Death Spirals & Gas Birds!

we may like to believe. Discover this and more as we answer the age old question when doesn't aunt mosh pit get deadly? Joining me today to talk about the particle physics of bugs, reindeer, birds, and humans is particle physicist and co host of Daniel and Jorge Explained the universe Daniel Whitson, Welcome, Hi, Katie. Think very much, but I have to admit it's been a long time since I've been in a mosh pit with humans, particles or ants.

Is that all right? That is okay. I'm a fan of metal, but I've never been in a mash pit because it terrifies me. So I have spent a lot of time in Europe driving in circles in one of those roundabout yes, the cyclone. It's called the American trap here. I'm so excited to have you on for this episode because it's one of those times where usually I kind

of focus on the individual animals behavior, their biology. Maybe when I zoom out, I'm kind of talking about evolution, but in this case, it's looking at groups of animals and what happens when you have this massive swarm or a flock or herd, and how animals start to behave in ways that can be eerily un animal like and more like a particle, even like sub atomic part of holes or or elementary particles. And it's it's I think

it's fascinating and a little spooky. Yeah. Well, one of the amazing things that happens in physics is that you have these tiny little particles which have certain behaviors, but then when you get a lot of them together a thousand, a million, ten to the twenty seven, new behaviors emerge. You know, you get things like phases, liquids and crystals and gases and plasmas that can do all sorts of

crazy things that particles themselves can't do. So I'm very excited if we are now talking about emerging properties of animals, or we're gonna be talking about like liquid ants and crystals of reindeers and stuff like that pretty much. So, yeah, animals have extremely interesting behaviors as individuals. But what happens when individuals get together as a group. There's something very strange.

You get these group dynamics where the individual becomes part of a larger whole, like a single molecule in a stream of water. Er and the ways that groups of animals behave, such as herds, flock, swarms, and even human crowds, is uncannily like water or a fluid or even a gas. It acts like it is a new thing, not just a group of something like reindeer, but a new phenomenon that is much greater than each individual reindeer, which is I suppose very inspiring speech to reindeer. But yeah, that

is what we are talking about right now. Let's talk about cyclones. So a weather cyclone forms when a core of low atmospheric pressure causes the air currents to basically like swirl around it kind of like water going down a drain. But there are all sorts of cyclone like activity in the universe. Uh, what I mean I am not a physicist, so maybe this is wrong, but it seems like the Milky Way kind of circles around a center, like a big, very slow, but very huge cyclone. Yeah. Absolutely,

the cyclones are everywhere in the universe. It's super fascinating. And it's typically, as you say, you have some low pressure region or some force pulling you towards the center. So in the case of a hurricane, you have like warm water in the ocean which heats and moistens up the air above it, which rises and creates this low pressure center and things rush in. And you might wonder like, well,

why does a hurricane spin. Why doesn't everything just float towards the center in straight lines, And the answer is that the Earth spins, and this creates this weird effect, this corioles effect, because winds at different latitudes are traveling at different speeds, and so, for example, the equator is traveling faster than other latitudes just because it's further away

from the axis of the Earth. And so if you have something which is on the same scale as the Earth, then you know particles moving away from the equator are faster, and that makes the whole thing spin, which means that on the other side of the Earth, they actually do spin the opposite direction. It's not true that if you flush your toilet in Australia it spins the other way. But cyclones really do spin the other way on the southern hemisphere. So a really big toilet, maybe it would

spin the other direction. Come on, Australia, you just called I think you just called Australia a big toilet. Oh no, I would never It's more like a giant Petrie dish filled with the most dangerous animals in the world. But I love I love you Australia, I really do. And it's not something that's limited to Earth. We see cyclones on Mars and dust storms. There are cyclones on Saturn. You know, the Great Red Spot is like the biggest

storm in the Solar System. That's a cyclone. So you're right, this sort of swarthy behavior is all over the universe and also in animals as well. So, uh, the first thing that we're going to talk about is actually we're starting with a very small animal, one of the you know, I wouldn't say one of the smallest animals, because of course there are so many teeny tiny microscopic animals but

we're talking about ants. So uh, there is something called an ant mill or death spiral, which I'll let you decide which one would be the better metal band album name. But what this looks like is a spiral of ants, uh, circling around and around. Usually there's like a pile of collapsed ants in the center. It's like this moustrum, like this hurricane of ants. And they can basically do this

behavior until they die. So they form this cyclone and keep walking around and around until they collapse and die of exhaust gin. And this raises the question of like, good God, why would they do this? So our aunts really just like little mental robots that will follow the instructions from pheromones even to their death pretty much. So yeah, it's interesting because aunt colonies are quite intelligent each individual aunt.

