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How Frogs Work | Stuff You Should Know Podcast (Transcript)

Length: 54 mins

Welcome to you Stuff You Should Know, from howstuffworks.com.

Josh Clark: Hey, and welcome to the podcast. I’m Josh Clark and there’s Charles W. “Rivet” Bryant. There’s Jerry “Budweiser” Roland.

Charles W. Chuck Bryant: [Laughs] Oh man, that’s a… Old call back. The Budweiser frogs.

JC: Yeah, man. They were no Spuds McKenzie, I’ll tell you that.

CB: I know. Remember when they were on their lily pads going, “Wassuuup!

JC: Oh, yeah, I loved that guy, those guys. Man, we’ve seen a lot of ads in our lifetime, haven’t we?

CB: We’ve recorded a lot of ads in our lifetime.

JC: We have, we’ve really been contributing to the pile. How you feeling?

CB: I’m feeling great.

JC: You’re feeling froggy?

CB: [Laughs]

JC: I’m really sorry. I had no idea this was gonna happen.

CB: I am feeling froggy and, right off the bat, we should go ahead and thank Tracy “TV” Wilson, Tracy V. Wilson. From Stuff You Missed in History Class, because this is one of her great, great animal articles.

JC: Yeah, she’s written the best.

CB: She really has.

JC: This one doesn’t contain the words “mouth…” What was it mouth?

CB: Mouthparts?

JC: Mouthparts, that’s right.

CB: [Laughs] Yeah, she tried to work it in.

JC: It got edited out, I think.

CB: [Laughs] That’s right.

JC: So we are, we’re talking frogs today, Chuck. I can’t believe we haven’t talked about them before.

CB: I know. I love frogs.

JC: I love them too and it’s sad for us then because it turns out that frogs, apparently, are going extinct at an alarming rate; entire species just dropping off the face of the earth. In fact, one species went extinct here in our fair city of Atlanta. Did you know that?

CB: Oh, really?

JC: Yeah, last September 2016, so about a year ago. The very last Rabb’s fringe-limbed treefrog died at the Atlanta Botanical Garden.

CB: Oh, wow.

JC: His name was Tuffy and, from what I understand, he didn’t like to be handled. That that was his choice, you know? So he was the last of it. The species was found, I think, in the late 80s or late 90s and we figured out, pretty quickly, that they were endangered, and the last one that was heard in the wild was in, I think, 2005. And so they thought Tuffy was the last one and so a frog species went extinct in Atlanta. And, apparently, that’s just one domino out of many.

CB: Yeah.

JC: That’s going on right now. There was a study from 2015 that concluded 3%, which is about 200 species, of frog species have gone extinct since the 1970s, right? Which is like, “Wow, that’s…” Seems like a lot. Prepare for it to seem like even more. You’re ready for this?

CB: Yes.

JC: So amphibians and reptiles have really high extinction rates as it is. They, apparently, have an extinction rate of about 10,000 times other animals.

CB: Wow!

JC: And frogs’ extinction rate is higher than most other amphibians and reptiles. So the frogs are going fast and the reason why it matters, besides the fact that we love frogs, is that they’re also known as an indicator species. They’re particularly fragile, they’re found all over the world, and they seem to be trying to tell us that the earth is going lopsided as far as the global ecosystem goes.

CB: That’s sad.

JC: Yeah.

CB: Remember, we talked about those and, I think, it was Charismatic Megafauna?

JC: Yeah, I guess so.

CB: All right. So, we might as well get into this. I almost said jump into this, but now I’m hyper-aware of bad frog puns.

JC: Yeah, sorry for everything.

CB: So Tracy makes a great point here. Talking about frogs, and if you just said there, what 3% of different species is 200?

JC: Yeah.

CB: So that shows you how many different species there are.

JC: Yeah.

CB: It’s difficult to kind of talk about frogs in one big sweeping way because they differ so much species to species. They can be, what is it, the Gold Frog is less than a centimeter.

JC: Right.

CB: Then you have Goliath Frogs.

JC: Oh, man.

CB: That are over a foot.

JC: Yeah.

CB: Head to tail.

JC: A foot? 32 centimeters?

CB: Yeah, a lot of them like to be out at night, some of them are more active in the morning and the afternoon, sometimes they live for a couple years, sometimes they live, well, not many, many years, but several years.

JC: Yeah. One of the main things that frogs are known for, which is croaking or ribbiting, it would seem like that’s universal; it’s not. There’s plenty of species that don’t make any noise.

CB: Yeah, you think of green or brown, there are pink frogs.

JC: Right.

CB: All kinds of colors, there are blue frogs. The difference between toads and frogs isn’t… We might as well just consider them one thing from what I can tell, right?

JC: Yeah, toads, true toads belong to the Bufonidae family.

CB: [Laughs]

JC: Pretty sure there’s a better way to say it, but it’s a specific family that belongs to the order ‎Anura, which all frogs belong to the order ‎Anura.

CB: Yeah.

JC: So toads are frogs. But even within that distinction, there are some things that are like, “No, that’s actually a toad.” Like, toads tend to have eyes that are lower on its head.

CB: Yeah.

JC: And more football-shaped, whereas a frog has eyes higher up on its head and they’re usually quite round, right? But there are certain toads that have those kind of eyes and there are certain frogs that have toad-like eyes. You can’t pin frogs down.

CB: Unless you’re in science class. [Laughs]

JC: Right, even with their tails. That was great, man, by the way.

CB: [Laughs]

JC: But even with their tails, right? So their order, like I just said, ‎Anura, means tailless.

CB: Yeah.

