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Speaker 1: When most people think of leeches, they're immediately disgusted, or

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Speaker 1: at least that's been my experience when I talk to

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Speaker 1: people about leeches. But what is it about leeches that

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Speaker 1: results in so much more disgust than we feel when

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Speaker 1: we talk about other blood suckers like mosquitoes. Maybe it's

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Speaker 1: that scene from Stand By Me or that scene from

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Speaker 1: African Queen, or maybe it's something else altogether. And look, today,

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Speaker 1: I'm sure we're not going to convince most of you

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Speaker 1: that leeches are beautiful. But I hope that when you

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Speaker 1: listen to this episode, Anna and I are able to

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Speaker 1: convince you that leeches are Okay, fine, maybe they're disgusting,

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Speaker 1: but they're all so fascinating and maybe they're even helpful

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Speaker 1: to people. So, for example, you know, maybe you've heard

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Speaker 1: that leeches used to be used to try to draw

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Speaker 1: blood to treat just about any problem that humans used

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Speaker 1: to have a long time ago, But did you know

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Speaker 1: that leeches are still used in particular medical cases and

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Speaker 1: they're actually helpful, and that leeches produce anti coagulants, which

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Speaker 1: are these chemicals that make sure your blood doesn't clot

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Speaker 1: up that are useful in a variety of medical settings,

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Speaker 1: so understanding leeches can be helpful for human health as well.

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Speaker 1: On today's episode, we have doctor Anna Phillips, who's the

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Speaker 1: curator of earthworms and parasitic worms at the Smithsonian Natural

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Speaker 1: History Museum in Washington, d C. And I can't think

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Speaker 1: of a better person to talk to us today about leeches.

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Speaker 1: So welcome to Daniel and Kelly's extraordinary and sometimes a

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Speaker 1: little bit disgusting universe.

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Speaker 2: Hi. I'm Daniel. I'm a particle physicist, and I've never

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Speaker 2: been bitten by a particle.

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Speaker 3: Hi.

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Speaker 1: I'm Kelly Wienersmith. I'm a parasitologist and I've been bitten

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Speaker 1: by leeches and it was okay, it was fine.

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Speaker 2: Ends clearly they've infected you with some sort of brain

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Speaker 2: disease that made you think it was okay.

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Speaker 1: You know, we're gonna learn today the surprisingly they don't

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Speaker 1: vector a lot of diseases. I'm like mosquitoes and ticks,

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Speaker 1: they're not so bad. They're just hungry, which I get.

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Speaker 2: I get that you've been brainwashed, you've been leech washed

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Speaker 2: by leeches. I am not okay with being bitten by leeches.

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Speaker 1: Well, I'm hoping that we can leech wash at least

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Speaker 1: a few of our listeners today into thinking that leeches

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Speaker 1: are maybe still gross, but that there's absolutely some fascinating

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Speaker 1: stuff to learn from them.

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Speaker 2: All right, well, then my question for you today, Kelly,

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Speaker 2: is what is the grossest thing you have been bitten by?

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Speaker 1: Oh? Gosh, the grossest thing I've been bitten by? I

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Speaker 1: guess that's gotta be ticks.

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Speaker 2: Ticks are the worst.

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Speaker 1: I hate ticks. I really hate ticks. Like leeches. I'm

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Speaker 1: okay with ticks, man, I hate them. You know. So

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Speaker 1: you get a take, you pull it off, and you're like, oh, well,

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Speaker 1: now should I send it in for testing? Do I

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Speaker 1: have to worry that I got lime disease? What about

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Speaker 1: you know, Rocky Mountain spotted fever? And whereas if you

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Speaker 1: get bit by a leech, just like, oh I'm bleeding

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Speaker 1: a little. That stinks, but you don't worry about what's

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Speaker 1: going to happen afterwards, like that's the end of the encounter.

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Speaker 1: And I get bit by ticks pretty often and it

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Speaker 1: kind of freaks me out. I regularly spray my clothes

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Speaker 1: with permethrin during the summer when I'm going to be

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Speaker 1: going out in the woods, and like every member of

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Speaker 1: our family has a set of permethrin treated clothes that

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Speaker 1: they wear if they're going to be going out into

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Speaker 1: the woods, because we've already had some lime in the

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Speaker 1: family and we don't want anymore. What about you, what's

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Speaker 1: the weirdest or gressest thing you've ever been bitten by?

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Speaker 1: Not a particle.

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Speaker 2: I was bitten by our pet rats once, so I

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Speaker 2: have had a rat bite, and in their defense, my

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Speaker 2: finger was covered with whipped cream and I stuck it

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Speaker 2: in the cage and they got very enthusiastic. I don't

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Speaker 2: think they were trying to bite my finger, but you know,

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Speaker 2: how could you control yourself? It's whipped cream.

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Speaker 1: I get it. I'm sorry. I understand the rats in

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Speaker 1: that case. I've also been bit by a boa constrictor

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Speaker 1: when I went to feed it a rat and I

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Speaker 1: wasn't really careful about what I was doing with my hand.

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Speaker 1: And then I also got bit once by an alligator

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Speaker 1: gar Have you seen these?

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Speaker 2: Is that like an alligator.

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Speaker 1: It's a fit with an alligator like mouth. They're common

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Speaker 1: in the South, but there's also some in Lake Eerie

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Speaker 1: and I was doing a fish survey and I thought

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Speaker 1: one had passed away, but even though it was very dry,

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Speaker 1: it was still kicking. So I grabbed it by the

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Speaker 1: tail and it turned around, and I was like, ah,

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Speaker 1: I'm so.

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Speaker 2: Sorry it's biting you and you're apologizing to it. Wow,

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Speaker 2: you're so polite.

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Speaker 1: I mean, if I were on the way out and

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Speaker 1: somebody was harassing me, I would be grumpy about that too.

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Speaker 1: I understood where it was coming from, but yeah, sorry.

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Speaker 1: Your story reminded me of some of my other stories

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Speaker 1: that how could I have forgotten?

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Speaker 2: Well, your comment earlier about not being too grumpy about

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Speaker 2: giving blood to leeches made me think about mosquitoes, because

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Speaker 2: we recently had mosquitoes basically taking over southern California. When

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Speaker 2: I moved here twenty years ago, there were almost no mosquitoes,

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Speaker 2: and how their mosquitoes everywhere drives me crazy because I

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Speaker 2: would happily give up a little bit of blood to

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Speaker 2: mosquitoes if they didn't deposit the anesthetic that you then

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Speaker 2: react to like it frustrates me endlessly. I would like

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Speaker 2: set out a little pool of blood, you know, for

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Speaker 2: them every day. If we could strike a deal with

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Speaker 2: mosquitoes like stop giving me bites and drink my blood,

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Speaker 2: I would happily give up blood to avoid mosquito bites.

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Speaker 1: Oh, man, only we could have like a doctor Doolittle.

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Speaker 1: But who could communicate with the mosquitos to set that

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Speaker 1: kind of exchange up? That would be ideal. Why do

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Speaker 1: you have so many more mosquitos? Has a new species

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Speaker 1: moved in? Is it wetter? With more standing pools of water?

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Speaker 1: Would change?

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Speaker 2: I read this story once that claimed that they all

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Speaker 2: came in one shipping container to Long Beach from China

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Speaker 2: and they basically took over like it was a huge

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Speaker 2: invasion of this Chinese tiny mosquito, not like the big

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Speaker 2: American mosquitoes, but these little ones that also bite you

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Speaker 2: multiple times, so you don't just get like one bite,

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Speaker 2: you could like a series of bites. Oh really, not

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Speaker 2: a fan?

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Speaker 3: Wait?

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Speaker 1: Why was China shipping us mosquitoes? They just accidentally got

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Speaker 1: into a shipment? Is that the deal?

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Speaker 2: Or somebody ordered mosquitos on Amazon and now we're all suffering?

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Speaker 4: No?

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Speaker 2: I think it was an accident. Yeah, there was some

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Speaker 2: pool standing water in this shipping container and they survived

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Speaker 2: the transit and they opened it up in Long Beach.

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Speaker 2: Dot dot dot. My life is now terrible.

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Speaker 1: That's the worst. I'm sorry. We've got an Asian longhorn

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Speaker 1: and tick, which I think also accidentally got here, and

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Speaker 1: it can reproduce without finding a mate. You get one,

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Speaker 1: and then you've got ten, and then you've got hundreds.

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Speaker 1: And there are cattle out here that are getting like exsanguinated.

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Speaker 1: If they're not checked on regularly enough, they end up

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Speaker 1: getting tons of them and then they don't have enough

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Speaker 1: blood to do what they need to do.

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Speaker 2: So anyway, exanguinated, my mental image is that you go

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Speaker 2: out to check on your cow and it's just like

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Speaker 2: a dry heap of skin and bones. Is that what

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Speaker 2: we're talking about.

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Speaker 1: I think they die before they look how you might

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Speaker 1: imagine Dracula looks waking up in the morning. But yeah,

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Speaker 1: I mean the dying from lack of blood. And I

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Speaker 1: think there's some concern that there's a hemorrhagic fever in

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Speaker 1: the native area that like could jump to here and

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Speaker 1: now instead of in addition to lime, you'd have to

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Speaker 1: worry about hemorrhagic fevers. And anyway, it's so great that

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Speaker 1: we can ship stuff around the world, but it's got

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Speaker 1: its downsides.

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Speaker 2: All right, Well, today we're not just talking about what

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Speaker 2: Daniel doesn't like to be bitten by, and what Kelly

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Speaker 2: doesn't mind being bitten by. We're talking about all the

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Speaker 2: exciting signs behind leeches.

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Speaker 1: And so we asked you what is the first thing

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Speaker 1: you think when you think of leeches? And I got

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Speaker 1: to say, I got a couple answers that I expected,

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Speaker 1: a couple that were very unexpected. And if you would

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Speaker 1: like to be asked what you think about a topic

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Speaker 1: we're going to talk about on the show, email us

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Speaker 1: at questions at Daniel and Kelly dot org. So let's

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Speaker 1: hear what our listeners had to say.

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Speaker 3: A picture that I've seen of a black hole eating

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Speaker 3: the material from a closely orbiting star.

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Speaker 5: Honestly, they're just the wist and I can't think of

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Speaker 5: anything more disgusting. The first thing I think of is

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Speaker 5: medical grade leeches that are used to drain blood from hematomas,

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Speaker 5: bruises under the skin that have a lot of blood

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Speaker 5: in them.

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Speaker 6: The first thing I think of when I hear leeches

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Speaker 6: is traveling down the Brasis River in Texas on a

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Speaker 6: boy scout trip and on an inner tube and coming

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Speaker 6: out with leeches stuck to the inner tube and a

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Speaker 6: few to my legs. No fun.

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Speaker 4: Watching the movie The African Queen with Katherine Hepburn and

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Speaker 4: Humphrey Bogart, and they have to tow his boat through

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Speaker 4: the swamp, waiting in the swamp, and when they get

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Speaker 4: out there covered with leeches, and they have to spread

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Speaker 4: salt on the leeches to get them off.

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Speaker 7: Medieval medical practices where they were used for almost everything

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Speaker 7: from headaches to ingrown toenails. I don't know conjunct to

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Speaker 7: fight us not all it being one of Dracula's favorite pets.

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Speaker 1: They've seen and stand by Me where they're swimming across

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Speaker 1: the swamp and they suddenly discover that they're covered in leeches.

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Speaker 2: I think of the movie stand by Me.

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Speaker 6: Wasn't there an old black and white movie called Attack

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Speaker 6: of Leeches?

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Speaker 3: Or something seen from stand by Me?

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Speaker 5: The third thing that comes to mind is the irs.

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Speaker 2: I think of the way they ribed and twisted.

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Speaker 1: When I discovered them as a kid, I thought it

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Speaker 1: was swimming around my finger in a strange way.

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Speaker 2: Then I pictured my mom screaming.

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Speaker 5: The barber surgeon from the Middle Ages applying them meditionally

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Speaker 5: up with that in quotes.

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Speaker 1: So I love that. The very first answer that hit

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Speaker 1: my inbox was a picture that I've seen of a

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Speaker 1: black hole eating the material from a closely orbiting star.

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Speaker 1: I was like, Wow, in my world, that is not

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Speaker 1: what you would expect the answer to be. But like,

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Speaker 1: I see that, that's a fascinating answer. That was great.