While I hesitate to call any animal like stupid, they it's not so much that they're stupid, but they depend on a set of rules guided by their sensory abilities, and they will they simply lack the perspective to know that they are in a death spiral. So the key thing is that this isn't just any ant that will do this. This is done specifically by army ants. So army ants, also known as legionary ants, is a name

for over two hundred species of ants. They are related and they all show similar behaviors, although it's thought that these behaviors may have evolved many different times in a case of massive parallel evolution, which is always really fascinating because if you have related animals and they're very similar and they have similar behaviors, you assume that they it's basically a tree branching off evolutionarily, instead of basically having

like many many different types of individual parallel evolution without necessarily all sort of flowing along the same evolutionary path. Well, I think you said something really interesting a minute ago about how behavior emerges in ants, that the individual ants are kind of dumb, but together they can be smart. I think that's just another example of this like emergent phenomena, where the individual pieces are doing one thing, but together

they're doing something really qualitatively totally different. Like our neurons individually are not that smart, and some of them can make decisions that lead you to your death, you know, press the metal, press the pedal to the metal on the highway or something, but collectively we do have some intelligence. So that's interesting that ants can have both intelligence emerge and also these weird death spirals emerge. Yeah, yeah, it is.

It's definitely a double edged toward this group behavior. It can lead to an emergent greater intelligence, but it can also lack the perspective that allows them to see basically, oh, this is a bad situation, and so why doesn't this die out evolutionarily? Like, if this leads to mass death of them, you think that they wouldn't propagate this behavior. Well, that's what's interesting is because typically the very things that make them such a successful species and typical circumstances is

what occasionally will lead them to this death spiral. So army ants, like any other kind of aunt, have hierarchical you, so colonies they have a single queen, worker ants and soldier ants. These are all females, and the soldier ants are like these beefy ants with large mandibles. The only male ants in the colony are there for reproduction. They have wings, tubby bodies, and in fact they're called sausage ants because entomologists are really judgmental. It's it's very funny

to me. It's like you have the worker ants and the soldier is and the sausage ants and near Chicago or they called sassage sassage ants. Yeah, man, I don't put anything but mustard on your sassage ants. Nice little sassage ant sandwich. What what would That's not what? They don't call them sausage sandwiches in Chicago sassage sandwich is like uh. Another key trait of army ants is that they are nomadic. So when you think of ants, you

typically think of an ant hill, a colony. Maybe it's in a hill, maybe it's in a dead log, maybe it's in your cereal in your kitchen, but it is one location that the ants stay in. They will build their nests and tunnels and it's really fascinating. But army ants don't do this. They are purely nomadic. Instead of having a single home like an ant hill where they live, they continuously roam, forming large migratory rivers of ants. Wow, that sounds like a nightmare of ants. It is actually

for anything that gets in its path. It is a true nightmare. So infamously, these rivers of army ants will take down any animal in its path small enough to fall victim, to the voracious troops of pillaging ants. Now I say small enough because like, these ants aren't going to take down say like a deer, but uh, they can take down things that are much bigger than themselves.

So things like grasshoppers, scorpions, spiders, giant beetles, anything that is able to become basically overwhelmed by these ants in a matter of just a couple of minutes, like they will be taken down and broken down by these ants. I imagine I could be overwhelmed if I was swarmed with ants. It doesn't seem impossible to me if you The thing is, though, as a human you start to get bitten by these little ants and you go out and you move away and swat your leg and you're

all right. Annoying, yes, but unlikely to kill you. Now, if someone like tied you down, I guess, like a damsel on railroad tracks, and then like set you in the path of army ants and you could not move, I would imagine that, yes, you may be in a bit of trouble. Well, that's not a typical weekend activity for me, so I have to worry. But I did once have a brush with a river of ants in

real life, no joke. We have these tiny little ants near my house in southern California, and one time, before giving my son a bath, I turned on the water and this river of ant poured out of the faucet. They must have been like climbing up the pipes. It must have been thousands and thousands of them. I was just so glad that I hadn't put my son in the bathtub before turning on the water. That's like, that's like a horror movie where you turn on the faucet

and a bunch of spiders come out. This time a bunch of ants coming out. Wow, that's incredible. This is what happens when you encroach on nature in the southern California suburbs. Yes, these army ants really do behave like an army that will go around pillaging and destroying everything in their path. And what's interesting is they don't really follow a single leader, but they follow the pheromone trails

of their comrades. So if enough ants become interested in a target like an insect that they want to eat, others will follow that trail. And in as each one follows that trail, they are also depositing pheromones, so that trail gets stronger. You mentioned neurons earlier, which I think is really interesting because neural pathways work in a very similar way. You can strengthen neural pathways by using them,

like repeating them. So like with these ants, if you think of these ants and the pheromones is like neurotransmitters. The more they go along the same path, the stronger that path becomes, the more likely other ants are going to join them on That path just compounds on itself exactly. And so another thing that is troubling for these ants is that army ants are typically nearly blind, so these

pheromone trails are vital for them to group together. It is they're basically they're only means of pathing, of of forging a path forward, and that is what leads them to their doom in these death spirals. So you know, do you remember that game Snake. It would be on like those old flip phones, and it's like you're a little pixelated snake and you eat other pixels to get bigger, but then if you hit your own body, it's game over. You die. Oh. Absolutely, one of the best games ever invented,

is so simple and get so compelling. Yeah, no, that was that was very exciting, obviously to any zoomers listening right now. This may be a foreign concept, but we used to have phones that would fold in half, and we did not have an endless app store where you could get any number of wonderful, colorful graphics, heavy games. It was snake and that was about it, I think, and you would just control this little snake. But it was endless, endless hours of fun. Um. But this is

what happens to these poor army ants. If an aunt accidentally crosses an older pheromone trail, this will cause it to loop back around. So it hits this old trail and then it goes instead of keeping forward. It's like, oh, here's some pheromones. And then it loops loops back around on its own old trail, and then it loops to the front again. And now that's even stronger, and it's like, oh, hey, this is a really strong trail. I should keep following it.

