We Hate To Tell You This, But Some Leeches Can Jump

This episode explores the surprising behaviors and diverse nature of leeches, particularly focusing on newly discovered jumping terrestrial leeches.

1. Leeches are more diverse than commonly believed, with over 800 species exhibiting various feeding habits and behaviors.
2. The episode debunks the myth that all leeches are bloodsuckers; some are carnivorous, preying on small animals.
3. Mai Fahmi's observation of a jumping leech in Madagascar provides new insights into leech mobility, challenging long-held scientific perceptions.
4. The episode discusses the broader ecological implications, emphasizing the need for conservation and the potential unknowns in leech behavior due to climate change.
5. Terrestrial leeches are crucial for biodiversity but are threatened by habitat loss and climate change.

1: Introduction

Regina Barber introduces the episode with Hannah Chin, discussing common misconceptions about leeches.
Regina Barber: "When I think about leeches, I think about old-timey doctors using them to treat illnesses."

2: Leech Diversity

Discussion on the diversity and ecological roles of leeches.
Michael Tesler: "A leech is a wormhouse that feeds on blood, and they do so using strong anticoagulants."

3: Jumping Leeches

Mai Fahmi discusses her groundbreaking observation of jumping leeches.
Mai Fahmi: "I saw this leech on a leaf, and as soon as I took out my phone, in under 10 seconds, that leech jumped twice."

4: Scientific Implications

The implications of new findings on leech mobility and the historical context of their study.
Mai Fahmi: "You can go back to Victorian era times when leech naturalists were coming on the scene, and a lot of them have conflicting opinions."

5: Conservation Concerns

Discussion on the effects of climate change on leech populations and biodiversity.
Mai Fahmi: "Old, pristine rainforests are unfortunately disappearing globally."

1. Learn about local wildlife to help in conservation efforts.
2. Support biodiversity initiatives that protect species like leeches.
3. Educate others about the misunderstood roles of creatures like leeches in our ecosystems.
4. Participate in or support ecological studies and wildlife observations.
5. Advocate for policies that protect natural habitats from climate change and deforestation.

Generally, we at Short Wave are open-minded to the creepies and the crawlies, but even we must admit that leeches are already the stuff of nightmares. They lurk in water. They drink blood. There are over 800 different species of them. And now, as scientists have confirmed ... at least some of them can jump!

People

Michael Tesler, Mai Fahmi

Guest Name(s):

Mai Fahmi

Content Warnings:

None

NPR Sponsor
This message comes from NPR sponsor Greenlight. Want to teach your kids financial literacy with greenlight, kids and teens use a debit card of their own. While parents can keep an eye on kids spending and savings in the app. Get your first month free@greenlight.com. nPR.

NPR Sponsor
This message comes from NPR sponsor Instacart. Worried about letting someone else pick out the perfect avocado for your perfect impress them on the third date guacamole. Well, good thing Instacart shoppers are as picky as you are. They find ripe avocados like it's their guac on the line. So let Instacart shoppers overthink your groceries so that you can overthink what you'll wear on that third date. Download the Instacart app to get free delivery on your first three orders while supplies last. Minimum $10 per order. Additional terms apply.

Short Wave from NPR
You're listening to short wave from NPrdem.

Regina Barber
Hey, short waivers. Regina Barbour here. And today I'm joined by producer Hannah Chin, who's on the pod for the first time.

Short Wave from NPR
Hey, Regina, welcome. Thank you.

Regina Barber
They are here to grace our short waivers with a story about leeches. And, Hannah, to be honest, when I think about leeches, I think about old timey doctors using them to treat illnesses.

Short Wave from NPR
Yeah, that's a pretty common conception. There's actually this famous story about someone that you might be familiar with.

Michael Tesler
I believe that George Washington, when he was dying, had a giant quantity of leeches, like 100, 200, maybe more leeches I don't remember on him at the time.

And that surely didn't help matters.

