and of course I'm
Speaker 1: evoking uh, vampire lore here, but you know you can't.
Speaker 1: You can't hibernate. You have to live in this very
Speaker 1: specific area, um and kind after night you must go
Speaker 1: out and kill, well not the kill perpect blood. One
Speaker 1: thing that makes me think about you. You've done freelance work,
Speaker 1: of course, freelance writing, uh and I have as well.
Speaker 1: And at times you do you like like like myself,
Speaker 1: You've probably ticket You've thought yourself, well, could I just
Speaker 1: depend up solely on freelance writing? And I feel like it.
Speaker 1: You end up getting into this sort of vampire bat
Speaker 1: situation where you're like, yes, if I, if I pray,
Speaker 1: if I get enough gigs on a regular basis in
Speaker 1: the in the just the right environment, and I never sleep,
Speaker 1: never hibernate, then I can make it work. I can
Speaker 1: just barely make it work, and I can survive and
Speaker 1: and and pay all my bills. And then you end
Speaker 1: up just defecating and urinating on yourself all the time
Speaker 1: to avoid having to deal with any loss of energy, right,
Speaker 1: and you're always looking for that that next that next kill,
Speaker 1: that next job. Yeah, it is. It's kind of I
Speaker 1: like that analogy. Yeah, the vampire bat is living on
Speaker 1: the margins here, you know, it's just it's it's it's
Speaker 1: found this niche. But it is a hard niche to
Speaker 1: exist in. Indeed, it is. I want to point out
Speaker 1: that we do have a few fossil vampire bats, including
Speaker 1: the biggest vampire bat that that ever existed as far
Speaker 1: as we can tell from the fossil record, and that's
Speaker 1: the thirty percent larger uh do Modus dracula, which is
Speaker 1: of course a great great name for a vampire bat
Speaker 1: or some sort of a you know, Gothic band uh
Speaker 1: And they were they were total vampires. They were not
Speaker 1: any kind of transitional form, and they existed farther up
Speaker 1: into the America's But the idea is, this larger bat
Speaker 1: is depending on the blood of larger species, and if
Speaker 1: those species died out in these sorry times, so did
Speaker 1: this And so the domain of the vampire bat was
Speaker 1: once larger and contained more species than it shrinks. And
Speaker 1: it's then it's confined to these these hot tropical zones
Speaker 1: and the few animals that they can still prey on
Speaker 1: for blood. Ah. But what of global warming, which is
Speaker 1: actually warming up many parts of the world, and this
Speaker 1: has led some people to say, hey, we think that
Speaker 1: there is going to be an increase in the vampire
Speaker 1: bat population, specifically in North America, in Texas and some
Speaker 1: parts of Louisiana in the next couple of decades, so
Speaker 1: they might be coming to a city near you. Yes,
Speaker 1: all right, so, um, we've given you guys a description
Speaker 1: of these bats, but if you would like to see
Speaker 1: them specifically on a vamp cam, you can at this
Speaker 1: very moment. In fact, there's a there's a camera in
Speaker 1: there twenty four hours a day you can observe these
Speaker 1: and this is at the Organization for Bat Conservation, So
Speaker 1: that's bad Conservation dot Org. Yeah. I was looking at
Speaker 1: the other day and they're they're really adorable where they're
Speaker 1: scurrying around. That's the thing about the vampire bad It's
Speaker 1: like part of this responds to them, and we with this,
Speaker 1: uh this something kind of cute about them, But then
Speaker 1: there's also something that in the very depth of our
Speaker 1: genes we we can't help but find a repugnant. They
Speaker 1: walk that line. Well, the distance though of the vamp
Speaker 1: cam makes it all sorts of adorable. Sure, like my
Speaker 1: hand's nut in that cage with them, So that's so
Speaker 1: cute that they're cuddling right now. And it's not full
Speaker 1: color either, so it's got that going for it. So
Speaker 1: there you go, the vampire bat, the evolution of the
Speaker 1: vampire bat, the physiology of the fampire bat. I I
Speaker 1: hope it it allows everyone to have even more respect
Speaker 1: for these amazing creatures and just rethink the vampire equation
Speaker 1: in general. Like it really made me rethink our ideas
Speaker 1: of a vampiric human and what that would be like.
