I’M PRIVILEGED to observe a fascinating diversity of animals outside where I live, but the term “Outsider Animals” was new to me. It’s the title of a recent book by today’s guest, Marlene Zuk, a leading expert in behavioral evolution and a professor at the University of Minnesota.

The book’s subtitle is “How the Creatures at the Margins of Our Lives Have the Most to Teach Us” (affiliate link), and among her subjects are ones that many gardeners may know—or think they know—like raccoons, cabbage white butterflies, cowbirds and snakes (like the garter snake, above, devouring one of “my” frogs in the garden some years ago).

All these animals have one thing in common, she writes: “When we see them, we ask, what are you doing here?”

Outsider animals were the topic of my conversation with Dr. Zuk, the Regents Professor of Ecology, Evolution and Behavior at the University of Minnesota, and a member of the National Academy of Sciences.

Plus: Comment in the box near the bottom of the page for a chance to win a copy of the book.

Read along as you listen to the April 13, 2026 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify (and browse my archive of podcasts here).

outsider animals, with marlene zuk

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Margaret Roach: Beyond what I said in the introduction, I guess we should start by explaining what outsider animals are. I said that they’re the ones … You say that they’re the ones that when we see them, we say, “What are you doing here?” Can you define it beyond that a little more fully for us?

Marlene Zuk: Sure. So to back up, I’m a scientist who studies animals and I’m interested in all kinds of animals. And just recently, I’ve gotten intrigued by the animals that we tend to see whether we want to or not. They’re animals that impinge on our lives whether or not we have them as pets, or we use them in farms, or we want to go see them in nature documentaries or at the zoo. And we often encounter those animals when we don’t want to, or when we’re surprised by them.

And so I really wanted to explore their lives a little bit more. And as you say, they’re raccoons and snakes, and I also have a chapter on gulls that might go after your sandwich at a picnic. And I think we often have a lot of opinions about those animals, and I wanted to look into their lives a little more.

Margaret: Yes. And we have opinions, and we tend to anthropomorphize, of course, and you can call me guilty on that score. I can’t seem to help myself [laughter]. And we characterize animals, don’t we? We say crows and octopus and chimps—we think they have big brains and are so smart. And I think as you write about in the book, we’re inclined to rank them, like who’s the smartest and so forth. And I love what you say about that. You say, “Asking if one animal species is smarter than another is like asking if a hammer is a better tool than a screwdriver.” [Laughter.]

Marlene: That one’s actually, I have to say it’s not original to me. Brian Hare, who’s an expert on dogs, actually came up with it. And yeah, I’m really interested in how people do this. They automatically want to know, oh, which is smarter? You can Google animal IQ tests and you will get a lot of responses, which kind of blows me away that people really … It’s not enough that we can give IQ tests to people; they want to give IQ tests to fish. And where are we going with all this? And I’m particularly interested in how we come up with these ideas about animals that are very familiar to us like raccoons or rats or cabbage white butterflies.

Margaret: Yeah. Well, speaking of raccoons, I mean, that’s one where … Well, there’s a raccoon on the cover of the book. They’re adorable. Their faces are adorable [laughter] with the little mask. And they have those forepaws, those “hands,” so they have dexterity. And I was fascinated in the book you gives a little bit of history about them and the research into them and so forth. And you talk about how years ago some researchers wanted to use them as lab animals.

And I was like: herding cats (speaking of stereotyping an animal)! I was like, because I’ve had the experience having been the host on the deck of my front porch to a scat latrine, a.k.a. a bathroom that was established and used one summer every night by 13 raccoons. So much for them being solitary animals, as it says in all of the books that I’ve read [laughter].

And all they did was that chittering noise. It was hysterical. It was like there was a wild party going on and everyone was pooping and peeing on the front porch. Well, anyway, so when it said “lab animals,” I thought, “Oh my goodness.”

