- Despite tens of thousands of papers on lab rats, rat scholar Michael Parsons say we know next to nothing about their relatives that inhabit our cities: the urban, wild rat.
- Recent research shows that not only are rats clever, but they have a sense of justice and are sentient organisms.
- Parsons argues that rat issues in urban areas should be dealt with by cleaning up the city, instead of acting reactively and often cruelly.
“Wild rats are as different to laboratory rats, as probably a wolf is to a Chihuahua. That’s not an embellished analogy … The biggest misconception, I think, is that we know something about these animals.”
As a veteran rat scholar and researcher, Michael Parsons says we know shockingly little about urban rats. Despite around 24,000 published papers a year on lab rats, the urban rats many city dwellers regularly encounter are dramatically understudied.
Parsons is an urban ecologist, has nearly 50 peer-reviewed scientific articles, 12 research grants, and is currently working on a book on his experience with rats. He is currently a visiting research scholar at Fordham University.
Parsons says he’s excited by the urban rat’s research potential. With new studies alluding to rats’ emotional and intellectual complexity, Parsons makes the case that urban rats need to be studied in depth — not only for the sake of lab research, but to foster a healthier and cleaner urban relationship between humans and urban rats, one where the latter manage themselves better due to less human waste and food reaching them.
Parsons spoke with Mongabay’s Jansen Baier by phone to discuss all things urban rats, including the many misconceptions about the lab and urban varieties, their negative portrayal in society, and potential solutions to the problems they pose. The following interview has been edited for length, clarity and style.
Mongabay: Before talking about rats, could you just tell me who is Michael Parsons?
Michael Parsons: I’m an urban ecologist, and my title is visiting research scholar at Fordham University. My primary interest within urban ecology is rats. I went down this path of trying to, from a behavioral perspective, influence their behavior, so that you could either capture them through attractants, or somehow repel them through aversive scents or odors. That’s how I got interested in rats.
But then, after I got more familiar with them, I realized there’s more research than could be done in a lifetime. I realized just how many research gaps there were regarding rats and how little was being done. So, it just kind of snowballed from there.
We’ve worked with COVID rats. We’re working with colleagues in Tokyo and Warsaw on behavioral issues, trying to trap rats. Because they’re so intelligent, it’s likely they’re neophobic: they’re scared of new sights, sounds, or smells, and so it’s very difficult to trap them. We’re trying to produce new traps and repellents and various tools to repel them, or at least influence their behavior.
And then we started microchipping them. Once we did, it led to a lot of other behavioral types of questions. What started out as an applied rat control project really became more like this epic rat project.
Mongabay: What is the first thing that you think of when I ask you what the biggest misconception about urban rats is?
Michael Parsons: I think because there are like 24,000 papers written per year on rodents in the scientific literature around the world — 24,000 — and because there’s so many research papers written on rodents, people tend to think that that somehow covers urban rats. But it doesn’t, because like 99.0001%, is all about laboratory animals. And it’s not about wild rats in their natural environment.
Wild rats are as different to laboratory rats, as probably a wolf is to a Chihuahua. That’s not an embellished analogy. There’s just so much difference between the docile, cute, hooded, or albino laboratory rats, versus a real wild rat. It’s a different organism entirely. So, the biggest misconception, I think, is that we know something about these animals.
Mongabay: Why do you think this is? Is it a lack of funding? A lack of interest?
Michael Parsons: People don’t want to study things that they would rather pretend didn’t exist. It’s that social problem. It’s cognitive dissonance. I spoke to a reporter once who was so confused to start out. He’s like “On the one hand, you’re telling me that there’s potentially millions of rats in New York.” Between 2 million and 32 million, probably closer to the lower end of that number. “But now you’re telling me, no one’s got any rats. So, you can’t study the rats? How do you reconcile that?” That’s really it.
Everyone owns a property that these rats are found in. Either it’s city-owned and someone’s going to be responsible for, or it’s privately owned, and someone could get fined for it, so no one admits they have rats. Yet we always know they’re obviously around.
We offered a reward, citywide to anyone in New York to let us study their rats. I was going to pay them from my pocket, I wasn’t even using grant funds, because we were so desperate … Here we were, cash in hand, and people are saying, “I don’t want your money, I don’t want your money, go away, go away, go away.”