JC: And it separates them from the other amphibians, the fact that frogs don’t have tails across the board. Actually, no; there’s two species that have tails.

CB: Yeah, they’re very vexing. There’s a coastal tailed frog and the mountain tailed frog, and I looked them up. You know, they’re little tiny tails and they are the reproductive organs of those species.

JC: It’s a penis, then. I don’t understand why they don’t just call it the penis frog. There actually is a scrotum frog. And get this, there’s a scrotum frog population at Lake Titicaca.

CB: [Laugh]

JC: You can’t make this up. This is what frogs are here for. It’s just to say amazing things.

CB: Here’s one thing I didn’t know, and we’re gonna be dropping in frog facts throughout, they molt. I had no idea that frogs can molt. Every two days they can molt.

JC: Yeah.

CB: And they start out by eating their own skin around its mouth. They basically eat the skin around the mouth then pull the rest of their skin over their head like a dirty tee shirt, and then they eat that like a dirty tee shirt.

JC: Right. Imagine that, man. You know when your lip gets chapped and you kind of bite it, like a little piece, and you pull it off and it’s like…

CB: I’m doing that right now.

JC: Oh man, it’s a little raw.

CB: Yeah.

JC: Imagine if that piece was your whole skin.

CB: Yeah.

JC: And then you’d be a frog.

CB: [Laughs] Or a toad.

JC: Either one.

CB: I think I’m more down with the toads because frogs are generally the slicker skin.

JC: Yeah.

CB: Toads are the ones that kind of have the bumpy, drier skin and I think they’re the ones, when you pick them up and look at them, they stare into your soul right back at you trying to talk.

JC: The toads do?

CB: I think so.

JC: Huh.

CB: Am I getting that confused with frogs?

JC: I don’t know. Have you ever kissed a frog?

CB: [Laughs] No, but I would.

JC: Under what circumstances?

CB: I don’t know. A couple of drinks.

JC: [Laughs] A frog or a toad?

CB: [Laughs]

JC: Or would you kiss either one?

CB: I would kiss a toad, but then I would be a little, just because I love animals and think they all deserve affection, but I would not… I would think twice, and we’re gonna go over this later, but licking a frog for hallucinogenic, good times.

JC: Yeah, you might want to think even more than twice.

CB: Yeah, I would not want to go down that road.

JC: Right.

CB: But we’ll get to that. I think you can kiss a frog and not necessarily hallucinate.

JC: You can. You just have to plant it right on its big old mouth.

CB: That’s exactly where it goes.

JC: And if the frog really likes you, he’ll be like, “Here, take my skin. I was gonna eat it myself, but you can have it.”

CB: [Laughs] The reason why I made that bad but good science joke about pinning frogs down is they are one of the go-to animals that you will dissect in school. And the reason why they’re one of the go-to animals, it’s not just because teachers hate frogs or that teachers love frogs, but it’s that frogs, they’re trying to teach kids about internal organs and not that of a frog; they’re trying to teach them about themselves because it turns out, when you cut open frog, you might remember this, it’s not a circuit board or a series of balloons or golf balls. When you cut open a frog, there are heart and lungs and a stomach and a pancreas and a gallbladder and intestines and a liver.

JC: Yeah, largely connected in a way that’s similar to humans.

CB: Yeah, just all packed in that tiny little guy.

JC: Yeah, I mean they’re all tiny organs.

CB: Very cute too.

JC: Appropriately sized.

CB: Yeah.

JC: They are cute. Remember that smell, though?

CB: Of the formaldehyde?

JC: The formaldehyde stink of death. Man, that was not a good smell.

CB: That was not good.

JC: And so beyond just the internal organs too, Chuck, if you look at a frog’s skeleton, especially its arms, its extremities, it bears a resemblance to human anatomy as well, right?

CB: For sure.

JC: You’ve got a humorous, a radius, and an ulna, just like with your arm. And then the frog’s legs and back, they have a femur, a tibia, and a fibula, just like your legs too.

CB: Yeah, the only difference is the radius and ulna are fused and the tibia and fibula are fused.

JC: Right.

CB: Whereas they are not in our bodies.

JC: And they have a scapula and clavicles.

CB: Yeah.

JC: Collarbones and shoulder blades too, right? So they’re just basically little people with big mouths.

CB: Sort of.

JC: Well, there’s actually some big differences too.

CB: They have fingers and toes.

JC: They do. They have, usually, and again it’s tough to generalize here, but a lot of frogs have four fingers on their front feet, and five on their back.

CB: Yeah, and these little digits are gonna vary from species to species according to what the frog’s locomotion needs are.

JC: Right.

CB: So if it’s a tree frog, they’re gonna be long and flexy so they can grab stuff, if they’re swimmers, and all frogs and toads, we should point out, need water to live.

JC: Yeah, we really have to get into that part.

CB: Which we will. But they have little webbed feet and toes, of course.

JC: Yeah, it makes it easier for them to swim.

CB: And what about the little burrowers?

JC: Yeah, some of them, I get the impression that they burrow to hibernate or estivate.

CB: Yeah.

JC: Emilio Estivate. [Chuckles]

CB: [Laughs]

JC: We’re feeling silly today, huh?

CB: I was watching Breakfast Club last night for the first time in years.

JC: How was it?

CB: It holds up, and I know that movie by heart, it’s really remarkable how well I know that movie.

JC: But it does hold up?

CB: I think so.

JC: Wow.

CB: The only thing that… T’s not a very diverse movie like…

JC: No.

CB: You know, it’s five white kids and a white principal.

JC: Throwing a little bit of casual racism here there.