Other ants do the same thing, and they're all leaving their pheromones around as well. I think you can guess where this is going. So you end up getting this massive spiral of doomed ants, not understanding that instead of going forward on their typical path of destruction where they eat everything in their way, they are spiraling around and around until they are simply going to collapse and die

unless something interrupts them. If something fortunately happens to fall in their path and then they get diverted, that may save them. Otherwise they are doomed. Doesn't that mean you can protect yourself from these ants just by spraying that pheromone in like a circle around your house. Is any animal like evolved to mimic this pheromone and like you know, badgers or whatever. Yeah, you don't even really have to

spray a pheromone at them. You would just kind of like if you just guided an ant to turn around and hit its own pheromone path, that's enough. So I don't know if any animal though that's exploited this about them, but yeah, you know that that would be an interesting evolutionary strategy, especially if you're an animal that like likes to eat ants, because if you lead them to loop around and around, basically you've got an aunt buffet. Yeah exactly,

It's like an ant smoothie that makes itself. I love that. I'm sure many insectivores would love that idea. I just don't know if any is actually taken advantage of that, but you should patent that and pitch that to forest dwelling in sectivores. Well, our mascot here at, you see, irvine is the ant eater. So maybe we should develop some like robotic ant eaters that have that sort of strategy in them. There you go, what could go wrong with robotic ant eaters. So the largest ant mill or

death spiral ever recorded was described in nineteen one. It was one thousand, two hundred feet or three hundred sixty five meters in circumference. That is a nightmare with a horror movie. Yes, And the problem with the spiral is that it runs counter to their evolutionary strategy. When they form that river that's like marching forward and then kind

of diverting to insects that they find to eat. They have a pretty good strategy, which is, as you go forward in the forest, you're bound to come across prey and be able to eat them. But if you're going in a spiral, even if you happen to luckily find some prey within that spiral, that's going to get eaten pretty quickly. Uh, and then you're not going to find anything else as you spiral around and around and around, and eventually they just run out of fuel, which you know,

in biological terms that means dying of starvation. So what fraction of all the ants on Earth were contained in this one spiral? Oh? Probably in this one in I don't know, probably point zero zero zero one person of ants because there's a lot of ants, I know. So if this one spiral is so big, it must have had like what millions of ants in it. Now you're telling me that it's a tiny fraction of all the ants. Basically you're saying that Earth is all ants pretty much. Yeah,

that's uh. I believe the matt Like, if you added up all the mass of ants, I think it's much more than the mass of all humans. Uh So what's fascinating about these death spirals is that there is not there is no single ant that is deciding to go into this spiral, and even collectively, they have not decided that this is what they should do. They are following a set of straightforward biological rules like computer programming, and if they get stuck in the loop, there's no nobody

to tell them to get unstuck. There's no executive looking at the ants from above. There's no like eyes in the sky aunt traffic helicopter warning them on their little Aunt radios that there's bumper to bumper snarl ant spiral. So it is this emergent intelligence that when it goes haywire, there's no executive function to unhywire it. I feel the same way sometimes, you know, when my brain gets haywire,

I'm like, what is the magical button to press this disaster? Well, that's what's That's something that's so interesting about human consciousness is we are if we look at our neurons as like these ants, you know, we do have this emergent intelligence from neural activity, but we do have the sense that we do have like an executive function. We're able to like zoom out and maybe see problems as they're happening.

Or are we like that? That's a big question, is like we we have the sense that we have a central executive control over our brains. So we have that like ant helicopter looking above at the ant spiral, But do we really That's that's a huge question in psychology. It's we have there's no like part of the brain that you can point to, like here, this is where the little you sit, you know, you're the president of your brain, sits and oversees all of your brains activity.

That that doesn't exist, even though we have the sense that we have this like executive control over our brain. It's a it's not necessarily true. Yeah, it's actually a really interesting question and active discussion in philosophy as well, whether in principle it's possible for everything that we experience to just emerge from the complex sort of tooing and throwing of little bits following their microscopic rules. Can reductionism

explain everything? Can even consciousness be explained from little bits and pieces, you know, like rocks we don't think are conscious, but they're actually made out of the same things that you and I are made out of. So somehow consciousness would need to like emerge from how those pieces are

arranged and interacting with each other. But there are other philosophers that argue that emergence has its own special rules, that there may be properties of things at one scale, like the human brain that don't just come from the little bits they're made out of. There like extra additional rules that come into play when things come together. I don't know if I believe that, but it's an active

area of philosophical debate. But then what isn't right, which again kind of is uncannily like what you physicists talk about in terms of particle physics, where you have the individual rules of say a single particle, but when they're in a group, that group of particles will behave in a way that is is unique and different than what you would think just based on one individual particles behavior

