Short Stuff: Why do kangaroos hop?

Hey, and welcome to the Short Stuff. I'm Josh, and there's Chuck and Jerry's here for Dave, where we're just hopping along talking about kangaroos and how they hop.

That's right. I want to thank our old colleague Kristin Conger for writing this article from How Stuff Works back in.

The day and creator of Unlady Like the podcast too.

As well as Jennifer Horton wrote another article that I used.

Great to hear Jennifer and then take.

The San Diego Zoo website and nat Geo all pitched in for this one.

I thought this was a particularly well researched short stuff, so I should have known that Jennifer Horton and Kristin Conger had something to do with it.

Yeah. So we're talking about kangaroos a little bit, mainly going to get to how and why they hop, but we should start out by talking about the fact that rus are marsupials or pouched mammals, because they have a marsupium, which is a little pouch where their little joey develop.

Yeah. We talked to think a lot about this in the Naked Mole Rat episode where essentially like the marsupial fetus does not develop as long inside the body of the mom as it does inside the pouch. Essentially, at some point it's what you would call born, but really it's just crawling out of the birth canal outside into

Yeah, that's maybe the fact of the podcast for me. That's kind of nutty.

Oh, I'm sorry I took that. I didn't realize that it was.

What do I have to always take the fact of the show?

I like to, you know, I.

Mean, I know it's in my contract and not yours, but I'm willing to give every now and then.

That's very generous of you, think you.

All right, So Australia is obviously what people you know, what comes to mind when you think of marsupials in general, because koalas and kangaroos. But we have done a great episode on the opossum, which live all over the place, especially North Central and South America. But we're talking about kangaroos and wallabies here because they don't have four legs like our opossum friends. They have two big old feet and two little littler arms.

Yeah, that's a great way to think about it. They don't have four legs. They have two legs and two arms. And it makes sense like if you've ever seen a kangaroo, or you just bring one to mind, if you're capable of using your mind's eye. They're sitting on their feet and they're standing or sitting up right, and they're little almost Titanica arms are just kind of hanging out there, not doing much of.

Anything, Yeah, except boxing, probably the kangaroo. The first sightings apparently traced back to a Dutch merchant named Francisco Pelsert who got shipwrecked off the coast of Australian sixteen twenty nine, and about one hundred and fifty years later they were pretty well known throughout Europe and by seventeen ninety one they had brought those things over to London.

England, here's the fact of the podcast for me, Chuck, Okay, can I take this one too? Or should I tee you up?

No? Double up? Baby.

So the name kangaroo the word, as far as anyone is able to say, we don't know for sure. It's apparently an Aboriginal word for I don't know. Isn't that awesome? I don't know.

That's pretty funny, it is. Here's the deal, though, is kangaroos are the only large mammals to hop. And that's basically as like they're you know, bunnies will hop a little bit, but the kangaroo moves around primarily by hopping, and I guess you wouldn't consider a bunny a large mammal anyway. Here's the deal. If you go back to twenty five million years ago and look at the fossil record, they didn't hop because Australia was a rainforest at the time.

Yeah, So they actually developed what ends up helping them hop long before they actually started to hop. We called it the fourth toe. If you look at a kangaroo's foot, you can see how it's how it's hopping, and Chuck, I think I've kind of set us up for an ad break and we're gonna come back and finally talk about how kangaroos hop. What do you think?

All right, let's do it shop shop stop.

Okay, where I left off, Chuck, I was talking about the fourth toe, and this is the this is the design element that allows the kangaroo to hop. Because if you look at a kangaroo's foot, the first toe, looking at the kangaroos foot from the inside of the foot outward, the first toes pretty puny, might not even be there. The second and third toes they're okay, they're like smallish and they each have a nail, but they seem to

That's what everyone always asked. It's just the second third toe on one foot or had always been stuck together.

But surely it would have to give you an advantage to some degree. I don't know.

I can't remember the last time I swam with her.

Well, next time you get a chance to race her and let me know how it turns. Out all right. Finally we get to the fourth toe, and the fourth toe is like this, this massive beast of a toe, and it's in line with the the leg bones of the kangaroo's legs, and this is where the actual hopping begins.

Yeah, that's an actual adaptation, and like you said, that preceded their ability to hop. So I'm not even sure what the deal is with why they adapted that to begin with. But I mean, maybe it's just because they went from rainforest to sort of dry, grassy planes and they needed to get around more, and they don't know learned it eventually. They do have a fit though, we

Yeah, like a spring. When they go downward, all of that tendon gets a bunch of energy, kinetic energy stored in it, and then when they bounce upward, it gets it's released, and it can send them flying. Chuck. I had no idea how far they can hop and how fast did you?

Yeah, but it's always fun to relearn that, you know, because it's pretty astounding.

