Today, we're talking about rats. They've been in the news a lot lately - whether at the center of a ongoing downtown coney feud or suburban communities wrestling with the problem. So what actually works? What don't we know?

Dr. Bobby Corrigan is a rodentologist who has spent his life learning and learning to control these animals.

A transcript of the conversation is below, and if you don't see the podcast player above you can listen to the local episode here.

Transcription of the conversation with Dr. Corrigan

Joining me on the line is Bobby Corrigan. He has a PhD in Rodentology, and considering the things that Metro Detroit is dealing with and the conversation happening right now, I couldn't think of anyone better to talk to. Bobby, welcome to Daily Detroit. I love niche things, and I love experts in things that I know very little about. So, I'm excited about this. Welcome!

Bobby Corrigan: Thank you, Jer. It's a pleasure to be here!

Jer Staes: Rats are pretty much everywhere in the United States, right? Like I feel like Metro Detroit is not alone in this kind of rat conversation, am I right?

Bobby Corrigan: Correct. The rats are pretty much all over the United States and most cities and not only the United States, but the rats, for the most part, are a global pest all the way around the world with only a few exceptions.

Jer Staes: So, what about the rat makes them so well adapted or able to adapt to so many different environments? Uh, they seem to be this kind of, I mean, I know some people are freaked out by them, but kind of a magical creature.

Bobby Corrigan: Wow! That's a great term, magical creature. You know, even though humans, we love to hate rats. The rats really get us upset and scare us, and they've been in the movies. And you've never heard James Cagney say, “You dirty mouse!” You know? It's always the rat. Sometimes when people curse instead of using a curse word that's offensive, they say, “Rats!” You know? Something went wrong today at the office. But, you know, it's an incredible mammal. It's one of the most successful of all mammals out there. And part of the reason for that, to your question is, what makes them so successful is this is an animal that works very hard at getting life done. And it, it also has a propensity for, you know, taking every opportunity that presents itself for food, to, to sample that food. And so it has adapted from, you know, it was originally from Mongolia out in the plains and what have you, and now, as you just stated, you'll find rats in almost every suburban, urban, rural environment. And another part of the reason for that, by the way, is, you know, they're great at hugger muggering. We call it hugger mugger. They get together in little tight balls, you know, take a basketball. You could fit a family of rats inside a basketball, and they're going … they're okay by them. So, they don't complain about having spaghetti three nights in a row. They, you know … they get the job done. It's an amazing mammal.

Jer Staes: Do rats get a bad rep?

Bobby Corrigan: Yes and no. Um, you know, interestingly and paradoxically, you know, Jer, it's this animal, you know, we actually as a species owe more thanks as a species to the rat than any other mammal on planet Earth. And the reason for that is we've studied the rats because they're so much like us. So, we've studied them for every medicine we've used, every cosmetic, mental anguish. We, you know, we've studied this animal backwards, forwards, upside down, and they have probably given us as a species another 20, 30 years of life just by all the benefits. So, do they get a bad rap? Um, there's the other side of that great thing and that is, unfortunately, they hang out in some pretty disgusting areas that harbor germs, and like decaying garbage in alleyways and backyards, where they love sewers. You know, this is a denizen of the sewer systems the world over. And you can imagine the kinds of germs you might find growing on the walls of a filthy sewer below a street where everybody's toilet bowl empties into that. So, when they come up above ground, we have to be concerned about what's on the feet of that rat. Should it run across a park bench or something?

Jer Staes: What really attracts rats in a major way? I think about, you know, here, here in Metro Detroit, they have been talking about issues, officials in different cities been talking about places where they're deploying feral cats to take care of rats. There are issues where when there's construction, rats will disperse. There are issues in the city and the suburbs. I know that a lot of people like to say, you know, here in Metro Detroit, or here in Detroit, you know, there is this current issue where there's a fight between two of our iconic Coney Islands and rat issues between the two of them. One of them's been closed a couple times. The other owner has been very loud about their rat-fighting issues. Meanwhile, other people will post social media videos of rats in or nearby their establishment. So there's like a lot of back and forth about rats. But at the end of the day, what really attracts them and can you really ever get to rat zero?