might be possible. Yeah, and sometimes you can explain it in terms of the underlying bits, and sometimes it's a question mark. You know, in physics we look at the passage of physics. We look at the interactions of tiny little particles, and they seem, for example, to be symmetric with time, Like the rules don't seem to care whether time flows forwards and backwards. But when you drop an ice cube into a hot cup of coffee, they definitely

moves in one direction and not the other. So sometimes even in physics without consciousness, we don't understand how rules emerged for the big stuff from the little bits. It's a really fascinating thing to study, right, And what's interesting is like, we don't even need little bits, right, we can have something as big as like a reindeer acting in a strange way when you put them in a group. So like with aunts, I think it's easier to think of like, yes, of course, and aunt may behave like

a particle. It's basically like a teeny tiny robot anyways. But a reindeer um, while perhaps not the most intelligent animal in the world, but I mean, what is this a competition? They are, They're a large animal. They each have their own, you know, ways of thinking, and they are you know, we can have that sense of this animal's consciousness much more clearly than we can with an aunt. However,

reindeer also will form things like cyclones. Now, fortunately, if people are starting to get nervous that Santa's reindeer get into a death spiral of their own, don't worry. In this case, the reindeer cyclone is a great benef fit to the reindeer. It protects them rather than harms them. So reindeer are real animals. They are not just Santa's means of conveyance. Uh. They're also known as caribou. They live in a geographical circle around the North Pole and

they can form massive herds of up to a million individuals. Now, of course, uh as, I seem to increasingly have to say, um, you know their populations are declining due to climate change, but they still conform these massive, massive herds. So you're telling me that caribou and reindeer are the same thing. Yes, yes, they are so. So every time I've ordered a caribou steak, they might be giving me a piece of reindeer. Yep, you might be eating rootolf. I do have to ask

how often you're able to get caribou steak. I don't eat a lot of exotic meats, but my son is keeping track of the number of different animals he's ever eaten in his lifetime. So whenever there's an opportunity, you see something on the menu, like oh, Ostrich Burger, let's go for it. He's a bit like Darwin in that respect. Darwin loved to eat animals, like animals he would newly discover, and one of his main questions was what does it taste like? Does echo better with cheese on top or

without cheese on top? A new paper by Charles Darwin his Hidden Manuscripts. But reindeer are used to dealing with threats. Even aside from your voracious son, there are a lot of predators that have a taste for reindeer meat. Brown bears, polar bears, wolves, human hunters. Even golden eagles will sometimes prey on reindeer calves. So you can imagine that reindeer

have a reason to be a bit paranoid. But that makes me wonder if army ants have ever taken down a reindeer calf, Like, what's the biggest thing an army ant could eat? Could cyclone of army ants takedown and baby reindeer? I mean, they wouldn't inhabit the same habitats at all. I don't think they could take down a baby reindeer unless that baby reindeer again was like already sick or couldn't move. Just a horrifying idea all around. Thank you for bringing that up. I'm not saying we

should do the experiment. I'm just saying it's an open question. Uh. You you just disappointed. Some biologists were like, oh, I shouldn't do that experiment, darn it. Uh. But reindeer are not so helpless. They have a trick up their furry little sleeves. When a danger threatens the herd, they will circle the wagons. They form a defensive cyclone. It's like a whirlpool of reindeer. Uh, and it is it is

stunning to see. You should definitely look up video of this and I'll will include that in the show notes. But it is, it's it's mesmerizing. And is this like a bug in the programming of reindeer the way it is for army ants or is this actually like defensive? Does this help them in some way? This is helpful to them? It is not a bug, it's a feature. So um by making this whirlpool, they make it extremely difficult for a predator to focus on a single individual

and take them down. Even an intelligent predator like a human, will find it difficult to do something like aim an arrow as they swirl around and around in this dizzy mob. It's because like you can't just necessarily, as a predator, run randomly and start chomping like usually the goal is you eye a certain target and try to take that down. But if you can't even keep track of what your

target is, it's very difficult to take anything down. So this behavior has actually been observed by researchers in captive reindeer herds. When reindeer are corralled, they start to form the cyclone. And this is what's so strange is that this cyclone seems to typically run counterclockwise. This preference for left word movement is also paralleled by a preference reindeer have for using their left hoofs to dig up grass.

