SciShow Tangents - Tails

Episode Date: January 17, 2023

From a bunny’s seemingly-useless fluffy li’l puffball to a scorpion’s practical and deadly venom-filled stinger, the world is filled with all sorts of wonderful tails! And heck, some of them aren’t even tails at all, but that’s ok!SciShow Tangents is on YouTube! Go to www.youtube.com/scishowtangents to check out this episode with the added bonus of seeing our faces! Head to www.patreon.com/SciShowTangents to find out how you can help support SciShow Tangents, and see all the cool perks you’ll get in return, like bonus episodes and a monthly newsletter!And go to https://store.dftba.com/collections/scishow-tangents to buy your very own, genuine SciShow Tangents sticker!A big thank you to Patreon subscribers Garth Riley and Tom Mosner for helping to make the show possible!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Ceri: @ceriley Sam: @im_sam_schultz Hank: @hankgreen[Trivia Question]Seahorse square tail segments https://today.ucsd.edu/story/why_the_seahorses_tail_is_square_and_how_it_could_be_an_inspiration[Fact Off]Swallowtail butterfly tails protect from attacking damagehttps://www.sciencenews.org/article/butterfly-wing-tail-loss-break-birds-escapehttps://phys.org/news/2022-06-evidence-butterflies-tails-distract-predators.htmlhttps://royalsocietypublishing.org/doi/10.1098/rspb.2022.0562Bird-of-paradise light-absorbing tail feathershttps://www.nature.com/articles/s41467-017-02088-whttps://www.allaboutbirds.org/news/new-vogelkop-superb-bird-of-paradise-changes-up-the-old-song-and-dance/https://www.theverge.com/2019/8/20/20813054/vantablack-ultrablack-black-material-surrey-nanosystems-carbon-nanotubes-science-materials[Ask the Science Couch]Evolutionary tail loss in some primates (apes)https://www.science.org/content/article/jumping-gene-may-have-erased-tails-humans-and-other-apes-and-boosted-our-risk-birth-defectshttps://www.biorxiv.org/content/10.1101/2021.09.14.460388v1https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263034/https://pursuit.unimelb.edu.au/articles/why-don-t-humans-have-tails[Butt One More Thing]Ant head mimicry on wasp tail/metasomaImage: https://www.researchgate.net/figure/Posterior-metasomal-tergites-and-ovipositor-of-Clistopyga-caramba-sp-nov-holotype_fig2_281632324https://www.biotaxa.org/Zootaxa/article/view/zootaxa.4013.2.9https://phys.org/news/2021-09-segments-scorpion-metasoma.html

Hello and welcome to SciShow Tangents, the lightly competitive science knowledge showcase. I'm your host, Hank Green. And joining me this week, always is science expert sari riley hello and our resident everyman sam schultz hello this is our first recording after after uh returning from the break that's not going to seem like it to you but we do things all out of order here on sideshow tangents so we're we we recognize that we're a little rusty so we spent the first 10 minutes just talking one of the things we talked about was the fact that sam i think thought that panic at the disco was a panic at the disco song is that right i don't actually didn't i didn't think

that until you said that it maybe was and then i looked it up and it wasn't it does sound like they would have a song called that. I think I was the one who said it, to be fair, and to, like, lampoon myself. Is this a good Weird Al song, Panic in the Discord? Which it would be if Panic at the Disco were a song, which unfortunately it's not. Sometimes Weird Al does those mash-em-ups of a bunch of songs, you know? He does, like, his polka thing. So his polka song for a new album, Weird Al, hit me up if you're listening.

I'll help you write it. Is Panic in the Discord. And it's all Panic at the Disco songs about the internet or something, I guess. Oh, so he polkas and he actually does a parody in the polka which he doesn't usually yeah which he doesn't usually do i love that i love that and uh and it's like a five minute song that's just i could not name for you a panic at the disco song i'm gonna lose fans with that do they do high high hopes is that them what'm thinking is, When I was a young man, my father took me into the city.

That's not Panic! at the Disco? No. I don't actually know. Welcome to the Black Parade. That's fans called Welcome to the Black Parade. No. Yeah. Everyone who's our age is yelling right now.

Yeah, they are. They're yelling at their kids that's my chemical romance. My chemical romance. That one. Of course. I apologize. Now I really will lose fans. I have no idea how related those two bands are.

