Unseen City: Wonders of the Urban Wilderness

Roman Mars:
This is 99% Invisible. I’m Roman Mars.

Roman Mars:
We built the cities for us. The concrete, the metal, and the glass were formed into countless austere structures designed to give comfort to squishy, hairless bipeds. When we made the cities, we were largely unconcerned with the feathered, the spineless, or the photosynthetic. But to quote our greatest scientist, Dr. Ian Malcolm… of Jurassic Park, “Life finds a way.”

Roman Mars:
But the life that found a way to thrive within our city limits isn’t celebrated for its ingenuity or lauded for its fortitude. The plants and animals that have made it, the life that found a way, is reviled. Familiarity has bred contempt at worst or indifference at best. We kick pigeons. We poison snails. We mow down even the most useful weeds.

Roman Mars:
But in Nathanael Johnson’s new book, “Unseen City”, he implores us to slow down and notice the beauty and resilience of the life that thrives within our urban landscape. He uncovers weeds that are tastier than you’ve imagined, squirrels that are smarter than you suspected, and pigeons that exemplify their aristocratic origins. He writes about all the gross stuff they do, too. They’re no grosser than us humans, but let’s just say that every time you admire the green, iridescent shimmer of the neck feathers on a pigeon, you will also be reminded of a thing called pigeon milk. It will haunt your nightmares.

Roman Mars:
A few weeks ago, I interviewed Nathanael Johnson in front of an audience at NightLife, the adults-only, nighttime weekly event at the California Academy of Sciences. I had such a good time there, and I enjoyed “Unseen City” so much that we thought we’d share it as a special episode.

Roman Mars:
I started out by asking Nathanael what a synanthrope was, and why he decided to write a whole book about them.

Nathanael Johns:
Synanthropes are the creatures that thrive together with humans. So, “syn” is together in the Greek, and “anthro” is humans; so synanthropes. And these are all the creatures that are living right alongside us. The weeds springing up through the cracks, the starlings that are growing generation after generation in your attic. I’ve always been kind of a wannabe naturalist, who is interested in these types of things. But for some reason, these particular creatures always seemed like they weren’t worthy of real study.

Nathanael Johns:
So I kind of ignored them until I had a baby girl, and she didn’t ignore them. She was incredibly interested in these creatures. So I started looking at them, too, and when I started looking at them in the way that she did, through these fresh eyes, I started seeing things that I’d never seen before. And that was really cool, because you can go out into the woods and find something new that you’ve never seen before. And it’s like, that’s amazing.

Nathanael Johns:
But it’s even more magical when it’s been there, right in front of you, day after day, right underneath your nose. Then you are able to look at it in a new way and see something that just pops out and is amazing.

Roman Mars:
Do you remember the first thing that she pointed out that you felt like you had to find an answer for her?

Nathanael Johns:
Yeah. There was this thing that would happen, pretty much every day as we were going to her daycare. I’d have her in the front pack, and she would point at basically everything that we passed. She’d be like, “What’s that?” and I’d say, “That’s a tree,” and she’d say, “That?” “That’s still … That’s actually the same tree.” (Roman laughs). So I had this terrible choice between saying “tree, tree, tree,” over and over again, or listening to her scream for the entire time.

Nathanael Johns:
So I decided to complicate the game a little bit by making a new rule, which was that I could only say the same thing one time. So I could say tree, but then I would have to say branch, twig, leaf, stamen. By doing that, this one time I saw these tiny little flowers on this tree that I’d never seen before. We just got close to it, and there were these beautiful little yellow flowers. So then, I had to go find what the tree was, and it was just this wonderful moment. Then, came back later and saw those same flowers, and we saw they were developing into seedpods. And she remembered, and she was like, “Whoa, that’s cool.”

Nathanael Johns:
So that was the first real moment, where I was like, there’s stuff out here that I could be noticing that I’m not.

Roman Mars:
Right. You keep a kind of a toolkit for noticing things. One of my favorites… So, like on my show, 99% Invisible, we have a saying. It’s, “Always read the plaque.” It’s not because all plaques are fantastic. Many of them are really boring and factually incorrect. But at least, if you’re the type of person that reads the plaque, you’re a person who notices the story in places.