Bobby Corrigan: You know, it's actually simple and complex at the same time, Jer. I taught rat control and rat biology for 16 years at Purdue University in a class, and simple or not, I would put on the blackboard, you know, four words that pretty much sums it up: No food equals no rats. And, you know, this is a mammal. They're a mammal and just like you and I and all the listeners, right? Most people are going to plan on eating today and tonight and the next day and so forth. We're mammals, we must have food. And so we're not going to do well and you, we all know like some days if we're all so busy if something we even miss a meal or two, and you just don't feel right. You don't can't think right, you may be, you know, worried excessively or you need food for your brain, you need food for your energy. The rat needs all of that as well on a regular basis. So when rats are pervasive around an area, people say, well, you know, maybe we should get, you know, hire an exterminator, maybe we should get some cats, maybe we should do something. The first thing I say is, “Look, if you see rats regularly, it's because there's food. Make no mistake about it. They're not there by mistake. If you see them over and over again, usually within 100 to a couple hundred feet, they're getting regular food, and because they must have it, just like us. They're mammals. Their brains need it.” And so forth and so on. So, the interesting thing about us, whether it's Detroit or New York, or Rome or whatever, we are not great as a species with our waste. Now, some of us are. Some of us … we're meticulous, and we keep everything clean. And if you drop in on someone's house, you wouldn't find a speck of dirt kind of place. Well, there's about 20% of the humans, when they walk down the street, Detroit or Dearborn or any place like this, they're dropping garbage, and they're dropping food and they're dropping and they throw something at a litter basket, and if they miss, they don't pick it up. Those folks are the ones that sustain rat colonies. Or, if you walk down your own block, let's say you have a block of 10 beautiful homes in a suburbia area of Dearborn, and one of those properties out of 10 have cheap plastic garbage cans with that spill over all the time. All the rats of that block will use that one property, even though they're running up and down the entire block for different places to hide, and it's that one out of 10 or two out of 10, 20%. So it's about food. It's always about food.

Jer Staes: What about things like gardens? Or, you know, I think about in my backyard sometimes, I'll grow things like tomatoes. Is that a huge attractor?

Bobby Corrigan: Yes, it is. If there's rats in the area, and I'm a gardener, too. I love to grow my own vegetables and flowers and, you know, I'm into it. Um, if there's rats in an area, they have [a] terrific sense of smell. They will smell those vegetables, especially tomatoes, as they're getting ripe. just, you know, like we do in the supermarket, we hold it up [to] see if it's right. So, you know, it's the issue there, though, if there's rats nearby your garden, where the garden's going to get raided, there's usually better food nearby somewhere in garbage. They must have protein. They can't survive just on garden vegetables, like you and I. We can't eat apples every day and expect to do very well. So, if there's rats that you're worried about in your garden, nearby, there's going to be food and garbage, like meats and chicken and fish and, and breads and waste and that kind of thing.

Jer Staes: So gardens are really second order. Like, they'll get raided, but that's not the primary … that's not the primary thing. They're looking for protein.

Bobby Corrigan: Yeah, that's the best way to put it, secondary, Jer. And, you know, they must have protein. Without protein, you're not going to have good birth, you know? That's the building blocks of life is the protein. But, they want the same thing we want. They want nutritional balance. They want the pyramid on the back, on the back [of] your envelopes, you know. So, they need carbohydrates for energy, and they want some sugars. You know, if they bump into chocolate, they're going to love that for dessert. You know, but they need, yeah, they need meats, fish, chicken, lots of protein, and if it's greasy, all the better.

Jer Staes: Really? So greasy foods really attract them?

Bobby Corrigan: Totally do. I, you know, rats, I've seen rats literally licking grease off the sidewalks in area where it's leaking out beneath some sloppy restaurant's door. And in the back of a restaurant if the dumpster is greasy on the sides and spilling grease, they will lick that grease. For them, grease is … it contains what they need for calories and nutrition.

Jer Staes: Fascinating, fascinating. Are there plants that they don't like or avoid?

Bobby Corrigan: You know, not really, you know, there's been a lot of misconceptions and tales about, you know, certain plants that they'll avoid if you plant them in the garden and and so forth. But not really. If they were that easily deterred by the smell of a type of plant, you know, it would be a pretty wimpy animal. But it takes a lot to deter a rat, uh, from an area except no food. That, that sends them running.

Jer Staes: So, let's talk about structures. Can structures keep rats out? Are there things that you can do? Uh, you know, in city environments, structures are very close together, but you also see environments in suburbs where you'll see rats come in. I feel like sometimes cities, I mean, it's because that's their availability of food and that concentration of food. But is there something about structures that can be better or worse about keeping in rats or keep or keeping out rats?