They seem like they'd be best friends or worst enemies. I don't know which one. Just remember I'm 42 years old. I listened to very cool music before My Chemical Romance existed. But not since. But I do think it would be cool if every band had to write and perform a song that was their name. They Might Be Giants have a song called They Might Be Giants. So my favorite band fulfills this rule.

It's just called They Might Be be giants and the lyrics are largely they might be giants over and over again that's fine yeah even if a band's um theme song as it were yeah is just them singing the name of their band over and over and over again i would accept that as a as a valid entry into it the better ones will be like a great tv show theme song where there's some backstory you get a little bit about each of the members maybe you get the vibe of the band yeah some history just packed into a 30 second jingle that really is an earworm yeah i don't know i don't know what's going on what i missed on this band if i was showing up to this concert and i knew

nothing i desperately need that, apparently, for My Chemical Romance and Panic at the Disco. I need them to have written that song. Sarah, have you heard the Monkees theme song? No, I have not. It's literally what you just described. Hey, hey, we're the Monkees. People say we monkey around.

I'm an innovator. That's all you need to know. But we're too busy singing to bring anybody down. That's the vibe, right? We're just having a good time singing. We would never be mean. That's like a pretty good vibe to go into as a band. We're not mean.

We like to sing. I know so much about the Monkees now, never having heard a single one of their songs. And I bet I would know even more if I actually listened to it because then I know what their music sounds like. Yeah. So I think this is our new podcast where we come up with theme songs for all the bands. I like that. We write.

Tuna will write the music to it. Oh yeah. Just put it on Tuna. A full song in the style of every different musician that's ever existed. I want to know. So hit us up on Twitter where I will get secondhand information from someone with any other bands that have written their own theme songs. I think that if you're My Chemical Remnants,

it's a little bit too, like you're trying to be very, you're trying to be pretty cool. And it's not very cool to be like, My Chemical Romance, we're just a couple of bros, man. And just like going, and then like naming each of the bros. I think that was really cool. I think that'd be great. Yeah.

Let's look at who the bros in My Chemical Romance are. Their names all rhyme so perfectly. Come on, guys. They do. There's Gerard Way. There's Ray Toro. Ray rhymes with way. And then there's Frankie Arrow, which rhymes with Toro. And there's Mikey Toro Ray rhymes with way and then there's Frankie Arrow

which rhymes with Toro and there's Mikey Way which rhymes with way and Ray you're just leaving money on the table folks it writes itself the theme song

writes itself come on and Hank Hardy wrote the first line Gerard this is unacceptable that you haven't done this yet I know Gerard listens to the podcast

because he is a huge dork from everything I've ever read or heard about him. So I assume that he's going to take our advice. Every week here on SciShow Tangents, we get together to try to one-up, amaze, and delight each other with science facts while also trying and failing to stay on topic. Our panelists are playing for glory and for Hank Bucks, and I'll be awarding those as we play.

And one of them at the end of the episode will be crowned the winner but first as always we're going to introduce this week's topic with the traditional science poem this week is going to be from sari we're my chemical romance i need some help and here's the thing What's the word for a sort of biological string? It's outside, not hidden within the gut, and tends to stick out behind the butt. Some are twisty and long and free to wrap around some grass or the branch of a tree. Some are strong and stout and flat to paddle in water or compress a mud mat. Some are fluffy and point up towards the sky.

Others hang down unless they're swatting a fly. It's not an arm or leg or wing or hoof. It's on creatures that honk and on critters that woof. And lots of things don't have one at all, tucked away with the spine, vestigial and small, or it never evolved. Their body just ends in a hard or soft casing that doesn't extend. It's really bad luck that

my brain chose to fail at recalling the name of this appendage that trails behind whales and whales and horses and dales oh well let's see what this podcast entails wow that was like the platonic idea of a science film that was so good yeah the topic of the day is tails which i predict is going to be undefinable yeah it's gonna be a hairy one for sure yeah because there's there's all kinds of things that like sometimes the tail is just made out of feathers sometimes the tail is made out of chitin or like a like a scorpion has a tail but like does that count even a must right but that's a totally different sort of like biological thing than like the extension of the vertebra uh like the extension of the vertebral column that is

is like a mammal tail or a vertebrate tail that's the the divide and that's where it gets finicky is how precise do you want to be with your language when you're talking about tail and for what purpose are you are you saying the word tail if you just mean the thing behind the animal the tail will do probably for so many different things the whether it's feathers or the back part of an insect. Kind of like how we use butt for the butt fact. It's just like, it's the back part. It's a butt. It's the sticky-outy part.