Roman Mars:
You have this corollary that I love, that’s sort of the equivalent in the natural wonders of the cityscape, “Always eat the weed.” So, how does that sort of work into how you cultivate awareness in the natural world?

Nathanael Johns:
So if you always eat the weed, you walk through the world in a very different way. I should say that we’re talking about edible weeds here.

Roman Mars:
Don’t eat every weed.

Nathanael Johns:
But there’s a surprising number of them that are edible. All these things that grow in these gritty situations, a lot of them happen to be pretty tasty, if you catch them in the right situation. We just interact with nature generally through our eyes. We look at stuff. Sometimes, maybe we’d listen to birdsong or smell the roses or the skunk or whatever. But we rarely interact with nature by putting it in our mouths.

Nathanael Johns:
When you do that, all of the senses snap into focus, because you’ve got the feel in the mouth, the scent goes up the back of your nose. There’s a crunch, and the taste, of course, and you also start seeing things differently. Because as soon as the brain registers that that’s food, this mishmash of weeds that you couldn’t really distinguish before comes right into focus. I’m terrible at remembering different species’ names, but if it’s something that I can eat, for some reason there’s this evolutionary thing that it’s like, “Oh, that.” I remember the nasturtiums and the dandelions, when they’re just coming in, and the mallow, and that sort of thing.

Roman Mars:
So, let’s talk about pigeons. I kind of view them as disgusting, lice-ridden lizards. You don’t view them that way, obviously. By the end of the chapter, I didn’t feel that way. So, why do we hate them, because universally, people don’t really like them. What are we getting wrong about pigeons?

Nathanael Johns:
I think that what happened with pigeons is that, I mean, they are legitimately revolting. Let’s just put that on the table.

Roman Mars:
Noted.

Nathanael Johns:
But all the things that we find really loathsome about them are really caused by us. By humans. Because we bred them to be massively productive, and then we put them in this situation where we’ve fed them all kinds of food, and we’ve created this massive amount of food waste that they could eat. And they reproduce like crazy, and so then they’re overpopulated. They’re all squished together, and they get parasites and diseases. A lot of the things that we find disgusting about them are a result of that.

Roman Mars:
Those are our things.

Nathanael Johns:
Those are our things.

Roman Mars:
But they didn’t start like that. These had noble origins, these pigeons.

Nathanael Johns:
Right. So, pigeons are really a bird of the aristocracy. They were first domesticated probably in the Middle East, and then they spread around Europe with the Romans. With Roman upper class, really. They were built into the architecture of Roman houses. One of the classic elements of the Tuscan villa is this belvedere, this top-like structure that you can go out and see the beautiful view, and that was a pigeon house. This open-roofed structure at the top of the building. And now, it’s this common feature of a beautiful, stately, upper class house.

Nathanael Johns:
Then, they came to the U.S. with the upper crust as well. Samuel Champlain, the first governor of Quebec, was the person to bring them to the new world. They spread across the U.S. because governors and dignitaries would give them to each other, and you had to have a pigeon roost in your house or nearby. So, they spread with upper crust.

Nathanael Johns:
But then they became really successful, and as America became more and more successful and we started producing more and more food and started building these plazas with statues in the middle of them, pigeons started taking to those places and taking them over. You can’t really maintain your status as a symbol of the aristocracy, if you’re an incredibly common thing.

Nathanael Johns:
So, they fell from grace. You can see this happening in the language, too. One of the interesting things about pigeons is the words pigeon and dove, for a long time they were just mixed together. There’s no scientific distinction between those two things. It’s all kind of the same family, often the common name of something will both be a pigeon and a dove. But at some point, everything good was a dove, and everything bad was a pigeon.

Nathanael Johns:
You can see it today. I mean, if you try and change it around, there’s this huge cultural antipathy toward pigeons. Right. So if you think of “Pigeon” soap, or “Pigeon” chocolate bars, it just doesn’t work. Or you could think about it in the uses in the Bible, like the Holy Spirit descending from heaven in the form of a pigeon.