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Speaker 2: That's our audience right there. Physics biology crossover.

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Speaker 1: Yeah, it's amazing. And then most of the other responses

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Speaker 1: were like I expected people to mention stand by me,

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Speaker 1: and I expected people to mention that one movie with

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Speaker 1: Catherine Hepburn African Queen I think it was, and then

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Speaker 1: mostly to be grossed out. And so that was more

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Speaker 1: or less what I was expecting. What did you think?

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Speaker 2: Yeah, these answers basically mimic my thoughts about leeches. I'm

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Speaker 2: totally uninformed. I don't know anything about leeches compared to

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Speaker 2: anything else except that I'm grossed out with anything bites me.

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Speaker 2: So I'm curious to learn what is the science of leeches,

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Speaker 2: what are leech scientists leechologists working on. What motivates somebody

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Speaker 2: to get into leeches anyway, rather than basic any other

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Speaker 2: field of science. So yeah, I want to meet your

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Speaker 2: friend and hear all about leeches.

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Speaker 1: Wait, wait, so would you say that this is at

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Speaker 1: the bottom of the list of science jobs you would

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Speaker 1: want studying leeches.

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Speaker 2: It's not near the top, that's for sure. I wouldn't

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Speaker 2: put it in the top fifty or one thousand science jobs.

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Speaker 2: I mean, I think I'm pretty capable of getting interested

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Speaker 2: in almost anything, but yeah, this is a bit of

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Speaker 2: a gross out factor for me.

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Speaker 1: I gotta say, if somebody said you could be the

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Speaker 1: leech person at the Smithsonian Museum, I'd be like, I

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Speaker 1: enjoyed studying space, but I'm studying leeches now, and I

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Speaker 1: would make that jump. All right, So today we are

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Speaker 1: talking to doctor Anna Phillips. She works for the Smithsonian

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Speaker 1: Natural histor Museum in Washington, DC, and she is just

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Speaker 1: delightful and she's going to tell us all about leeches.

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Speaker 2: And wait for it, I'm going to make a connection

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Speaker 2: between Kelly's two passions, space and leeches.

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Speaker 1: Yeah, that was pretty clever at the end there, All right, enjoy.

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Speaker 1: Doctor Anna Phillips is a research zoologist and curator of Klitalata,

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Speaker 1: which is a class of anilid worms also known as

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Speaker 1: earthworms and parasitic worms. At the Smithsonian Museum of Natural History.

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Speaker 1: She studies biodiversity and the evolutionary history of parasitic worms

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Speaker 1: and specializes in leeches and tapeworms. She's my hero in

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Speaker 1: my world. She's a legend for doing her leech dance

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Speaker 1: in a video for the BBC, which we're going to

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Speaker 1: discuss later in the show. Welcome Anna, I I'm excited

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Speaker 1: to be here. I'm excited to have you here. Did

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Speaker 1: I say klitalada rte or did I say it wrong?

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Speaker 3: Works for me?

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Speaker 1: Nice? Oh man. I always love it when I get

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Speaker 1: those slam dugs right from the beginning. So, you know,

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Speaker 1: I think for a lot of people when we're growing

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Speaker 1: up as kids, like I thought maybe I would study

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Speaker 1: tigers or elephants, or you know, maybe anything other than

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Speaker 1: worms living in the brains of fish. What was your

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Speaker 1: path to getting excited about leeches.

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Speaker 3: I was definitely not a five year old who thought

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Speaker 3: I would grow up to study worms. It was a

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Speaker 3: little bit of a winding road. When I was a kid,

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Speaker 3: I was really excited about dinosaurs. They were sort of

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Speaker 3: a good introduction into the scientific world for me. But

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Speaker 3: as I got older, I realized there were a lot

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Speaker 3: more other cool animals out in the world. And when

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Speaker 3: I was an undergraduate, I applied for an internship through

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Speaker 3: a program run by the National Science Foundation called Research

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Speaker 3: Experience for Undergraduates, the RIU program, and it's funded by

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Speaker 3: the National Science Foundation, and it's an opportunity for students

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Speaker 3: to go work in science labs and working with me,

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Speaker 3: a real scientist, and to work on projects and learn

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Speaker 3: about the scientific research process. And there were many different projects.

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Speaker 3: There were ones on scorpions and bats and bees and catfish,

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Speaker 3: and there was one on leeches. And I thought, oh, no,

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Speaker 3: one will apply for the one on leeches. I'll have

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Speaker 3: better odds. That's amazing. Yeah, so I applied and it

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Speaker 3: turns out six people applied. Oh, but I was selected.

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Speaker 3: And that summer ended up being everything I thought science

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Speaker 3: should be. There was work with specimens, there was field work.

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Speaker 3: I went to a conference, got to work in a

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Speaker 3: molecular lab, and we ended up being able to publish

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Speaker 3: it nice. So then my advisor invited me back for

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Speaker 3: a PhD to expand the project from my internship, and

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Speaker 3: it was the rest is history.

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Speaker 2: Do you think that you were lucky that you happened

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Speaker 2: to stumble on a field you were fascinated by, or

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Speaker 2: are you just the kind of person who can dig

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Speaker 2: into anything and find the mysteries and the juicy questions,

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Speaker 2: and that you just happened to end up in this field.

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Speaker 3: I think there's a quality of researchers who like to

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Speaker 3: dig in and find the juicy questions. So in some

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Speaker 3: sense I could have ended up in other places and

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Speaker 3: studying other animals, but leeches ended up being a really

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Speaker 3: good fit for me. I had always found worms to

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Speaker 3: be more interesting than like molluscs or insects or other things.

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Speaker 3: It's also a good fit in the sense that, like,

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Speaker 3: no matter where you go in the world, people know

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Speaker 3: what leeches are. It's like the one worm that everyone

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Speaker 3: You can say like all the bloodsucking worms, and you know,

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Speaker 3: sort of point to your skin and people are like, oh,

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Speaker 3: I know what that is. So even if they don't

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Speaker 3: speak English, I think things worked out in a way.

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Speaker 3: But yeah, I do kind of get distracted sometimes and

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Speaker 3: find other things that I could dive in on and

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Speaker 3: have to go no. No, remember parasites.

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Speaker 1: So when students contact me and they say, oh, I

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Speaker 1: want to go into marine biology, I'm like, Okay, I

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Speaker 1: know you're excited about the dolphins, but an easier way

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Speaker 1: in is the dolphin parasites Because fewer people are excited

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Speaker 1: about those, and then you can become a marine biologist

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Speaker 1: through the parasites. And I'm really hoping that they're going

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Speaker 1: to get hooked on the parasites. And I have been

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Speaker 1: surprised by how many students do get hooked on the

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Speaker 1: parasites and then they're like, yeah, yeah, the dolphins are cool,

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Speaker 1: but have you looked at the look at this worm.

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Speaker 1: And I'm like, yes, we've hooked you exactly.

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Speaker 3: Yeah. And this is what I tell a lot of

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Speaker 3: students coming through is that it's good to have a

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Speaker 3: goal and to be ambitious and to be aiming for something,

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Speaker 3: but also flexibility, to have flexible interest, I would say,

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Speaker 3: because like I said, I wanted to study dinosaurs and

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Speaker 3: now I study worms and they don't even have fossils.

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Speaker 3: But you know, it worked out. I'm pretty happy.

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Speaker 1: I'm glad you're happy. So let's talk about where leeches

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Speaker 1: are on the tree of life, so like what are

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Speaker 1: their closest relatives, and then also like how many species

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Speaker 1: of leeches do we think that there are? So, like

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Speaker 1: you said in your intro, leeches are clidalate anaalids, so

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Speaker 1: an analyta, these are the segmented worms with body cavities.

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Speaker 3: So there's all the polykeets, which are the marine worms,

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Speaker 3: which I don't focus on those because I don't work

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Speaker 3: in marine environments very often. And then the other anelids

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Speaker 3: are the clydalit anelids. This includes the oliga keats, which

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Speaker 3: includes earthworms. It also includes brankie of deeladins, which are

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Speaker 3: the crayfish worms, so they are symbiotic worms that live

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Speaker 3: with crayfish. They're not parasitic, they're commensal organism. And then

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Speaker 3: they're the leeches. With leeches, about half of them are

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Speaker 3: blood feeding and the other half aren't.

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Speaker 1: What are the other half doing?

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Speaker 3: They're eating insect larvae, bacterial mats, just about anything and

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Speaker 3: getting their mouths around. But they're not sucking blood, so

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Speaker 3: they're not as interesting.

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Speaker 2: So what are the big open science questions about leeches?

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Speaker 2: I think it's fascinating that Kelly's first question is like,

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Speaker 2: how do these relate to other living critters? Where do

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Speaker 2: you put them on the tree of life? How do

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Speaker 2: we organize them? Is that the motivating question? Is it,

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Speaker 2: like all to try to understand how everything got here

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Speaker 2: in the evolutionary history of it? Or are there still mysteries,

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Speaker 2: but like, how do leeches accomplish this amazing thing they do?

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Speaker 2: What are the sort of biggest open questions there in leeches?

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Speaker 3: My research is with systematics and evolutions, so looking at

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Speaker 3: the number of species, describing new species, how they're related

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Speaker 3: to each other. So that's most of what my expertise is,

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Speaker 3: and that's also what I find interesting. There are so

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Speaker 3: many other aspects of leech biology that have many interesting questions.

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Speaker 3: So for leeches, there's probably between eight hundred and a

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Speaker 3: thousand species of leeches in the world, which compared to

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Speaker 3: a lot of other worm groups, is pretty small. Like

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Speaker 3: Nematodes has probably more than sixteen thousand species. So the

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Speaker 3: order of tapeworms that I work in has more than

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Speaker 3: thirty five hundred species, so eight hundred is pretty small.

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Speaker 3: But what's really cool about leeches is to all the

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Speaker 3: different evolutionary transitions within that group. In terms of the

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Speaker 3: interesting questions it's looking at, like, wow, we have so

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Speaker 3: many different feeding strategies. They occur in so many different environments.

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Speaker 3: There's marine leeches, there's terrestrial leeches, there's burrowing leeches as

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Speaker 3: well as the blood feeders, and so with all of

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Speaker 3: these different evolutionary transitions. It's a more tractable group to

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Speaker 3: explore those questions because you don't have to go through

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Speaker 3: five hundred species. You can look at smaller groups with

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Speaker 3: twenty or something, which is easier to approach. And then,

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Speaker 3: like I said, they're pretty accessible. You can go to

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Speaker 3: a lot of different places in the world and find

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Speaker 3: leeches a lot of different habitats, and that can be

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Speaker 3: easier than like studying things in the deep sea, for instance,

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Speaker 3: where it's very expensive and revolves a lot of equipment

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Speaker 3: and planning.

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Speaker 1: So when we asked our audience what they think of

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Speaker 1: when they think of leeches, a number of them noted

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Speaker 1: that in like medieval times, leeches were used to treat

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Speaker 1: like every single disease you could imagine, And so I

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Speaker 1: was wondering if you could speak at all to the

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Speaker 1: current use of leeches in medicine. I know that's not systematics,

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Speaker 1: Is it okay to ask you about that?

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Speaker 3: Sure? Yeah, yeah. This is actually one of the points

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Speaker 3: of why leeches are important to the world because of

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Speaker 3: their use in medicine, they've also been used as a

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Speaker 3: model organism in a number of other fields, like neurology,

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Speaker 3: and some importance in pharmacology and developmental biology studies. But

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Speaker 3: when it comes to their use in medicine, yeah, they

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Speaker 3: were really popular in the seventeen eighteen hundreds for blood letting.

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Speaker 3: Prior to that, people would cut open arteries and veins

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Speaker 3: to balance the humors and get some with the blood out.

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Speaker 3: But leeches were an improvement on the situation because it's

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Speaker 3: easier to get it to stop bleeding versus when you

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Speaker 3: slice open artery in vain that it can be a challenge. Also,

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Speaker 3: if you want to take more blood, you put more

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Speaker 3: leeches on. If you want to take less blood, you

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Speaker 3: take them off. It was a more controllable way of

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Speaker 3: blood letting.

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Speaker 1: Just to be clear, it wasn't helping anything, right, It

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Speaker 1: was just like a less damaging way to damage your patient,

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Speaker 1: and that was the benefit back then. Is that right?