CB: Yeah, but I mean, you know, John Hughes has been accused of that in recent years.

JC: Oh, really?

CB: Yeah, just sort of…

JC: Oh, Long Duk Dong was his too, huh?

CB: Yeah.

JC: Yeah.

CB: Of course. And the only time there were people of different ethnicities in his movies, they were kind of joked about or aped.

JC: Yeah. I’m sure… It’s funny how history can just turn on you, you know?

CB: Yeah.

JC: He was probably like, “Wait, no. Everybody loves me; I’m John Hughes. What do you mean?”

CB: [Laughs]

JC: “We all thought this was great, don’t you remember? I’m John Hughes, don’t you know me?”

CB: [Laughs] Yeah, it’s very sad.

JC: Yeah.

CB: He was gone too soon. Where were we? Oh, Emilio Estevez.

JC: Oh, yeah. They Emilio Estivate, which is…

CB: [Laughs]

JC: Like hibernation in warm temperatures or hot temperatures, when it gets so hot out.

CB: Yeah.

JC: That, for all intents and purposes, you can’t go hunt. You’re just like, “It’s too hot.”

CB: Yeah.

JC: “I’m gonna dig myself a little hole and lay here until it cools off a little bit.”

CB: Yeah, and the whole point of that was that their feet and hands are shorter and wider like shovels. And like Emilio Estevez, ironically. [Laughs]

JC: Yeah, that guy can dig a hole faster than anyone you’ve ever seen.

CB: What are some of the different things? They don’t have necks. If you look at a frog, he doesn’t have a big long neck that turns around and looks at you; they’re just sort of these little squat heads sitting directly on their bodies.

JC: Yeah, like Fred Flintstone.

CB: Yeah.

JC: And, as a result, they can’t turn their heads, right?

CB: No.

JC: They can’t lift them up or down or turn them.

CB: If a frog ever turns his head and looks at you, then that is a evil possessed frog.

JC: [Chuckles] Right. Which, if a frog sitting there staring at you, especially if they’re suddenly joined by some companions, you should probably run away.

CB: [Laughs]

JC: There’s just something super creepy about them. I can’t remember the movie, Chuck. What was the horror movie that features lots and lots of frogs?

CB: Oh, I don’t know.

JC: It’s like the point of them. I can’t remember the name of it. It’s from the 80s, I believe.

CB: I don’t know.

JC: I will happily respond to anybody who writes in.

CB: Was it The Day the Frogs Took Over?

JC: [Laughs] That’s right. The Day the Frogs Stood Still.

CB: Frognado?

JC: Frogs! With an exclamation point.

CB: [Laughs] What else? They don’t have ribs, they have a pelvis that can slide up and down to help them jump.

JC: I thought that was pretty cool.

CB: Which one, the pelvis?

JC: Yeah.

CB: Yeah.

JC: What, it has a hole in it and it slides up and down the spine?

CB: I think so, so it can help it jump.

JC: Yeah, I think that’s pretty cool.

CB: And what else?

JC: They have… Well, their eyes, Chuck, the eyes.

CB: Oh, yes.

JC: Like I said, frogs typically have eyes that sit on the top of their head and they can see quite well in a very wide angle. They have a wide wide view.

CB: Yes.

JC: Vantage point. Could’ve put that better, but that helps compensate for the fact that they can’t turn their heads, right?

CB: Yeah.

JC: But apparently, as Tracy says, what one eye is getting in information is not really overlapping with the other eye, so they don’t have binocular vision; they have vision from two different eyes. And it sounds like, “Okay, whatever. Who cares?” But if you think about the depth perception it would take to pick a fly out of the air with your tongue…

CB: Yeah.

JC: It suddenly becomes quite impressive that they don’t seem to have binocular vision.

CB: Totally.

JC: And have did you do any research on their tongue?

CB: No.

JC: So, Chuck, their tongue, right?

CB: Yeah.

JC: They don’t have a tongue that’s anchored to the back of their mouth like we do.

CB: Sure.

JC: It’s anchored to the front and they can throw it out. And there’s this one researcher, who I think is working out of Georgia Tech, who filmed leopard frogs. The leopard frog can catch an insect with its tongue in 0.7 seconds.

CB: Wow.

JC: Which is five times faster than humans blink.

CB: Holy cow.

JC: Right. So researchers wanted to know how are they doing that? If you’re hitting on a fly with your tongue, you’re gonna knock it away from you. How do they grab it?

CB: It’s sticky, right?

JC: They figured that, yes, there was something sticky and they determined that frogs’ saliva is a non-Newtonian fluid, which, remember we covered that.

CB: Oh yeah.

JC: In the ketchup up episode. And just like ketchup, a frog’s saliva can turn sticky or it can turn less sticky when you apply force to it. So when the tongue, and the saliva on the tongue more importantly, comes in contact forcefully with an insect, it thins out and it covers the insect. But the moment it starts coming back and the force reverses, and I’m sure I just got that wrong.

CB: [Laughs]

JC: I’m gonna hear about it, about physics from everybody.

CB: Yeah.

JC: But once it stops being thin, it goes back to being viscous and somewhat sticky, and so now the fly or the insect has been covered in the sticky goo and is attached to the tongue and is being brought back into the frog’s mouth.

CB: Wow.

JC: All that happens in less than 1/800 of a second.

CB: That’s crazy.

JC: Yeah.

CB: I’m sure they have some pretty super cool slow-mo.

JC: Yeah, they do for sure.

CB: Well, but since you mentioned the tongue, though, because it isn’t anchored in the back of their mouths, they can’t use the tongue to push food down. So when a frog eats… They also don’t have a jaw that they can chew, like you would think and like humans do.