Yeah, I don't think anybody's gotten better from having 100 or 200 leeches on them.

Regina Barber
What? Like, I definitely know George Washington. I didn't know this story, though.

Short Wave from NPR
Yeah, well, that's Michael Tesler. He's an evolutionary biologist who specializes in these creepy crawlies, aka a leech expert.

Regina Barber
Okay, so other than the fact that some of them witnessed the death of our first president, can you just run through some of the basics we know about them for me?

Short Wave from NPR
Yeah. So there's over 800 known species of these little guys.

Regina Barber
Wow.

Short Wave from NPR
But most of them are pretty simple when it comes down to it.

Michael Tesler
A leech is a wormhouse that feeds on blood, and they do so using strong anticoagulants and slurp up a whole bunch of blood and then often take a long time to digest it.

Short Wave from NPR
Michael says that leeches are kind of like the vampire cousins of your common earthworm. You know, the kind that you see in your backyard wow.

Regina Barber
Okay.

Short Wave from NPR
And most leeches, not all drink blood. Some of them actually eat animals.

NPR Sponsor
What?

Michael Tesler
There are non blood feeding aquatic leeches, ones that eat invertebrate larvae. There are some that come onto land, actually, and eat very large earthworms. Some have frills on their side. Some feed on turtles. Some feed on fish. There's a lot of different things that aquatic leeches can and will do.

Regina Barber
Cool, cool. So bottom line, overall, leeches are carnivorous worms.

Short Wave from NPR
Yeah, exactly.

Regina Barber
Wow.

Short Wave from NPR
Michael said they range in size from a few millimeters long up to, like, the length of your forearm.

Regina Barber
That's horrifying.

Short Wave from NPR
I know.

And they're almost everywhere, except for, like, Antarctica. Most of them are in the water. Theyre aquatic leeches, which make up about 90% of leeches that we know exist. But there are 10% that are not aquatic. Theyre terrestrial, which means they live on land.

Regina Barber
Okay.

Short Wave from NPR
And the reason that I want to tell you about them today is because conservational biologist Mai Fahmi accidentally learned new information about them when she was working on her dissertation in Madagascar. She was collecting leeches to pop in her bag and bring back to study, when suddenly she got this idea one afternoon.

Mai Fahmi
I thought it might be fun to, instead of immediately spotting a leech and putting it in a bag, to sort of sit next to it and see how it behaves and what it does, sort of to get myself acquainted with this new study species.

Short Wave from NPR
And so that's what she did. She found a leech, and she sat down, and she did exactly the same thing that I do when I see a cool thing in the wild. She took out her phone.

Mai Fahmi
I saw this leech on a leaf, and I sat down next to it. I mean, as soon as I took out my phone, in under 10 seconds, that leech jumped twice. I thought, well, if it jumped that quickly, surely everyone's seen a leech jump.

I really thought nothing of it. And I came back and I showed my colleagues, my lab mates. They couldn't believe what I had.

Short Wave from NPR
Mai's work, some of which she's done with Michael, is really changing what we know about terrestrial leeches and their behavior.

Regina Barber
So today on the show, leeches, they're everywhere, even on land. So what do scientists know about them? What do they still have to learn? And should we be afraid?

Short Wave from NPR
Gina, don't fear monger.

Regina Barber
It's a genuine question that you actually scripted in for me.

Short Wave from NPR
Okay. Blame the production team.

Regina Barber
Yep, you're listening to short wave from NPrdem.

NPR Sponsor
This message comes from Apple TV original podcasts presenting my devo from the producers of anything for Selena and the Pulitzer Prize winning podcast Suave comes My Devo, a podcast about roots dive into the legendary life, music and lasting influence of Latin Americas most prolific songwriter and showman, Juan Gabriel El Divo de Juarez, hosted by Maria Garcia. This is Mydivo, an Apple original podcast produced by Futuro Studios. Follow and listen on Apple Podcasts.

