True Facts: Snake and Lizard Tongues

bob there's something out the window no i'm not making it up bob it's can you come here bob bob let's back up a bit do you like tongues well if you do you'd like the work of dr kurt schwenk that's a good science name schweink now dr schwenk is no run-of-the-mill amateur tongue man you might meet in a bar no dr schwink goes deep he's been studying tongues for decades no jerry it's not a fetish if a scientist does it it's an area of interest in particular dr schwenk has been fascinated by reptiles in the order squamata this includes all jerry do we have a different shot this includes all lizards all snakes jerry that's not a snake i know it's on its belly but it has legs jerry all right it includes all lizards all snakes and the emphys beanies the worm lizards which is apparently a thing all of these animals arose from a common ancestor but as they evolved they didn't all quite agree on what exactly the tongue should be used for now the early tongue was sort of a basic swallowing assist but the ancestors of the squamates asked evolution if there was time for a modification evolution was like oh yeah there's time and so they said we'd like to wait for it smell with our tongue cough really alright we'll figure it out but the snake ancestor pulled evolution aside and said i'll give an arm in the leg to be the best at it and that was the start of the negotiation but by the end of it the snake had a tongue that was 100 percent committed to a kind of smelling wait how do i swallow the snake said evolution winked oh you'll get the hang of it so the snakes evolved a tongue that is long and thin and smooth it is deeply forked and each time tapers to a microscopic tip that may or may not look like a stone age sex toy some lizards like the monitor lizard devolved a very similar tongue but with one very interesting difference which we'll get to in a minute now we say that these animals smell with their tongues but that's sort of like saying people think with their dicks it gets you in the ballpark of a behavior pun intended but it's not really true like most squamate tongues these tongues are used to sample molecules on the ground in front of them but these forked tongues have an advantage the tines spread apart and allow them to sample two different points one to the left and one to the right in a single flick they can sense the difference between these two points this allows them to sense the edges of a trail they are following it's sort of like they can smell in stereo here's the thing though these tongues are more like fingernails they don't sense anything directly they have to transport these molecules to two little holes on the roof of their mouths which lead to the vomero nasal organs now i know what you're thinking you little smarty nipple how do tiny molecules on the bottom of the tongue tines get a little holes in the mouth on the top and how do they do it while keeping the two signals separate so they can smell in stereo and here's the other thing when they open up their mouths you might be wondering where the hell'd the tongue go it disappears into a hidey hole sheath like a dog's erection it's not that big hole that's the glottis a tube that allows them to breathe when they're deep throating a squirrel's butt here you can see one of the tines beeping out the sheath and yes that's dr schwenk's blood right there he's a badass so here's how they do it it's pretty obvious isn't it it looks like one of those ink plots that the brain witches make you look at and they say there's no right answer but it's always a demon with horns can't fool me brainwitch anyway here is the tip of the tongue above it are the ducts that lead to the vomeronasal organ and below it are salivary glands and you can see that the tips rest in these little grooves here's a slightly more simplified version there are grooves on the bottom of the mouth lined with salivary glands the tines rest in these grooves and as the mouth closes it creates two separate channels a further squishing forces saliva in each of the channels up and into its own duct but in that process saliva washes over the tines and releases the molecules to be sensed and that is how they can smell in stereo now snakes do something that other fork tongue lizards don't do they flick their tongues in the air in a repeated oscillating up and down movement you try try flicking your tongue up and down very quickly when humans do this it's called an hr violation but why do the snake do dr schwenk know why they seem to have figured out how to sample molecules in the air in a way that still lets them sense the difference between concentrations on the left and on the right if you farted in an elevator with a bunch of snakes they would all turn to you none of this smelt it dealt it bull butt molecules in the air are all mixed sorry but molecules in the air are all mixed together so dr schwenk wanted to know how they did it he had a snake oscillate its tongue through a bunch of floating particles illuminated by laser light during this little snake rave he noticed two pairs of vortices little spinning pockets of air two on top two on the bottom these spin in such a way that they pull in air from the left and from the right and then shoot it upwards or downwards between the vortices this creates two distinct columns of air through which the tines move these streams of air allow the tines to collect molecules from the left and from the right at concentrations that can be sensed so the snake has that going for it now meanwhile there was a bit of a kerfuffle with the skinks the skinks have lovely tongues a bit wider not forked and its surface is covered with overlapping scale-like papillae making it very smooth good for sensing and tracking prey but also for swallowing a nice balance but there was this one punk always sucking on blue raspberry jolly ranchers until it became permanent let that be a warning she wanted more help catching food because let's face it those little hands are useless so the blue tongued skink evolved a tongue that has the ability to deform itself into a kind of prey mitten it also produces a thick mucus to make that smooth surface stickier think sinus infection but in your mouth are the new viewers gone yet now when the word got out that you could use your tongue like this well the iguanians wanted to go all in the iguanians include iguanas but also many other species of lizards all of which have evolved tongues highly specialized for capturing prey they still use the tippy tips of their tongue to sense the world by licking it like it was a postage stamp from the 80s but when it's time to eat they roll that part back and under this exposes an area of the tongue which is a marvel of engineering instead of being scaly and smooth it's bumpy and looks a bit like a snowman's baby maker these are covered in a forest of finger-like papillae and the tips of the papillae are covered in the shag carpet of plumos cells but this is a shag carpet of doom these papillae can stick to prey through wet adhesion now you've probably experienced some wet adhesion not like that you perv you've experienced this if you've tried to separate two surfaces with a thin layer of liquid between them you perv i know what you're thinking you naughty bunlet why have so many why not just have a single giant papillae well this is because the resistance to being separated has to do with the tendency of liquids to form this curve or meniscus around the outside of the contact area therefore the resistance is proportional to the circumference and not the area of contact it's quite a compelling graphic isn't it having lots of small papillae gives you more circumference in total and therefore more resistance now once contact is made the prey is pulled back incredibly quickly although it is totally the prey has inertia on its side which resists the sudden acceleration the papillaes stretch and absorb some of this force before their adhesion breaks but there's a backup plan a special watery stringy mucus that gets stiffer under tension holds onto the prey through the violent snap and because of all this there is very rarely a miss now this cricket already thinks it's having a shitty day it gets worse wait for it told you in the same way that the snake went all in on the sensory tongue there is one iguanian that took tongue precapture to the extreme the chameleon has a tongue that acts like something between a slingshot and squeeze popping a watermelon seed between your finger and your thumb prior to the shot a series of muscles put tension on collagen fibers and like stretching a rubber band this stores potential energy which is then released in an explosion of tongue chameleons can so accurately sense the distance to their prey that just prior to contact a dimple forms on their tongue ball although they are equipped with iguanian papillion mucus to hold on to the prey they also make use of this tongue glove to wrap around it and hold on this is necessary because on the way back things get a little floppy it's like when you feed out a tape measure just a little too far or take half a viagra so if someone tries to impress you by tying a cherry stem into a knot you just say big deal what else can your tongue do no that's suggestive isn't it big deal how fast can you flick it nope that's how about call me when that thing's covered in mucus that's good [Music] no i told them that i was working on something called taste but they wanted to smell with it no i hear you it's crazy oh and i forgot to tell you about the gecko you know what it said it said it wants to lick its own freaking eyeballs so i asked why and it said it doesn't want eyelids anymore you know how long it took me to make those i mean sometimes i don't even know why i'm putting in all this effort lick your eyeballs why don't you go ahead and lick your i mean at least our tongues are normal not like all those tongues [Music] you

Channel: zefrank1

Views: 1,589,739

Rating: 4.980854 out of 5

Keywords: true facts, true facts, squamata, chameleon, snakes, agama, bearded dragon, skink, blue tongue skink, iguana, horned devil

Id: wjuVq9BRNAI

Length: 10min 39sec (639 seconds)

Published: Tue Nov 17 2020

Reddit Comments

[u/guavaberries3]

that was a great video

[u/DickBoShaggins]

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