Rats: Bringers of plague, schleppers of pizza slices, garbage gobblers. These rodents have adapted over the millennia to survive and thrive in human company, much to our amazement and (often) disgust. But love them or hate them, our past and our future is bound up with these little hustlers.
EMMA MARRIS (WRITER): I was on this amazing hike in one of most beautiful parts of Kauai high up on the mountains on out a knife-like ridge. We were covered in mud. We were climbing using ropes. It's so steep and muddy and gorgeous and huge vistas.
VAUGHN WALLACE (HOST): Emma Marris is an environmental writer.
Recently she wrapped up a big story for National Geographic magazine — a story all about rats — And when I caught up with her she was just back from a bit of a working vacation on the Hawaiian island of Kauai.
MARRIS: And we come around the corner and we see one of these traps and there's a sort of a penumbra of dead rats.
WALLACE: That’s right. Even after MONTHS of reporting on rats - Emma just couldn’t get away from them. That’s because they’re an invasive species in Kauai. Their population’s out of control and they’re wreaking absolute havoc on local endangered seabirds.
The rats in this mini-graveyard were killed by an extremely effective extermination solution. It’s something that seabird conservationists had been trying out.
MARRIS: The presence of the rat triggers a CO2 pressurized CO2 capsule that shoots a bolt into the head of the rat. Kind of like at a slaughterhouse except on a much smaller scale.
WALLACE: What a way to spend your time in Paradise, right?
MARRIS: Once you get hooked on rats you can't really stop
WALLACE: Emma’s Hawaiian rat safari sounds terrifying but also strangely captivating. I mean, rats occupy this weird place in our psyche. Why do we gleefully compare horror stories about the big old rat we saw behind the dumpster and then cheer when we see one carrying a whole slice of pizza down a flight of stairs on YouTube?
I’m Vaughn Wallace and you’re listening to Overheard at National Geographic. It’s a show where we get to eavesdrop on the wild conversations Nat Geo explorers and scientists are having everyday. And then we follow them to the edges of our big, weird, and beautiful world.
This week? We’re unpacking our special relationship with humanity’s little rodent frenemies. Rats versus humans: a love story.
Emma says, rats are part of a larger family: the kleptoparasites.
Meaning, they make their living stealing from other species (in this case US as humans) and exploiting all of our weaknesses — like the plastic bags of garbage we leave all over our streets each week.
MARRIS: They sort of just adapted to hang out with us. And then as we moved around the planet you know trading down the Silk Road or across oceans in voyaging canoes or in big sailboats, they just came with us.
WALLACE: They sorta hitched their wagon to the human race.
But despite that dependency, the rats that make their homes in our cities don’t give too many people the warm fuzzies. This is an animal that eats garbage. And they’ve carried some pretty serious diseases — you know, like the plague. So Darwinists would say, our repulsion to them is actually a pretty useful adaptation.
JEFFREY LOCKWOOD (PROFESSOR, UNIVERSITY OF WYOMING) We can get sick from something that is disgusting.
WALLACE: That’s Jeff Lockwood. He’s a professor of natural sciences and humanities at the University of Wyoming.
LOCKWOOD: That’s why things like feces, and blood, and decaying bodies right? All of those are likely to be carrying something that is bad for us.
WALLACE: Jeff’s done a lot of thinking about disgust.
LOCKWOOD: For a few years I had a blog on a Psychology Today website and I would blog about insects and fear and disgust and whatnot.
WALLACE: He’s also written a book about disgust, The Infested Mind. And since most of us find these garbage gobblers pretty gross — I figured Jeff would be just the guy to help unpack the rat ick-factor.
LOCKWOOD: As far as we know, all human cultures on Earth have expressions of disgust. So it's a, we can think of it as a grand uniting human phenomenon.
WALLACE: Jeff told me something that REALLY changed the way I was thinking about disgust.He says that the emotion we describe as disgust is actually a much deeper, more primal emotion. It screams “pay attention to me.”
LOCKWOOD: squeal or meal.
WALLACE: Squeal or meal. [laughs]
LOCKWOOD: Right. Squeal because it could inflict pain...
WALLACE: Or meal - because maybe it could be a tasty treat. You know that feeling when you see a cockroach skittering across the kitchen floor when you turn on the light?