NPR Sponsor
This message comes from NPR sponsor American Express take your business further with the smart and flexible American Express business Gold card. It offers flexible spending capacity that adapts to your business. You can also earn up to dollar 395 in annual statement credits on eligible purchases at select business merchants. That's the powerful backing of American Express terms. Apply. Learn more@americanexpress.com businessgoldcarde okay, so we're gonna.

Regina Barber
Start with a kind of historical retrospective here. Like, even though land leeches are brand new to me, I guess we've known about them for like a long time. Yeah.

Short Wave from NPR
Mai actually recounted a very rich history.

Mai Fahmi
For as long as people have been visiting places where they're found or for as long as people have lived alongside them, there are records, historical records that refer to them.

Short Wave from NPR
The earliest reference Mai and Michael found dates all the way back to the 14th century.

Mai Fahmi
So quite a ways back where people have been harassed by these leeches and talked about it in their travel journals. Certainly the people who live in terrestrial leech territory encounter them pretty regularly and are intimately familiar with their behaviors.

Short Wave from NPR
And Mai said terrestrial leeches live in rainforests across the Indo Pacific region. So in Madagascar, in south and southeast Asia, even Japan, all places where people have lived for a while.

Mai Fahmi
So they are descended from an aquatic ancestor. And we know that they've likely arrived where they are today by latching on to things that move and fly far distances. It's likely that they arrived in Madagascar on things like migratory birds and likely only took hold after Madagascar moved down to its current latitude.

Short Wave from NPR
Classic leech stuff. Stick onto a bird or something, hitchhike your way to a rainforest. Leeches don't actually need warmth, which I was surprised about. They mostly just need a lot of healthy forest canopy and a damp environment. So end up in a lush rainforest, decide it's nice, move in.

Regina Barber
So if I were to go to one of these places like these rainforests, what would I be looking for? Like, what do these leeches look like? Do they look like an average, like, slug?

Mai Fahmi
They actually come in a surprising variety of colors and patterns, specifically the ones that tend to be found living in shrubs, in greenery. Those tend to be the more colorful variety presumably to camouflage among the leaves. So you've got terrestrial leeches that have got these bright greens and oranges, white polka dots.

Regina Barber
Okay. I'm not gonna lie. This is painting a very, like, pretty picture.

There's these bright colors, lush forests, and these, like, little baby leeches.

Short Wave from NPR
I know, right? The whole thing sounds pretty cute. And the terrestrial leeches are little. They're, like, a lot smaller than aquatic.

Mai Fahmi
Leeches, and they're more tube shaped, whereas aquatic leeches are kind of more flattened in terms of their body plan. So aquatic leeches sort of swim in an s curve, and terrestrial leeches seem to inchworm around and jump.

Short Wave from NPR
And that inchworming is also what sets them apart from worms or slugs. They move way differently.

Mai Fahmi
So an earthworm is sort of like a floppy piece of spaghetti. Right?

Whereas a leech is essentially a tube with two suction cups, one on each end.

And they use these suction cups to move. So there's one in the back, and the leech will anchor itself, sort of wave around and then land the front sucker and then unsuck the back sucker and in that way, sort of inch worm along.

Regina Barber
Sort of like a slinky.

Short Wave from NPR
Yeah, yeah, yeah. No, exactly like a slinky.

Regina Barber
But Hannah, I pulled up the video you sent me, like the one that mai took. We'll put it in the episode notes. Don't worry. Yes, and leeches, they do way more than inchworm along. They jump.

Short Wave from NPR
Right? Which, it turns out is a big deal. Mai said this is an issue that's been debated among experts for a really long time, like hundreds of years.

Regina Barber
Wow.

Mai Fahmi
You can go back to victorian era times when leech naturalists were coming on the scene, and a lot of them have conflicting opinions. Some of them are hardcore opposing the notion that any leech can jump at all, that it's not even possible physically for a leech to jump. And then you dig a bit deeper, and you realize that some very early explorers, like Ibn Battuta from the 14th century recording, oh, no, leeches jump.