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Speaker 3: They thought it was helping. Okay, but now we know

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Speaker 3: that leeches are only beneficial in certain cases. It's not

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Speaker 3: going to cure your headache, it's not gonna to your hysteria,

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Speaker 3: So the blood letting only helps certain situations. So today

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Speaker 3: in modern medicine, leeches are still used. They were approved

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Speaker 3: as a medical device in the US in two thousand

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Speaker 3: and four, so they're not experimental. So what they're usedful

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Speaker 3: in modern medicine is because leeches have antiquagulants in their saliva,

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Speaker 3: so when they're abiding, they're exuding this ty wagulants blood

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Speaker 3: thinner that's going locally into the wound, and it helps

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Speaker 3: the leech because the wound continues to bleed and the

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Speaker 3: anti wagulant prevents it from clotting, so that means that

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Speaker 3: the leech can ingest the liquid blood easier. But once

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Speaker 3: the leech has finished feeding and it leaves, that wound

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Speaker 3: continues to bleed because those anti coagulants are in a tissue.

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Speaker 3: We take advantage of this in medicine, so in cases

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Speaker 3: where you have a skin graft that has been attached,

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Speaker 3: or if digit reattachment so you cut your finger off

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Speaker 3: and they put it back on. They can attach a

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Speaker 3: lot of the small vessels that bring blood into the digit,

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Speaker 3: but the veins that take the blood away are thinner walled.

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Speaker 3: It's harder to attach those, and a lot of times

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Speaker 3: they get the major vessels together, but they have to

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Speaker 3: wait for those veins to regrow on their own. In

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Speaker 3: the meantime, this means all the blood is rushing into

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Speaker 3: this digit, it's swelling up, it's turning purple. It's painful.

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Speaker 3: We can give anti coagulants and blood thinners systemically, like

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Speaker 3: through the whole body, but you have a risk of

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Speaker 3: major bleeding and it's kind of overkill when you just

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Speaker 3: need to get it into that digit. So leeches have

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Speaker 3: really tiny mouths and we can put them on the

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Speaker 3: ends of fingers and noses and ears, and when they

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Speaker 3: start feeding, that anti coagulant goes locally. It helps keep

432
00:21:17,600 --> 00:21:20,199
Speaker 3: all of the blood flowing so there's no clotting, and

433
00:21:20,240 --> 00:21:24,000
Speaker 3: then they're relieving that pressure by sucking the blood out

434
00:21:24,800 --> 00:21:28,520
Speaker 3: and it encourages oxygenated blood to get into this damaged tissue.

435
00:21:28,640 --> 00:21:31,760
Speaker 3: And so you can see within hours these fingers and

436
00:21:32,000 --> 00:21:35,120
Speaker 3: toes go from being purple and swollen just suddenly looking

437
00:21:35,200 --> 00:21:38,000
Speaker 3: much more normal and pink and healthy.

438
00:21:37,720 --> 00:21:40,359
Speaker 1: Again, aside from all the leeches hanging off of it.

439
00:21:41,359 --> 00:21:44,960
Speaker 3: Well, yeah, I mean they feed pretty quickly, so they're

440
00:21:45,000 --> 00:21:46,040
Speaker 3: not going to be there too long.

441
00:21:46,840 --> 00:21:49,320
Speaker 2: It almost sounds like you're recommending leeches.

442
00:21:49,119 --> 00:21:54,000
Speaker 3: In certain cases. Wow, they can be a preferable option

443
00:21:54,520 --> 00:21:57,399
Speaker 3: to other options. Yeah, we also have machines that you

444
00:21:57,400 --> 00:22:01,240
Speaker 3: can put and suck out blood. But those you typically

445
00:22:01,280 --> 00:22:04,520
Speaker 3: adhere better to broad surfaces like your back or your leg,

446
00:22:05,240 --> 00:22:09,080
Speaker 3: But things like fingers and noses and ears have funny shapes,

447
00:22:09,359 --> 00:22:11,480
Speaker 3: so leeches they attached better.

448
00:22:12,080 --> 00:22:15,360
Speaker 2: That blows my mind. I think the pop side understanding

449
00:22:15,480 --> 00:22:17,679
Speaker 2: of leeches, at least, you know, the superficial one that

450
00:22:17,760 --> 00:22:20,199
Speaker 2: I have as a total non expert, is that, like,

451
00:22:20,240 --> 00:22:22,680
Speaker 2: people used to use leeches back when they understood nothing

452
00:22:22,720 --> 00:22:25,280
Speaker 2: about the body, and it was crazy, like drilling holes

453
00:22:25,280 --> 00:22:27,680
Speaker 2: in your head. But now you're telling me that there

454
00:22:27,680 --> 00:22:30,840
Speaker 2: are some scenarios where leeches can actually improve the outcome

455
00:22:30,880 --> 00:22:33,080
Speaker 2: for a patient. And that makes me wonder, do you

456
00:22:33,080 --> 00:22:35,399
Speaker 2: think those experiences one hundreds of years ago before we

457
00:22:35,480 --> 00:22:38,600
Speaker 2: understood stuff, are what encouraged people to continue using them

458
00:22:38,600 --> 00:22:40,120
Speaker 2: that sometimes they actually did help.

459
00:22:40,280 --> 00:22:43,359
Speaker 3: I think there's a quality to that definitely. Like I said,

460
00:22:43,520 --> 00:22:45,520
Speaker 3: they're not a cure all, but there were some cases

461
00:22:45,520 --> 00:22:47,880
Speaker 3: that leeches are helpful.

462
00:22:48,119 --> 00:22:48,439
Speaker 2: Wow.

463
00:22:48,760 --> 00:22:51,160
Speaker 3: And then that also promoted a lot of research into

464
00:22:51,240 --> 00:22:56,159
Speaker 3: why so as we developed more questions, part of that

465
00:22:56,240 --> 00:22:58,439
Speaker 3: is looking at those anti coagulants and saying, like, well,

466
00:22:58,440 --> 00:23:01,960
Speaker 3: what anti coagulants are using and can we take that

467
00:23:01,960 --> 00:23:05,760
Speaker 3: into a pharmacology setting and you know, use those mechanisms

468
00:23:06,200 --> 00:23:09,520
Speaker 3: without having to actually use the worms themselves. And what

469
00:23:09,560 --> 00:23:12,800
Speaker 3: they found is that a lot of leeches have heuridin

470
00:23:13,920 --> 00:23:16,400
Speaker 3: and this is an anti coagulant that's actually the most

471
00:23:16,400 --> 00:23:20,640
Speaker 3: powerful anti coagulant known. In fact, we don't use it

472
00:23:20,720 --> 00:23:25,480
Speaker 3: in modern medicine because it's too good. So one of

473
00:23:25,560 --> 00:23:28,760
Speaker 3: the things about anti wagulants is that when it's causing

474
00:23:28,800 --> 00:23:30,840
Speaker 3: the blood to continue flowing, we also want to have

475
00:23:30,880 --> 00:23:33,560
Speaker 3: the ability to stop that. If you have an anti

476
00:23:33,640 --> 00:23:36,879
Speaker 3: wagulant in your system and you have a major bleeding episode,

477
00:23:36,880 --> 00:23:38,399
Speaker 3: we want to be able to stop that quickly. And

478
00:23:38,680 --> 00:23:41,520
Speaker 3: heurdin is not the best for that. We have a

479
00:23:41,560 --> 00:23:43,680
Speaker 3: hard time getting it to stop. So we have other

480
00:23:43,720 --> 00:23:46,280
Speaker 3: options now, but it is something that's out there and

481
00:23:46,400 --> 00:23:49,760
Speaker 3: the scientific community is working with understanding the mechanisms and

482
00:23:49,800 --> 00:23:52,240
Speaker 3: the process to improve drug development.

483
00:23:52,560 --> 00:23:56,000
Speaker 1: So mosquitoes and ticks also make anticoagulants. Why don't we

484
00:23:56,119 --> 00:23:59,159
Speaker 1: use them when your finger falls off or leach is

485
00:23:59,200 --> 00:24:01,120
Speaker 1: just even better or less creepy.

486
00:24:01,680 --> 00:24:06,359
Speaker 3: In terms of why the leech anti coagulants would be preferable,

487
00:24:06,400 --> 00:24:07,280
Speaker 3: I actually don't know.

488
00:24:08,520 --> 00:24:11,240
Speaker 2: I refuse to believe the mosquitoes could do anything useful

489
00:24:11,240 --> 00:24:11,719
Speaker 2: for anybody.

490
00:24:11,760 --> 00:24:14,560
Speaker 1: They are purely even I'm not a fan either.

491
00:24:14,600 --> 00:24:16,800
Speaker 3: A lot of people would agree with you. I think

492
00:24:16,880 --> 00:24:20,639
Speaker 3: leeches are much more controllable versus mosquitoes and ticks, especially

493
00:24:20,800 --> 00:24:24,159
Speaker 3: in a medical setting. And the other aspect is that

494
00:24:24,280 --> 00:24:28,199
Speaker 3: leeches carry far fewer diseases than mosquitoes and ticks.

495
00:24:28,720 --> 00:24:29,800
Speaker 1: Could you tell us more about that?

496
00:24:30,240 --> 00:24:34,120
Speaker 3: So to this point, they've done a ton of research

497
00:24:34,200 --> 00:24:39,199
Speaker 3: looking at our leeches vectors for bloodborne diseases, and some

498
00:24:39,320 --> 00:24:41,640
Speaker 3: of the work that was done, especially in the nineties

499
00:24:41,640 --> 00:24:44,719
Speaker 3: when people were really investigating HIV, to see if leeches

500
00:24:44,720 --> 00:24:47,240
Speaker 3: were a vector for HIV. What they found is that

501
00:24:47,720 --> 00:24:51,560
Speaker 3: when a leech feeds on a mouse, for instance, that's

502
00:24:51,560 --> 00:24:54,679
Speaker 3: infected with these viruses, you can still isolate the virus

503
00:24:54,720 --> 00:24:57,080
Speaker 3: from the blood meal inside leech. But when they fed

504
00:24:57,240 --> 00:25:00,399
Speaker 3: the leech on the next mouse that didn't have those visviruses,

505
00:25:00,520 --> 00:25:04,240
Speaker 3: it doesn't necessarily transmit. Okay, So if you're out getting

506
00:25:04,240 --> 00:25:07,400
Speaker 3: bitten by leeches, you know, could you get viruses and

507
00:25:07,560 --> 00:25:12,000
Speaker 3: bloodborn pathogens from that? It's possible, but it's a very

508
00:25:12,080 --> 00:25:16,040
Speaker 3: very low chance. That's also a good thing about using

509
00:25:16,119 --> 00:25:20,040
Speaker 3: leeches in modern medicine versus things like mosquitoes and ticks,

510
00:25:20,080 --> 00:25:24,919
Speaker 3: which transmit a lot of really scary, dangerous viruses.

511
00:25:25,720 --> 00:25:28,280
Speaker 1: And other hosts for leeches. There are a lot of

512
00:25:28,359 --> 00:25:30,800
Speaker 1: leeches that, for example, specialize on turtles, Like do they

513
00:25:30,880 --> 00:25:34,280
Speaker 1: transmit diseases between turtles or in general, are leeches just

514
00:25:34,880 --> 00:25:36,600
Speaker 1: not good at transmitting diseases.

515
00:25:37,080 --> 00:25:39,560
Speaker 3: Actually, it's great that you bring up leeches and turtles

516
00:25:39,600 --> 00:25:42,119
Speaker 3: because there's a couple of cases of different types of

517
00:25:42,119 --> 00:25:46,000
Speaker 3: blood born parasites between the turtles. So, for one, we

518
00:25:46,080 --> 00:25:49,000
Speaker 3: know that they can transmit t for panasomes, which is

519
00:25:49,000 --> 00:25:52,560
Speaker 3: the same organism that causes African sleeping sickness, but it's

520
00:25:52,560 --> 00:25:55,639
Speaker 3: not making turtles sleepy. So we do know that leeches

521
00:25:55,720 --> 00:25:58,360
Speaker 3: have been transmitting panisomes with turtles.