[sound of startled breath]
LOCKWOOD: You know almost nothing that scurries in that way is really good news.
WALLACE: But while disgust is universal that response isn’t.
LOCKWOOD: Because insects have been and still are in many cultures very important food sources. I mean that's a highly loaded protein and lipid snack. it's sort of an energy bar on legs.
[sound of crunching]
WALLACE: Turns out, a lot of our feelings of disgust are linked to culture. Type “blue cheese smells like” into a Google search and Google's going to autocomplete to: blue cheese smells like vomit, ammonia, feet. And yet it’s hard for some to imagine a Cobb salad without that sprinkle of crumbly, moldy cheese on top. It just isn’t the same. In fact a lot of the things we eat are pretty disgusting.
LOCKWOOD: Do you like raw oysters?
WALLACE: I do not. No.
LOCKWOOD: Okay, well yeah, and that's because it's sort of like the animal world view of snot.
WALLACE: Slippery, slimy foods like oysters. Stinky cheese. These things grab our attention, and they trigger a kind of arousal. And our culture tells us whether to embrace it or to turn away.
WALLACE: While she was reporting her story, Emma visited a community where rats aren’t loathed. They’re revered. Throughout New Zealand rats are super invasive. They feast on the eggs of endangered seabirds and so the government’s trying to wipe them out.
But rats also have a really special history on New Zealand’s North Island. The Ngatiwai are an indigenous people who have a cultural connection to rats that goes back CENTURIES.
More than a thousand years ago, when Polynesians were exploring the Pacific they intentionally brought rats aboard their canoes as a portable FOOD source. Making what Emma’s described as a kind of rat confit.
MARRIS: So they would cook them in fat and then allow the fat to congeal. So then they'd be sort of in this block of fat and that would allow them to hold onto them hold onto the meat for a while as a preservation technique. It also probably made them really like rich and delicious.
WALLACE: The Ngatiwai also used the rats’ fur.
MARRIS: they would keep the little skins and make these enormous very grand looking cloaks with them which kind of boggle the mind. I can’t imagine how may rats it would take to make a big impressive fur coat like that.
WALLACE: Now, let’s be clear — these rats are pretty different from city rats... You know, the kind you’d see skulking around the alleyways of New York. For one thing, they’re a lot cuter.
MARRIS: It’s almost more mouse-like looking. It’s kind of fluffy and round. I saw a couple when I was on Kauai running across the trail and my first thought seeing them was not “eek” but sort of like “awww.”
WALLACE: But they’re a threat to endangered birds in New Zealand, and that’s why the government wants to wipe them out. But the Ngatiwai stepped in.
MARRIS: They see themselves as guardians of the kiore, the Pacific rat. The the Maori word for it is kaitiakitanga. This sort of guardianship this this role that you play taking care of a part of the natural world.
WALLACE: They successfully lobbied New Zealand’s Department of Conservation to limit the poison and to set up sanctuaries for the rats.
WALLACE: So, no matter what, rats get our attention. And once you get over your cultural disgust, there are a lot of things about rats that make them objectively awesome.
ROBERT CORRIGAN (URBAN RODENTOLOGIST): I grew up thinking I was gonna be like Jacques Cousteau. Quite frankly
WALLACE: That’s Bobby Corrigan—
WALLACE (on tape): Does your business card actually say rodentologist on it?
CORRIGAN: It it does, it says URBAN rodentologist.
WALLACE: For year Bobby has consulted with cities, and businesses who have big rat problems. His job is to help get rid of them. But in the process Bobby’s developed a sense of awe and wonder, a Jacques Cousteau of the rodent kingdom, if you will.
CORRIGAN: I actually enjoy being around rats. That sounds bizarre but it's just such a cool mammal. Once you understand it, I don’t see how anybody could be repulsed by rats.
WALLACE: I’m going to have to let Bobby make the case for why the rats we see scaling New York City trash cans AREN’T repulsive. First, he says they’re resourceful predators …
CORRIGAN: I saw the rats in the sewers completely chase down and disassemble cockroaches just like we disassemble a lobster at a restaurant. We'll disassemble that to get to the meat of the lobster.
WALLACE: I mean, without the little plastic bib... I’m assuming. But they don’t stop there. Bobby says rats enjoy hunting another common city pest: the pigeon. A.K.A. the rat with wings.