Bobby Corrigan: You know, I, I love that question. It's like the $60,000 question, Jer. I, yes, structures can be made rodent proof, right? Even though it's true that if you have a determined rat and it's really desperate and they smell some food leaking out the side of a garage door in suburbia, can they gnaw through the wood to get into that house? The answer is, yes. But if, you know, we keep our structures in solid shape, we use, you know, uh, door sweeps in the bottom that are rodent proof that you can buy online or have installed by a pest professional, and you keep foundations in good shape and you make sure, you know, the foundation remains solid, you can completely rodent proof a building. There's a lot of people who believe, oh, you can't do it. There's too many spaces and it's impossible, and they can squeeze below doors and everything. None of that's true. You know, there's pieces and parts, but if you're determined you don't want any rats and mice inside your building, one, do your garbage correctly. Sounds kindergarten, but that's true, and don't attract them to that property. And two, have if you want to do it or get download how to pest proof your house. It's not that complicated nor expensive. And three, if you don't want to do that, hire a pest professional who knows how to do that.

Jer Staes: Are there materials that are better at keeping them out than others?

Bobby Corrigan: Absolutely. You know, so, again, there's a lot of myths. I hear people say, well, they can chew through anything. That's not true, right? They're not magical creatures that can, you know, gnaw through metals, for example, and what have you. They can go through wood easily. They can go through even some soft metals such as aluminum and copper, you know, easily. And but, you know, they can't go through brick, they can't go through cement. They can't go through, you know, metal that's attached to, you know, good, uh, rodent proof materials. So, you know, and all of that, quite frankly, even now with AI, you can go online and say rodent proof materials for a building and, you know, AI will dump that on your, on your computer right in front of you. It's, so, you want to go and do your homework. You don't want to listen to myths, you know, I always encourage people to, you know, go to sites that have .edu at the end. So you get, you know, quote, the experts, if you will, to put together university leaflets on how to do those kinds of things.

Jer Staes: In a more dense situation, a dense urban situation, and I know you have experience with New York and other places, how do you prevent, like, let's say you've got a neighbor that's got an issue. Is it possible to keep the things separate?

Bobby Corrigan: You know, that's the, that's the conundrum. That's the the problem is you can keep your property super clean, let's say in a, in a dense situation with multiple apartment buildings attached and nearby and so forth. But if you have a sloppy neighbor or even a, you know, a sloppy litter basket from the city nearby, you know, it's almost out of your control except, you know, to probably call the local Board of Health and ask them to, you know, stop by and and try to resolve the issue. You know, if you know your neighbor, you know, you can say, you know, I've been seeing rats around, but that's a very sensitive thing and most people are not going to approach your neighbor about their garbage cans and what have you. Even dog poop, you know, sometimes people just have their dog poop, and they'll walk away from it. Well, dog poop's like a … it's like an energy bar to rats. And that night, the, you know, that dog poop sounds disgusting, but it's true. They'll … rats will feed on that. You know, it is, uh, frustrating when you have neighbors close by and they may be the cause of the rats that you're seeing passing by or stopping by on your stoop and this kind of thing. So, the best deal is to to work with your county Board of Health and your health inspectors and see and landlords, if maybe there's an independent landlord, you know, you want to work it out as best as you can.

Jer Staes: You mentioned dog poop and that made me think of my next question. We're talking about the cities. What about ways to prevent things in a more suburban area with a little bit more space between people?

Bobby Corrigan: Well, it's in suburbia, you know, it's easier, of course, because you have that space you're mentioning. So, but, you know, again, uh, you can have one house, even with several acres separating it from yourself, and if they don't take care of their property, you know, their garbage, their if they have dogs and they put them out in pens or something like this. If they put out a lot of bird feeders and they don't keep that maintained, you know, there's all kinds of things that it can attract rats to a suburban house and yard and garden area that could actually be a startup. But, so suburbanites have the same responsibility as the urbanites, and that is, as best as you can, don't do anything to attract any wildlife. And that, by the way, rats are one example, but you don't want raccoons foraging around your backyard. Those are little demons that can do a lot of damage. So you want to just, you know, keep everything as tidy as possible and use good garbage cans, don't leave clutter in your backyard and let piles of lumber or abandoned cars sit there forever. All of that can also provide harborage for these animals in addition to some food.