It's a tail. It's anything that's close to butt-like. So is it kind of sticky-outy behind the back end of an animal? It's a tail. Does a snake have a tail? Eh, kind of. It's there. A snake definitely's a tail it is a does snake have a tail it kinda it's there it definitely has a tail like it has like a part of the body where the digestive tract ends and then there's like just it's then it's just muscle and bone like it doesn't anything like you definitely don't

have intestines in your tail right but augusta worm does Is a worm just one tail? Where's the two of worms butt? Is it at the other end? It's right at the end. Yeah. So I wouldn't think that he'd have a tail. As I believe we have said on the podcast before, worms are just an intestine. It's a digestive tract. Yeah. Right. So I don't think worms have a tail. I think it has to be after your butt to be a tail. Post butt. So I don't think insects have butts that have tails.

Yeah. And then a scorp scorpion tail its anus is at the end of its little it is a little bit yeah so technically they don't i would have said it was like a snake yeah yeah where there'd be a pooper and then the tail would go out but it poops out of its stinger and pooper do they poop on their heads or do they point it behind them they can point that thing wherever they want they sometimes probably poop on their heads when they want to oh shoot yeah they can do it wouldn't you do it sometimes if you could no just once to see if you could what it felt like all right we'll do it we'll do a quick poll of the audience if you had a tail that could reach your head would you poop directly onto your head just once? As a baby,

I would have. As a kid, oh, absolutely. Like, when I had no control and I rolled around in mud for fun, I would absolutely poop on myself

just once. Oh my God, there'd be a name for it. It'd be like, oh, little Jimmy had his first head turd. First and only,

I hope. So I'm satisfied that we're not even gonna get close to the bottom of this one no i can try a little bit harder to get a little bit okay away from the bottom if you want to do it in terms of bone and skin and muscle then the we have different types of vertebrae in our spine like for example the cervical vertebrae are in your neck and then the thoracic vertebrae in our spine. Like for example, the cervical vertebrae are in your neck and then the thoracic vertebrae anchor your rib cage. The lumbar vertebrae are in your abdomen. The sacral vertebrae are with your pelvis. And then the caudal, C-A-U-D-A-L vertebrae are the tail vertebrae. And so in humans and other tailless primates, they are called the coccygeal vertebrae. They are fused into the coccyx, which is your tailbone. But in other,

like in a cat or a dog or a lizard, then the caudal vertebrae are what make up the interior of the tail. And so if you want to dive in zoologically and try a little harder to define tail, then it includes the caudal vertebrae and then some sort of muscle skin tissue wrapped around the outside. And by that very narrow definition, then you need to have a spine.

So with vertebrate cilius, we can kind of say, do we know where the word tail came from? As far as i can tell and as far as the oxford english dictionary can tell uh it just came from hindmost part of an animal like it it meant that okay all the way back to old english so it's just a word old germanic yeah but but like a hairy butt kind of. So the primary sense seems to have been like tuft of hair, as opposed to like the hairless tail of a scorpion or a bee or something like that. But where that etymology shifted is kind of mushy. And another word in addition to tail that they used for tail as like the tail end of something was start which i thought was really interesting so the tail of an animal was called the start so

you're just like ah the animal started there uh and that little ropey thing is the tail of an animal yeah that's very confusing that's not that doesn't seem right at all opposite of what they are supposed to be well i feel like i start up at the top but i don't know where do i start anyway i think this might be time for us to do the game do you guys want to do the game okay yeah okay we're gonna be playing a game called where's the lie uh in this game i'm going to be describing to you a you in a few sentences something kind of science-y. Some kind of science-y story thing. And it will be true, except for one thing.