522
00:25:58,440 --> 00:26:00,359
Speaker 1: Could you tell if a turtle with sleep they move

523
00:26:00,400 --> 00:26:03,679
Speaker 1: pretty slow. Maybe it does make them sleepy and we

524
00:26:03,760 --> 00:26:04,359
Speaker 1: just can't tell.

525
00:26:04,520 --> 00:26:07,119
Speaker 3: Someone should look into it. The other thing is that

526
00:26:07,119 --> 00:26:11,680
Speaker 3: they'll to transmit hemogregrons, which are our small blood worn pathogen,

527
00:26:11,880 --> 00:26:13,879
Speaker 3: but as far as we know, it's not making the

528
00:26:13,920 --> 00:26:17,960
Speaker 3: turtles sick. What we found is that turtles that have

529
00:26:18,080 --> 00:26:23,320
Speaker 3: a small home range have fewer species of hemogregrans versus

530
00:26:23,320 --> 00:26:28,399
Speaker 3: turtles that have a wider range encounter have more species,

531
00:26:28,560 --> 00:26:31,680
Speaker 3: which means that they're encountering more leeches and more different

532
00:26:32,320 --> 00:26:35,600
Speaker 3: types of bloodborn pathogens. But it means that the turtles

533
00:26:35,640 --> 00:26:38,680
Speaker 3: that are wandering farther away, which we would assume would

534
00:26:38,720 --> 00:26:41,440
Speaker 3: be they'd be healthier, they actually have a higher number

535
00:26:41,480 --> 00:26:45,040
Speaker 3: of these blood parasites. So in this case it may

536
00:26:45,040 --> 00:26:47,639
Speaker 3: indicate that the turtles are doing better. So maybe the

537
00:26:47,640 --> 00:26:50,760
Speaker 3: blood parasites they don't hurt them that much, and so

538
00:26:51,200 --> 00:26:53,520
Speaker 3: the healthy turtles are moving around a lot, and when

539
00:26:53,520 --> 00:26:56,439
Speaker 3: they get blood parasites, they're like whatever, yeah, as far

540
00:26:56,480 --> 00:26:58,760
Speaker 3: as we know, h Okay, interesting.

541
00:26:59,080 --> 00:27:01,639
Speaker 1: Yeah, we're going to take a break, and then we

542
00:27:01,680 --> 00:27:04,439
Speaker 1: are going to talk about other kinds of hosts that

543
00:27:04,440 --> 00:27:23,880
Speaker 1: we find leeches on. Okay, so Anna, I'm generally interested

544
00:27:23,960 --> 00:27:26,840
Speaker 1: in the different kinds of species that end up getting

545
00:27:26,880 --> 00:27:29,600
Speaker 1: bitten by leeches, but I really want to know what

546
00:27:29,720 --> 00:27:32,320
Speaker 1: is the weirdest place you've ever heard a leech found

547
00:27:32,440 --> 00:27:33,080
Speaker 1: on an animal.

548
00:27:33,880 --> 00:27:37,600
Speaker 3: Leeches will feed on a lot of different hosts, but

549
00:27:37,680 --> 00:27:40,560
Speaker 3: it depends on the kind of leech. So some leeches

550
00:27:40,600 --> 00:27:44,400
Speaker 3: have preferences and others don't really care. So in North

551
00:27:44,400 --> 00:27:48,400
Speaker 3: America like Macrobdella decora, the North American medicinal leech, for instance,

552
00:27:48,880 --> 00:27:53,200
Speaker 3: they just want vertebrate blood. It doesn't really matter. They'll

553
00:27:53,240 --> 00:27:56,960
Speaker 3: go for frogs a lot of frog blood. But also

554
00:27:57,400 --> 00:28:02,320
Speaker 3: they'll feed on fish mammals including humans. So some leeches

555
00:28:02,440 --> 00:28:05,719
Speaker 3: doesn't really matter. Other leeches can be pretty specific, like

556
00:28:05,960 --> 00:28:10,680
Speaker 3: they prefer turtles and maybe a fish, especially in the

557
00:28:10,840 --> 00:28:15,399
Speaker 3: marine environments fish leeches they will actually prefer certain groups

558
00:28:15,400 --> 00:28:18,760
Speaker 3: of fish. So yeah, it's all over the place, but

559
00:28:18,840 --> 00:28:20,679
Speaker 3: it does depend on the type of leech and what

560
00:28:20,720 --> 00:28:21,640
Speaker 3: their preferences are.

561
00:28:21,960 --> 00:28:24,119
Speaker 2: Why would a leech evolve a preference. Isn't it better

562
00:28:24,200 --> 00:28:25,760
Speaker 2: to be able to suck on lots of different kinds

563
00:28:25,760 --> 00:28:26,199
Speaker 2: of stuff?

564
00:28:26,400 --> 00:28:29,280
Speaker 3: You would think This kind of gets into like generalists

565
00:28:29,320 --> 00:28:33,400
Speaker 3: versus specialists and biology and it's what's working for it.

566
00:28:34,359 --> 00:28:38,000
Speaker 1: So most of our audience is physics and astronomy geeks.

567
00:28:38,080 --> 00:28:39,720
Speaker 1: So could you just go into a little bit more

568
00:28:39,720 --> 00:28:41,400
Speaker 1: detail on specialists in generalists?

569
00:28:41,440 --> 00:28:44,800
Speaker 2: Do we understand in general why evolution produces both kinds

570
00:28:44,840 --> 00:28:48,600
Speaker 2: of things? What would inspire one direction versus another, what

571
00:28:48,760 --> 00:28:50,800
Speaker 2: causes it, and do we understand that at all.

572
00:28:51,400 --> 00:28:52,840
Speaker 3: I'm not sure we do in leeches.

573
00:28:53,880 --> 00:28:55,600
Speaker 1: Okay, so here I'm just going to spit ball for

574
00:28:55,640 --> 00:28:58,160
Speaker 1: a second. I can imagine that it could be great

575
00:28:58,240 --> 00:29:01,440
Speaker 1: to be able to drink the blood from any mammal

576
00:29:01,640 --> 00:29:04,280
Speaker 1: you come across. It'd be easier to find food. But

577
00:29:04,320 --> 00:29:08,280
Speaker 1: if you're a specialist, maybe you are more used to

578
00:29:08,320 --> 00:29:10,680
Speaker 1: a particular kind of blood, so it's easier for you

579
00:29:10,720 --> 00:29:14,280
Speaker 1: to extract resources or energy from it. Here's a question

580
00:29:14,360 --> 00:29:17,920
Speaker 1: when leeches bite a host, is there anything in the

581
00:29:17,960 --> 00:29:20,600
Speaker 1: host like that's an immune response that tries to attack

582
00:29:20,680 --> 00:29:23,960
Speaker 1: and kill the leech or do leeches just get free

583
00:29:23,960 --> 00:29:26,560
Speaker 1: meals everywhere they go? Because I can imagine if you

584
00:29:26,600 --> 00:29:28,440
Speaker 1: specialize in a certain kind of host, maybe you get

585
00:29:28,480 --> 00:29:30,560
Speaker 1: good at avoiding their ways of trying to kill you.

586
00:29:31,240 --> 00:29:33,240
Speaker 1: But I guess do leaches just not have those kinds

587
00:29:33,240 --> 00:29:34,360
Speaker 1: of problems.

588
00:29:34,080 --> 00:29:37,440
Speaker 3: With other types of parasites That immune response is really important.

589
00:29:37,560 --> 00:29:40,560
Speaker 3: And I agree in that point with leeches, because they're

590
00:29:40,600 --> 00:29:44,840
Speaker 3: temporary ectoparasites, They're not there long enough to really have

591
00:29:44,920 --> 00:29:47,800
Speaker 3: to deal with host immune system all that much. I

592
00:29:47,800 --> 00:29:51,800
Speaker 3: don't know how much that's playing a role in their

593
00:29:51,840 --> 00:29:56,000
Speaker 3: feeding preferences. I think it's probably more along the lines

594
00:29:56,040 --> 00:30:01,360
Speaker 3: of how frequently they encounter good hosts. So, especially leeches

595
00:30:01,400 --> 00:30:05,440
Speaker 3: and marine environments that are feeding on fish aren't always

596
00:30:05,480 --> 00:30:09,120
Speaker 3: great swimmers, so when they get on a fish, they

597
00:30:09,120 --> 00:30:11,800
Speaker 3: tend to stay there, and then there is the possibility

598
00:30:11,800 --> 00:30:13,440
Speaker 3: that if that fish gets eaten by another fish, they

599
00:30:13,480 --> 00:30:16,000
Speaker 3: may transfer at that point. But a lot of that

600
00:30:16,120 --> 00:30:18,840
Speaker 3: is like very short distances that they can cross on

601
00:30:18,880 --> 00:30:24,160
Speaker 3: their own. So maybe fish that occur in schools where

602
00:30:24,160 --> 00:30:27,200
Speaker 3: there's many options and so the leech doesn't have to

603
00:30:27,920 --> 00:30:31,040
Speaker 3: go very far. That would be an instance where being

604
00:30:31,080 --> 00:30:33,480
Speaker 3: a specialist, you know, they can get by with it.

605
00:30:34,120 --> 00:30:36,200
Speaker 3: But for a leach to this out in like a

606
00:30:36,240 --> 00:30:40,440
Speaker 3: pond and may not have all that many individuals of

607
00:30:40,480 --> 00:30:43,440
Speaker 3: a frog, for instance, they would then want to have

608
00:30:43,520 --> 00:30:45,400
Speaker 3: more options available and so that they can go for

609
00:30:45,440 --> 00:30:48,440
Speaker 3: the fish or the frogs or you know, a bird

610
00:30:48,840 --> 00:30:52,400
Speaker 3: or the occasional person. So I think it's more about

611
00:30:52,440 --> 00:30:56,520
Speaker 3: like how many different species they're encountering in the abundance

612
00:30:56,520 --> 00:30:57,880
Speaker 3: of those species.

613
00:30:57,600 --> 00:31:01,560
Speaker 1: Okay, cool, So when I look at leech, I always

614
00:31:01,560 --> 00:31:03,880
Speaker 1: get frustrated when people say, oh, parasites, they're just these

615
00:31:03,920 --> 00:31:06,800
Speaker 1: degenerate organisms, but like you know, they don't appear to

616
00:31:06,800 --> 00:31:09,160
Speaker 1: be able to move around much and they don't seem

617
00:31:09,200 --> 00:31:11,920
Speaker 1: to have a lot of sensory organs. How do leeches

618
00:31:12,120 --> 00:31:14,160
Speaker 1: find and get to their hosts because they just look

619
00:31:14,200 --> 00:31:17,160
Speaker 1: like these little blobs. How do they navigate their environment?

620
00:31:17,360 --> 00:31:19,560
Speaker 3: There's a lot of questions about this. I will say

621
00:31:19,600 --> 00:31:22,320
Speaker 3: this is a very well it should be an active

622
00:31:22,320 --> 00:31:27,600
Speaker 3: area of research. So leeches have incredible senses. Many leeches

623
00:31:27,640 --> 00:31:31,400
Speaker 3: have eyes, so there are little pigment cumps that detect light,

624
00:31:31,560 --> 00:31:34,120
Speaker 3: dark and movements. They're not like our eyes that actually

625
00:31:34,160 --> 00:31:37,760
Speaker 3: see images, but they don't like light because that means

626
00:31:37,760 --> 00:31:39,960
Speaker 3: that they're exposed and they're easier to be eaten. So

627
00:31:40,600 --> 00:31:43,239
Speaker 3: they want to kind of gravitate towards darkness. But at

628
00:31:43,280 --> 00:31:46,080
Speaker 3: the same time, movement in a potential host is nearby,

629
00:31:46,560 --> 00:31:49,440
Speaker 3: they want to go towards that. So they have eyes.

630
00:31:49,960 --> 00:31:53,400
Speaker 3: They have sinsily on their bodies that these little pepili,

631
00:31:53,400 --> 00:31:55,920
Speaker 3: these little bumps that when they're in the water, they

632
00:31:55,960 --> 00:32:00,520
Speaker 3: can feel the vibrations and that helps them swim. Granted

633
00:32:00,560 --> 00:32:04,280
Speaker 3: they're not the fastest swimmers, but they will swim in

634
00:32:04,320 --> 00:32:07,360
Speaker 3: the direction of that movement. To go investigate and say, oh,

635
00:32:07,400 --> 00:32:08,800
Speaker 3: is there something I can eat over here?