I had the door slammed in my face a number of times … It’s almost like you’ve got to have really thick skin.
I told my wife, I feel like I’m a pariah. I’m not this Ph.D.-level professional.
But I found one colleague at Arrow Exterminating in Long Island. So here I was in Westchester county, having to commute to Long Island to study rats, because he was the only person that would really give me a shot. I’ve had two companies in a number of years who have really opened their doors to me. But as far as individual people, it’s hard to remember any more than one or two people who said it’s OK.
Mongabay: I was going to ask if you think this lack of research on urban rats contributes to the negative cultural perception, but it seems like it’s this negative feedback loop where the already negative cultural perspective makes it so that they’re not studied. Which in turn increases the negative portrayal of them. Would you agree with that?
Michael Parsons: Yeah, I think you really got it. Because even a few years ago, we participated in the film on rats. And we thought it was going to be like this educational television show that featured rat research. And it ended up being like this dark, macabre horror flick. It was a Morgan Spurlock documentary called Rats (2016). All you have to do is look at the film Rats, and you’ll understand.
We felt we were going to have a chance to educate the public and it ends up turning into: let’s scare them. It even debuted at midnight in the theaters to add to the fear and creepy elements. So, again, it’s that cycle that you’re talking about. People fear something. They don’t want to admit it exists. But yet they’ll go to a theater and watch it like a horror film.
Mongabay: So where does this negative perception of rats come from?
Michael Parsons: Rats are obviously the harbinger of all sorts of microbes and potential pathogens. And it’s associated with a lot of unsanitary conditions. So, if you’re associated with rats, or even if you research rats, that must mean you’re getting your hands dirty, right? People are fined for having rats on their property. If you’re a restaurant owner, or you own a deli and there’s rats in your place of business, you lose that business. It’s really pretty negative all around.
And it’s possibly because of the lack of education. Because people don’t really understand that it’s urban hygiene that contributes to rats, more so than individual or family hygiene. It’s more our practice of leaving garbage out on the curbside all night that contributes to rats. But if the city would take better care of their garbage at night, there would be fewer rat food sources.
It’s a city problem, not a person problem.
Mongabay: There’s the perception of rats as disease spreading, how true is this historically and presently?
Michael Parsons: Rats are associated with everything from the Black Plague right to E. coli and salmonella. And they’re sort of on opposite extremes.
On E. coli and salmonella, we know that rats carry a lot more of that than they’re being implicated for. Because whenever you go to the doctor with salmonella poisoning, they think you’ve been using a cutting board without washing it properly, or maybe the utensils are dirty. They don’t ask you have you had a rodent in your property. So, we tend to underestimate the salmonella and E. coli cases associated with rats.
The Black Plague was a little bit different. There are many people who think we overestimated rats’ role in the Black Plague. In fact, some people are saying other species of rodents, or even humans, vectored their own fleas that led to Yersinia pestis, the bacteria that caused the plague. From either extreme, rats, either being underimplicated or overimplicated, they’re just always associated with it.
And of course, rats frequent our sewers. They’re burrowing animals, and they burrow underground where sewers are. They use those sewers, not only for food and waste, from which they do get nutrients, but also, we’re not down there bothering them, because it stinks to us. So, we leave them alone. Then they migrate from sewers into people’s residences. They can travel and they do commonly travel up through the plumbing.
There’s a really cool article on National Geographic, it’s an animated graphic, it actually shows you how rats move their way up through a plumbing system and a high-rise building. They just keep going and go on and on until they pop up through your toilet on the third floor … It’s about rats associated with sewers and, of course, rats commonly carrying diseases, whether we can directly implicate them or not.
Leptospirosis is one that can be more regularly traced to rats because it’s one of the only primary causes of leptospirosis.
Mongabay: Rats are generally perceived as disease-spreading animals that only create negative effects on society. But they’ve also been vital for scientific experiments, medical research, and the history of human health. How important have rats been for scientific and medical research? And how do we reckon with this dichotomy?