CORRIGAN: It's very common to watch a rat stalk that pigeon from the shadows and from the back they launch. And they grab them by the neck and they will drag a live pigeon right down their burrow and kill it, like we see on the Serengeti.
WALLACE: I’m just imagining the next Nat Geo Wild special replacing lions in the Serengeti... with rats in a city park. But comparisons to African wildlife aside - Bobby says another thing you’ve got to admire? Rats are athletic.
CORRIGAN: I call them gymnasts. They're they're unbelievable animals at being able to contort their bodies and make twists and turns and use their tails and squeeze through tiny openings.
WALLACE: An average-sized city rat could squeeze through a hole the size of a quarter.
CORRIGAN: The ribs somewhat have a hinge on them, if you will, and it can collapse and do the hula through the rest of it and get the body through eventually.
WALLACE: Rats can also hold their breath for up to THREE minutes, which, by the way, explains how they can get up into your toilet - something that Bobby says occurs more often than any of us would like to think about.
CORRIGAN: When humans designed pipes right away we designed rodent highways.
WALLACE: And rats travel down these highways because they have an almost unquenchable curiosity.
CORRIGAN: They take chances they don't have experience maybe like an 18 year old that first gets their driver's license. Their insurance rates are high for a reason.
WALLACE: Oh and - in terms of breeding, rabbits ain’t got nothing on rats. One rat couple is capable of producing fifteen thousand offspring in just a year. No one really knows how many rats there are, but in some cities population estimates are rising. So yeah, rat baby booms are a totally a thing and they keep people like Bobby pretty busy.
CORRIGAN: You're going to have to get somewhere close to 96 percent elimination of that population. If you get 88 and you walk away and thinking, “Okay. We beat the rats of this park,” they'll be back. If it's winter, you know it's a year. If it’s summertime, they can be back in six months
WALLACE: If that’s not a sobering thought, I don’t know what is. But Bobby’s given me a lot to think about. Like us, rats are scrappy. They’re athletic. They’re ambitious and they explore everything. And man, do they hustle. They’re like the anti-hero of the urban jungle.
And they’re relatable in this other way too … Emma Marris came across an experiment involving rats. Okay, so it worked like this: there were two rats, one in a cage and the other roaming free. The free rat’s got a choice - it can either liberate the trapped rat, or it can go chow down on a piece of chocolate. Despite the temptation of the sweets, the free rat chose to release its friend in most cases.
MARRIS: Yeah, and then once they've freed this other rat the two rats kind of get close to each other and sniff each other and touch each other, in what researchers suggest is a kind of a consoling behavior like we might give somebody a hug after they'd been through something horrible.
WALLACE: But if you’re still finding it hard to appreciate rats, you’re definitely not alone. And we may have some good news. Remember Mr. Infested Mind, Jeff Lockwood from earlier? The guy who described disgust as a grand uniting human phenomenon? He actually thinks that the hatred of rats might be just the thing to bring us all together.
LOCKWOOD: Think about the fragmentation and the polarization of society right now politically and blah, blah, blah.
LOCKWOOD: So maybe what we need to do is get together black, white, brown, men, women, gay, straight. All right? Sitting around a table and say okay we're going to begin by everybody telling us a rat or roach story.
WALLACE: There it is. If we’re talking about making society great it’s just our acknowledgement that we all find rats creepy...
LOCKWOOD: That’s right, so...
WALLACE: ...and disgusting.
LOCKWOOD: So we're going to have a new slogan right? make America disgusted again.
WALLACE: Make America disgusted again.
You can read Emma Marris’ Rats feature from National Geographic magazine by checking out the links in our show notes. They’re right there in your podcast app.
And while you’re there - go ahead and subscribe to Overheard at National Geographic.
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Overheard at National Geographic is produced by Emily Ochsenschlager, Kristen Clark, Brian Gutierrez, Robin Miniter and Jacob Pinter.
Our editor is Casey Miner, with help from Ibby Caputo.
Hansdale Hsu composed our theme music and engineers our episodes, with additional help from Nick Anderson, Devin Ocampo and Grahame Davies.
Special thanks to: Pineapple Street Media, April Ehrlich and Val Curtis.
This podcast is a production of National Geographic Partners, Susan Goldberg is our editorial director.
I’m your host, Vaughn Wallace. Thanks for listening, and meet you back here next week!