And it's up to you to figure out what the untrue part of my science story is. It's tricky. It's like you're going to well actually me, right? You'll be like, oh yeah to well actually me, right? You'd be like, oh yeah, that's close, but not quite. So round number one, we're going to start with the fat-tailed dwarf lemur of Madagascar. And it depends on its fat tail as a way to survive its hibernation periods. The lemur usually weighs about four to 10 ounces, but to prepare for torpor, its hibernation, weighs about four to ten ounces but to prepare for torpor its hibernation the lemur will eat fruits and nectar to double its weight and roughly 60 percent of its total body weight

during this phase will be in the lemur's tail providing a fat store to keep it alive as it rests in tree holes or in underground burrows what was the lie the the 60 i bet it's more than 60 of its body weight you are right that it is that part of the fact okay but you should have shut up there uh but i'll give it to you it is in fact 40 uh it's less than 60 of its body weight that is correct no sam gets it um so the tail ends up being 40 of the total of the lemur's total body weight 60 will be a lot more than 60 will be a heck of a lot but who knows it doesn't even sound very impressive anymore how fat is that tail that's not that fat come on fat-tailed lemur i've seen fatter tails so uh madagascar doesn't get very cold so you'd think maybe they wouldn't need to have hibernations

but droughts can drive a lack of food that requires animals to conserve energy and dwarf lemurs are the only primates on madagascar known to deal with this by hibernating, and they rely on their tails to do that hibernation. They might breathe once every 10 minutes during this hibernation and have a heartbeat of just six beats per minute. And it can last for up to seven months, though they will take breaks to reset their heart rate and their body temperature sometimes during their little torpor period. Wow. Cool. And they're really cute, too. So, round number two. In the 1970s, researchers studying a Persian gecko

found that it had an oval-shaped growth on its tail with long scales coming off of it. Since then, scientists have learned that the strange growth on its tail is a spider-shaped lure meant to draw in birds and other prey. This method of attracting prey with one's tail is called caudal lure luring uh just like sari said c-a-u-d-a-l caudal and it's found in other animals

like the common death adder which decor on its tail is too scary. Because if I was a bird or a predator or something, I would be scared of that. And so maybe it looks more wormy instead? Maybe more wormy than spidery. Is that the lie? That's not the lie. Sam! Oh oh okay this is a death adder thing the lie something about that does it not does the death adder not do that okay nothing to do with the death adder sari what do you have okay i'm still fixated on this growth uh there were not

scales coming off of it they were like um nodules or whatever is inside of intestines but on the outside like skin skin tags super floppy instead of hard and scaly that's terrible no that's not it uh it's not the purging ge. It's some other kind of gecko. Oh, God. Say that. It's just very, that's very close. Not even another kind of gecko. It's just some other kind of guy. Totally.

Yeah. Well, it's not a Persian gecko. It is, in fact, a Persian horned viper. So it's a kind of snake, not a kind of lizard. But I'm not going to give that to you, Sam. So the Persian horned viper in the 1970s the growth seemed like a like an unusual thing but they weren't sure if this viper was like a separate species but it wasn't until 2006 that scientists were able to determine that they had actually

been watching a different snake species which they named the iranian spider-tailed viper so it was none of it was true it wasn't a persian gecko or a persian viper but we thought it was a persian viper for a long time uh and it turns out it is a separate species that has its own little tail lure the researchers actually put a couple of these vipers in an enclosure with a bird and that when the bird was around they would wiggle their tail to make it look like a crawling spider and trick the bird into attacking it so that the snake could attack the bird. What a nasty guy. That does more sense than a gecko trying to do it.

Because a gecko can't do anything about a bird. Yeah, the bird would just be like, hell, I'll eat you too, I guess. Yeah. All right. Round number three. All right. Round number three. Ring-tailed lemurs live in Madagascar,

and they get their name from, of course, their tails, which are decorated with 13 bands of black and white. The tails, it turns out, are useful for maintaining their home. When traveling as a group, the ring-tailed lemur will keep their tail pointed into the air as a flag that keeps everybody together. And when potential rivals enter their territory, the lemurs will use their tails to whisk dirt into their rivals' eyes. That's really cute.

It's cute, but it's also kind of down dastardly. It is kind of a dirty trick, isn't it? You can't just throw dirt in people's eyes. See people's face, yeah. Hmm. I have heard the thing about their tail leading people like like keeping them together but maybe that's not true so i'm gonna guess that first is not true the tail you're wrong you're wrong that's real okay i think that they don't spray dirt at their enemies that feels inefficient

maybe they like their tails are really long maybe they like if they're prehensile they like, their tails are really long. Maybe they like, if they're prehensile, they like chuck objects at them or like whack their enemies or do something else with their tails. You've got it pretty much spot on. So they do not use their tails to whisk dirt into their rival's eyes. But when a rival lemur encroaches on their territory, the male ring-tailed lemurs, what will they do to get them to go away? They'll just shake their tails at them oh that's apparently enough uh instead uh it's actually to uh throw smelly compounds into the rival's face so there's not there's no uh there's no kind of a fart attack it's a bit of a fart attack okay The male ring-tailed lemurs have glands on their wrists that they can use to produce chemicals that vaporize in the air. And the males can use those glands to mark trees.