Michael Parsons: They’re so closely associated with us that we took advantage of them. We don’t need them directly for food the way some nations do. For instance, in Vietnam, people will consume them for food. From what I’ve heard it’s not that bad, because rats’ meat, the actual muscle tissue, is not disease-carrying, it’s the parts of the rats that are being cast aside. So, it’s probably not as gross as it might sound to us.
In Western society, we didn’t eat rats, but we did use them in our medical experiments because they were easy to breed, and they thrived alongside humans. They eat what we eat. They adapt so quickly to our foods and our internal ambient conditions, and they reproduce so prolifically. So, they were really easy to breed for science. And, of course, their physiology is similar to ours. What we’ve learned about anatomy and physiology and medicine, over the last few hundred years, wouldn’t have been possible without laboratory rodents, both mice and rats.
Mongabay: These are lab rats you are talking about that are responsible for these studies?
Michael Parsons: Correct. Ninety-nine percent of the time it’s lab rats. Although in our most recent research, we’ve justified why research actually should be natural. Instead of in the laboratory, you should have studies in the wild, where animals could literally behave on camera. In the wild, there’s a lot more variation. We do expect that there will be more wild studies in the future. We just hope they’re humane rat studies as much as possible.
Mongabay: What do you think needs to be done to move past this cognitive dissidence of rats as a net negative on society, but they’re also vital for medical research?
Michael Parsons: Well, that sort of downplays the wild rat. And wild rats are really, really exceptionally important. I mean they’re important to understand and to study because they’re so associated with humans. And they have been for so many hundreds of years, if not thousands.
Wild rats themselves are just now becoming better appreciated for their intelligence, and for their social justice. Rats have recently been shown to have a sense of social justice. They will forego a direct reward to save another rat. They literally will put themselves in harm’s way to save a conspecific [belonging to the same species], in the same way primates and humans and other animals do.
But rats are also being associated with remorse and happiness. Rats have recently been shown to have this giggle response, and it’s associated with happiness. They have certain high-frequency sounds they make during these giggling responses. If you can recreate those frequencies, whatever you’re doing to get those frequencies going, might be associated with happiness. We’re learning more and more that they almost have these emotions that are more like your pets, than just this wild sewer rat that we tend to think of.
You’ve probably heard of the little rats that are driving robotic cars in the laboratory. I mean, so now we’re starting to appreciate their intelligence. They’re more like a pet than a pest. And that leads to a whole host of problems. They’re important because they’re sentient organisms. But because they’re sentient organisms — that’s really what I wanted to hit on with the wild rat — because their feelings matter, and they have feelings.
And their presence is not their fault, their presence is our fault: through our littering, and our poor hygiene, and our city hygiene, and our poor policy. That’s the real issue. It’s really a shame that we hurt these animals because they’re just doing what they do. They’re sort of like the unwanted pet in a sense.
And so, when we poison them … not only is it leading to secondary poisoning in the wildlife, but it’s also very, very painful. The poison is an anticoagulant, so these animals bleed out … just the process of bleeding out — the abdominal pain, and the agony, the shortness of breath, the suffocation — it isn’t a picnic. And it sometimes takes days.
After microchipping rats and studying them, I found myself becoming more appreciative of rats as an organism. And of their welfare. I started to become a little more protective of them. I actually kind of fell for them. What is the term for the effect when the captee falls for the captor?
Mongabay: Stockholm syndrome?
Michael Parsons: Yeah, it’s sort of like Stockholm syndrome here. I just thought it was an end to a means. And I started to realize that these animals have great personalities. And I started thinking of them the way I think of our pets. And so now I care more about control mechanisms that start with people, instead of just poison.
It starts in people’s practices. That’s kind of like one of my pulpit responses is just urban hygiene. Let’s clean the city. Let’s stop leaving rubbage out. Let’s be responsible. Let’s stop leaving grease vats outside of our restaurants.
Mongabay: You mentioned with these wild rats, there are recent findings suggesting they are highly emotional, that they’ll give up a reward for another rat. Are we seeing these same traits in lab rats as well? Or no?