636
00:32:09,000 --> 00:32:11,320
Speaker 2: Did they ever latch onto the wrong thing? Like they

637
00:32:11,400 --> 00:32:13,680
Speaker 2: latch onto something they think is a person. They try

638
00:32:13,720 --> 00:32:15,400
Speaker 2: to suck on it, and it's just like you know,

639
00:32:15,400 --> 00:32:17,480
Speaker 2: a slimy blob of moss or something.

640
00:32:17,680 --> 00:32:20,120
Speaker 3: Well, I don't know how much the slimy blob of

641
00:32:20,120 --> 00:32:22,640
Speaker 3: moss is moving, but I don't know if they're trying

642
00:32:22,680 --> 00:32:25,880
Speaker 3: to bite, But they definitely will investigate things they're moving.

643
00:32:26,360 --> 00:32:28,160
Speaker 3: Something else about a lot of leeches that they like

644
00:32:28,240 --> 00:32:31,280
Speaker 3: flat surfaces. It's easier for them to stick to, and

645
00:32:31,280 --> 00:32:33,560
Speaker 3: so a lot of times when we're out, especially in

646
00:32:33,720 --> 00:32:36,840
Speaker 3: places where there's a lot of debris and trash, they

647
00:32:36,840 --> 00:32:40,040
Speaker 3: will stick to broad surfaces of things like bottles and

648
00:32:40,520 --> 00:32:44,560
Speaker 3: pie plates and just any kind of flat debris. They'll

649
00:32:44,600 --> 00:32:46,440
Speaker 3: just kind of hang out there. I don't think they're

650
00:32:46,480 --> 00:32:49,120
Speaker 3: nicely looking for a host, but something you know, they

651
00:32:49,120 --> 00:32:51,040
Speaker 3: can get underneath, and they can stick too easily.

652
00:32:51,400 --> 00:32:52,720
Speaker 1: I've seen them on soda cans.

653
00:32:53,000 --> 00:32:56,520
Speaker 3: Yeah, exactly. Yes, it was another part to your question.

654
00:32:56,640 --> 00:32:58,640
Speaker 1: Well, so I was gonna interrupt and tell the story

655
00:32:58,640 --> 00:33:01,560
Speaker 1: about like why in my world you are so famous,

656
00:33:01,600 --> 00:33:03,800
Speaker 1: and it's because you got to be on the BBC

657
00:33:03,880 --> 00:33:06,400
Speaker 1: once and you use the fact that they respond to

658
00:33:07,240 --> 00:33:10,760
Speaker 1: vibrations or movements in the water and you danced in

659
00:33:10,800 --> 00:33:14,600
Speaker 1: a BBC video to attract the leeches. Is that usually

660
00:33:14,680 --> 00:33:16,520
Speaker 1: how you attract the leeches. Does that mean that they're

661
00:33:16,560 --> 00:33:18,880
Speaker 1: biting you for you to get them or tell us

662
00:33:18,880 --> 00:33:20,880
Speaker 1: about collecting leeches and then we'll get back to the

663
00:33:20,920 --> 00:33:21,680
Speaker 1: sensory stuff.

664
00:33:22,960 --> 00:33:25,120
Speaker 3: Yeah. So one of the things that we have done,

665
00:33:25,240 --> 00:33:27,280
Speaker 3: those of us who have been trying to collect as

666
00:33:27,280 --> 00:33:30,080
Speaker 3: many leeches as we can for our research, is to

667
00:33:30,160 --> 00:33:33,480
Speaker 3: use ourselves as bait. This obviously only works in the

668
00:33:33,520 --> 00:33:36,080
Speaker 3: blood feeders, but when we go out into a pond,

669
00:33:36,720 --> 00:33:39,840
Speaker 3: we want to get out and look everywhere. So this involves,

670
00:33:39,920 --> 00:33:42,640
Speaker 3: you know, getting into the water about knee deep. We

671
00:33:43,680 --> 00:33:47,760
Speaker 3: look through plants, submerge debris like I was talking about,

672
00:33:47,760 --> 00:33:51,320
Speaker 3: but it's also like tree limbs and rocks and anything

673
00:33:51,400 --> 00:33:53,720
Speaker 3: that a leech could be hiding under. And while we're

674
00:33:53,760 --> 00:33:55,440
Speaker 3: doing all of that, we're making a fair bit of

675
00:33:55,720 --> 00:33:58,120
Speaker 3: you know, motion in the water and we're disturbing it

676
00:33:58,160 --> 00:34:01,800
Speaker 3: a lot. For the BBC interview, we were specifically interested

677
00:34:01,880 --> 00:34:04,840
Speaker 3: in the Macrobdella leeches that I was talking about earlier

678
00:34:04,880 --> 00:34:08,040
Speaker 3: the North American medicinal leeches. So when we got out

679
00:34:08,040 --> 00:34:09,960
Speaker 3: into the water, one thing we were doing was trying

680
00:34:10,000 --> 00:34:12,400
Speaker 3: to make a lot of movement, a lot of disturbance

681
00:34:12,440 --> 00:34:14,759
Speaker 3: to try and to track the leeches. Is kind of

682
00:34:14,800 --> 00:34:18,359
Speaker 3: like a leech dance, trying to just get as many

683
00:34:18,480 --> 00:34:20,520
Speaker 3: ripples in the water as possible so that when they

684
00:34:20,520 --> 00:34:23,480
Speaker 3: do detect that motion, they'll swim closer. But they're not

685
00:34:23,640 --> 00:34:26,080
Speaker 3: super fast and so it takes some time. So we

686
00:34:26,120 --> 00:34:28,080
Speaker 3: get in, we make some ripples in the water. You know,

687
00:34:28,440 --> 00:34:31,280
Speaker 3: everybody has their own style, Like some people are more consistent,

688
00:34:31,400 --> 00:34:33,840
Speaker 3: you know, up and down, so people are side to side.

689
00:34:34,280 --> 00:34:37,640
Speaker 3: A lot of room for individuality here. But do you

690
00:34:37,680 --> 00:34:39,480
Speaker 3: do that and then you kind of let everything quiet

691
00:34:39,520 --> 00:34:42,960
Speaker 3: down so the leeches, you know, can swim closer, and

692
00:34:43,000 --> 00:34:45,040
Speaker 3: then you have to kind of go again because they

693
00:34:45,040 --> 00:34:46,160
Speaker 3: take a minute.

694
00:34:45,880 --> 00:34:48,920
Speaker 1: Because they're slow. Can you see them coming towards you

695
00:34:48,960 --> 00:34:50,440
Speaker 1: and catch them in a net or do you not

696
00:34:50,560 --> 00:34:52,640
Speaker 1: know until they've bit you that Like I have a

697
00:34:52,680 --> 00:34:54,000
Speaker 1: specimen for the museum now.

698
00:34:54,880 --> 00:34:57,080
Speaker 3: I like to try and see and get them before

699
00:34:57,080 --> 00:34:59,279
Speaker 3: they're attaching, because when they're attaching, they're going to try

700
00:34:59,280 --> 00:35:02,000
Speaker 3: and bite, probably because they're hungry, that's why they're seeking

701
00:35:02,000 --> 00:35:05,200
Speaker 3: out a host. But many leashes, you'll see them swimming

702
00:35:05,239 --> 00:35:07,080
Speaker 3: across the surface of the water and you can use

703
00:35:07,080 --> 00:35:08,879
Speaker 3: a net or you can use your hands and grab them.

704
00:35:08,880 --> 00:35:10,960
Speaker 3: But some leeches are more sneaky and they kind of

705
00:35:11,000 --> 00:35:14,399
Speaker 3: dive down and then you don't know. So when you're

706
00:35:14,400 --> 00:35:16,360
Speaker 3: doing the leech dance and you're making all these ripples

707
00:35:16,360 --> 00:35:18,080
Speaker 3: in the water, you have to stop periodically and also

708
00:35:18,120 --> 00:35:21,279
Speaker 3: do a leg check foot check to make sure they

709
00:35:21,320 --> 00:35:24,399
Speaker 3: haven't gotten somewhere that you can't see because it's below

710
00:35:24,440 --> 00:35:27,560
Speaker 3: the water. And if you do get them before they bite,

711
00:35:27,640 --> 00:35:30,440
Speaker 3: then that's a bonus. But if you don't, sometimes you

712
00:35:30,480 --> 00:35:32,400
Speaker 3: find the leach when it's already bitten and it's being

713
00:35:32,800 --> 00:35:34,560
Speaker 3: worst case scenarios. You pull your leg out of the

714
00:35:34,560 --> 00:35:36,400
Speaker 3: water and it's already bleeding and the leach is gone.

715
00:35:36,760 --> 00:35:39,960
Speaker 1: Oh yes, as a scientist, that is a bummer. I've

716
00:35:39,960 --> 00:35:42,360
Speaker 1: never seen Daniel make this space before, to be honest,

717
00:35:42,360 --> 00:35:44,480
Speaker 1: and Daniel and I have been working together for a while.

718
00:35:46,239 --> 00:35:48,040
Speaker 2: Well you know, I'm a particle physicist and I've never

719
00:35:48,080 --> 00:35:50,160
Speaker 2: been bitten by a particle, and I don't really have

720
00:35:50,200 --> 00:35:52,680
Speaker 2: to worry about that. I have to like take one

721
00:35:52,719 --> 00:35:55,399
Speaker 2: for the team for science. Is this a regular thing?

722
00:35:55,480 --> 00:35:57,760
Speaker 2: Like how many times have you been bitten by leeches?

723
00:35:58,080 --> 00:36:00,399
Speaker 2: Is it like so many times you can't even count?

724
00:36:00,520 --> 00:36:04,759
Speaker 3: Imagine exactly I've lost count. I mean, actually I try

725
00:36:04,760 --> 00:36:10,280
Speaker 3: to avoid getting bitten me too. Yeah, open wounds, and

726
00:36:10,640 --> 00:36:13,799
Speaker 3: you know, muddy water can invite other problems that I'd

727
00:36:13,800 --> 00:36:17,280
Speaker 3: like to avoid. But also a lot of people over time,

728
00:36:17,360 --> 00:36:18,920
Speaker 3: you know, if you do this for your whole career,

729
00:36:19,000 --> 00:36:21,120
Speaker 3: you know, so thirty years of getting bitten by leeches,

730
00:36:21,440 --> 00:36:23,920
Speaker 3: some people develop an allergy to it, and I'd like

731
00:36:23,960 --> 00:36:27,000
Speaker 3: to avoid that. The other possibility is that you can

732
00:36:27,000 --> 00:36:30,239
Speaker 3: always wear waiters broad surface the leech will attach to,

733
00:36:30,600 --> 00:36:33,479
Speaker 3: so you make the movement, but it's less fun.

734
00:36:34,800 --> 00:36:37,440
Speaker 2: You make it sound like anybody wearing anti leech protection

735
00:36:37,600 --> 00:36:40,440
Speaker 2: is like a wimp or something you could if you

736
00:36:40,480 --> 00:36:40,759
Speaker 2: have to.

737
00:36:41,040 --> 00:36:44,120
Speaker 3: Oh well, I actually have converted to waiters recently. So

738
00:36:44,560 --> 00:36:46,840
Speaker 3: the only problem with waiters is they get hot.

739
00:36:46,800 --> 00:36:49,560
Speaker 1: So hot, and then you're sweaty and you stink the

740
00:36:49,600 --> 00:36:52,240
Speaker 1: rest of the day. And sometimes they get a leak

741
00:36:52,320 --> 00:36:54,640
Speaker 1: and then it's hard to walk because your feet are heavy.

742
00:36:55,360 --> 00:36:58,120
Speaker 1: And I totally get not wanting to go in with waiters.

743
00:36:58,480 --> 00:37:01,040
Speaker 2: It's not even a question from me. So much rather

744
00:37:01,160 --> 00:37:03,960
Speaker 2: be hot and stinky than bitten by leeches.