But they also rub their wrists on their tail. And then they shake their tail to release the chemicals as a smelly message to the rest of the world. And during much of the year, lemurs will use a set of chemicals that are bitter and leathery smelling to warn off males. Imagine if Spider-Man couldn't shoot webs out of his wrists, instead had to like rub it on his tail. He's got stinky wrists. That's all I can picture now. Yeah, well, I mean, I don't really understand why spider-man got his spider glands on his wrists instead of the butt instead of his butt he didn't he has to make web shooters he just has them on

his wrist he does not have organic web shooters that's a great noise sam you're kind of far away from the mic i don't know if everybody else heard it I mostly just didn't want to have to say it, but. It's like you've said this to us before. No. I'll say it again. I've said it before. I'll say it again. I was more embarrassed for myself that I was about to say it.

Oh, I thought you were embarrassed for us. No. I didn't want to know it, but I did know. Well, that leaves us with Sam and Sari tied at one point. Next up, we're going to take a short break. Then it'll be time for the Fact Off. All right, everybody. all right everybody welcome back get ready for the fact off our panelists have brought science facts to present in an attempt to blow my mind and after they have presented their facts i will judge them and award hank bucks any way i see fit But to decide who goes first, I have a trivia question. While most animal tails have cross sections made up of circular or oval segments,

seahorses are unusual in that they have tails made up of square segments. These squares make their tails stiffer and stronger. How many square segments make up a seahorse's tail? 13. I'm just going to throw out a number. That's a number. That feels like an okay number. 20.

They have 36 segments. Sam, you get to decide who goes first. I will go first. So kites have tails, as we know. And the purpose of those tails is to add some weight and stability to a kite to help it stay stable as they swoop and soar through the summer sky and several species of butterfly especially butterflies in the swallowtail family also have tails trailing off of their wings and you might think like i did that those probably help the butterflies also swoop and soar through

the summer sky similar to a kite's tail i didn't think much more of it and that also was apparently what scientists must have thought because at least according to a quote i read nobody really seemed to have done a deep dive into what butterfly wingtails did until a paper was published in may of 2022 with some convincing evidence that they acted a little less like kite tails and a little more like lizard tails So many lizards famously are able to drop off their tails when escaping danger, which sounds not super fun, but more fun than having your head bitten off. And for that matter, some lizards have brightly colored or patterned tails to encourage predators to target their tails over more vital parts of their body. So their tails just look delicious.

So based on that concept and the knowledge that butterflies also use wing coloration to draw attacks away from their main body parts, a group of scientists began to wonder if a swallow tail's tails were another part of their predator escaping toolkit. So the first thing they did was go out and catch a bunch of swallow tails. And what they found was that 47% of the swallow tails that they caught had damage to at least one of their tails. So that was a pretty promising start. to at least one of their tails so that was pretty promising start uh the next step was to glue some real butterfly wings onto fake butterfly bodies on sticks and then wiggle those around in front of a bunch of uh wild great tits that they caught which looked really goofy and and fun and the birds attacked the dummy butterflies and the scientists took a look at where they were taking

chomps and they found that 73 of the chomps were out of the back wings and about 40% of those attacks were centered around the tail, which made the tail the most attacked part of the butterfly wing. And last but not least, the researchers tested how hard it was to rip different parts of a swallowtail's wings apart. And they found that the vein that the little tail has inside of it was the most fragile part of the wing. So it's easiest to rip off. And that all sounds like pretty good evidence to me and there's also research that suggests that spiders might mistake certain butterfly tails and wing spots for their antenna and head so they think that the butt is the head of the thing and while it's not explicitly stated in the paper a little conjecture for me birds might similarly be making that same mistake trying to eat a butterfly's head and actually just taking a little snip off its butt because

they're stupid sam also has a theory yeah that's really cool that moss have the tails too but they use them for completely different reasons they're like baffling that they're like baffling bat sonar and oh they like make the signal of the else okay yeah that's wild i love that i had never thought of it you know like you look at a butterfly and you don't think what's the purpose of this beauty you just think that's pretty um but of course they're not pretty for us that's really cool i love that that's a good one sam thanks sarah what do you got so while they're not pretty for us. That's really cool. I love that. That's a good one, Sam. Thanks. Sarah, what do you got?