Michael Parsons: There’s a lot of variation among wild rats, right? And just like people, you know, they’re so different, their personalities. You got aggressive people, you got passive people. If you were an alien from another planet, and you picked up any random train from the subway, and you just looked at the people, and you picked out a few and you say, “Wow these humans are aggressive, or these humans are something.” And you’ve missed the whole boat. A lot of humans are actually very passive, or very calculated, or very introverted. It just depends on the sample you get. Wild rats, it depends on the sample you’re looking at.
But when you’re looking at lab rats, they’re so homogenous. They’re almost like these little robotic automatons. The majority of them have the same kind of personality. They’re so inbred that you’re not getting a lot of variation. And that’s done on purpose, that’s done intentionally to increase the yield and sample. But in the process, you’re really, really missing out on the variation of wild rats.
Mongabay: Can you define what you mean by sentient organisms and speak further on the evidence about this?
Michael Parsons: It’s a thinking, feeling, a sinking feeling organism that expresses remorse, happiness, joy, the emotions we typically think of with humans and, quote, “the higher-end organisms.”
Mongabay: Could you speak a little bit more about kind of the evidence for what you’ve seen on that?
Michael Parsons: It’s a trove of literature. It’s just, it’s enormous. The literature shows just how cunning these animals are and how feeling they are. The idea of remorse as well. We don’t like to think that they are remorseful but they are.
It certainly would make me feel guilty if I left a glue trap out, and the glue trap captured a rodent and it sat and suffered and, say, gnawed its leg off. It’s just about how you feel about yourself. Because of my hygiene, I’ve caused this animal to suffer.
Mongabay: I think one of the only ways to change a cultural perspective is by putting a different perspective out there. On social media, I’ve been seeing some accounts where owners of domesticated rats feature their rats and talk about them. Have you noticed any change in the perception of rats due to this on social media?
Michael Parsons: Not really. I have a colleague, he’s an exterminator, and he had a pet rat. Someone was going to dispose of it and he took it home with him. And he became quite attached to it. When the rat finally passed away of old age, he was quite shaken by it. He got so used to it and its individual habits.
Among my circle, there are a few people that like, “Yeah, rats are really cool. They’re fun.” But for, I think, the average people, I’m used to just the squeamishness … I think it just grosses people out. Studying rats is like studying pus in a wound. It’s important, but people would rather not look at it.
There was a book about rats that came out that had a big impact on people’s perceptions [Rats: Observations on the History & Habitat of the City’s Most Unwanted Inhabitants, by Robert Sullivan].The author, he’s actually more like an investigative journalist, he didn’t want to just write about rats. He wanted to experience them, so he went out to a couple of popular New York alleyways, and he literally sat out … and he just lived with the rats. And then he wrote a book about his experiences.
It was almost like this anthropology study, except here he was in lower Manhattan.
Mongabay: We already discussed the downsides to the current method of using rodenticides on rat populations. A big problem you mentioned is the cleanliness of our cities. Is the way we’re treating wild rats right now solving anything? Is it making the problem worse? What do you think we should be doing?
Michael Parsons: Right now, we’re being mostly reactive. We’re waiting until there’s a problem, and then we’re throwing money at it. But it should be a proactive thing because rats reproduce so fast. Once they’re there, they’re hard to get rid of. What you have to do is be more proactive. I hate that that’s such a trite saying, but by being proactive, you actually have to plan for cleanliness. And that really just starts with education.
It could be posters. It could be more trash receptacles, trash receptacles that are not overfilled, reminders, or community education. People who rent to their tenants need to make a point about if one neighbor gets rats, the others can get rats. They need to have a mechanism there, so that people can actually stop rats before they get out of control. My idea was you could have neighborhood sentinels that are being hired and being given a job. In that job, they can do some proactive, prophylactic maintenance. That could just be cleaning up, it could just be educating other people. It could be picking up other people’s trash. It could be picking up garbage that sat out overnight and storing it in, like, a halfway location until the garbage truck arrives. There are little things like that could be done.
Mongabay: What is your ideal future for human-rat relationships from a cultural perspective and a conservation perspective?
Michael Parsons: Small populations of rats can actually manage themselves. Small populations of rats will keep new rats from coming in. If there are limited food resources, they’ll be very, very territorial. So, it’s hard for rats to migrate to another place if there’s a family of rats or a colony of rats that are already fighting fiercely over the available food.