Marlene: Well, yeah, that was one of the many amazing things that I got to uncover when I was doing the research for the book—because I mean, I work on animals, but I certainly was not an expert on all the species in them. And the raccoon thing was hilarious that at the beginning … And what I liked about finding all this out is that it gives you a real insight into how science operates because, O.K., how do you want to pick an animal that’s going to help you learn about basic principles in life? And in this case, it was two psychologists at two different universities who both came up with the idea. They were interested in how we understand learning. How do we understand not just how people learn, but how animals learn. And that was a big topic at the beginning of the 20th century, the early 1900s.

And these two different people both said… People were much more rural then, and so pretty much everybody had encountered raccoons. And raccoons are, as you say, they’re so interesting in how they’ll manipulate objects. They seem like they can figure things out. And they thought, “O.K., this would work. We could do experiments with them.” And plus you can tame them. They don’t make very good pets, as I point out in the book.

And so they thought, “All right, well, let’s try and do this.” And for quite a few years, they were championing this. And again, with the benefit of hindsight, you think, “Oh gosh, what were they thinking?” Because imagine if instead of cages of rats in all the psychology laboratories or the medical schools even of the country, we had to have cages of raccoons.

And anyway, first of all, it’d have to be so much bigger. And second of all, well, they’d have to have really good locks on them because raccoons can get out of almost anything. And so you can imagine that the researchers coming in every morning and finding disaster and chaos with all the raccoons having broken out, and then they’d have to make new ones. And how would … [laughter] Anyway, the mind really just boggles. And both of the people eventually backed off of this.

And as you know, I mean, obviously we do not have a world in which raccoons were the model system the way rats or pigeons or mice are for a lot of our experimentation. And so it’s always tempting to me to think about one of those alternative histories where you know how they write books about what would’ve happened if the South would’ve won the Civil War, or something like that. Well, imagine writing a whole book on what would’ve happened if they’d been successful, and then what would the world have looked like? What would we have learned if we’d used raccoons for this? What would our cities and … Anyway, it’s- [Laughter.]

Margaret: Yeah. Well, I know you point out a trait they have that’s unusual. Neophilia, would that be how to say it? I don’t know. Yeah.

Marlene: Yeah, neophilia. So -philia always means love of or liking for, and neo- is new. And so many, many animals are what’s called neophobic. They’re afraid of new things. Raccoons are neophilic. They like new things, and they’ll come and mess around with new things and explore. And one of the most interesting things that people have learned in doing research on them is how that tendency to explore affects their ability to solve problems, their ability to learn, and various other things. So I think there is a lot that raccoons can teach us, but I’m really kind of glad that we didn’t seize on them as the main model system in science. [Laughter.]

Margaret: Yeah, no. So speaking of exploring… female cowbirds: You write about cowbirds. And it was funny, I saw cowbirds: What are cowbirds doing in this book? And they’re the bird that everybody loves to hate, I guess.

Marlene: Yeah.

Margaret: But the female cowbirds are pretty impressive in the sense that they, not explore exactly, but they have sort of have, I think you liken it almost to an inner GPS in the book. They have to find where they can deposit… They’re brood parasites. They have to define where they can deposit their egg and time it to be an appropriate moment. [Above, a cowbird egg in a nest of phoebe eggs; Wikipedia photo by Galawebdesign.]

Marlene: Yeah. And they have to remember where they left… where they’re basically scoping out. So I suppose, do we want to backtrack and just briefly explain what a brood parasite is? I never know whether people know.

So cowbirds are interesting for a whole bunch of reasons. And as you know, you got it exactly right, the part of why I wanted to include them in the book is that they’re animals that even animal lovers will make a thing about hating cowbirds.

And they kind of hate them for two reasons. One is that they are brood parasites, which means that the female cowbird, rather than laying eggs in her own nest and rearing the chicks either with or without her mate, the female cowbird will deposit her eggs in the nest of another bird species, maybe a warbler or something else. And then she leaves and what’s called the host species raises her chick for her.

And sometimes the cowbirds will destroy the chicks in the nest where they are, or the eggs. And so they can actually have a really detrimental effect on the host species. And so first of all, people just kind of think, ew, because they think it’s just kind of a nasty lifestyle.