Speaker 1: I feel like we focused, we focus far too much
Speaker 1: on the supernatural aspects of of a humanoid vampire. We
Speaker 1: focus on the viral aspects of like vamp vampirism as
Speaker 1: a disease in these fantasy and scenarios, and of course
Speaker 1: we end up fantasizing and focusing on like the sexy
Speaker 1: and alluring aspect of some sort of a fictional vampire,
Speaker 1: whereas if we look to the biological example, if we
Speaker 1: look to the vampire bat, it paints an entirely most
Speaker 1: entirely different idea about what evampiric human would look like.
Speaker 1: I think the closest we've come is the nos Ferato
Speaker 1: of the classic film and some of the rehashes we've seen,
Speaker 1: which is kind of like this withered figure. Um, not
Speaker 1: this robust character wearing shades and a leather jacket and
Speaker 1: like ruling the night. No, because even the vampire bat
Speaker 1: does not rule the night. It knows it. I mean,
Speaker 1: I'm I'm anthromorphizing here. It knows it doesn't rule the night.
Speaker 1: It has to stick to the shadows as a conservative energy,
Speaker 1: and it has to get the easiest, uh most filling
Speaker 1: meal it can. So the idea of this slim, ghastly
Speaker 1: corpse like nos Ferato, you know, reeling in the shadows
Speaker 1: like that's that's I feel like that's the corporate we've
Speaker 1: we've managed to get. I agree. I wish that Jim
Speaker 1: Jarmus is a new movie. Only Lovers Left Alive would
Speaker 1: have explored that idea, would you explored in a blog
Speaker 1: post by way Um, So check that out af if
Speaker 1: you want to kind of do some reimagining of Dracula
Speaker 1: and popular Lure. Yeah, I do want to see Only
Speaker 1: Lover's Left Alive. I didn't think that I would want
Speaker 1: to see another vampire film, but that one looks pretty good.
Speaker 1: Till the Swinton The Magical unicorn of a human is
Speaker 1: in it, so you kind of I mean, I have
Speaker 1: to see it just for that alone. Yeah, I want
Speaker 1: to see that. I also want to see Neil Jordan's Byzantium,
Speaker 1: which sounds in like, on the surface, it sounds like
Speaker 1: just another scenario of like to two vampires, like a
Speaker 1: mother and a daughter vampire and they they're, you know,
Speaker 1: trying to find their way in a world of vampires
Speaker 1: living in the shadows. But it's it's misunderstanding each other. Yeah,
Speaker 1: but it's her mother daughter, but it's it sounds more
Speaker 1: interesting because it's like strong, supposedly strong female characters based
Speaker 1: on a play by a female play right, So there's
Speaker 1: there's something about that that I want to give that
Speaker 1: one a shot as well. All right, So what about
Speaker 1: you guys and gals out there, what do you think
Speaker 1: about the science of a vampire bat the physiology and
Speaker 1: evolution of vampire bat um. How does that make you
Speaker 1: rethink these curious creatures? How does it make you rethink
Speaker 1: the myth of the vampire as it exists in folklore
Speaker 1: and in popular culture. Um, we'd love to hear from you,
Speaker 1: and you can find us at all the normal places
Speaker 1: there is, of course, Stuff to Blow your Mind dot com.
Speaker 1: That's the mothership that should be your your first stop
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Speaker 1: up to? Well, go to Stuff to Blow your Mind
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Speaker 1: our videos there. We have a number of cool new
Speaker 1: projects that we're pushing out in the weeks ahead. Indeed,
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