So they'll use these very these cup shaped hoofs to dig up snow to get at like the vegetation underneath the snow. And they tend to seem seem to favor the left hoof. And they also run in a left words direction when they form these cyclones like this counterclockwise direction. And it's completely unknown why this happens or if there's even a significance to this happening. Wow, and do they also vote Democrat? I don't know. I'll do a straw pole of the reindeer, but I'm worried they just eat

the straw um. But I have a question, is this surrounding the Is this surrounding the danger? If something wants to eat the reindeer, they'll surround it or the or the danger is like on the outside of the cyclone and it can't even like and it can't even like visualize which one to eat. It's the latter. Yeah, So they're not surrounding the predator. It's usually the predators on the outskirts, and it's trying to pinpoint a reindeer to pick out to try to take down, but it can't

because it's just the swirling vortex of reindeer. Uh in the center. I have read that sometimes in the center it's like the younger reindeer the calves, but I have been unable to find like research that has verified that. It's just like sort of observation of it seems like maybe the younger reindeer tender stick in the middle. Um. And what's so interesting about this is that, I mean, first of all, I mentioned that that I haven't been able to find research on whether it's true that like

reindeer calves are in the center. It's because research on these reindeer cyclones is kind of surprisingly incomplete. Um. And so it's it's hard to really know exactly what's going on, which is a big hint for you know, Santa out there to start funding some research on reindeers. Um. But yeah, what is so strange about this is what exactly is going on with these reindeer. They don't use pheromones in the same way that army ants use um. But I suspect that it's not so much that the reindeer have

decided to form this cyclone. There's not like a all hooves meeting that they, you know, decided like, well, if we come across the predator, let's form the cyclone, so it confuses them. Instead, what's far more likely is that they have a set of instinctive rules. And when you have each individual reindeer with that set of instinctive rules and you combine them in this herd, you get a

similar group behavior as you see with the ants. So even though reindeer are more complex more intelligent than an army ant, once you get them in this group setting, they're probably operating on a similar set of rules that these army ants. Instead of using pheromones, they're probably using their relative closeness to other reindeer, and they're probably using directional cues from these other reindeer. And by using the set of rules, they then collectively form the cyclone without

any individual knowing exactly what they are achieving. Here, it feels to me, like when you're that kid who wants to get on the Merry go Round, Like when you're when you're that kid who wants to get on the carousel, but it's already started and it's moving too fast, and so you can't even like grab onto one of the horses or the reindeer to jump on it. But that makes me wonder, like in my mind, all carousel's spin counterclockwise. Is that true? Is that the arrived from the reindeer vortex?

That's an interesting interesting thought. I think like the carousels tended to be they weren't they like originally sort of a a toy that was supposed to be mimicking sort of uh, combat on horseback, like where you you know, you'd have your lance, and like I think originally like there was like a golden ring that you're supposed to try to like hit with a stick or something while you're on the carousel. That's supposed to be mimicking sort

of lancing. So that that was a really interesting question. But now I want to see a reindeer carousel because that would be much more biologically accurate. We've talked about a couple of cases of group dynamics and how instinct can lead to complex mob behavior that can either be deadly in the case of those poor army ants, or life saving in the case of reindeer cyclones that protects them from predators. But now I want to talk more about the actual physics behind a group behavior. So, Daniel,

you are a particle physicist. Do you think that an animal can behave like a particle? Well, particles follow physical laws, and so do animals. You know what can particles do? They can like fly through space. They can also change directions, but to do that they have to like emit something. They have to like cast ne to like shoot off a photon for example. Like if you're an astronaut and you're floating through space and you want to turn, you gotta fire a little rocket or like throw a rock

off in one direction to change direction. So there's not that much that particles can do other than fly through space, change direction, and bounce against each other. But you know, put them together in a huge collection and then they can do all sorts of other weird stuff like become chocolate cake. Oh I like, I like the idea of particles becoming chocolate cake, But that does make the segue weirder because we are talking about starlings, who, as far as I know, you know, you can bake them into

a pie, but that seems kind of disgusting. Starlings are these beautiful, little black but also iridescent birds, and they have these white speckles, and that's why they're called starlings. They look like a star speckled sky. To me, they look like a night sky. That and that rainbow sheen on their wings actually kind of looks like one of those NASA colored images of a galaxy. They're they're stunningly

beautiful in my opinion. Yeah, and so you're saying that you've never seen enough starlings come together to make a chocolate cake, not yet, one can hope through sheer probability. Well, you know, the number of particles in a chocolate cake is approximately ten to the twenty six, So I think probably you just need to wait for enough starlings together and the huge cosmic chocolate cake might just emerge. But again another open question in science. I think the math

checks out on that. So, uh, starlings do form giant flocks, not quite tin to the what tinto the twenty six is what you said, not quite that large, um, but millions of individuals. So when they are in these giant flocks, if you live somewhere where these starlings live, or if you've just seen videos, they will generate these murmurations. What a murmuration is is when you see like a flock, and then you see a pattern kind of like flow across these birds, like a dark band kind of flow

across these birds. Um, it's these undulating patterns and designs where they kind of look like there's some singular shape shifting creature in the sky or smoke or or something. But really it's just a bunch of birds responding to each other's movements. It's amazing and I always wonder what's

it like to be one of those starlings. Is it wonderful you're like doing synchronized swimming with a million of your friends, or is it like a nightmare, like you're stuck in traffic like American in the traffic circle in Europe? You know, is it fun or is it terrible? Well, that's a really interesting question. I think it very much depends on the circumstances. Sometimes these murmurations are in response to predators, So in that case, yeah, I'd imagine they're

a little bit concerned. But sometimes these birds will form these flocks and start to do these murmurations, and it's not even exactly clear what they are responding to what they're doing, or if it's simply fun for them. So, just like we may sometimes run and jump when we are scared when there's something coming at us, sometimes we run and jump because it's fun. So I think it's very situationally dependent how these birds feel. But I would say in gen role they like the traffic, like when