JC: Right.

CB: So they just swallow it in a couple of gulps and they actually, since they can’t use their tongue, they use their eyeballs.

JC: [Laughs] Yeah.

CB: Their eyes sink into the skull to push food down.

JC: So I just have to ask, Chuck. Where do frogs stand in relation to jellyfish and octopi now?

CB: Oh, wow. Not ahead of those too.

JC: Okay, so third, fourth, fifth, seventeenth?

CB: Well, if we’re talking all animals, I don’t know where to rank them, but if we’re talking crazy Stuff You Should Know animals, I would go with number three.

JC: Got you.

CB: For now.

JC: Okay.

CB: And on those eyes, they have what’s called a nictitating, is that right? Nictitating membrane. You’ve probably seen when frogs or toads go to dive underwater, they have a film like… What’s the other animal that does that? Seems like we talked about that.

JC: We have.

CB: They have a film that covers the eye.

JC: I think alligators, probably?

CB: Oh, that sounds about right.

JC: Yeah. I think that’s right, yeah. Which would make sense because alligators are reptiles.

CB: Yeah.

JC: And these guys are somewhat related to reptiles.

CB: All right. So that’s a lot of initial frog stuff, frog body stuff. So let’s take a break and let’s talk a little bit more about frog body stuff. [Chuckles]

JC: All right.

JC: All right, dude, so we’re back. We were about to talk about frogs getting it on.

CB: Well, quickly though, we never mentioned the ears.

JC: Oh, yeah, that’s a big one.

CB: You probably noticed that frogs don’t have these big, funny ears that stick off their head.

JC: Right.

CB: They do have ears; they’re just not external.

JC: That’d be hilarious.

CB: They just have the little… [Laughs] That would be funny. They just have the little tympanum, the little eardrum behind each eye.

JC: Yeah, and you can, apparently, if you know what you’re doing, in most frog species, tell whether a frog is a male or female based on the size of their tympanum to their eyeball. In a male, I think the tympanum is bigger than the eye and, in a female, it’s either about the same size or smaller.

CB: Yeah.

JC: So there you go, now you know, frogs.

CB: And finally, we would be remiss without talking about the vocal sac because frogs and toads are most known, at least to me, for that great, great sound they make in the evening time in the American south and all over the world.

JC: Yeah. It’s pretty awesome. So you know, you’ve seen pictures and video of a frog’s, their skin under their chin just suddenly turns into a huge bubble?

CB: Yeah.

JC: So what they’re doing right then is they’re taking in a tremendous amount of air and they’re holding it in their air sac, right?

CB: Yeah.

JC: And they’re moving it, keeping it in their air sac, they’re not releasing it, but they’re moving it around across their vocal chords. That’s what makes the ribbit sound or the croaking or the trilling sound.

CB: Yeah.

JC: It’s pretty awesome. One of the reasons why they’re making those sounds, or at least one of the sounds, is they’re attracting a mate, right? They’re talking to one another, they’re saying, “Hey, what do you think?”

CB: Yeah, and that sound can be everything from a croak to a ribbit to there’s this, I don’t know, there may be more than one species, but there’s this one I’ve heard this summer that sounds, and I’ve heard people call the police, because it sounds like a child that’s in danger.

JC: [Chuckles] Yeah, can you do an impression of it?

CB: No. I wish I could. It’s just super loud and it sounds like a child that’s hurt. It’s like a screaming sound.

JC: Oh, I’ve not heard of that one.

CB: Oh, man. It’s crazy sounding.

JC: Wow.

CB: Yeah, I’ll send you a link. I bet there’s a YouTube recording or something.

JC: It’s like peacocks going, “Heeeelp!”

CB: [Laughs] Yeah.

JC: It’s off-putting, isn’t it?

CB: I still say that to this day because of you.

JC: “Heeeelp!”

CB: Because we have a neighborhood peacock that I’ve talked about.

JC: So, Chuck, when frogs are making these mating calls, right?

CB: Yes.

JC: They’re saying, “Hey baby, how’s it going?” And the frog might come over or the, the male frog might say, “I like your look. I’m gonna climb on top of you, how about that?” And there’s actually, because frogs are, in a lot of cases, not sexually dimorphic, like you can’t visually tell the difference between a male and a female frog of that species.

JC: Yeah.

CB: Apparently, that extends not just to us humans but to frogs as well because there’s something called a release call to where if a male frog has mounted another male frog, the male frog that’s been mounted will have a release call saying like, “I’m a dude, buddy. Keep looking.”

CB: Yeah, actually, they’ve actually recorded that sound in nature.

JC: Oh, yeah?

CB: And I think it’s something like, “Whoa, whoa, whoa, whoa!’

JC: [Laughs] Right.

CB: [Laughs]

JC: “I like you as a friend.”

CB: [Laughs] Yeah.

JC: So the frog will move on. It’s funny that they get confused just from looking as well and that it takes a reactive.

CB: Yeah. [Laughs]

JC: Process to handle that, you know?

CB: Yeah, it’s called the amplexus, which is the position that they’re in.

JC: Yeah, that’s the mounting position.

CB: Yeah, and the male literally gets on the back and clasps the forelegs around the lady frog’s middle.

JC: Right.

CB: And they can stay there for days like that.

JC: However long it takes.

CB: Pretty much.

JC: It’s just a sensual seduction.

CB: [Laughs] Basically just waiting for the female to release her eggs. As far as reproduction goes, and this is something that we all learned about when we were little kids with frogs, with the tadpoles, we’ll get into that, but the general rule of thumb with most is that they’re all sexual reproducers and all frogs and toads will be hatched from an egg.