So while they might not be direct extensions of the spinal cord, I had to put that copy out. Sam's weren't even close to actual tails. So many bird species have really fabulous looking tail feathers called retrices that can be precisely controlled by muscles. Their tail feathers can help with all sorts of things from stability and steering during flight to elaborate mating displays. And the male superb bird of paradise and vogelkop bird of paradise both use their long voluminous tail feathers for these wooing purposes the superb species splays out its feathers to form an elongated oval while the vogelkop species forms a crescent shape instead so like an oval with the bottom cut out but what's more impressive than the shapes of their tail feathers is the color of them specifically their black feathers

have thick dense almost tree or seaweed like barules, which are those horizontal keratinous structures that make a feather feathery, that scatter light so intensely that the inky black color approximates human-made ultra-absorbent black materials. And according to measurements in a study published in January 2018, these super black feathers can absorb up to 99.95 percent of directly incident light and from what i found the various carbon nanotube structures and material science labs have achieved around a maximum of 99.96 percent to a max of 99.995 percent absorption which is pretty good uh and even when these bird of paradise feathers were coated with a reflective metal like gold, they still remain black because of how the barbules bounce around light, which is very cool. Who did that research? Just like, like nano deposit gold on a, on bird feathers just to see what happens?

Same study. Yeah. That, that January, 2018 study, they took a black feather from a different bird and black feather from this bird and then sprayed them with gold. And as with many extreme visual adaptations, scientists think that these tail feathers are so light, swallowingly black

in order to highlight a couple of bright blue feather patches during their mating dance, which end up looking kind of like a haunting smiley face in a void. It's very weird. I highly recommend watching a video because it's very silly. They don't think so. They think it's extremely important and sexy.

Yeah. Yes, to my human eyes, it's like, what are you doing? You've got a void and then some blue pinpricks of light. And scientists have tried to mimic the structural color of a variety of animals, including certain butterfly wings, extracting blackness from them. So we could probably learn a thing or two about these tail feathers that could give telescopes or other optical engineering feats a boost. It's also cool that it's not about, you can coat it with gold and it's still black because it's not about the color that the substance itself is. There's something, there's like an effect on photons where they can't get out. And that's why it looks black.

That's cool. You guys are tied too. So now I really have to pick. So I have to think about, and they both make good TikToks. Sari, can you find me a picture of the gold feather next to the not gold feather, but that both have been sprayed with gold? I can find you pictures of butterflies. I know they are good.

Butterflies are good. I mean, there's one in this paper, but I don't know if you can use whatever you want on TikTok. I don't know how. Yeah, I don't have a rights Bible. I own. That's so cool. That little carbon, that little electron microscope image, too.

That's freaking dope. All right, Sari, congratulations on your win. Ah, damn it. And now it's time to ask the science couch where we have a listener question for our couch of finely honed scientific minds. Ariandia on Discord and at Alexandre on Twitter asked, why did we lose our tails? I'm sad I don't have one. Are you sad you don't have one, too? I think I am sad I don't have one, but I don't know.

I might be really gross, too. I think I'd only want one if everybody had one not to be a conformist but yeah i don't like if i had like a really awesome pre-insult tail and it was super useful i kind of still wouldn't want one if i was the only one um can i say on something that is not an answer to the question yes thank you um i think that it will be pretty easy if we want to to give people tails in the future robot or organic tails organic tails just like you know yeah germline engineering you gotta like just change change the change the genes i bet i bet it won't be hard to unlock the tail i bet it's all still in there people are gonna want tails too if avatar 2's box office is anything to go off

you know i don't think our tales really like paying you for that i don't i don't think that our tales will be as um elegant or multifunctional as the Avatar tails, though, unfortunately. That's sad. Yeah, I don't actually know why tails were enough of a disadvantage. Does it have to do with bipedalism? No, chimps don't really have tails.

They have a little thing, don't they? Do they just get too big? Because gorillas don't have tails, so maybe there's a certain size thing. I think they have nubs as well. No, I think gray apes, which I think a gorilla is one of, has similar genetic mutations as us that do not have tails. So the rationale behind it is still up in the air.