Margaret: Baby murderers, right?

Marlene: Exactly. And then also because they are in the nests of … They are native themselves, so cowbirds are native to the Americas. But also because of that, they can have a detrimental effect on native species. And in some areas like the Kirtland’s warblers in Michigan and some vireos out in the West and several other iconic species, they can have bad effects on the native populations. And so they’ve been vilified because of that.

And so I guess I wanted to push back on both of those. The brood parasite thing: I really think people should stop having value judgments about the way animals’ lifestyles are. I mean, people are also kind of negative about predators, and everybody’s got to eat.

Margaret: Yes.

Marlene: Yeah. And so with the brood parasites, one of the things I wanted to do was help people see how extraordinary they are, which gets back to your issue about female cowbirds.

So O.K., imagine that you’re a bird and so you’re not going to build a nest. You need to find somebody else’s nest. And you need to find somebody else’s nest that is at exactly the right stage where you can rush in, lay your egg and rush out, so that your egg will develop with the care of the host parent, and that you can do it undetected. Well, doing that is a really hard thing to do. And female cowbirds will go around from place to place looking for nests.

And so I’m just going to pause here. And I know a lot of gardeners, I love looking for … If I find a bird nest, I feel like it’s an extraordinary thing like, “Oh, look, we found a robin’s nest,” or “We found a warbler nest or a wren nest.” And I know a lot of gardeners want to put nest boxes in their yard so they can encourage that.

Well, imagine that cowbirds are having to find all these nests. It’s hard. And what they have to do is remember where the nest was because they can only come back at the appropriate time to lay an egg, and then they have to lay the egg incredibly quickly so that the mother bird doesn’t find them and chase them away. And that requires, as I refer to it in the book, is sort of an internal GPS.

So they have to remember all those directions of turn left at the cedar or go two miles down the riverbank or whatever they need to know, and then they’re going to find the nest. So they not only need to find it once, they need to find it again. And it’s just an extraordinary accomplishment, and their brains actually have an enlarged structure, it’s called a hippocampus, that is used in direction finding. It’s also used in direction finding in people. And they have amazing brains that allow them to do that. And the males don’t have that, because the males don’t need to find the nests.

Margaret: Right. Well, and the other thing that I love is the question that you asked in the book: How in the world does a baby cowbird that hatches in this nest that is not of its species, the parent is not of its species, how do they know kind of who they are, so to speak? How do they learn the characteristics of their species if they’re raised by another? And young males typically listen to the adult males of their species and learn the songs and whatever. Well, where does that happen? How do you learn who you are when you’re in that kind of a place? That’s amazing.

Marlene: Yeah. And scientists have studied it a bunch, and they don’t have the complete answer. One of my good friends, Mark Hauber, who’s with the CUNY system in New York, has worked on this for many years and found that the young juvenile cowbirds will gather in groups of other juvenile cowbirds and they’ll kind of learn from each other. And the way they do that is it’s called sort of self-referential learning. Or sometimes people refer to it as kind of the armpit effect, where that came from someone who was studying mammals where they smell. And so if you wanted to know what you smelled like, you could smell your armpit. Well, what cowbirds do is they look. And Mark and his colleagues did this great experiment where they made the feathers of the cowbird darker, and that changed how the cowbirds responded to each other. So it’s like they’re looking at their own plumage and the plumage of others, and they’re getting information about who they are from that.

I mean, it’s more complicated than that, but that’s at least a stab at the answer. Because again, for years I would read that people said, “Oh, well, they just are born knowing that they’re cowbirds.” And that’s a very unsatisfactory answer because that’s sort of like saying, “Well, they know they’re cowbirds because they know they’re cowbirds.” And it’s like, “Oh, come on.”

Margaret: Right. Yeah. Well, it’s fascinating.

Marlene: It’s a super-interesting question. And I think that it does illustrate how common animals that we don’t necessarily think about can open up very basic major questions about the nature of behavior, and the nature of the abilities of organisms to find their way around and to recognize others, and all kinds of big questions.