Rats can manage themselves if there’s not an enormous amount of food available. But they have no reason to manage themselves if it’s like, “Hey, join the party. There’s plenty of food here. Beer and pizza to go around, knock yourself out.” The current situation is they’re not managing themselves.
Mongabay: From my understanding, the major step for rats to manage themselves would be making sure that cities are clean, so there isn’t this massive food source for them. Correct?
Michael Parsons: Correct. And awareness, just a general awareness that people have to understand that rats are cute, but that doesn’t mean you should be feeding them. They reproduce so prolifically. One rat could give birth to like 12 pups in as little as six to eight weeks. And each of those pups could potentially, if there are enough resources, give birth to another 12 pups in six to eight weeks. And then if you do the math, you know, it’s like, in a year, it’s like hundreds of thousands if not millions of rats.
Mongabay: Is there a reason why rats can grow this massive population so quickly?
Michael Parsons: Rats are territorial, ferociously territorial when there’s food to fight over. But if there’s plenty of it to go around, then they just reproduce so fast because they’re going take advantage of it.
A rat expert, Bobby Corrigan, said that rats are nature’s perfectly adapted organism. Because they can live almost anywhere. They’re like the [mammal] version of the cockroach. They’re hard to kill. They reproduce so fast that even when you’re killing them, you don’t really understand that you’re killing them. If there’s food available, that birth rate allows for rapid population growth. But that birth rate slows down if there are a lot of predators in the area, or there are limited resources. If so, a rat does not give birth to 12 pups, it might give birth to two or three pups. And even those rats may not make it, maybe only one of those three survives.
Mongabay: Is there a relationship between COVID-19 and rats? Have we learned anything about zoonotic diseases in relation to rats, or rats in relation to zoonotic diseases?
Michael Parsons: So, we’ve published one paper, one paper is in review, and one paper is in preprint. And another one is in progress. So, we’ve really covered the COVID rats’ angle, and other rodents. And, basically, what we observed was when restaurants closed, there was a major source of rat food that was taken off the menu for rats. Because of that, rats were sighted more often in public. Probably as they’re migrating from one location to another. Whereas rats, typically, wouldn’t move more than 50 meters [160 feet] from their food source.
There are a lot of people thinking there are many more rats during COVID-19. It’s actually more cognitive dissonance, because there are actually 30% fewer rat calls in the early stages of the pandemic, as compared to before the pandemic. But with the fewer calls, they were more likely to be concentrated nearby closed restaurants. How do you make sense of that? Well, because the restaurants are closed, the rats are on the move to new locations. And so, people are more likely observing the rats as they’re moving to nearby food sources.
We believe the rat populations have rebounded since the restaurants have reopened.
Mongabay: What about from the angle of disease spreading, are rats able to carry COVID-19 and spread it to humans?
Michael Parsons: There are two different ways that a rat could transmit COVID. One of those is by transmitting through its fur or feet. It picks it up in one location, and it carries it. We’re talking about a possibility, not a certainty, but a possibility.
The other way is if the rat is infected by COVID, and then transmits it to another rat. So, here’s the thing about the second one, we’re not as sure about it. We’re waiting for evidence of whether rodents in the wild can be infected, and transmit it to other animals or humans. We know rodents in the lab can be infected.
It would be a bigger surprise if rats if wild rats did not carry COVID. They crawl through our sewers, so it would be a bigger surprise that they didn’t carry COVID than if they did.
Mongabay: Could you talk about the justification for why we should be doing more wild rat studies?
Michael Parsons: There are two reasons. The first, of course, is that we need rat wild rat studies to understand how to influence their behavior and limit our risks in association with them.
There’s a number from an economist that rats cause $19 billion per year in damages and lost food. And it’s not counting businesses that have closed, diseases and fires of unknown origin. Many times, the fire marshal cannot pinpoint the reason for a particular fire, but they’ve estimated that a certain percentage of those are caused by rodent gnawing. So, we’re talking about billions and billions of dollars to the world’s economy. So, of course, if you don’t study one of the most important animals in terms of risks, and economy, that’s just extraordinary. There’s your cognitive dissonance: there’s not enough research on an animal that’s one of the most important animals in the urban environment.