Nathanael Johns:
So they’ve undergone this radical transformation, and I sort of feel for them. If you look at them closely, they’re these beautiful birds, if they’re not diseased and rabid.

Roman Mars:
We’re kind of in this cold war, maybe even a hot war, with pigeons all the time. It doesn’t really work all that well. So what are the ways that we deal with pigeons in cities?

Nathanael Johns:
Right. So, there’s the pigeon control industry. It’s a pretty massive industry. You can do a lot of things. You can put spikes out to stop the pigeons. You can put netting that blocks them. They even have miniature electric fences to keep pigeons away. And none of it works. I mean, it all works to a certain degree, in that you can push pigeons off of one building. But they can just go to the next building. And that’s what they do. As long as the food source is there, the pigeons will be there.

Roman Mars:
Okay, so let’s get onto the pigeon milk. Okay. Please. I read this, and it was really upsetting to me. So I want you to upset all these people here in this room. What is pigeon milk?

Nathanael Johns:
So, normally we think of mammals giving milk in…

Roman Mars:
Yes. That’s exactly right.

Nathanael Johns:
But it’s a really useful delivery device of nutrients, and birds have figured it out, too. Or at least, pigeons have figured it out, too. It’s completely convergent evolution. It’s not like this is something that has spread up the evolutionary tree. It’s very similar in its structure, but it’s completely independently derived.

Roman Mars:
Right.

Nathanael Johns:
Essentially what happens is, the birds secrete some nutrients through the inside of their throats, and there’s a little pouch that birds have inside their throats, called the crop. And it collects in the crop, and it’s this sort of yellowish, cheesy …

Roman Mars:
Yeah, not gross at all. You’re right.

Nathanael Johns:
Then the squabs, the little birds, stick their heads down the parents’ throats and thrust to get the pigeon milk out. Both the males and the females produce this. It’s a beautiful wonder of nature.

Roman Mars:
When you were researching pigeons, you noticed that a bunch of them have messed up legs. There’s a mystery to why so many pigeons have messed up legs.

Nathanael Johns:
Yeah. So, I don’t know if you’ve seen this, but I started seeing this as soon as I started looking closely at pigeons, that they often would be missing a toe or they’d be missing their foot entirely. It was just the stump. And it was like, this huge percentage. Every time I would look, I would see … There’d be like, 10 pigeons out there, and one or two of them would have something wrong with their feet.

Nathanael Johns:
When I started looking for the answers about this, I found all of these ideas. People were pretty sure that there were predators like cats were attacking their feet. But why would they just attack the feet? You know? Or they were getting staph infections. It took me a really long time to figure this out. It was sort of throughout the entire course of the research, I was tracing down these different threads.

Nathanael Johns:
Eventually, what I found … the premier pigeon researcher said … all of this is nonsense. What happens is that they pick up little bits of thread or hair, which is incredibly common in cities. It gets tangled around their feet, and they don’t have any way to get it off. It just gets tangled tighter and tighter, and it causes these lesions. Normally, birds don’t get this because most birds hop. Pigeons kind of shuffle, and so, they’re really well-adapted to cities in many ways, except for this one terrible, grotesque flaw.

Roman Mars:
Some reason their beaks just, they’re not capable of taking them…

Nathanael Johns:
They’re not capable of untangling it.

Roman Mars:
Wow. That’s sad. Okay, I feel bad for pigeons now. In the book, most of the flora and fauna are species that thrive in the concrete landscape. But humans didn’t purposely make it easy for them to survive. That’s not the case for the ginkgo biloba, which is a tree that probably wouldn’t exist anymore if it weren’t for people planting them in cities. So, why are ginkgos unsuitable for nature, and why do they do so well in cities?

Nathanael Johns:
The golden age of ginkgos was the Cretaceous, when ginkgos ruled the world, as we all know. That’s what we think of that era.

Roman Mars:
They just shared it with dinosaurs. They didn’t care.

Nathanael Johns:
Really, they were in charge. At that time, ginkgos had some evolutionary partner. They had some kind of creature that would help them distribute their seeds. Today, we have no idea what this is. It’s this mystery that people are still trying to figure out. It’s a double mystery, because their seeds smell like microwaved death. It’s just … terrible. There’s male and female ginkgos, and the females produce the seeds. If you’re around them, around September, November, you’ll notice, stop. That’s one thing you can open your eyes to. You can stop and find the seeds and notice just how terrible they smell.