745
00:37:04,160 --> 00:37:08,360
Speaker 1: Like I've talked to people who study mosquitos and to

746
00:37:08,400 --> 00:37:10,680
Speaker 1: keep the mosquito colony alive, you know, they can get

747
00:37:10,719 --> 00:37:12,960
Speaker 1: blood bags, but sometimes if they know that they're not

748
00:37:12,960 --> 00:37:15,520
Speaker 1: infected by anything, they'll feed them with their arms. Does

749
00:37:15,560 --> 00:37:18,560
Speaker 1: stuff like that ever happen with leeches where you're like, oh,

750
00:37:18,600 --> 00:37:20,759
Speaker 1: these need to stay alive for another week or two,

751
00:37:21,440 --> 00:37:23,960
Speaker 1: but I don't have anything other than my arm, or

752
00:37:24,000 --> 00:37:25,879
Speaker 1: does that just kind of not happen with leeches. How

753
00:37:25,880 --> 00:37:27,240
Speaker 1: do we feed the medical leeches.

754
00:37:27,560 --> 00:37:29,760
Speaker 3: I actually don't know how they're feeding them in the labs,

755
00:37:29,920 --> 00:37:32,840
Speaker 3: But for leeches for my research, I'll bring them back

756
00:37:33,040 --> 00:37:35,200
Speaker 3: live a lot of times. And I like to show

757
00:37:35,239 --> 00:37:37,680
Speaker 3: people leeches because I work at the Natural History Museum,

758
00:37:37,760 --> 00:37:39,600
Speaker 3: so we have a lot of visitors and if we

759
00:37:39,640 --> 00:37:42,440
Speaker 3: have the opportunity, I like to keep live leeches around

760
00:37:42,840 --> 00:37:46,600
Speaker 3: to show off. But they don't need to eat all

761
00:37:46,600 --> 00:37:52,640
Speaker 3: that often, so they can survive for several months without eating.

762
00:37:52,920 --> 00:37:54,080
Speaker 1: Wow, that's convenient.

763
00:37:54,239 --> 00:37:58,120
Speaker 3: It's very convenient, especially because it can be a little

764
00:37:58,160 --> 00:38:00,520
Speaker 3: bit of a process to feed them. Like you said,

765
00:38:00,560 --> 00:38:02,719
Speaker 3: you know, getting bags of blood leeches. You can't just

766
00:38:02,760 --> 00:38:04,960
Speaker 3: pour the blood in the water. They can't like absorb it.

767
00:38:04,960 --> 00:38:07,480
Speaker 3: They have to suck it out of something. So usually

768
00:38:07,480 --> 00:38:10,880
Speaker 3: we'll get blood from a biological company or the butcher

769
00:38:11,960 --> 00:38:14,640
Speaker 3: and put it in a nitroplastic glove focohole so the

770
00:38:14,680 --> 00:38:16,600
Speaker 3: leeches know what's in there and then they will go

771
00:38:16,719 --> 00:38:17,080
Speaker 3: for it.

772
00:38:17,400 --> 00:38:19,279
Speaker 2: I was sure you were going to say interns. They

773
00:38:19,360 --> 00:38:21,839
Speaker 2: use you higher summer interns and use those to feed

774
00:38:21,920 --> 00:38:22,520
Speaker 2: the leaches.

775
00:38:23,280 --> 00:38:24,440
Speaker 3: Way too much paperwork.

776
00:38:25,680 --> 00:38:30,440
Speaker 8: This is the federal government, but it has happened occasionally

777
00:38:30,440 --> 00:38:32,520
Speaker 8: where everybody's kind of you know, in the break room

778
00:38:32,600 --> 00:38:34,480
Speaker 8: on a Friday evening and they're like, hey, anna bring

779
00:38:34,480 --> 00:38:38,440
Speaker 8: the leeches. So, but it's hard to get them to

780
00:38:38,440 --> 00:38:40,800
Speaker 8: feed in that kind of setting because when they're feeding,

781
00:38:41,160 --> 00:38:43,400
Speaker 8: they use all of the muscles in their body just

782
00:38:43,480 --> 00:38:45,800
Speaker 8: suck the blood out and then they move the blood

783
00:38:45,880 --> 00:38:47,359
Speaker 8: through their body with.

784
00:38:47,400 --> 00:38:50,080
Speaker 3: All of their muscles. That means they're really vulnerable to

785
00:38:50,120 --> 00:38:53,920
Speaker 3: predators during that time. So when they're feeding, they need

786
00:38:53,960 --> 00:38:57,280
Speaker 3: to feel super safe. So if it's dark, if it's quiet,

787
00:38:57,960 --> 00:39:00,719
Speaker 3: and that is not necessarily the break room afternoon.

788
00:39:01,120 --> 00:39:02,560
Speaker 1: But if you turn down the lights and you sing

789
00:39:02,600 --> 00:39:05,279
Speaker 1: it a nice song, sometimes it works out.

790
00:39:06,040 --> 00:39:09,640
Speaker 3: Yeah, sometimes exactly, and if they're hungry enough. But no

791
00:39:09,680 --> 00:39:13,440
Speaker 3: one here has ever fed leeches. I believe you one

792
00:39:13,520 --> 00:39:14,120
Speaker 3: hundred percent.

793
00:39:14,239 --> 00:39:16,719
Speaker 1: Do we know anything about the evolution to get from

794
00:39:16,840 --> 00:39:20,479
Speaker 1: earthworms to blood sucking leeches? Do we know anything about

795
00:39:20,480 --> 00:39:22,960
Speaker 1: the steps in between? Like how do you get from

796
00:39:23,000 --> 00:39:24,560
Speaker 1: one strategy to another?

797
00:39:24,760 --> 00:39:26,839
Speaker 3: It's a great question. That's something that we have been

798
00:39:26,840 --> 00:39:31,280
Speaker 3: debating for over one hundred years with leeches, especially because

799
00:39:31,360 --> 00:39:33,440
Speaker 3: the closest relatives are the brank you of deladens the

800
00:39:33,440 --> 00:39:37,760
Speaker 3: crayfish worms, and they're commensals, so they're not necessarily feeding

801
00:39:37,840 --> 00:39:40,960
Speaker 3: on blood. Now, what's interesting is that the crayfish gets injured,

802
00:39:41,040 --> 00:39:43,120
Speaker 3: like it loses a leg or a claw comes off,

803
00:39:43,480 --> 00:39:46,480
Speaker 3: and there's break you of deleadens nearby. They will all

804
00:39:46,560 --> 00:39:49,520
Speaker 3: go to that wound and start feeding on the crayfish blood.

805
00:39:49,840 --> 00:39:50,080
Speaker 1: Huh.

806
00:39:50,280 --> 00:39:52,799
Speaker 3: But they won't necessarily make the wound themselves.

807
00:39:53,200 --> 00:39:55,120
Speaker 1: Okay, So that seems like it could be like a

808
00:39:55,160 --> 00:39:58,719
Speaker 1: step on the way, Like you live with the crayfish,

809
00:39:58,760 --> 00:40:00,440
Speaker 1: and then you feed on it when it gets hurt,

810
00:40:00,480 --> 00:40:03,239
Speaker 1: and then you eventually have the ability to hurt them

811
00:40:03,239 --> 00:40:03,960
Speaker 1: and suck their blood.

812
00:40:04,120 --> 00:40:06,600
Speaker 3: Yeah, but the branci ofb delins, there aren't any parasitic

813
00:40:06,640 --> 00:40:09,880
Speaker 3: branchib deeldins. And then with leeches, there's been this long

814
00:40:09,960 --> 00:40:13,000
Speaker 3: debate about the ancestral leech was a blood feeding or not,

815
00:40:14,120 --> 00:40:16,359
Speaker 3: And we still don't know the answer to that because

816
00:40:16,400 --> 00:40:19,880
Speaker 3: it happened so long ago. Our molecular data, the DNA

817
00:40:19,960 --> 00:40:24,880
Speaker 3: sequences haven't kept that signature very strong in the data,

818
00:40:24,960 --> 00:40:27,760
Speaker 3: so we still kind of debate about that. Within certain groups,

819
00:40:27,760 --> 00:40:31,040
Speaker 3: we can tell that yes, there was a blood feeding ancestor.

820
00:40:31,120 --> 00:40:33,399
Speaker 3: So for instance, in the group that I have spent

821
00:40:33,440 --> 00:40:37,200
Speaker 3: the most time working on, the jawed leeches, they have jaws,

822
00:40:37,640 --> 00:40:40,279
Speaker 3: they have teeth, they make little bites, and then they

823
00:40:40,320 --> 00:40:43,719
Speaker 3: suck blood out of that wound. But there's also species

824
00:40:43,719 --> 00:40:46,480
Speaker 3: that don't feed on blood. They still have teeth though,

825
00:40:46,760 --> 00:40:48,960
Speaker 3: and that's usually it helps them to chew up their

826
00:40:48,960 --> 00:40:51,160
Speaker 3: earth farms as they're eating them, or to chew of

827
00:40:51,239 --> 00:40:54,520
Speaker 3: the insect larvae as they consume it. And what's interesting

828
00:40:54,560 --> 00:40:57,160
Speaker 3: about that group is it does look like the ancestor

829
00:40:57,400 --> 00:41:01,200
Speaker 3: of that group was a non blood feeding leech. And

830
00:41:01,239 --> 00:41:03,640
Speaker 3: then there was a transition to blood feeding within the group,

831
00:41:03,880 --> 00:41:07,040
Speaker 3: but there's also been several independent transitions back to non

832
00:41:07,080 --> 00:41:10,480
Speaker 3: blood feeding. Huh, So it seems like something that does change,

833
00:41:10,840 --> 00:41:13,279
Speaker 3: you know, depending on the group and what environment they're

834
00:41:13,280 --> 00:41:16,160
Speaker 3: found in. Yeah, there's a lot of different feeding strategies.

835
00:41:16,600 --> 00:41:19,120
Speaker 1: It doesn't seem like it's a hard strategy to transition

836
00:41:19,200 --> 00:41:21,400
Speaker 1: to if it's happening multiple times.

837
00:41:21,680 --> 00:41:21,960
Speaker 3: Right.

838
00:41:22,160 --> 00:41:24,960
Speaker 1: Interesting. I would have guessed that processing blood would be

839
00:41:25,000 --> 00:41:26,840
Speaker 1: way different than eating an earthworm.

840
00:41:27,239 --> 00:41:31,040
Speaker 3: It should be, Yeah, but these leeches have found a

841
00:41:31,080 --> 00:41:35,000
Speaker 3: way to maximize where they are, and once that transition occurs,

842
00:41:35,120 --> 00:41:37,759
Speaker 3: you know, there's several species that will maintain that. Yeah,

843
00:41:37,800 --> 00:41:40,680
Speaker 3: it seems to be relatively plastic. I would say, Okay,

844
00:41:40,719 --> 00:41:41,160
Speaker 3: all right.

845
00:41:41,080 --> 00:41:43,040
Speaker 1: Well let's take another break and we'll come back and

846
00:41:43,080 --> 00:42:02,760
Speaker 1: talk more about some weird leeches. Okay, so we're back,

847
00:42:03,280 --> 00:42:05,319
Speaker 1: and I have to ask you about something that I

848
00:42:05,360 --> 00:42:08,600
Speaker 1: heard once over drinks with friends, but I am not

849
00:42:08,760 --> 00:42:11,319
Speaker 1: actually sure that it was a real fact. And it

850
00:42:11,440 --> 00:42:15,080
Speaker 1: is that there is a leech that specializes specifically on

851
00:42:15,160 --> 00:42:17,759
Speaker 1: hippo butts. So the only way you would find this

852
00:42:17,880 --> 00:42:20,960
Speaker 1: leech is if you were searching hippo butts. Is it

853
00:42:21,000 --> 00:42:22,600
Speaker 1: true that there is a hippo butt leech.

854
00:42:22,920 --> 00:42:27,200
Speaker 3: You are correct, there is Placodilla's yeager school die. It

855
00:42:27,360 --> 00:42:30,160
Speaker 3: is typically found in the rectum of hippos.

856
00:42:30,600 --> 00:42:33,280
Speaker 1: In the rectum of hippos, that's an even more extreme environment.

857
00:42:33,360 --> 00:42:36,280
Speaker 1: So that leech needs to not just find a hippo,

858
00:42:36,600 --> 00:42:38,040
Speaker 1: but it needs to find a hippo, and then it

859
00:42:38,080 --> 00:42:40,000
Speaker 1: needs to figure out which end is the back end.