JC: Right. Depending on how they come out, there’s big differences too like most… Well, I don’t even want to say most; I saw somewhere like half of frogs come out fully formed, just super small.

CB: That’s adorable.

JC: I’ll bet. The other, say, half come out as tadpoles and that’s the one that every little kid knows about. It’s frog reproductive biology, right?

CB: Yeah, and depending on the species, they can do crazy adaptive things. Like there’s one species that incubates, like the female frog clears out her belly and then incubates the eggs in its belly.

JC: Right.

CB: For the whole time, and the frog is born out of her mouth essentially.

JC: Right. She’s like, “Go forth.”

CB: There’s another one where, because we always have been saying that moisture is super important to their survival.

JC: Right.

CB: There are some that, if they’re in very dry areas, the daddy frog will… I think it’s the daddy frog, or is it either one of them?

JC: It’s the dad from what I understand.

CB: The dad will pee on the eggs.

JC: Right.

CB: To keep them wet.

JC: That’s the, I think, the strawberry poison dart frog does that. And after they hatch into tadpoles, the mom, apparently, carries them on her back to little pools of water that are collected in like a plant.

CB: Right.

JC: And each one gets its own little pool of water. Isn’t that cute?

CB: Yeah. I didn’t know this, but they can hatch and grow in a regular full body of water, like a lake.

JC: Yeah.

CB: But I think the process is just a lot slower there than it is the temporary pool.

JC: Yeah. So, like a rain pool or something like that or just a huge puddle that’s developed. It’s gonna be much faster because they have less time to work with, right?

CB: Yeah, I couldn’t figure it out. Is that the deal?

JC: Yeah, That’s what I understand.

CB: Okay.

JC: So, their developmental process is accelerated, but again, you can’t just say, “This is how it is for all frogs.” There’s differences with all of them, but for the most part, ones that are hatched from eggs as tadpoles will start to eat, and again, some are born with teeth, which I can’t even imagine how small those teeth are, and might be herbivores… No, they might be omnivores; others are herbivores. But frogs grow up to be carnivores I believe, right?

CB: Yes.

JC: But they start out, as tadpoles, as vegetarians in a lot of cases.



CB: Yeah, so they start eating a bit, the metamorphosis is taking shape, as we all saw in the filmstrip in elementary school, those little back legs start to grow.



JC: Yeah.



CB: Their little internal organs start to change, they get their tiny, little lungs, they get their little digestive system going, and then that tail just shrinks and shrinks and, eventually, just is absorbed into the body.



JC: Yeah, and as their tail is shrinking, their front legs are growing and their digestive system is altering itself from a plant-based diet to a meat-based diet.



CB: Yeah.



JC: And then they leave land, and when they leave land, they’re considered a froglet, I guess, until their tail fully goes away.



CB: Yeah.



JC: And then they’re a frog, and they say ribbit.

CB: They do, and then they say, “I’m hungry. “I want to eat some insects and I want to try to try to avoid being eaten by something bigger than me.”



JC: Yeah, so they eat a really surprising range of things. They’ll eat insects, obviously, flying insects, mosquitoes, flies, grasshoppers. They also eat worms, snakes, mice, baby turtles, other frogs.



CB: Yeah.



JC: They’ll eat it all. They’ll cannibalize one another, which if you think is so wrong, cannibalism is just so wrong, it’s actually a pretty easy and low-hanging fruit check.

CB: [Laughs]

JC: On overpopulation.

CB: Yeah.

JC: If the species polices itself or polices its own population, that’s actually pretty smart, really.

CB: Yeah, it’s true.

JC: It’s still dreadful.

CB: Like, “Paulette over had 24 little baby froglets.”

JC: [Chuckles] Right.

CB: “And I’m kind of hungry.”

JC: Yeah. Apparently, some tadpoles, the ones that will eat meat or vegetation, they’ll eat other tadpoles too.

CB: Oh, really?

JC: Yeah.

CB: That young?

JC: Yeah.

CB: Man.

JC: I know, they start them young.

CB: So I just talked about avoid being eaten there; frogs are very famous for having some pretty advanced defense mechanisms. A lot of times, it’s just all show, like they’ll be super brightly colored or the, the four-eyed frog, the… Well, I was gonna say the scientific name, but why bother, right?

JC: I practiced.

CB: Okay.

JC: The Physalaemus nattereri.

CB: Oh, very nice.

JC: It sounded so much better when I practiced.

CB: Well, because what you do is you say it like that once and then the second time you say it just like it’s in your vocabulary.

JC: Yeah, but I’ve said it, like, four, five times. There you go.

CB: Yeah, but you have to do it like right in a row. You know what I mean?

JC: Oh, I see.

CB: Like, say it again.

JC: Physalaemus nattereri.

CB: [Laughs] I think you just do it with a little pizzazz.

JC: Yeah.

CB: So, anyway, that’s the four-eyed frog and that’s the dude that has spots on its back that look like eyes near the back legs and, to a predator, they’re like, “I don’t like the looks of that thing,” even though it’s just for show.

JC: Yeah, which is kind of weird, because if you look at it, it just looks like a frog going one way or the other. I don’t know what’s intimidating about it.

CB: Maybe that’s what’s scary, like, “I don’t know which way that dude’s gonna jump.”

JC: I guess so.

CB: “Is he going forward? Is he going backward?”