Nathanael Johns:
But there was something that must have liked this smell and must have eaten it and carried it to different places. At some point, the seed distributor probably died out, and it simply meant that the ginkgos couldn’t outrun the glaciers, as the climate changed. So you see them all across the world. They have these really tough, leathery leaves, so they make great fossils. People find them all over the place. Then they retreat, and they retreat, and they retreat, until there are just a couple valleys in China where they’re left. Their entire family gets wiped out, too. They’re the only remaining species of this whole division of plant life that remains.

Nathanael Johns:
Then, people come along. People fall in love with ginkgos. It turns out that ginkgos kind of love us, too. They can thrive in polluted air. They do well in concrete. They do well in partial light, which is perfect for cities. They’re famously good at taking abuse, being backed into by a delivery truck or close to an atom bomb. There’s one just a kilometer away from the Hiroshima bomb site that survived and regrew.

Nathanael Johns:
It’s this kind of amazing story, where they just barely hung for millions and millions of years, and then they happened to find themselves in this crazy point in the earth’s history where they could thrive in human cities.

Roman Mars:
Because the fruits, the seeds are so stinky, we tend to plant only the male of the species, right?

Nathanael Johns:
That’s right. People try to just plant the males, and sometimes they get it wrong. It’s like, 30 years before they become sexually mature, so then it’s like, oops. I guess that was a female. But even the males have their downsides, because then, they produce tons and tons of pollen.

Roman Mars:
Yeah.

Nathanael Johns:
So, one way or the other.

Roman Mars:
So, you discovered that ginkgo seeds were edible at a certain point, once you get rid of that really stinky flesh that’s around them. I just have this quote that I want to read from your book, which I really liked a lot. It says, “Ginkgo toxin is similar in structure to Vitamin B6, and eating too much of it interferes with our ability to synthesize the vitamin. That can provoke a biochemical cascade that, especially in children, may lead to seizures and even death. This sounds alarming, but it wasn’t enough to deter me.”

Roman Mars:
What does deter you from eating things, and in general, are we a little too paranoid about poisonous nature?

Nathanael Johns:
Yeah, I think we’re a little too paranoid about poisonous nature, and just poisons in general. For the previous book that I did, I ended up researching a whole bunch about our relationship with plants. When you look at that relationship, that coevolutionary exchange between animals and plants, it’s a history of chemical warfare. Plants produce crazier and crazier chemicals to try and protect themselves from animals. You would think that they would just win, right, because they have these amazing laboratories where they can just synthesize stuff that would make people at the NSA just salivate. You know? This crazy stuff.

Nathanael Johns:
But they don’t, because animals are really, really tough, and basically animals are like, “Pretty good poison there, plant. Guess I’ll eat a little bit less of you.” So, we’ve evolved the ability to deal with this. You spend enough time with this history, you really take in the lesson that the dose makes the poison. With ginkgo seeds especially, yes, there is this possibility of poisoning, but also there is this history of millions of people eating this for thousands of years. So I felt pretty okay with it.

Roman Mars:
You felt safe with it. How did they end up tasting?

Nathanael Johns:
So, first of all, I tried to do it myself. I was a little bit paranoid about the poison, and so, I cooked it and cooked it and cooked it. Then I cracked open the ginkgo nut, and it was this shriveled little brown thing. I was like, “I wonder if that’s how it’s supposed to look.” I was like, “It’s really hard and kind of caramel tasting.” Then I went to someone who’s a Chinese-cooking enthusiast and knows how to prepare this correctly. She made it, and it was a little bit of a letdown, because it was so mild. It’s just this … It’s kind of a tacky, very mild, slightly bitter, but not especially flavorful nut. It’s kind of like, overcooked gnocchi. It’s just a little bit …

Nathanael Johns:
And it’s really valued more for its texture in Chinese cuisine than for its taste.

Roman Mars:
Right.

Nathanael Johns:
And its supposed medical properties, as well.