Margaret: Yeah. So I want to spend a teeny bit of time on the cabbage white butterfly, the teeny butterfly, a non-native species that looks more like a moth to many people, and is familiar to vegetable gardeners everywhere who’ve tried to grow brassicas. And this was one that struck me as an oddball. I was like, “Well, how did that get in the book?” [Laughter.] So before we move on to snakes, one of my favorite subjects, I wanted to just know a little bit about the cabbage white. I mean, how the heck did it get in there? [Above, a cabbage white on garlic chives at Margaret’s.]

Marlene: Well, actually several reasons, one of which is a little bit silly, which is that I study insects myself. I’ve mostly done … So I’m kind of a bug person anyway, and until I decided to include the cabbage whites, I only had cockroaches in there. And although I do deeply love cockroaches, and we could talk about cockroaches, I really wanted another insect.

And cabbage whites are great because first of all, they are introduced, and yet people don’t rage about cabbage whites the way they do about maybe starlings or house sparrows, or many of the, of course, introduced plants that are invasive plants that we’re worried about.

And so cabbage whites, they seem like such an innocuous invasive species, and they kind of are and kind of aren’t invasive. They are pests, of course. They’re definitely major pests, as you say, of Brassicaceae. And yet people don’t ever think about how useful they have been, both in understanding how organisms spread in the environment, how they depend on different kinds of plants, and again, how they learn what’s a good plant and what’s not.

Another colleague of mine here at the University of Minnesota, Emilie Snell Rood, is working on how cabbage whites can or can’t tolerate human pollution. And so they turn out to be great subjects for understanding what we’re doing to the environment and which kinds of wildlife can withstand that and which ones can’t.

And sometimes the answers … They certainly surprised me. So that road salt, for instance, which is a major issue in Minnesota where I live and in many other parts of the country, gets into the water and then is absorbed by plants and then of course affects the animals that eat those plants.

And it turns out that road salt doesn’t have nearly as bad an effect on cabbage whites, at least, as a lot of people had thought, which in turn influences what kinds of plants and what kinds of places we want to put host plants for butterflies, like highway medians and roadsides and places like that. So this very unassuming little butterfly can help us do a lot for conservation and nature preserves that we wouldn’t have thought possible otherwise. And so again, what I like is drawing these threads where you say, “Oh, but this is just a common trash animal.” And then it’s like, “No, this animal has taught us about the whole world.”

Margaret: Yeah. So I want to take our last five minutes on snakes [laughter]. Now everybody’s freaking out.

Marlene: The other thing, and before we do finish, I always want to try and remember this part that I’m always curious to have people tell me, and they can do that in the comments or whatever they want, or you can do that. So what animal did I leave out? What’s your outsider animal that you think I should have included? And who knows, maybe there’ll be a Volume 2. But at any rate, I love hearing people’s thoughts about their own outsider animals.

Margaret: Sure. So I want to talk snakes for our last few minutes. So no other animal stirs me so, and I mean that like viscerally. And I say that also living in one of the areas in the Northeast that I live among Eastern timber rattlers. So I am an ophidiophobiac; I am afraid of snakes. Less so than since I’ve lived here full time in the last 20 years or whatever; I’ve gotten to be more snake-friendly.

But it’s a visceral, primitive reaction. And indeed, as you explained in the book, I think the quote is, “Snakes may have shaped the evolution of the primate brain, the only outsider animal to do so. ” So briefly kind of tell us a little bit about that history.

Marlene: Sure. So snakes of course evolved with humans in Africa where they’re some of the oldest companions, if you want to call them that, of early humans. And there have been some scientists that have postulated that part of why we are all so aware of snakes. So I’m not afraid of snakes, but I certainly know lots of people who are, but we are all very aware of snakes.