JC: A lot of frogs will use color. I was like, “What is the evolutionary adaptation of bright, bright colors for frogs? It doesn’t make any sense.” Apparently, they do that to basically advertise to predators, “Hey, man, I’m super poisonous. You do not want to eat me.”

CB: Yeah.

JC: And it works.

CB: Even though they may not be.

JC: Yeah. It could be a fluke or a fake, I mean.

CB: I’ve heard enough about that, though, that if I was traveling in, like the Amazon and I saw a bright blue frog, I wouldn’t kiss that guy.

JC: No, that’s a poison dart tree frog.

CB: Well, that’s the other thing. I was talking about a lot of it is for show, but a lot of it isn’t. Some frogs have very highly concentrated toxins, like the poison dart frog, like you said, and those dudes can be harmful to the touch to a human.

JC: Yeah, you can absorb that toxin through your skin. And, apparently, they make this toxin by collecting it from ants that they eat; they eat poisonous ants.

CB: Crazy.

JC: And the toxic alkaloids from the ants’ own toxin accumulates in these storage glands in the frog but doesn’t affect the frog; but brother, it’s gonna affect you.

CB: Yeah, so even that same… If you have a poison dart frog that’s been raised in captivity and not fed those ants, I think it might have a little toxicity but nothing like…

JC: Yeah.

CB: The real deal.

JC: I think that’s how they found out. They were like, “Oh, wait a minute, this doesn’t make any sense. Why would they become less toxic in captivity?”

CB: Yeah, “I’ve been licking this guy in the cage…”

JC: “Nothing.”

CB: “Since he was born.”

JC: [Chuckles] Right. So let’s, let’s take a break; our last break, Chuck.

CB: Okay.

JC: And then, we’re gonna come back because we have more to say.

JC: Okay, dude. So we talked briefly about, you mentioned how they need water. Water is essential to frogs throughout their life process, right?

CB: Yeah.

JC: This is one of things that makes them really fragile. In some cases, they’re fragile because there are places where they may run out of water, their water supply might dry up. And that would be really bad for a frog because not only does a frog get a lot of its water through its skin, it gets some of its oxygen and does carbon dioxide and oxygen exchange, in large part, through its skin as well, right? So for all of this stuff to happen, it needs to be wet, which means that if the water that they’re coming in contact with, since they’re so permeable and they take in that water so readily, if there’s stuff present in the water, like toxins or pollution or something like that.

CB: Yeah.

JC: It’s gonna affect the frogs as well. And since the frog species are fairly fragile as far as species go, they’re kind of like the glass Joe of the animal kingdom. Remember him from Mike Tyson’s Punch Out, the first guy you’d fight?

CB: I never played that.

JC: What?

CB: I never played Punch Out.

JC: You never did?

CB: No.

JC: Man, that was a great game.

CB: Yeah?

JC: I’m not gonna do my patented thing.

CB: [Laughs] What, which is, “I can’t believe you’ve never played that?”

JC: Yeah.

CB: I don’t think I had that system. What system was that on?

JC: The original Nintendo.

CB: Yeah, I never owned one. I had various roommates with those, so I was sort of subject to whatever games they liked.

JC: Got you.

CB: I never played Zelda either, you know.

JC: I was never into Zelda either. I liked Metroid, though.

CB: I don’t think I played that.

JC: All right.

CB: We, we played a lot of Super Mario Brothers, though.

JC: Yeah, that was so good.

CB: Yeah.

JC: Well.

CB: Glass Joe.

JC: Yeah, that’s right.

CB: [Laughs]

JC: So that’s what frogs are. They’re basically a really fragile group to begin with, but if you start contributing to their demise through pollution and stuff, it’s gonna pick up much more rapidly. And we’re starting to see that, right?

CB: Yeah, I mean that’s… I often rant about not using chemicals in my yard. It’s not just because I have dogs, but it’s runoff from that stuff affects everything around my house.

JC: Right.

CB: And that’s just on a small level.

JC: Yeah.

CB: You see it in large scale with huge farms that use pesticides and insecticides and that affects the local ecosystem as a whole.

JC: That’s right. And it gets across if you have those sewers where they stencil spray paint, like a fish or something, and it says…

CB: Yeah.

JC: “Goes to wetlands,” or a stream or something like that.

CB: Yeah.

JC: I think that’s really effective. I think they should put that on all sewers, basically.

CB: Yeah, or maybe even a sign so you don’t have to be walking over it to see it.

JC: Yeah, there you go.

CB: Like, when you’re driving by.

JC: Or just make it common knowledge.

CB: I think people know that, but they need reminders.

JC: Yeah, I think they do too.

CB: So that’s one threat to frogs because of man. Another one is, well, people eating and hunting frogs to eat.

JC: Yeah.

CB: They try and raise them on farms, but it’s not the easiest thing to have a frog farm, apparently.

JC: No, they’ll hop out of there.

CB: So hunting and capturing frogs to put on the menu, in some parts of the world, is a very big deal, so they’re in steep decline in those places.

JC: Have you ever eaten frogs?

CB: I have had frog legs before.

JC: What do you think?

CB: But it’s been a long time and it won’t happen again.

JC: I used to, as a kid, go to this dinner theater in, I think, Grand Rapids, Michigan is where it was.

CB: [Laughs]

JC: And on the buffet, they always had frogs’ legs.

CB: Yeah.

JC: And I would eat piles of frogs’ legs.

CB: [Laughs] Yeah.

JC: As a 7, 8-year-old kid.

CB: [Laughs]

JC: It was really crazy how adventurous I was, right?

CB: I would do anything to have a videotape of that. [Laughs]

JC: And I got fat off of frogs’ legs. That’s tough to do.