Roman Mars:
Yeah. What’s the deal with the medical properties?

Nathanael Johns:
I don’t know. I mean, the medical properties that we generally talk about have to do with compounds in the leave. Ginkgo biloba has been shown to help facilitate blood flow, and so, and that can help with things like facilitating blood flow in the brain. So maybe, yes, there might be some way in which it makes you smarter. But it’s kind of a stretch. It does facilitate the blood flow by kind of thinning the blood, too, so it can have some dangerous complications … if you’re already on blood thinners or such. So….

Roman Mars:
I wanted to hit on one more species before we wrap it up. But there’s a bunch of them in the book, and you should definitely check it out. I want to talk about crows a little bit. Crows are the species in the book that seem to most knowingly take advantage of human city scapes. I mean, they’re shockingly bright. Things that are probably not good for us as humans, like streetlights, people think that upsets our circadian rhythms. Crows are all about streetlights. So, tell us a little bit about that and how they’ve particularly worked their way into our lives.

Nathanael Johns:
There’s this mystery, because there’s this boom in crows. It doesn’t seem like there’s really a boom in crows, but actually just a concentration of crows in cities. So then the question is, why are crows coming into cities? One explanation for that is streetlights, because if you’re a crow, the scariest thing in the world is a great horned owl, because they just fly around in the dark, and they’re huge, and they’re silent. And they just swoop down and totally eat you. If you have streetlights, you can see them coming.

Nathanael Johns:
So, that may be why crows are moving into cities.

Roman Mars:
Wow. We’re protecting them.

Nathanael Johns:
We’re protecting them.

Roman Mars:
With our awful lights on, all the time. Fundamentally, when I was reading this, I was like, it’s really all about story. So, we hear stories about sort of mundane and ugly things all the time, and I can be seduced, like, the ugliest building – if it has a good story, I’m all about it. We did a story about those inflatable tube men, you know? Those are dumb as hell. But you have this guy talking about them, and he’s from Trinidad, and he goes, “They’re dancing up a storm,” like that. It’s the greatest thing ever. Now I love those things.

Roman Mars:
That’s really what this is about. You find the story of these things, and all of a sudden, this nature, which is kind of set up to be a nuisance, sort of like in our heads, is like a nuisance, is a thing you can fall in love with.

Nathanael Johns:
Every time I pass one of those tube men now, I’ll think of that story. It makes my life a little bit richer, because I hear that guy’s voice. I think of that whole story. The same is true with all of these creatures that I’ve started to get to know, because on my way to work, if I stop at the bus stop in the morning, instead of just being kind of annoyed in the back of my head that there’s a crow cawing, I’ll look up and see if it’s having a squabble with a squirrel, and wonder what that’s about. Or I’ll stop to look closely at the flowers that are coming out in the tree and be like, “Oh, that’s telling me something about that particular tree.”

Nathanael Johns:
All of these things are telling stories to us. I just would like to be able to read those stories and fully follow the narrative back. These creatures are passing out newspapers, the way the guys do in the city at the top of the subway. And I’d like to really be able to read those newspapers and have that rich understanding of my world, as I walk through it.

Roman Mars:
So if people here, they leave here, they want to go out and do what you did. Do you have … an assignment for them, to sort of begin to notice something?

Nathanael Johns:
Yeah, so … there’s a bunch of things that you could do. But one thing that’s right in front of you. I mean, there’s pigeons everywhere. We’ve talked a lot about pigeons. Can anybody tell me what color a pigeon’s eyes are?

Roman Mars:
Reddish, green, blue.

Nathanael Johns:
I heard a correct answer. But why don’t we just leave it, and take a close look next time you see them. It’s really crazy.

Roman Mars:
So when you do it, find it. Put it on Twitter, tag it with “Unseen City”, and we’ll watch for it. So if you’re like me, and you read in bed next to your spouse, and you like to go, “Hey, you know what about snails? They have two antennae so that they can find calcium,” this is the book for you, my friends. Every five minutes, you’re going to be saying something like that.

Roman Mars:
Nathanael, thank you so much for being here.

Nathanael Johns:
Thank you.