Okay, so they can go up to fifteen to twenty miles per hour. Yeah, and for those of you in Australia who don't know, that's about twenty four to thirty two kilometers per hour. That's fast. That's like golf cart speeds at top speeds.

Even that's faster than a golf cart.

Yeah, and then it can propel itself about twenty five feet forward, almost seven or more than seven and a half meters and six feet high. Yeah, nearly two meters high. So we could jump right over either of us chuck.

Yeah, absolutely. I mean you're taller than I am, so you might get your forehead grazed.

It could just barely clear me. I'm five foot eleven and a half if I'm fully honest.

Yeah, they would look at me and just be like, no problem, shorty.

They just free willy right over you.

I used to be five to ten, now I'm more like five to nine. I'm shrinking, as we all argue, yeah, what is up with that? You shrink?

You know are? But I mean does that mean our vertebra are fusing together, or like our knees are getting shorter. Have we compacted the shin bones and our legs and that's what's doing it? That doesn't make any sense.

To well, we should do an episode like a shorty maybe on the shrinking as you age, because that's it's definitely a thing. That's why, like you see an old man that has these giant ears, they didn't always look that way.

Oh I didn't know that. Yeah, wow, what a development.

All right, So back to the kangaroo, we need to talk about their tails a little bit because they have those huge tails that act as a counterbalance to the hind feet. So if you look at a kangaroo hop, that tail moves down like in mid air, that tail is moving down to meet kind of where the feet are, and when they land, the tail raises, so it kind of just does this little opposite motion to balance everything out.

And it makes a really satisfying, boring sound.

Of course.

So what's great about this? You said that the kangaroo is the only land animal that or an only large mammal that hops, and the reason why it hops is because it's actually a tremendous adaptation for moving quickly across land in a really efficient manner because the way that the kangaroo is built, the bast they hop, the less energy they have to expend. It's a pretty beautiful system.

Yeah, it's pretty crazy and one of the most efficient travelers in the animal kingdom overall. You know that, Like you said, they had that great range. And part of what's going on with their efficiency is is they have a like when they're bending down to jump and then leaping up, that's contracting and suppressing their respiratory system, which

Yeah, and they also have to use less muscle energy in their legs because when they jump really far high and fast, when they land, those super elastic tendons that help them hop just contract even further, and that means that they expand or spraying i think is the technical term, even further. So when they get going, they really can just they can just keep going a while. They're also their heart is really attuned to this kind of endurance

Yeah yeah, why does it say fifth in here?

That's so weird? I know, because they specifically said that their two front arms.

You know, hey, well maybe i'll get in touch with the color. It gives me a good reason get in touch with her. Say what the hell did you mean this fifth leg thing all those years ago?

You're going to ruin her week?

She's like, who is this?

Right?

I guess we'll close quickly, just on a little you know, I mentioned the wallaby the slight differences between the wallaby and the rue. Mainly it's the kangaroo is just a lot bigger. They have a lot more link between their ankles and their knees, and they're just taller. They can be like eight feet tall, whereas a wallaby is maybe like three feet a little over.

Can you really say it any other way than that?

I don't think so.

I mean, why would you anyway? Yeah, this is probably long after your wheelhouse, But did you ever watch Rocco's Modern Life.

Never heard of it.

It's a great cartoon. Yeah, it's a cute little cartoon. It was on Nickelodeon and Rocco was a wallaby.

Oh nice.

Did you ever watch Dark Winged Duck?

Never heard of it?

No, that's not it. What was the Duck with Jason Alexander as the duck?

Oh, I don't think. I don't think I know of such a show.

It was like a raunchy com like superhero duck show that. It's pretty good. Whatever the name of it was. Look it up. Jason Alexander, George f and Seinfeld played the main duck.

Oh wow, and that was a good one too.

Yeah. I think Dark Wing Duck is like a Duck Tails spin off. That's not what I'm talking about.

All right, Well, I mean if we're recommending animated shows, I might as well. And we're in Australia, I gotta recommend Bluie again. Still watch that?

Okay? I never watched that one. Yeah, So, stepping out of the animated shows, but continuing with the recommendation, I watched the Jake Gillenhall movie Enemy last night. Oh yeah, it was Denis. Have you seen it?

Yeah, I saw back back then.

Man, it is a good movie.

Yeah, crazy ending, yes, but.

So like it was one of those movies that I was like just sitting there thinking about it afterward, and so I love those If you go look them up online, there are people who have given great thought to explaining these things, and I found, I think, on slash Film a really great explanation of what was going on. But before warned if you watch Enemy, you may regret reading the explanation of it. It's almost to me it was better before I knew, and I just had to accept it on its own terms.

Yeah, love that movie.

All right, Well that's it for Enemy, and that's it for obviously kangaroo hopping. Right, that's right. Short, Stuff is that.

You?

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