And part of that may have been that human beings evolved a visual system that’s particularly sensitive to snakes in the environment. And there are scientists who’ve worked on this and who postulate that there are parts of our brain that see snakes before we would see other things. And you can do these experiments where you show people slides and they will respond, as you say viscerally, that’s exactly right, to snakes in a slide when they will say they didn’t see one, but their body reactions will react to one.

And snakes certainly are dangerous. They’re not dangerous to urban or suburban or even rural… I mean, you’re not going to usually run into a snake in North America living in a city or even living in the country, but there’s something that we evolved with as part of a threat. And again, you can look at how our visual systems seem to have evolved.

There is some controversy about this, but I was just intrigued. And I used to teach vertebrate biology and there is just nothing that will get the student’s attention for the entire rest of the day than finding a snake. You can find a rare bird. They’re like, “Oh, that’s O.K.” You can find frogs, you can find lizards, they like them all, but you find a snake and everybody is alert for the entire rest of the day.

Margaret: Right, right. Well, and they’re very different. I mean, they’re limbless, they sort of slither. I mean, they’re very different. They’re very different. And so it is … [Laughter.] Yeah, they’re fascinating.

Marlene: I mean, I think they’re amazing. And what I don’t buy is this idea that people have an innate fear of snakes because I don’t think we do. And I think our fears are shaped in such a complex way by both … Of course, there’s genetic influences on things; there’s genetic influences on lots of things. But I think our environment also really makes a difference.

And I think people who say, “Oh yes, I’ve always been afraid of snakes.” And you say, “Oh, well, how do you know you always have been?” It’s like, “Well, because my parents were always afraid of snakes, and so they screamed every time…” It’s like, so you don’t think that maybe how you were raised influenced…?” O.K., never mind.

Margaret: Right. At the end of the book, you suggest that even though in a sense we invented who the outsiders are, that we might at least look at them as the extraordinary creatures they are. That would be one thing you’d hope that we’d do by reading this.

And what little bit of other advice for sort of, O.K., the next time … I’ve had about the last four or five weeks every night a black bear visit, and the opossum runs around, and everybody’s busy at night lately as spring is springing. And the gray squirrels are going to spend all day disbudding the espaliered pear on the back of my house [laughter]. So you have these reactions, right? But instead, I’m going to look at them as the extraordinary creatures they are, as you said, or any other advice for us as we encounter-

Marlene: Well, let me elaborate a little bit on the extraordinary part, which is that I just recently heard a wonderful talk by someone talking about awe, and how awe is good for us psychologically. It’s an emotion that we don’t acknowledge very often. And he showed a very short film [above] about a guy in Los Angeles who took his telescope out on the street, just because he was bored, and he started showing people the moon.

And it’s a beautiful little film and it shows every single person from all walks of life, old people, young people, all ethnicities, looking through the telescope and you see their faces and they go, “Oh my God.” And then the next person looks, “Oh my God.” And then they’ll look up and they’ll say, “I never knew. Oh my God.”

It’s this powerful experience. And I looked at that and it was well after the book came out, but I thought, “Yes, that’s what I would like to help people in looking at these animals.” We see the moon every day and we don’t think, “Oh my God,” and we should.

Margaret: Yes, yes. It’s a privilege, I think.

Marlene: Yes, exactly.

Margaret: To live among them. And so yes: awe. Good. Well, a good way to end. And thank you, Marlene, for making time. And I hope I’ll speak to you again, and congratulations on it.

Marlene: Thanks so much. This is a lot of fun.

enter to win a copy of ‘outsider animals

I’LL BUY A COPY of “Outsider Animals: How the Creatures at the Margins of Our Lives Have the Most to Teach Us”” by Marlene Zuk for one lucky reader. All you have to do to enter is answer this question in the comments box below:

Is there an “outsider animal” you’ve met in your garden who’s opened your eyes to something?

No answer, or feeling shy? Just say something like “count me in” and I will, but a reply is even better. I’ll pick a random winner after entries close at midnight Tuesday, April 21, 2026. Good luck to all.

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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 17th year in March 2026. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the April 13, 2026 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify (and browse my archive of podcasts here).