Jer Staes: So yeah, you're mentioning lumber, something like firewood, stuff like that in like a house in a home situation.

Bobby Corrigan: Correct. And firewood in particular, you know, should be elevated off the ground with a holder away from a wall, an area where, you know, it's easy to look quickly with even just your your Apple phone with a flashlight to make sure nothing's going on because when you stack lumber and forget about it or just leave it off in a corner of someplace in the yard, the the rats and other animals will just say this, this is what we grew up on. This is trees stacked, and we move into trees that are dying and so forth. So, you want to keep your lumber or your lumber for the winter and everything, all your firewood neatly stored.

Jer Staes: When it comes to pesticide control and things, I'll see cities talk about rat traps. I'll see DDAs talk about these things. I'll see cities, as I mentioned at the top of the show, talk about, well, we're going to encourage feral cats. Are those generally effective? Do they have a lot of side effects? Like is what is a good, what is the so is the…  is taking care of your stuff like the primary vector of stopping this?

Bobby Corrigan: So, pest control and rat control specifically, Jer, is really important. One, you're dealing with a, again, a large and very aggressive when challenged mammal that's very smart. And, you know, we hear all these things, you know, the myths about rats being smart. Well, that is not a myth. Rats, all kinds of research has shown they're very intelligent mammals that can figure things out. They make decisions, they even regret when they make a bad decision and so forth and so on. So when it comes to pest control, controlling rats, you know, it's really in the hands of a professional, quite frankly, in most cases. But sometimes, you know, the public will say, well, let me give this a shot myself, or let me just go online and push a button and I can get the same stuff the pest control people use, which in many states is actually true. The difference is with the traps and the baits and those kind of materials, you usually need a training course and you need experience to know them to go up against such a formidable animal as the rats. I would say you mentioned cats. You know, cat enthusiasts and and by the way, I own a cat so I'm totally good with cats. I love cats. But cats do not control rats except in very, very unique small cases where maybe a rat got trapped in the backyard and there's a cat nearby and the cat's really good at hunting, you know, although they're hunting birds as well. But cats are not going to control rats and populations and they can't be used for cat, you know, workable cats that can be put out into downtown cities and clear out the rats. Lots of research on that by credible science and so forth. So, cats are not a tool that people should be thinking about when it comes to rodent control. And you can also get online and put in our rats chasing cats. You'll get plenty of that. You'll get plenty of that, right? So, but again, a cat is a wonderful mammal too, you know, but you know, best if kept indoors as a house cat. You know, we have to be careful of if it sounds simple and really like you just plug something into the wall and voila, no more pests. Um, again, .edu, check it out, do if there's no science to back things up, buyer beware, save your money.

Jer Staes: Before we go, what is your favorite thing about rats? You've been with these animals studying them for so many years. Like, I imagine to a degree you also have an affinity for them.

Bobby Corrigan: Yes, I do. Um, you know, in graduate school doing my PhD on rodents, I moved into barns infested with rats. And I literally moved in. And I, you know, I brought in sleeping bags and stuff and I laid on the floor so I could get close to these animals. They're wild rats. And, you know, the favorite thing I would say about this animal, even though we despise it and we worry about it and we don't like it and what have you, you know, it's an amazing mammal. It has the same emotions. You will see rats do the same things that dogs can do and cats can do. You know, they're very loyal to their families as long as they have food and shelter, what have you. You will see animals that actually care about each other. And again, proven by science, rats are giving their kind to and when things, they're altruistic, you know, and so my favorite thing about this animal is in many ways, even though if it just would stay away from our areas and properties, it's an it's an animal that I admire.

Jer Staes: If people want to follow something that you're doing or or learn more, what can they do?

Bobby Corrigan: You know, they can, um, I'm on X or what used to be Twitter. You can find me as rodentologist on X, you know, um I'll probably be on Blue Sky and these kinds of platforms. So you can follow me and you can check sometimes on local pest control, uh conventions and meetings in your state and sometimes I'm there lecturing.

Jer Staes: Well, Bobby Corrigan, a doctorate of rodentology, I really appreciate your time on Daily Detroit. This has been a fascinating conversation to me. And, uh, you know, thank you for all the work that you're doing and thank you for your time because I feel like I learned a lot today.

Bobby Corrigan: Thank you, Jer! It was a pleasure to be with you all.