they are inside that flock. If I was to kind of get into the head of a starling, I think I'd feel much more secure inside the flock than on my own. I don't think i'd feel claustrophobic or social anxiety. I think I would know if I'm surrounded by birds, I'm much like less likely to become a snack for some predatory bird. I mean, you also prefer like line dancing, because you're surrounded by hundreds of people doing exactly the

same moves, nobody can make fun of you. Well, It's why I enjoy improv better than stand up because with improv, you've got a lot of people that cover your mistakes with stand up. You've got nobody. And so if you start crying, everyone notices. If we bomb, at least we bombed together exactly exactly. So I'm very I very much

have a starling personality. The evolutionary advantage of these big flocks, these murmurations very much is like the reindeer we talked about, where they can dodge away from predators, and by being in this huge flock, not only is it more confusing to predators, but it's just law of large numbers. You're less likely to be the one picked out of the group. Um. But the huge difference between these birds and the reindeer in terms of physics is the birds are in completely

unrestricted three dimensional space. Reindeer run along the ground. I mean, I know reindeer are three dimensional and their movements are strictly speaking three dimensional, but they are more or less on a plane and like spiraling around this plane, whereas the birds can move in any direction that they want. It's much like in space when you have spaceships, and in sci fi it's always confusing why you'd have rear thrusters and not every which way thrusters, because you are

an entirely three dimensional space. Are you telling us that reindeer don't fly? I mean, you're just like really cracking your younger listeners. I hope they're I'm only talking, of course about the non magical reindeer. Of course, the magical reindeer fly, but Santa has to select those reindeer and feed them royal reindeer jelly that causes them to sprout wings. And I think I'm actually talking about bees now or aunt anyways, um birds fly in this three dimensional space

up down side to side three hundred sixty degrees. Uh, and so this causes really interesting waves and undulations that you won't necessarily see in other crowd behavior. So statistical physicist Dr Andrea Cavna and theoretical physicist Dr Irene Jardina studied the mini starling flocks found here in Italy, and they found that these birds were acting similar to particles or molecules whose group movements can be described as scale

free correlation. So I'm not a physicist, so Daniels, stop me if I say something wrong here, but from my research, it seems like scale free correlation is when individual particles or individual birds move not only based on their immediate neighbors, but on the entire flock or entire group of particles. Is that more or less correct? Yeah. Effectively, it's when your choices, your directions, are not just influenced by what's immediately around you, but sort of like longer scale forces

or influences. That's exactly what is happening with these birds. The movements of one individual bird will affect the movements of a bird way over on the entire other side of the flock. So each starling will adjust its direction and velocity based on its immediate neighbors. But that also means that the starling's next to that starling change their

velocity and trajectory and so on and so forth. Uh. And what this means is that because these birds are so sensitive to changing their flight behavior based on their neighbors and their neighbors based on their other neighbors, they are the actions of one starling in the flock has an impact a measurable impact on every other starling in the flock, and vice versa, and it creates this incredible complexity.

It's amazing to me that it's not just chaotic. I mean, if you have so many objects that are very sensitively responding to other objects. Why isn't it just like a crazy mess? You know, if you throw like a million ping pong balls down the steps, you don't get any sort of like emergent pattern, You just get insanity. And so it's amazing to me that the starlings don't just create a big mess. There must be some instinct to

also follow their neighbors, not just respond to them. That's right, that's right, And that's actually very good question because this is exactly what these physicists, these biological physicists are look into, and they found that these starlings are operating on a very precise set of rules um because they do not want to crash into their neighbors, but they don't want to leave the flock because if they're the slow one, the one that like makes a wrong direction and accidentally

leaves the safety of a flock, they are going to instantly be a target of like a hawk. So it is so important for each individual's survival to be able to set follow a set of rules, which is, I want to maintain proximity to my neighbors, close proximity to my neighbors without crashing into them. But I also want to change my direction sensitively to my neighbor. If my

neighbor turns left, I also want to turn left. Um but I And so by the fact that they have these complex rules means that the entire flock actually starts to behave more like a fluid or a gas. And when you look at um murmurating flock of starlings, it really doesn't look like it. It looks like something kind of alien or or you know, like when you look at say, you know, when you blow a candle out and you see like the smoke kind of swirling around,

it has these to our eyes unpredictable movements. But uh, it really is predictable movements if you have sort of a mathematical model of how this smoke behaves. But it's very complicated, so we can't just looking at this smoke kind of predict which way it's going to go, what

it's going to do. And the really weird thing is that these starlings are acting like the kinds of particles that you studied, Daniel, because they don't just adjust their velocity and direction based on their neighbors, but the sharpness of turns. So some physicists some of these physicist who are studying these birds actually call it the spin of

the starling, similar to the spin of an elementary particle. Wow, and that makes me wonder if there are quantum starlings out there spin up or spin down, or if you can have entanglement of starlings. I guess that's where the starlings are trying to avoid actually tangled up in each other. Yeah, they don't exactly want to become entangled. It does mean that they have the conservation of spin. So the cumulative spin of the flock is conserved when the starlings match