CB: Yeah.

JC: So I wonder now if I would like them, but that’s not to be because one of Umi’s greatest fears in the world is being anywhere near a frog.

CB: Oh, really?

JC: One of her top phobias is frogs just in general, everything about frogs. So there’s zero chance. There’s actually a negative chance that I will ever be able to eat a frog leg again.

CB: Right.

JC: At least with her around. I’ll have to fly up to Grand Rapids myself.

CB: That’ll be your big, dirty marital secret.

JC: [Laughs] Right. “Where have you been?”

CB: “Well, we had a show in Detroit so…”

JC: “Grand Rapids.” [Laughs] Yeah, we had a show in Detroit.

CB: Wow, scared of frogs. I’ve heard of that before I think.

JC: You haven’t?

CB: No, I have.

JC: Yeah.

CB: I mean I’m sure every animal out there has someone who’s afraid of it.

JC: Sure.

CB: But yeah, I didn’t know that, frogs. I like frogs. Good to know.

JC: [Laughs] Yeah. You’re like, “Umi, what do you think of this?”

CB: No, like I know not to do that.

JC: That’s good of you, Chuck. I wish I’d thought of that when I had done it.

CB: [Laughs] One of the other big threats to frogs is global warming. They are ectothermic animals so that means they rely on the environment to control their body temperature; they don’t have that internal regulation. So if it’s hot outside, the frog gets hot and if it’s cold, they get cold. In the case of the wood frog, they live north of the Arctic Circle and they can freeze, this is remarkable, they can freeze up to 45% of its body in the winter time to protect itself from damage and then they thaw themselves out again in the spring.

JC: Right.

CB: But that doesn’t help you if it’s too hot.

JC: Well, that’s when you Emilio Estivate, when it’s too hot. But this is like…

CB: Sure.

JC: This is just a few species that are capable of hibernating and estivating like this.

CB: Yeah.

JC: For the most part, frogs need, because they’re ectothermic, they need a pretty stable temperature.

CB: Yeah.

JC: And, from what I saw, even worse than high temperatures for frogs, that’s associated with global warming, are temperature swings.

CB: Right.

JC: Like big swings in temperature are really hard on frog populations. They think that’s one reason why frogs have been declining, but from that one study that really established there are 200 species that we’ve lost since the 70s, the guy who led the study was like, “I can’t say why. I have no idea.” He’s like, “It’s probably this, it’s probably this, it’s probably this, it’s all these different things.” But he said the thing that really made him nervous was that it was happening all over the world. But he didn’t think it was just climate change or just global warming that was doing it.

CB: Yeah.

JC: One of the other things that frogs face that they know all about but are having a tough time dealing with is a kind of fungus called kitrid, or chytrid. Which one did you come up with, pronunciation-wise?

CB: I said chytrid, but it could be either I guess, C-H-Y-trid. And that’s a fungus that feeds on keratin, which we’ve talked about before. Isn’t that what’s in our fingernails?

JC: Yeah, or your hair.

CB: Yeah. Basically, it makes skin tough and sturdy and little tadpoles just have a little bit of that stuff around their mouths, but when they grow, the parts that are most often in contact with the ground, like their cute little soft bellies or the soles of their feet.

JC: They’re delicious feet.

CB: Now I can just think of Umi, just her skin crawling listening to this thing.

JC: Yeah, I don’t know if I should’ve told everybody that one. It’s like her Achilles’ heel.

CB: Yeah. So as this stuff comes in contact with the ground more, they get that build up to where just they need tougher skin down there.

JC: Yeah.

CB: And that’s where this fungus will take root.

JC: Right, because that tougher skin is made of keratin, right?

CB: Yeah.

JC: So since the fungus feeds on it, they’re like “Oh well, it’s gonna kill the frog,” but they don’t actually know the mechanism by which the frog dies from the chytrid? Is that what you said?

CB: That’s what I said.

JC: They think that, possibly, it is that the fungus releases a toxin maybe?

CB: Yeah.

JC: That the frog takes in through its skin or that it inhibits that gas exchange of oxygen for carbon dioxide on the frog’s skin. But those are just a couple of hypotheses; they still have no idea. They just know it’s killing frogs and it’s killing them fast. And the reason why it’s spreading so well, they’ve traced it back to the African clawed toad.

CB: Yeah, which, it doesn’t have a poor effect on them, but they can spread it to other frogs and those have become an invasive species in lot of areas.

JC: Yeah, because they’re pets and people release frogs as pets when they’re no longer puppies.

CB: Which is something you should not do.

JC: No, no, no, no. Frogs takeover really, really quickly. Remember we did an episode on will toads give you warts?

CB: Yes.

JC: And we talked about the cane toad and how it’s just taken over Australia. Frog populations, as fragile as they are, can also, as an invasive species, just boom, right?

CB: Yeah.

JC: They also were ubiquitous because, for decades, starting in 1930, they were the fastest way to tell if you were pregnant.

CB: Oh, cane toads?

JC: No, the African clawed toad.

CB: Oh, okay

JC: Did you know about that?

CB: I don’t think so.

JC: Oh, allow me. You’re ready?

CB: Yeah.

JC: Back in the day, if you were a woman who wanted to know you were pregnant, you would go to your doctor, your doctor would take a urine sample and send it off. And at the lab, they would take a sample of your urine, inject it into a rabbit, and then they would kill the rabbit, cut the rabbit open and inspect its ovaries to see if it had reacted to a hormone that shows up only in pregnant women.

CB: Yeah.

JC: Human chorionic gonadotropin, right?

CB: Yeah, which I’ve heard of that.