860
00:42:40,840 --> 00:42:43,200
Speaker 1: And that sounds like a difficult search problem for a

861
00:42:43,239 --> 00:42:45,719
Speaker 1: tiny little leech. But this also sounds like a hard

862
00:42:45,719 --> 00:42:47,840
Speaker 1: thing to study because hippos are very dangerous. Do we

863
00:42:47,920 --> 00:42:50,279
Speaker 1: know how those leeches figure out which end of the

864
00:42:50,360 --> 00:42:51,560
Speaker 1: hippo is the right end?

865
00:42:51,760 --> 00:42:54,440
Speaker 3: It's a good question. I don't know. But there are

866
00:42:54,480 --> 00:42:57,840
Speaker 3: other leeches that tend to gravitate towards certain areas of

867
00:42:57,880 --> 00:43:00,600
Speaker 3: the body. So this is something that several types of

868
00:43:00,640 --> 00:43:04,160
Speaker 3: leeches have to figure out. So there's a lot of

869
00:43:04,239 --> 00:43:08,960
Speaker 3: leeches that feed on orifices, and that probably is because

870
00:43:09,000 --> 00:43:11,480
Speaker 3: they have fewer teeth and so it's harder to get

871
00:43:11,520 --> 00:43:14,560
Speaker 3: through the skin, and they're looking for areas with thinner

872
00:43:14,600 --> 00:43:17,160
Speaker 3: tissue and more blood vessels, so like inside mouths and

873
00:43:17,239 --> 00:43:20,239
Speaker 3: up noses, and so that's probably what the hippo butt

874
00:43:20,320 --> 00:43:22,640
Speaker 3: leach is doing is that, you know, hippo's skin is

875
00:43:22,640 --> 00:43:24,879
Speaker 3: pretty tough. They can't bite through that, so they're looking

876
00:43:24,920 --> 00:43:29,359
Speaker 3: for an area that is softer, softer tissue that they

877
00:43:29,360 --> 00:43:32,360
Speaker 3: can bite through. And unfortunately for the hippos, I would

878
00:43:32,360 --> 00:43:36,720
Speaker 3: guess I'm not sure their opinions on this, but yeah,

879
00:43:37,080 --> 00:43:39,279
Speaker 3: it's softer in there, so that's what they're going for.

880
00:43:39,480 --> 00:43:41,359
Speaker 1: What was the second part of your question, I've got

881
00:43:41,360 --> 00:43:42,840
Speaker 1: distracted by a more important question.

882
00:43:43,160 --> 00:43:46,160
Speaker 2: How did anybody discover this? Were they looking for something

883
00:43:46,200 --> 00:43:48,520
Speaker 2: else up the butt of a hippo or tell us

884
00:43:48,600 --> 00:43:49,120
Speaker 2: the story?

885
00:43:49,520 --> 00:43:49,719
Speaker 1: Right?

886
00:43:49,800 --> 00:43:52,839
Speaker 3: So hippos can be very dangerous, and so who ever

887
00:43:52,880 --> 00:43:56,400
Speaker 3: discovered this, I don't remember who it was, but I

888
00:43:56,440 --> 00:44:00,520
Speaker 3: guess they were looking for other things in the hippo wrecks.

889
00:44:01,239 --> 00:44:02,920
Speaker 3: I'm guessing it was a parastologist.

890
00:44:03,120 --> 00:44:04,720
Speaker 2: They lost their keys or something.

891
00:44:07,960 --> 00:44:10,040
Speaker 3: He had a reason, I'm sure, And then they found

892
00:44:10,040 --> 00:44:10,800
Speaker 3: a bunch of leeches.

893
00:44:10,920 --> 00:44:13,040
Speaker 1: For the species name. The species part that you said

894
00:44:13,080 --> 00:44:15,600
Speaker 1: sounded like someone's last name. Is it someone's last name?

895
00:44:15,680 --> 00:44:16,839
Speaker 1: Is that the person who found it?

896
00:44:16,920 --> 00:44:18,560
Speaker 3: I don't know if it was the person who found it,

897
00:44:18,600 --> 00:44:21,640
Speaker 3: Probably not, because when we name species after people, it's

898
00:44:21,640 --> 00:44:24,680
Speaker 3: typically not the person describing it, so I don't know

899
00:44:25,040 --> 00:44:28,080
Speaker 3: that person's association with that species, but it was in

900
00:44:28,160 --> 00:44:29,000
Speaker 3: honor of someone.

901
00:44:29,360 --> 00:44:31,440
Speaker 1: I would love to have a parasite named after me,

902
00:44:31,520 --> 00:44:33,560
Speaker 1: but it hasn't happened yet. One day, maybe I'll be

903
00:44:33,600 --> 00:44:34,160
Speaker 1: that important.

904
00:44:34,360 --> 00:44:37,440
Speaker 3: I'm not sure what this individual thought of having a

905
00:44:37,520 --> 00:44:39,000
Speaker 3: hippo butt leach named after them.

906
00:44:39,200 --> 00:44:40,920
Speaker 2: Kelly, it seems like the path is clear. You just

907
00:44:40,920 --> 00:44:42,480
Speaker 2: got to look up the butts of lots of weird

908
00:44:42,480 --> 00:44:44,200
Speaker 2: animals until you find your parasite.

909
00:44:44,200 --> 00:44:47,080
Speaker 1: Well, but Anna just said that you usually don't get

910
00:44:47,080 --> 00:44:49,160
Speaker 1: to name a species after you, you can name it

911
00:44:49,200 --> 00:44:51,720
Speaker 1: after someone you know. So I need to become friends

912
00:44:51,719 --> 00:44:54,440
Speaker 1: with the people who are checking animal butts. And I

913
00:44:54,520 --> 00:44:56,280
Speaker 1: thought that I was doing a good job of becoming

914
00:44:56,280 --> 00:44:57,880
Speaker 1: friends with the right kinds of people, but it just

915
00:44:57,960 --> 00:45:00,239
Speaker 1: hasn't happened yet. But I'm going to keep my fingers.

916
00:45:00,440 --> 00:45:02,480
Speaker 2: I'm not in that group. Yeah, your friendship with me

917
00:45:02,560 --> 00:45:04,279
Speaker 2: is not getting you any closer to that for sure.

918
00:45:04,320 --> 00:45:06,680
Speaker 1: Well, you're going to name a particle after me, probably right,

919
00:45:07,600 --> 00:45:10,160
Speaker 1: the Smith particle, I hope.

920
00:45:10,200 --> 00:45:12,600
Speaker 3: So I think there's a good chance, Kelly. I think

921
00:45:12,640 --> 00:45:13,520
Speaker 3: with your crowd.

922
00:45:13,880 --> 00:45:16,320
Speaker 1: There's a good chance of this in the future, I'm hoping. Okay,

923
00:45:16,360 --> 00:45:19,760
Speaker 1: so you're more likely to find leeches and highly vascularized

924
00:45:19,840 --> 00:45:24,640
Speaker 1: thin skin areas. And so I've seen leeches on like

925
00:45:24,880 --> 00:45:27,799
Speaker 1: fish sides with scales, Like, do they have ways to

926
00:45:27,800 --> 00:45:30,120
Speaker 1: get under the scales? I guess that's pretty easy to do.

927
00:45:30,160 --> 00:45:31,240
Speaker 1: You just kind of move them aside.

928
00:45:31,320 --> 00:45:34,040
Speaker 3: Yeah, they have very small mouths. And also there's a

929
00:45:34,040 --> 00:45:36,200
Speaker 3: lot of turtle leeches, and so you know, turtles have

930
00:45:36,239 --> 00:45:38,879
Speaker 3: scales and then they also have their shells. But on

931
00:45:38,960 --> 00:45:41,840
Speaker 3: the turtles, you know, they have different scuts in different

932
00:45:41,840 --> 00:45:44,560
Speaker 3: plates on the shells, and the leeches go for the

933
00:45:44,600 --> 00:45:47,040
Speaker 3: seams in between them. So they're not going to try

934
00:45:47,080 --> 00:45:50,320
Speaker 3: and feed through the skewed because it's keratonized it's hard,

935
00:45:50,560 --> 00:45:52,840
Speaker 3: but they'll go for the scenes in between because they

936
00:45:52,840 --> 00:45:55,080
Speaker 3: can get to the blood vessels easier there. But with

937
00:45:55,160 --> 00:45:57,520
Speaker 3: turtles especially, they're going for places where the turtle can't

938
00:45:57,520 --> 00:45:59,680
Speaker 3: scratch them off. So it's going up like around the neck,

939
00:46:00,120 --> 00:46:03,720
Speaker 3: behind the arms, underneath their legs, places that they can't

940
00:46:03,840 --> 00:46:06,480
Speaker 3: either scratch them off or go find a tree or

941
00:46:06,480 --> 00:46:07,799
Speaker 3: a rock to scrape them off.

942
00:46:08,239 --> 00:46:11,040
Speaker 1: Okay, so I tell people I study parasites and they're like, well,

943
00:46:11,080 --> 00:46:14,560
Speaker 1: that's gross, And then I try to get them excited

944
00:46:14,600 --> 00:46:16,160
Speaker 1: by being like, Okay, I'm not going to change your

945
00:46:16,200 --> 00:46:19,120
Speaker 1: mind about them being gross. That's fine, But like these

946
00:46:19,200 --> 00:46:22,520
Speaker 1: tiny little sacks of fluid, they're able to figure out,

947
00:46:22,560 --> 00:46:25,160
Speaker 1: like where the soft parts of people are, and they're

948
00:46:25,160 --> 00:46:28,080
Speaker 1: able to find them, and like they do do all

949
00:46:28,120 --> 00:46:31,839
Speaker 1: of these amazing things. They've like evolved these anticoagulants that

950
00:46:31,880 --> 00:46:34,280
Speaker 1: help them with their feeding. So when you tell people

951
00:46:34,840 --> 00:46:38,200
Speaker 1: I study leeches and they go uugh, do you have

952
00:46:38,280 --> 00:46:39,880
Speaker 1: like a speech that you give them to try to

953
00:46:39,880 --> 00:46:42,600
Speaker 1: be like okay, but they're gross but fascinating or are

954
00:46:42,640 --> 00:46:44,960
Speaker 1: you just like this is a lost cause. How do

955
00:46:45,000 --> 00:46:47,080
Speaker 1: you try to turn people into leech fans?

956
00:46:49,320 --> 00:46:51,839
Speaker 3: I think it depends on the individual. Okay, So I've

957
00:46:51,920 --> 00:46:54,719
Speaker 3: definitely been at places when people realize what I do,

958
00:46:54,800 --> 00:46:56,200
Speaker 3: they say, Okay, you don't get to talk for the

959
00:46:56,239 --> 00:46:58,319
Speaker 3: rest of the evening, and I go, oh, it's not

960
00:46:58,400 --> 00:47:01,759
Speaker 3: the best dinner conversation. But for people who are interested,

961
00:47:02,040 --> 00:47:05,440
Speaker 3: I mean, I agree, like bloodsucking worms can be gross.

962
00:47:05,520 --> 00:47:09,279
Speaker 3: I get it. I mean that's just a reality that

963
00:47:09,320 --> 00:47:11,120
Speaker 3: you have to face. But if we can admit that

964
00:47:11,120 --> 00:47:14,120
Speaker 3: there's a cool side to it and that there's a

965
00:47:14,160 --> 00:47:17,640
Speaker 3: lot that we can learn from leeches about their anticoagulants,

966
00:47:17,719 --> 00:47:20,560
Speaker 3: about where they occur in nature, how they're associated with

967
00:47:20,600 --> 00:47:23,520
Speaker 3: different verbrate hosts. We can learn a lot from them,

968
00:47:23,680 --> 00:47:26,799
Speaker 3: and that's I think the more important point. Trying to

969
00:47:26,840 --> 00:47:30,160
Speaker 3: appreciate them for what they're doing and that they're serving

970
00:47:30,480 --> 00:47:34,279
Speaker 3: an important role learn our ecosystems that hasn't always.

971
00:47:34,000 --> 00:47:38,640
Speaker 1: Been recognized is the angle that usually works best. They're

972
00:47:38,719 --> 00:47:42,160
Speaker 1: medicinally helpful and they're teaching us about anticoagulants. I'm guessing

973
00:47:42,200 --> 00:47:43,960
Speaker 1: that's the most convincing.