And then what about climate change? Climate change releases rats from their burrows. Rats wouldn’t be under burrows during the winters, they would be out reproducing during the winters. Whereas normally, they reproduce less frequently in the winter.
We talked about the perfect ideal of rats managing themselves through competition. The nightmare scenario is the perfect storm of climate change, urbanization, and disease.
Mongabay: Could you speak further about the relationship between rats and climate change?
Michael Parsons: We wrote a little popular piece a few years ago, just speculating on what climate change means for your rats. But if you look at just the northeastern U.S. — D.C., Philadelphia, Boston, New York — in those areas, we have primarily the Norway rats. And the Norway rats are burrowing rats. They typically like to burrow underground or in tree pits, or sewers. They like to go below ground. Especially when it gets cold, they like to spend prolonged periods below ground and they stop reproducing in the wintertime.
Our research showed that seasonally there are a lot fewer 311 calls for rats, in the period where rats are in their burrows. There are more calls for 311 in the spring and summer when rats have just been released by the temperature changes. And when more people are outside as well to see the rats which are emerging from the burrows.
Climate change has the potential to do the same thing: if the temperature warms, they’ll be spending less time below ground, reproducing more, and conserving less energy.
Mongabay: How does environmental racism factor into rats?
Michael Parsons: I started learning a few years ago that some of our most profound cases of persistent rat calls are coming from some of the same areas. Looking at rat 311 calls in different areas of the five boroughs of New York, we were noticing that some areas were more persistent over the years, and in other areas, they would come and go.
Just to be clear and explicit, in areas where people are underprivileged, and where their landlords are not doing their extermination, those areas are more likely to have persistent problems with rats. Also, rats in new locations are the ones that are more likely to be targeted, not rats in areas where rats have historically been seen. Rats are being preserved in these little pockets. That touches on environmental racism because a lot of these people are underprivileged people of color.
I was interviewed about NYCHA (New York City Housing Authority) in the Bronx a few years ago. There were dramatic cases where tenants had infestations where rats were coming out in the daytime. And when rats are seen in the daytime, that’s usually not a good sign.
But yet in other areas, there was this strong response. And there were cleanups and new recycling bins. There were all these things that were going in to encourage a cleaner area. But these other areas are simply not being cleaned year after year. So, people are coming out and saying this is pretty vicious.
One researcher even went as far as to show in her research that depression was more strongly associated with sightings of rats than violent crime. So, people were feeling more helpless and more out of control when they had rats in their homes, because they couldn’t break free and they couldn’t get them controlled. They couldn’t do anything to control them because there were so abundant. And once they’re there, you can’t just clean up, they’re there, they’re going to find you.
Yet, when it comes to violent crime, they could protect themselves. Whether it was through the police department, or whether it was a neighbor, or protecting themselves physically. So literally, rats were causing more depression than violent crimes.
Mongabay: Is there’s anything else really important or noteworthy about rat we didn’t discuss? Something you think goes under the rug too often, or something you want to leave people with when hearing this?
Michael Parsons: I think the rat issue is going to get bigger before it gets better. I think the issue that’s coming to a head is that, in the age of social media, as you mentioned about pet rats or intelligent rats, we’re becoming more and more aware of their sentience. And along with that, thanks to people out west, we’re learning more and more about secondary poisoning of our wildlife. I think this is becoming another little perfect storm of rodenticides.
I think rodenticides will be under fire, as people know more and more.
I’m being told it’s not convenient to do anything about urban hygiene. If you’re the municipal authority, you’re the mayor, you’re telling me it’s inconvenient. But if you’re the animal rights group, you’re telling me it doesn’t seem convenient to use rodenticides any longer. I don’t want to be a doomsday painter, but I’ll give you a best-case scenario and two of the worst-case scenarios. Urbanization is one worst case. Climate change and urbanization are the two worst cases. And the anti-rodenticide and pro-animal rights is the best-case scenario. Two storms and one utopia. And then the anti-rodenticide and pro-animal rights, I guess, would be the perfect storm. So, two storms. Two storms and one utopia.