They jump, for sure.

Regina Barber
It seems so strange that, like, it took scientists so long to agree that it jumped. When she found it so quickly with.

Short Wave from NPR
This video, Mai mentioned that actually, she said local communities had really already known this. Right. Like, they've been living alongside leeches for a really long time.

They agreed that leeches jump. It's just that scientists, like, western scientists. Western scientists, yeah. Hadn't studied them doing so. And Michael actually weighed in here. He and Maia did work together to study the Madagascar land leech again. And release a paper confirming that, like, terrestrial leeches jump, the rest of leech.

Michael Tesler
Biologists essentially said, no, this can't be. It's extremely unlikely, if not impossible.

Some were willing to concede that maybe leeches that climbed up things would detach their suckers and essentially fall down. But leeches are not weak animals.

They're muscular, and they very much, in this case, are using those muscles. I think for both Maya and for me, the video is so obvious. It's so clear what's happening. There's a leech. It jumps, right? It's like, yeah, that leech jumps. People's nightmares are true.

Regina Barber
People's nightmares are true.

Short Wave from NPR
Yeah. And I mean, it does kind of feel like the scientific community should have figured this out sooner. But Michael and Mai said there's a lot about terrestrial leeches that we still don't know.

Michael Tesler
Most invertebrates are painfully understudied. Leeches actually get more attention than most because people get grossed out by them and they're scared.

Mai Fahmi
There's so much mystery, you know, so much we don't yet understand about why they do what they do in terms of their I feeding behavior, the way they move, how long they survive, you know, what they're capable of doing or transmitting or teaching us, or. There's just so many unanswered questions still.

Short Wave from NPR
And here's the thing, Gina, researchers like Maya and Michael are worried that we might never answer those questions if we don't start seriously addressing climate change.

Mai Fahmi
Old, pristine rainforests are unfortunately disappearing globally.

They're taking leeches with them. And as we've discussed, we know so little about them, including their diversity overall, their behaviors, their inclinations.

That's part of, you know, the biodiversity crisis that we're living through and the effects of climate change that we're witnessing. We're losing what we don't know.

Short Wave from NPR
We have researchers estimate that we lost 3.7 million tropical rainforest last year. Thats like ten soccer fields every minute, which is huge on its own. Right? Like, these forests are important for sucking up and storing carbon dioxide, which otherwise gets released as a greenhouse gas and worsens climate change. Right. We dont need that.

Regina Barber
No. Thats so horrifying.

Short Wave from NPR
But it also means that we could lose all the biodiversity that comes with that forest. Rainforests are home to half the living animal and plant species in the world, and we might never get to learn about those species or how they support the local ecosystem or how they could be helpful to humans. For our human centric listeners out there.

Regina Barber
Like me, like you, Hannah, thank you so much. For making me care about leeches. I mean, this has been a really fun, yet very bloody story. And also, welcome to the pod.

Short Wave from NPR
Thank you so much, Gina. This was a lot of fun.

Regina Barber
This episode was produced and fact checked by Hannah Chin. It was edited by showrunner Rebecca Ramirez. And the audio engineer was Maggie Luthar. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to short wave from NPR.

NPR Sponsor
This message comes from NPR sponsor American Express. Take your business further with the smart and flexible Amex Business Gold card. It's packed with benefits that help unlock more value from your business purchases. Learn more@americanexpress.com BusinessGoldcard support for NPR and.

NPR Sponsor
The following message come from Rosetta Stone, the perfect app to achieve your language learning goals. No matter how busy your schedule gets. It's designed to maximize study time with immersive ten minute lessons and audio practice for your commute. Plus, tailor your learning plan for specific objectives like travel. Get Rosetta Stone's lifetime membership for 50% off and unlimited access to 25 language courses. Learn more@rosettastone.com nprezhen.