Why there are monkeys with tails and gray apes without tails, why that split happened and why it was evolutionary advantageous enough. We're not sure. A lot of people point to bipedalism or just general mobility, a tail while it can be helpful. It can also get in the way. Um, some people, there are like a couple small theories out there that may have to do with

like aggression. So as great apes get bigger, then the tail becomes another thing you can like yank on or or get at if in conflict that happens in avatar too they should have learned they showed us what our our current uh state of being could be. But what is interesting to me, and I don't think was really substantiated until recently, until 2021, around September when a paper was published, the tail disappeared quite fast in evolutionary history it was probably just one main mutation that switched from having a tail to not having a tail so your unrelated thing is actually very related because we could probably switch back to having a tail if we could like get

in there and change this this gene mutation so my my sense was correct. Yes, more correct than maybe you even knew. Where there is a gene called TBXT. This is getting into more intense genetics. So the names are all mushy and not as fun as Sonic the Hedgehog or whatnot. And there's basically a short DNAna insertion it's called an alu element there are a bunch of them throughout our genome a lot of them are just nonsense there's a lot of junk dna and throughout the genome but if you have a sequence like an alu sequence and then a reverse sequence kind of like two magnets on a string it'll like stick together and then a reverse sequence, kind of like two magnets on a string. It'll stick together and then mess with the translation

and transcription of that one part of the gene. And so what happened was there was an insertion, an ALU insertion, that messed up our TBXT gene, which is related to tail development. Do we know if this is related to when people do have tails? Because sometimes people do have tails. I don't think it is related to that. Okay. That's like a separate thing that's going on.

So, human embryos do sometimes develop in utero around like five or six weeks. So, really, really small still. A tail with a couple vertebrae in it but then it disappears by like eight weeks so it's some the the weird nebulous processing of human development it happens there but most tails that develop through birth are pseudo tails there are some sort of like teratomas which i think we've talked about before which is just like a cancerous mass of cells um and so there's like sometimes muscle and uh cardiovascular and other tissue in that um and i think it's just because of a concentration of stem cells around the spinal

area but it is not a true tale gotcha they're they're not innervated with the spine in that way they're just kind of like a flesh a fleshy mass um from what i could find in papers about it that makes sense and i like the idea that we lost our tails because we kept yanking on them that's doing we gotta get rid of these things to have a like handhold that's only good for hurting a person yeah we were too mean. We were too mean. Yeah, we were too mean. But the Avatar, people couldn't get rid of it because it does all that stuff. It's got a bunch of rolls.

That's their ponytails. That's not their tail. That's a different thing, Hank. Oh. There was that sigh again. There was that sigh again. I don't know if I should admit that I know this intimate detail about the avatars and avatars.

I thought it was their butt tails that they kissed with. No, it's their head, head's tentacles. Faith is super disappointed right

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Thank you for joining us. I've been Hank Green. I've been Sari Reilly. And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Sam Schultz. Our associate producer is Faith Schmidt. Our editor is Seth Glixman. Our story editor is Alex Billow.

Our social media organizer is Julia Buzz-Bazio. Our editorial assistant is Deboki Chakravarti. The sound design is by Joseph Tunamedish. Our executive producers are Caelan Hoffmeister and me, Hank Green. And we couldn't make any of this without our patrons on Patreon. Thank you, and remember, the mind is not a vessel to be filled, but a fire to be lighted. But, one more thing.

Technically, arthropod tails are the rearmost segment of their body called the metasoma, which includes classic bud anatomy like the anus or the ovipositor in certain species. And one of the most elaborate insect tails belongs to the wasp C. caramba, named after the Spanish exclamation, I caramba, because it was found in the University Museum Collection in Lima, Peru, and surprised Finnish researchers with its weirdness.

Specifically, this wasp has a super long metasoma ending in a dark-colored mass that looks scarily like an ant head with antennae, possibly to scare away spider predators or lure in prey. Either way, it has a butt head.

Very surprising. Enough to say, I has a butt head. Very surprising. Enough to say, I carumba. Like Bart would say. Bart discovered it, actually. They probably hid their identity. He did. He turned his life around and got into science, but he couldn't keep that one part of him at bay, the part that says, I carumba.

Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah.

Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah.

Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah.