Listener Q's: Upside down sharks and chimpanzee butts

something is wrong with the shark. Can you tell by watching if this is normal or not? Thank you Danny J. So the video that Danny sent me is a shark approaching a boat with a diving cage, and instead of eating everyone on board, it backstrokes and swims with its belly up. It kind of swims back, makes a half hearted attempt at biting part of the boat, and then swims away. So this looks like a great white shark to me in the video, it is unusual behavior actually,

because sharks do not typically swim on their backs. In fact, being upside down isn't a great position for the shark to be in because this can trigger a state called tonic immobility. My guess is that the shark got a little disoriented by the diving cage that it sort of bonked into and accidentally swam itself upside down, So that would be my guess. I think the shark made a bit of a clumsy kind of like meet cute clumsy girl. Move here. But I don't think it's like sick or anything.

But let's talk a little bit about tonic immobility and why it happens when sharks are flipped over. So sharks and rays experience tonic immobility when they are flipped on their backs and held there. It's so effective in some species of sharks and rays that researchers can exploit it to examine sharks or to outfit them with trackers. Sometimes

it's used instead of anesthesia because it's so effective. So while the shark is experiencing tonic immobility, the shark's breathing will slow down and they will be in a kind of catatonic state until they are released entered right side up. Orcas will sometimes use this to attack sharks. Actually, so orcas will slam into sharks and when the sharks flip over, the orcas will kind of try to restrain them and either attack the shark or wait for the shark to

drown before having a shark snack. And orcas will do this, especially to great white sharks. I now what we think of great white sharks as like the apex predators, they don't have anything to fear. Well, orcas are kind of buttholes and they will definitely attack great white sharks who are just vibing. So why how would a great white

shark drown underwater? It's a fish that doesn't make any sense. Well, great white sharks are what are called obligate ram ventilators, meaning that in order for their gills to process the oxygen from seawater, the shark has to be moving to maintain the flow of water. So not all sharks are obligate raum ventilators. So it's not true that all sharks have to keep moving to stay alive. In fact, the

majority of species of sharks do not. They actually have something that they have a buckle pump of pump in their cheeks that maintains the flow of water over their gills even when not moving. But there are some species of sharks that are ram ventilators. They have to move or at least have some kind of flow of water in order for their gills to work, and so great

white sharks are one of these species. So if they are held in a state of tonic immobility for too long, they'll actually suffocate because they aren't getting that flow of water over their gills and they are asphyxiating. So another way in which tonic immobility can be induced in is by overstimulating the sharks. So sharks have electro receptors in their snouts. These are called the ampulae of lorenzini. They are actually very sensitive receptors that can detect tiny electrical

signals and they can use this to locate prey. These are essentially pores in their snout filled with a conductive jelly and at the bottom is a cell a electroreceptor cell that is sensitive to the flow of electricity, and when that stimulates the cell, it releases a signal to a nerve which goes to the shark's brain, and the

shark notices the electrical pulse. And because they have rows and rows of these pores of these electric receptors, they are also able to tell the direction of the electrical signals. So that's how they use it to locate locate electrical signals underwater. And this is useful because muscle movements send off electrical little electrical signals, because your muscle movement is actually powered by electricity in a way, and so this is the way that the shark can locate prey in

the water. So, because these are so sensitive, if they are over stimulated, like by rubbing the shark's snout, this will actually trigger a state of tonic immobility. So you might have heard before that like bonking a shark on

the snout immobilizes them. That's somewhat true. I wouldn't like put yourself in the position where you have to try that, but yeah, like rubbing, rubbing the shark snowls getting a lot of sort of agitation on the shark's nose cana overwhelm that electro receptive system and then cause them to kind of go into a sort of dazed catatonic state.

In other species of sharks, such as the zebra shark, you can actually apply some pressure to the caudal thin, that is, the tail thin by firmly grasping it, which has been observed to also induce tonic immobility. So why do sharks have this secret power down mode when it doesn't seem to benefit in fact, seems to be somewhat of a liability. Well, there are three basic theories which are not mutually exclusive. The first theory is that it is a defensive technique to play dead if a predator

corners them. Obviously, it's not so useful for the great white when orcas are smart enough to exploit it. But it's potentially of vestigial response that benefited earlier evolutiontionary iterations of sharks. So not necessarily the great white that doesn't really need to fear predation too much, unless unless it is ironically stunned. But you know, the great white shark may have retained this trait. Maybe other species of sharks

that preceded the great white shark. This was useful for And remember, with evolution, outdated or bad adaptations don't automatically go away unless the selective pressure is strong enough or more positive mutation arises. So we can have a lot of evolutionary adaptations that used to be good for us, used to be helpful, but are no longer so helpful.

One of the theories of like that jerk that you do as you're falling asleep is that it's sort of this old trait that we had when we were tree dwelling and kind of having like this sense of falling or alertness when we're trying to fall asleep would actually be beneficial. Now it's not so beneficial, but it's not because it's not necessarily impacting our survival all that much. In terms of yes, it might be hurting some of our sleep quality, then the trade is not going away.

Now you might ask, well, for these sharks, the orcas are killing the sharks, that seems like it's impacting their survival, And yeah, you are correct. It's just like you need enough sharks to be killed in this way that it would be making quite a marked difference in terms of their survival, and you would also simultaneously need a mutation in sharks that allowed them to not have this catatonic response,

so either way. So the second theory as to why sharks have this tonic immobility response is that it's a part of courtship behavior, so the female will relax during mating. So when sharks mate, that's one of the rare times that the shark might be somewhat upside down. So this is supported by some evidence that female sharks are more

affected by tonic immobility. So the ability for the female shark to, like when she's upside down, to kind of like not thrash around and stuff might make matings more successful. The third theory is that it is to protect the shark from overwhelming sensory input, basically calming them down if

their senses are overloaded. This theory basically comes from the fact that sharks, when they're overstimulated, like I was talking about earlier with their electro receptors, will go into tonic immobility. I kind of, I mean, you know, personally, I find this the least compelling theory because I'm not sure how

being sort of soothed is necessarily advantageous. Usually there's some like reason, uh for for that tonic immobility that would improve your survival chances, not not just like oh, like they're overwhelmed and then this is a way to like protect them from overwhelming sensory input. I'm not I'm not totally convinced about that, but you know, maybe I'm not fully understanding it, so it could be true. Yeah, so that those are the main theories behind why sharks will

undergo tonic immobility when they are flipped over. And yeah, I mean it's it's a really interesting behavior. I feel like it kind of humanizes sharks a little bit. It's like they are also vulnerable. They are little little sea puppies that bite you real hard if you if you play with the wrong species. Anyways, we're gonna take a quick break, and when we get back, we are going

to answer another listener question. Next listener question, Hi, Katie, I've heard that because our primate cousins such as chimpanzees, bonobos, etc. Are primarily quadrupedal, they can recognize each other by just looking at their butts. Do you think that's just like how human brains are prime to identify faces, and we see faces in clouds trees and other patterns I eat

pair idolia. Perhaps chimpanzees look up at the clouds and see imaginary butts up there, or look at some patterns and tree bark and think, hey, that looks like a rear end. The world is full of butts. So this is from Luke. I love this question. So the question is whether pair idolia for butt centric primates might cause them to see butts in the clouds. And to answer this, we have to look into whether the way that primates see butts is the same way that that humans see

and recognize faces. So it is true that chimpanzees are primed to recognize them friends butts. I want to talk about a study that explored this because it's really interesting and also super funny. It's called getting to the Bottom of Face Processing. I gotta love upon in the title

of a study. So not only does the study demonstrate that chimpanzees are primed to recognized individual chimpanzee butts, but they also make the case that the ways in which chimpanzees sea butts is the same way that human beings see faces. And they even speculate that human faces may have evolved to look more like primate butts. Before you

feel insulted, let me go over the whole study. So researchers used photos of human faces, chimpanzee faces, human butts, chimpanzee butts, human hands and feet, and chimpans and feet, and they tested the recognition of these photos in humans by asking them to match same photos, so like, the same face, the same feet, the same butt, et cetera.

And then they did the same thing with chimp participants who were you know, they were raised in a lab facility in Kyoto where they have sort of a chimp population, a captive chimp population, who are used in behavioral studies. So there's something called the face inversion effect, where it's much harder and it takes longer for people to recognize

faces that are upside down. This is due to the mismatch between an upside down face and the schema, the template of the face that we have in our brains, which is right side up. So we're actually born with this schema, this template of sort of the normal proportions of a human face as we're when we're born, and

as we age, it develops in complexity. So humans are particularly adept at recognizing faces and because of our sensitivity to the facial pattern, we are sometimes getting false positives, so we'll see faces in random patterns such as clouds or dirt or tree bark. In some cases the opposite is actually true. So there are some people who have

a very difficult time recognizing faces. It's called prosopagnosia, also known as face blindness, and it can be very challenging for people with face blindness to tell people apart and actually for them like when there are these Sometimes there are paintings and stuff where they hide human faces in like a natural scene or pattern or like an a rock face, and people with prosapognosia have a much harder time seeing hidden faces that are intentionally put in paintings.

So onto chimpanzees. Chimpanzee butts might look unattractive to us, but to chimps they are beautiful and they can be signs of reproductive readiness. There are sexual swellings and coloration that indicate a female is fertile and receptive and being able to recognize the individuals but is really important because this can help them with sort of social situations in matings, so they don't have any kind of inbreeding and other

just social applications of knowing who this individual is. So in this study, the researchers predictably found a significant inversion effect for human participants trying to match upside down faces, just as what is expected. But they also found this

inversion effect for chimpanzees but with butts. So this means that the chimpanzees likely have a developed specific butt template that they have in recognizing other chimp butts, far more than they have in terms of recognizing faces, hands or feet, just as humans have a very specific template for faces. But we did really poorly on this test trying to recognize butts, hands or feet. So the I thought this was a really inventive study, a really really creative, interesting study.

The downside, which the author's acknowledge, is that there is a pretty small sample size of chimpanzee participants. There were only five who were trained to partake in the study, which, you know, it's just the limitations of you don't have access to a huge pool of chimpanzees who can participate in this study. They're also captive chimpanzee, so their behavior might be different from wild chimpanzees. Again, that's a really

hard to avoid limitation with studies on chimpanzee behavior. Still, I think it's a really interesting study, and I think it's really likely that chimpanzees have a mental butt template that is similar to our mental face templates that allow us to recognize faces. The study authors also speculate that as humans developed more upright postures, we switched from being interested in butts to being interested in faces. I mean,

obviously a lot of people still like butts. I'm not saying that people don't like butts, but faces became the primary target for recognition for sexual attractiveness, being able to determine someone was like, sexually mature, et cetera. They also speculate that faces may have evolved to fit the butt schema in terms of sexually attractive things, being similar to the same kinds of cues and butts that were sexually attractive. Like I'm not joking plump, red cheeks, red lips, and

symmetry all being attractive in both chimpanzee butts and human faces. So, I mean, to be clear, this is just these study authors speculating they don't really have evidence to show that human faces evolved to look like primate butts, But you know if you want to compliment someone by saying they look like a chimpanzee, but I'm not going to stop you. So in answer to the question, I would guess that, yes, I think chimpanzees probably do see butts in clouds, in

tree bark, I think they have paridolia. But for chimpanzee butts, I think it makes a lot of sense that if they are so primed for the pattern recognition of other chimpanzee but that they would see it in random patterns as well. They probably dream of butts. So you know, I think that that. I mean, obviously we cannot get inside the brain of a chimpanzee. No for sure that they see butts in these patterns, but I would guess

that they do. So we're gonna take another quick break, and when we get back, we're gonna answer another listener question. Next listener question, Hi, Katie, this terrifying wasp landed in my pool today. I live in Utah. Do you know what kind of wasp that is and why it needs a three inch long stinger? My kids won't go outside anymore. By the way, Love the podcast, been listening faithfully since you began. Thanks Tim f Hi Tim, So, good news, your kids can play outside without worry, at least when

it comes to this mystery bug. So let's talk about this mystery bug. So Tim sent me a photo of what looks like a wasp with a frighteningly long stinger, like longer than a flu shot needle. Also very thin, So overall, this is an extremely menacing looking wasp. It's you know, fairly big too. It's not not a little tiny thing it is it looks like if it stung you, you would be having a real bad time. But here's

the good news. This is not really a stinger in the same sense as we're used to on like honey bees or wasps that can sting you. This is actually an ovipositor. So an ovipositor is a long tube that is used to deposit eggs. So this is indeed a wasp. The bug that Tim sent me photos of, it's a species of ignumind wasps. They are actually parasitoids, meaning they lay their eggs in or on a host organisms and the eggs and larvae benefit from the host while also

harming and eventually killing the host. So, based on the photos Tim sentmi and the fact he lives in Utah, leads me to believe that this is the giant ignumind wasp also known as Megarisa macarus. It sounds menacing, but you actually have nothing to fear unless you happen to be a pigeon trimix horntail. So a pigeon trimix horntail is not a bird at all, but actually another insect. So horntails are in the order Hymenoptera, so they are related to bees, wasps, and ants. They look a bit

like a wasp, but without the hourglass figure. Uh. They use what is basically a drilling tool on their posterior end to bore into soft, decaying bark on unhealthy or dead trees. This drilling tail is fascinating in that it has microscopic interlocking valves with teeth that help drill into the tree bark by basically stepping forward and catching on the wood as it goes in. So it also uses a separate tube, the ovipositor, to lay eggs in the wood.

So here's where the giant ignumenoid wasp comes in. She detects the larvae of the horntail living in the wood, then she lifts her posterior, and her ovipositor is actually too long to start drilling in the wood. If you've ever sort of tried to use a tool from a weird angle, you'll know what I mean. Uh So, she has to coil up the ovipositor like measuring tape in

a special expandable sack on her posterior. So then when she's coiled this up, she shoves it into the bark and starts boring into the wood, and the ovipositor win unwinds as she bores. It's kind of like a drain snake. At this point, you can probably tell I do a lot of home maintenance. So not only does her ovipositor lay eggs, it does also inject venom, so luckily not into humans, but into the larva of the horntail. This

doesn't kill the larva. Even worse, it paralyzes it, so the wasp can lay her egg on the now frozen larva, and when her egg hatches, her larva feeds on the immobilized horntail larva with no resistance. Since the larva of the horntail is still alive, it stays fresher for longer as the wasp's offspring slowly eats it, it will eventually kill it once it has eaten enough of it. So if you're a horntail, giant, igneumenoid wasps are indeed terrifying

and that long ovipositor is a sign of death. But to humans they are completely harmless and they do not use their stingers on people. So unless you've been cosplaying as a dead tree for too long and a horntail has laid its eggs in you, then maybe yes you should be worried, but otherwise normally know they present no harm to humans. Interestingly, the stingers that we know from bees and wasps who can't sting us are actually evolved

forms of the ovipositor. So the ovipositor apparatus evolved into the stingers that we know and love maybe don't love that are on bees, wasps hornets that can sting us. So the venom will actually instead of depositing eggs in this instance, when it be or a wasp or hornet

stings you, it will deposit venom. And so it's an interesting thing to see this ovipositor in these ignominoid wasps because it is kind of like you have have like a stinger action going on because it does paralyze the larva host with venom, but it also is working as an overpositor to lay its eggs onto the host. So very interesting stuff. Thank you so much for sending me this picture, and thank you guys so much for your questions.

If you out there have a question a bug you're terrified of that you found in your backyard, I want to say hi, send pictures of your pets. You can write to me at Creature Featurepod at gmail dot com. I'll be answering the mystery animal sound game question next week, so stay tuned for that if you are interested in finding out what that mystery animal sound was from last

week's episode. And also thanks for bearing with me. If you notice my voice is a little huskier, a little a little more gravelly, I'm getting over just like a little cough, a little sore throat, so my voice should go back to normal unless it's permanently now really husky and gravelly. Who knows. Anyways, Thanks guys so much for listening, and thank you to the Space Cossics for their super awesome song XO. Lumina. Creature features a production of iHeartRadio.

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