their their neighbors. So like once starling doesn't just like if one starling turns left, the other starling isn't just thinking okay, I turn left now. It is also matching that sharpness of the turn. And like I mentioned earlier, the actions of one starling affects the actions of the entire flock and vice versa. And so this means that the entire flock of starlings can change its spin or

the sharpness of its turns almost on a dime. And this allows them to change directions in response to danger as if they are a single organism moving rather than a group of birds. That's incredible. Well, it's almost like together the starlings are a super brain. Yeah. And what's weird is that the mathematical models used to describe the physics of starlings are identical to that of super fluid helium. So when helium is cooled to almost absolute zero, Uh,

it becomes like a liquid, right Daniel, mm hmm. Yeah, the viscosity drops really really low, so you can like slide past itself with almost no friction and yeah, and that almost completely absent viscosity is the same thing that happens with these starlings because remember they don't want to buy into each other, right, because that that would also mean death. Like if you stray too far from the flock, that means death. You collide with the neighbor and you

both fall, that means death. So it is in in evolutionary terms, they have been turned into such precise flying machines where they are very careful not to collide, and by not colliding, they don't have friction. There's not that viscosity, and so they act like super fluid helium almost exactly. And I think the mathematical models that they use for these birds are the same ones, or at least incredibly similar to the ones that they use for super fluid helium.

It's incredible to me that we find these little mathematical stories that can describe the universe, and they don't just describe one part of the universe. You can use the same kind of mathematical stories to describe super fluid helium and also flocks of starlings. It's incredible and it makes me wonder if the mathematicians who say that the universe self is mathematical are really onto something. I mean, it is there's something. I guess it depends on your relationship

with math. It's either spooky or it's inspiring that math does seem to be behind so many things, Like you know, you look at a flock of birds and it's like, oh, well, you know, this is described by the same equation that you use to describe something that is about as different from a bird as you can think in terms of just like our superficial understanding of things like super fluid helium.

That's that's not birds, but it is acting. But you know, when you look at if you were like an alien who could only see in terms of these mathematical models, you would think like, well, these two things must be very closely related, this flock of birds in this super fluid helium, because the math that describes them both is is identical. Yeah, and that would make you wonder, as an alien scientist, what happens if super cool down a flock of starlings? Does it become even more viscous or

even less viscous? I'm just saying the question is open in science. If you had become an evolutionary biologist instead of a particle physicist, you would run a foul of so many of the ethics boards involved in designing biology experiments. Okay, I hope that wasn't an unintentional punt running a foul of these ethics sports. That's gonna that's gonna get you

even more trouble with the ethics sports. So we've talked about animals and their group physics Starling's reindeer ants and you think that you may think that group physics are only for these simple animals and not for intelligent animals like us humans. But uh, you'd be wrong. So even highly intelligent animals such as people, are subject to mob physics. Human crowds don't necessarily inherit the intelligence and decision making

of each individual human. Human brains in groups can be quite powerful, but that's only when the brains are capable of communicating. So, like you know, we have as societies developed amazing technologies, amazing medical breakthroughs and discoveries. Um, but that's because that is our brains kind of pulling together. But when you're in a physical crowd, our ability to communicate, one of our biggest strengths as humans, can be hindered.

So like beach or facial expression can get drowned out by a big enough crowd and more chaotic crowd, and the movements of people actually start to mimic not a

group of intelligent creatures, but a group of particles. That's incredible, But I guess it doesn't surprise me, because like economics is a thing, right, we can describe the behavior of huge groups of people based on the individual little choices they're making buying and selling and not buying nikes because they're more than a hundred bucks and buying them when they dropped to ninety bucks. So I guess that makes a lot of sense that there are emergent phenomena on

the scale of societies as well. Yeah, not like in economics, like when you have things like inflation that increases too quickly, sometimes that is due to these like small individual decisions that are being you know, it's maybe it is what did I call it a scale free scale free correlations, scale free correlations, because like your individual decision making will impact the entire economy, and the entire like economy, impacts

every individual's decision making. So is this feedback loop. And it's the same thing for for group physics crowd physics, and it can get actually quite dangerous as the movements of people start to resemble a fluid rather than a group of individual people who have brains and can think.

So researchers are actually looking into how to model human crowds through hydro dynamics, using observational data from real life crowd situations such as marathon runners, because the hope is that by modeling human crowd behavior we can actually save lives in crowd situations such as in stadiums or other enclosed spaces, where the crowding of people can actually lead

to injury or even in some cases death. Um So, crowd crushes are a rare but very tragic event in which people get crushed in crowds, not due to malicious actions by other people, but simple physics. So like if you have a big crowd in a stadium and then a choke point, things can get very dangerous very fast because the people at the back of the crowd can't see or hear what's happening in the front, so they may continue to move forward while the group of people

in the front start to get condensed together unable to move. Uh. And this is again it's like sometimes in these like crowd crush things, people think it's due to an unruly riot of people or people being you know, behaving in some kind of bizarre way, and that's not at all the case. It's just because of the way that a huge group will basically run into the constraints of physics, and then the inability of the people in the front of the crowd to be able to communicate to the