JC: Okay. So I guess it would be HCG is present in the urine of pregnant women and you can tell, very early on, if a woman is pregnant from the presence of it. But they had the most roundabout way of all time to find out, to detect the presence of it. Well, enter the African clawed toad, where this researcher with the name of, get this, Lancelot Hogben, thought to inject a toad with it and the toad stays alive, it just releases eggs or sperm if there is HCG present in the woman’s urine.

CB: Right.

JC: So that, for decades, Chuck, was how you would tell if you were pregnant. Somebody in a lab somewhere would inject your urine into a frog to see if they release sperm or eggs.

CB: Crazy.

JC: And then they’d say, “Mazel tov.”

CB: Yeah? That is nuts. You mentioned the cane toad in Australia, which we did talk about a little bit, but there’s a great documentary, a very classic documentary from the late 80s I think, or was it the 70s? I think it’s the 80s, about the cane toad. One of the all-time classic docs; if you haven’t seen it, you should check that out. But cane toads were, very famously, brought over in 1935, and it just seems like it always goes this way when someone says, “Hey, let’s bring in this to handle this.”

JC: Yeah.

CB: “Even though nature hasn’t.” It always goes wrong, it seems like.

JC: Yeah.

CB: So they brought these cane toads over to take care of the scarab beetle. But then once they got over here, the scarabs were eating the sugar cane crops, they realized that these big, fat cane toads couldn’t jump high enough to get to the beetles.

JC: [Laughs]

CB: For the most part. And so they, all of a sudden, were just there and they reproduced like bunny rabbits. And so, before you know it, Australia, very famously, had a cane toad problem, and I think still does, right?

JC: Oh, yeah, yeah, it’s big. They were advancing toward Sydney or Perth or some large city, just ruining cropland on the way. They have a huge problem still, as far as I know.

CB: I just saw one recent thing, I don’t know if it’s still the case, but I think they found some ant that will kill these cane toads.

JC: [Chuckles] Right.

CB: They’re called meat ants.

JC: Okay.

CB: It sounds like something of a horror movie.

JC: Yeah, that does sound pretty bad.

CB: But I don’t know if that’s still the case, but I do know that Australia has spent a lot of money over the years trying to control the cane toads.

JC: Yeah. And yeah, as far as I know, they still have a huge problem with it.

CB: Maybe, Josh, we will see some in 2018 when we, fingers crossed, visit Australia to do live shows.

JC: That’ll be great. We’re gonna go catch a couple and at least get a couple out of Australia’s hair while we’re there.

CB: Yeah. That is a sort of a pre-announcement. Hopefully, we’re gonna be hitting Australia and New Zealand next year.

JC: Oh, is that what you were doing?

CB: Yeah. If everything goes well, that is the plan.

JC: Okay. Yeah, I know I’m pretty psyched about it.

CB: I just have to find some good pills to get me through that flight.

JC: So I’ll tell you what you could do for the flight back.

CB: What’s that?

JC: You could take one of those cane toads, squeeze it and then lick the secretions.

CB: [Laughs]

JC: Yeah, so that’s a real thing. If you’ve heard, “Hey, we’re licking frogs, make me hallucinate.” That is actually a real thing, and there are, in the 80s, the Australian government, and this doesn’t just happen in Australia, they have outlawed cane toads secretion under the Drug Misuse Act and there’s another chemical, called Bufotenine, that is, in the US, a controlled substance.

JC: Yeah, from the Colorado River toad. And you can own a Colorado River toad but, buddy, you better not lick it because that is illegal.

CB: Yeah, so what do you do? You squeeze the parathyroid glands behind the ear drums.

JC: Yeah.

CB: There will be an oozy, milky substance that leaks out. And then you can either lick it right there.

JC: Right.

CB: Or you can collect it, dry it and smoke it.

JC: And here’s the thing, like, don’t do that.

CB: No.

JC: Do not do that. Not just because it’s illegal, it’s a controlled substance, but because you have no idea how toxic that chemical is, how potent it is. You can’t control the dosage.

CB: Yeah.

JC: And so if you overdose, you will probably suffer cardiac arrest and die. And there’s no way for you to know whether you’re going to trip because this stuff is from the same family as DMT, dimethylethylamine.

CB: Right.

JC: Ethylanamine. Man, I practiced that too, but DMT, it’s in the same family. So it will either make you trip or it will kill you and there’s no way for you to tell ahead of time. So there’s really no reason whatsoever for you to be licking toads.

CB: No.

JC: Your uncle Josh and your uncle Chuck are telling you straight out, don’t lick toads.

CB: [Laughs] Agreed, and yet people have been doing it since, at the very least, 1150 BC. They found archaeological evidence pointing to South American Indian tribes licking frogs. [Laughs]

JC: Yeah, Colorado River toad.

CB: Of course, it’s in Colorado.

JC: [Laughs] Right, exactly.

CB: Like, “Yeah man.”

JC: “I’m gonna christen these new hiking boots by licking the toad.”

CB: [Laughs] “These new sweet Vasques.”

JC: [Laughs] Right. What else you got?

CB: I got nothing else.

JC: That’s frogs. That was a long one.

CB: Yeah. We haven’t done a good old fashion animal episode in a long time.

JC: I know. I missed it.

CB: Well, if you want to know more about frogs and toads, TS because there’s nothing more to know. But you can support Tracy V Wilson by going and reading this article on howstuffworks.com. You can also go check out her work on Stuff You Missed in History Class, that great podcast.

CB: Agreed.

JC: And since I said Stuff You Missed in History Class, it’s time for listener mail.

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