974
00:47:44,160 --> 00:47:47,200
Speaker 3: Yeah, that's a strong point with leeches. Also because they're

975
00:47:47,200 --> 00:47:51,440
Speaker 3: commercially traded, leeches have played a important role in conservation

976
00:47:51,600 --> 00:47:55,600
Speaker 3: as well. So the rudo medice analysis is the European

977
00:47:55,640 --> 00:47:57,920
Speaker 3: medicinal leech. This was the leech that was collected the

978
00:47:57,960 --> 00:48:00,280
Speaker 3: most in the seventeen to eighteen hundreds from a dismal

979
00:48:00,320 --> 00:48:04,040
Speaker 3: purposes and for blood letting, and this species was also

980
00:48:04,120 --> 00:48:07,120
Speaker 3: one of the first species to have conservation measures put

981
00:48:07,400 --> 00:48:12,600
Speaker 3: in place about its collecting. So in Germany, especially in France,

982
00:48:12,840 --> 00:48:15,760
Speaker 3: the number of leeches that were collected for blood letting

983
00:48:15,800 --> 00:48:20,600
Speaker 3: purposes was astronomical. There were millions of leeches collected and exported,

984
00:48:21,000 --> 00:48:24,360
Speaker 3: and very quickly the governments realized that this is a

985
00:48:24,520 --> 00:48:26,440
Speaker 3: huge number that needs to be tracked, not just for

986
00:48:26,480 --> 00:48:29,799
Speaker 3: economic purposes. But then later as they started tracking the

987
00:48:29,840 --> 00:48:33,640
Speaker 3: populations the natural populations is seeing that, oh, there's not

988
00:48:33,680 --> 00:48:35,680
Speaker 3: as many leeches as you used to be. So they

989
00:48:35,680 --> 00:48:38,080
Speaker 3: started putting regulations in place to say, you know, you

990
00:48:38,080 --> 00:48:40,320
Speaker 3: can collect leeches, but there's only so many you can export,

991
00:48:40,400 --> 00:48:43,000
Speaker 3: and there's only so many that you can collect today.

992
00:48:43,239 --> 00:48:47,680
Speaker 3: And actually the root of minus analysis is considered vulnerable

993
00:48:48,360 --> 00:48:51,239
Speaker 3: because of the number of leeches that were collected back

994
00:48:51,239 --> 00:48:53,680
Speaker 3: in the seventeen eighteen hundred, so those populations still have

995
00:48:53,760 --> 00:48:58,000
Speaker 3: not recovered to this point. So today the modern species

996
00:48:58,080 --> 00:49:01,560
Speaker 3: that is used in blood letting is Rudo verbana. It's

997
00:49:01,600 --> 00:49:05,440
Speaker 3: another species rudo that's found farther east in Europe, and

998
00:49:05,480 --> 00:49:08,400
Speaker 3: that is the commercially traded leech. So today, if you

999
00:49:08,440 --> 00:49:11,560
Speaker 3: say that you have brudo and you're sending it to

1000
00:49:11,600 --> 00:49:13,440
Speaker 3: different places, one of the first things they want to

1001
00:49:13,440 --> 00:49:16,080
Speaker 3: ask is is it rudomus analyis because we need to

1002
00:49:16,120 --> 00:49:18,719
Speaker 3: be careful about that because it's considered vulnerable as a

1003
00:49:18,760 --> 00:49:22,040
Speaker 3: conservation status of being vulnerable or is it hrud of

1004
00:49:22,080 --> 00:49:24,680
Speaker 3: verbana and we need to track it because it's a

1005
00:49:24,719 --> 00:49:26,600
Speaker 3: commercially traded quantity.

1006
00:49:27,200 --> 00:49:32,160
Speaker 1: So like when the Rudo Mets analyis, was I really

1007
00:49:32,239 --> 00:49:34,720
Speaker 1: rocked that? I'm sure I didn't. So when those numbers

1008
00:49:34,719 --> 00:49:39,000
Speaker 1: started to go down, did anything noticeable happen in the ecosystems,

1009
00:49:39,040 --> 00:49:40,879
Speaker 1: Like were we able to identify that they had played

1010
00:49:40,880 --> 00:49:44,359
Speaker 1: an important role and when they fall down, like maybe

1011
00:49:44,360 --> 00:49:46,560
Speaker 1: the animals that ate them, their numbers go down or

1012
00:49:46,640 --> 00:49:48,239
Speaker 1: was there nothing obvious at the time.

1013
00:49:48,360 --> 00:49:52,439
Speaker 3: I don't think anyone was looking at that necessarily. Yeah,

1014
00:49:52,480 --> 00:49:55,560
Speaker 3: I'm unaware of work on that. A lot of people

1015
00:49:55,560 --> 00:49:57,600
Speaker 3: when they would study this would look at the leeches

1016
00:49:57,719 --> 00:50:01,319
Speaker 3: themselves and not necessarily how it played roles in the ecosystems.

1017
00:50:02,000 --> 00:50:04,520
Speaker 3: But I think this is something about parasitology in general

1018
00:50:04,640 --> 00:50:08,040
Speaker 3: that we're realizing how much more important that is. These days,

1019
00:50:08,600 --> 00:50:13,000
Speaker 3: scientists are starting to include parasites in looking at ecosystem questions,

1020
00:50:13,000 --> 00:50:16,320
Speaker 3: more so than ever has been in the past, because

1021
00:50:16,360 --> 00:50:18,880
Speaker 3: they are connecting different trophic levels and different parts of

1022
00:50:18,880 --> 00:50:21,440
Speaker 3: the food web, and parasites are doing a lot more

1023
00:50:21,440 --> 00:50:25,000
Speaker 3: in our ecosystems than I think we've ever recognized before,

1024
00:50:25,440 --> 00:50:31,080
Speaker 3: especially when you think about ecosystem decline and changing climate scenarios.

1025
00:50:31,640 --> 00:50:34,600
Speaker 3: That parasites can be a canary in the coal mine

1026
00:50:34,600 --> 00:50:37,239
Speaker 3: because they are connecting so many different points, and so

1027
00:50:37,280 --> 00:50:39,680
Speaker 3: when the parasites aren't able to make those connections, we

1028
00:50:39,880 --> 00:50:43,719
Speaker 3: can start to see perturbations and disturbances in these ecosystems

1029
00:50:43,719 --> 00:50:47,160
Speaker 3: and parasites long before we see the effect in the

1030
00:50:47,280 --> 00:50:48,719
Speaker 3: larger macrofauna.

1031
00:50:49,160 --> 00:50:52,520
Speaker 2: So do you think parasites or leaches more specifically, serve

1032
00:50:52,680 --> 00:50:56,759
Speaker 2: an essential, an inevitable role in an ecosystem. Let me

1033
00:50:56,840 --> 00:50:59,120
Speaker 2: put it to you in a different context that maybe

1034
00:50:59,120 --> 00:51:01,440
Speaker 2: you've never been asked before. Or say, we land on

1035
00:51:01,480 --> 00:51:04,160
Speaker 2: an alien planet and we observe an alien ecosystem, do

1036
00:51:04,239 --> 00:51:07,560
Speaker 2: you expect to find some form of leeches on that

1037
00:51:07,640 --> 00:51:10,280
Speaker 2: alien planet? Are there alien leeches? It's my question.

1038
00:51:11,080 --> 00:51:15,240
Speaker 3: I like the possibility of alien leeches. I would definitely

1039
00:51:15,320 --> 00:51:18,880
Speaker 3: expect there to be a parasite or many parasites, probably,

1040
00:51:19,600 --> 00:51:21,680
Speaker 3: but I don't know if they would take the form

1041
00:51:21,760 --> 00:51:25,319
Speaker 3: of leeches necessarily. The reason I say this is because

1042
00:51:25,360 --> 00:51:29,400
Speaker 3: parasitism is the most common life mode on the planet.

1043
00:51:29,680 --> 00:51:34,239
Speaker 3: Oh wow for eukaryotic organisms, right, yes, yes, of ukryonic organisms,

1044
00:51:34,520 --> 00:51:38,520
Speaker 3: it's ubiquitous. As long as there have been organisms, there's

1045
00:51:38,520 --> 00:51:40,439
Speaker 3: probably been something parasitizing it. Wow.

1046
00:51:40,640 --> 00:51:43,200
Speaker 2: Am I talking to the first astro parasitologists.

1047
00:51:44,040 --> 00:51:47,160
Speaker 3: I think you may be the first astro paristologists.

1048
00:51:48,800 --> 00:51:51,399
Speaker 1: There's so many cool parasites left to study here on Earth.

1049
00:51:51,400 --> 00:51:53,320
Speaker 1: When people are like, Kelly, would you move to Mars?

1050
00:51:53,400 --> 00:51:55,759
Speaker 1: And I'm like, there are still parasitic worms left to

1051
00:51:55,800 --> 00:51:59,600
Speaker 1: describe your people. Why would anybody go to Mars. There's

1052
00:51:59,640 --> 00:52:00,520
Speaker 1: too much work to do.

1053
00:52:02,360 --> 00:52:05,279
Speaker 3: Yeah, it's daunting and there's not enough of us doing it.

1054
00:52:05,400 --> 00:52:07,080
Speaker 3: So yeah, we got to pick up the pace.

1055
00:52:07,560 --> 00:52:08,040
Speaker 1: That's right.

1056
00:52:08,239 --> 00:52:10,799
Speaker 2: And I don't think the idea of getting sucked on

1057
00:52:10,880 --> 00:52:13,520
Speaker 2: by alien leeches is going to make somebody more likely

1058
00:52:13,760 --> 00:52:16,360
Speaker 2: to go to Mars or venture on to another planet.

1059
00:52:16,440 --> 00:52:18,520
Speaker 2: So it's not exactly doing a sales job.

1060
00:52:18,880 --> 00:52:21,000
Speaker 1: I mean, I think space is bad enough at selling

1061
00:52:21,000 --> 00:52:24,040
Speaker 1: space as it is, but I'm a bit biased and

1062
00:52:24,080 --> 00:52:25,960
Speaker 1: I know lots of people who disagree with me. So

1063
00:52:26,719 --> 00:52:30,080
Speaker 1: on that note, I have had so much fun. Thank you, Anna.

1064
00:52:30,280 --> 00:52:31,759
Speaker 1: Do you want to end by telling us what your

1065
00:52:31,760 --> 00:52:32,359
Speaker 1: favorite leech.

1066
00:52:32,440 --> 00:52:35,319
Speaker 3: Is I have to pick just one? I know they're

1067
00:52:35,360 --> 00:52:35,920
Speaker 3: like children.

1068
00:52:35,960 --> 00:52:36,839
Speaker 1: Now do you pick just one?

1069
00:52:36,920 --> 00:52:41,480
Speaker 3: I don't know exactly. I have a special affinity for

1070
00:52:41,520 --> 00:52:45,200
Speaker 3: the Macrobdella leeches in North America. Macro because they're large

1071
00:52:45,200 --> 00:52:49,160
Speaker 3: and bidella is a name for leech. They're big, they're

1072
00:52:49,200 --> 00:52:52,440
Speaker 3: brightly colored and since they're all agreed with orange polka dots,

1073
00:52:52,680 --> 00:52:54,880
Speaker 3: and I mean big is that there's several inches and

1074
00:52:54,920 --> 00:52:57,920
Speaker 3: a lot of people encounter them and they're pretty. It

1075
00:52:58,000 --> 00:52:59,520
Speaker 3: was one of the first groups that I studied as

1076
00:52:59,560 --> 00:53:02,920
Speaker 3: an intern long ago, so still hold a special place.

1077
00:53:02,719 --> 00:53:05,080
Speaker 1: In my heart. They sound wonderful and I bet a

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Speaker 1: lot of our listeners have encountered them, and maybe they'll

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Speaker 1: appreciate them more now.

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Speaker 3: I hope.

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Speaker 1: So all right, thanks Nanna. Daniel and Kelly's Extraordinary Universe

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Speaker 1: is produced by iHeartRadio.

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Speaker 3: We would love to hear from you, We really would.

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Speaker 2: We want to know what questions you have about this

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Speaker 2: Extraordinary Universe.

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Speaker 1: back to you.

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Speaker 2: We really mean it. We answer every message. Email us

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Speaker 2: at questions at Danielandkelly dot org, or.

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Speaker 1: You can find us at D and K Universe.

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