people in the back of the crowd. So basically you're saying physics kills respect our local physicists as if they were a swarm of army and your words, not mine. Uh, But yeah, I mean it is of course, you know, like physics is. It is the guiding principle of our entire lives and our our physical bodies. And so when you're in a crowd, you have to respect the physics of a crowd just as much as you have to respect the physics of gravity if you're jumping out of

a plane. So people who have survived crowd crushes or crowd collapse describe it as being carried away by a fluid force, like as if they're being carried away by a river. Sometimes their feet aren't even touching the ground. They're just unable to move of their own volition and just being carried away like they're being swept away by a river. Uh. And when people like if people see people ahead of them getting hurt, they of course may want to stop, and mentally they're thinking, oh, no, I

don't want to run into this person. I don't want this person to get hurt. But at that point they're actually kind of stuck as being a part article and this like fluid force of the crowd, and that, I mean, it's one of the one of the more scary things that I can imagine. Yes, the famous person particle duality we know of humankind. Sometimes you're a person and sometimes

you just feel like a particle. Yeah, exactly. And this has been a problem for humanity for as long as there's been crowds, and has actually been recorded since the seventeen hundreds. Uh. Sometimes it's blamed on the crowd, like during the Hillsboro disaster in nine where people in a football stadium were injured and killed during a crowd crush. Um. But this was not at all the people's fault. It was simply due to uh, the design of the stadium and the crowd control there was, you know, it was.

It is one of these situations where it's like you if you have a jug of water and you pour it into a cup of water and it kind of sloshes and splashes around. That is not the fault of the part coals inside the water. It's not the fault of the um the water molecules inside for splashing around. They are simply caught up in the group dynamics of being part of this group of water molecules that will behave as a fluid. It sounds like you're setting up physics to take the blame here. The fall guy. Uh,

Physics is always the fall guy. Really when you think about it, the whole reason we fall anyways, So I will take credit for that one. So I bring this up not to not to demonize physics or physicists, but to demonstrate some of the importance of understanding biological physics. If you can model the fluid dynamics of a crowd, you could use that data to plan the construction of things like buildings and stadiums, or the implementation of crowd control to make things safer for people. So it's these

kinds of things that we research. It's like, as amazing and interesting as they are, I think on their own, Like I want to know that birds can behave like helium because that's really cool, but it can also be really important for our society. Yeah, it's a fascinating topic with all sorts of wrinkles in physics, in biology, and in psychology. Yeah. Absolutely. But before we go, I do want to play a little game called Gifts Who Squawk and the Mystery Animal Sound Game. So every week I

play a mystery animal sound and do the listener. I try to gifts who is making up sound? It can be any animal in the world. Does that include physicists? Could be a physicist, could be a physicist that's right, you bunch of animals. Um So last week's uh mry animals sound hint was we've talked about the elephant in the room, but what about the rhinoceros in the room, who's not really a rhino? So ignore the bird sounds.

But did you hear that like hissing sound? Yeah, that sounds like what I hear in my freshman physics classes when I assign homework. So you're saying that your physics students are a group of rhinoceros beetles, because this is a rhinoceros beetle. Congratulations to the three fastest guessers, Joey P. Michael D. Shana S who gets correctly. Also honorable mentioned to Zoe H and Grant W. Who gets the specific species of rhino beetle, the common rhino beetle from Australia.

And thanks to everyone else who wrote in and gets correctly. Excellent job you guys. I am so so impressed. I don't think I could be as good as you guys at this game. I make the game, but I don't guess it, so uh, great job everyone. So this is the rhinoceros beetles, specifically the zylo troop. As you list these Australicus found in Australia, when they are bothered, they will hits that you like a cat. But that hissing is not coming out of vocal cords, which the rhino

slurspeetle lacks. Instead, it's stridulation, the vibration of its wing covers against its abdomen. Now onto this week's mystery animal sound. Don't blame the dog for this one, but it is the sound of a happy carnivore. So I promise that is not a rude sound. But if you think you know who is squawking, you can write to me a Creature Feature pot at gmail dot com. I'm also online at Creature feet cot on Twitter. That's t f ET. That is something very different. Thank you so much to

Daniel Whiteson for joining me today. If you want to hear more from Daniel and hear him talk more about the Mr Reads of the Universe and particle physics, check out his podcast, Daniel and Jorge Explain the Universe and sometimes I'm a guest host on that podcast, so yes, check that out. Thanks very much for having me on, Katie. Thank you guys so much for listening. If you're enjoying the show and you want to leave or rating or review, I would appreciate that so so so much. I read

every review and it means the world to me. It also really helps me out. Like when you leave a rating or review, it helps the podcast out. Uh. And it is a wonderful freeway to express your joy for the podcast and to help support the podcast. And thanks so much to the Space Classics for their super awesome song. Exoluminous Creature Feature is a production of I heart Radio. For more podcasts like the one you just heard, visit the I heart Radio app, Apple podcast, or Hey guess

what wherever you get your favorite shows. I do not judge you, and I will not tattle on you. See you next Wednesday. Ay,