“ … common approaches to managing rats often fail to address the most important factor contributing to infestations: humans and the prolific quantities of food that they waste. The more research we do on rats in New York City and worldwide, the more we realize that rat behaviors contribute less to infestations than do humans,” the pair wrote in the piece, which was picked up by several media outlets across the country, including in the Washington Post.

Munshi-South and Parson’s work links managing food-waste in cities to controlling the rat population. Rats adapt to human food sources and reproduce accordingly. Thus, the less food there is available, the less a rat will reproduce. 

As they explain in the piece, this food-focused approach involves changing deeply ingrained habits of city dwellers who often don’t think about the food-waste they produce. Munshi-South and Parsons recommend starting with giving people incentives to create effective and socially progressive strategies to create a sanitary environment.  

Click here to read the full piece in The Conversation.

“Dan Sullivan was a man of great faith and great intellect,” said Joseph M. McShane, S.J., president of Fordham.

“He was the embodiment of the Jesuit ideal, expressing his faith through scientific research and teaching. He was also a man of great practical wisdom and a warm and thoughtful colleague. Today the Fordham family mourns with Dan’s friends and loved ones. He will be sorely missed.”

A native of Rosedale, Queens, Father Sullivan joined the ROTC as an undergraduate, and was one of the founders of the Fordham company of the Pershing Rifles Military Society. He was commissioned as a second lieutenant in the United States Air Force Reserves in 1950. He entered into the Society of Jesus three months after his graduation in 1950; he was ordained in Innsbruck, Austria, in 1961 and pronounced his final vows in 1979 at Rose Hill.

Pairing Faith and Science

From the very beginning, Father Sullivan seamlessly paired a love of science with his religious calling. As a seminarian, he earned a master’s degree in biology at Fordham in 1958 before heading to the State University of Innsbruck in Austria for five years of studies under the tutelage of esteemed theologians Karl Rahner, S.J., and Josef Jungmann, S.J.

Before he returned to New York, Father Sullivan earned a doctorate of philosophy in entomology from the University of California, Berkeley, in 1969. There, he trained in the science of biological control, in which beneficial insects are enlisted to attack and control insect pests that destroy agricultural crops. He joined the Fordham faculty that year as an assistant professor, then went on to become a full professor in 1984.

Among the major works he published were “Aphids” in Encyclopedia of Entomology (Kluwer Academic Publishing, 2004), “Influence of Host Plant Resistance on Activity and Abundance of Natural Enemies” in Biological Control of Insects (Phoenix Publishing, 2003), and “Hyperparasitism” in Encyclopedia of Insects (Academic Press/Elsevier Science, 2003).

Father Sullivan lent a great deal of his talents to helping the international scientific community. In 1984, he traveled to Nigeria on a Fulbright fellowship to join a team doing research on the cassava mealybug; in 1988, he was a visiting scientist in at the Centro Internacional de Agricultura Tropical (CIAT) in Cali, Colombia. He was also the visiting scientist at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in Andhra Pradesh, India, in 1999 and again in 2004. He also had the honor of serving as President of the New York Entomological Society and President of the Fordham Chapter of Sigma Xi -the Scientific Research Honor Society.

In a Fordham News podcast last year, Father Sullivan said his Jesuit superiors actively encouraged him to travel and conduct research.

“Non-Catholics sometimes think there’s a contradiction between belief in God and science. It’s not that way at all. It complements it, in fact. I look back on some of the great scientists. Galileo was a Catholic. And Darwin, although not a Catholic, was a religious man,” he said. “And then of course one of the great geneticists, who started genetics, was Gregor Mendel, who was an Augustinian priest.”

An Invaluable Source of Knowledge

After retiring in 2006, Father Sullivan stayed on the faculty, living at Kohlmann Hall, and advising junior and senior biology students. At that time, he began sharing office space on the fourth floor of Larkin Hall with Craig Frank, Ph.D., a professor of mammalian ecological physiology and biochemistry, who’d joined the faculty in 1994.

Frank said that the letters of recommendation that Father Sullivan wrote enabled countless students to advance to medical school and graduate programs, and noted that many remained in contact with him after graduation.

In the Fordham News podcast, Father Sullivan shared some of the advice he’d dispensed to students over the years.

“I tell my students that the really great scholars in this world are not gonna give you a hard time. It’s the second-raters that do that,” he said.

Frank said that their office hours only overlapped once a week, but they developed a rapport over the years such that, several years ago, someone taped a picture of The Muppets characters Waldorf and Statler on their door. It was a testament to Father Sullivan’s good humor that he let it stay up, Frank said.

Though the biology department existed before Father Sullivan taught there, Frank said his contributions were numerous and influential.

“He was one of the founding fathers of the biology department. He was a very good friend, very pleasant to talk to, and his wit never diminished with age,” he said.

“He was an invaluable source of knowledge, and I viewed him very much as a mentor, even as recently as last week. I would just love sitting in our office during our office hours together, and just talking with him about university life. We didn’t always agree on everything, but it was always a joy talking to him.”

An Unmistakable Fidelity to Fordham

Father Sullivan’s fidelity to the biology department and the University was unmistakable. Every year, the annual newsletter detailing recent events of the department had his byline on it. This year, he penned the paper Historical Profile of the Biology Faculty: Past and Present. He also delivered the invocation and benediction at Fordham’s ROTC’s commissioning ceremony each May. Captain Dan Millican, executive officer and assistant professor of military science in the ROTC program, noted that Father Sullivan attended a 70th anniversary celebration of the Pershing Rifles just two weeks ago at West Point.

“He was a great supporter, and a great influence among the cadets,” he said.

“He could always drive the tone of the room to be more productive, and drive cadets toward service.”

In 2009, Fordham honored Father Sullivan with a Bene Merenti Medal for 40 years of service, citing his career as one that “reflects Ignatius Loyola’s international vision for Jesuits.” Jason Munshi-South, Ph.D., an associate professor of biological sciences, said he was the most dedicated attendee at the department’s annual colloquium.

“I can’t imagine these seminars without his presence near the front every week. He was always able to make a personal connection with the seminar speaker given his varied travels around the world as a Jesuit and biologist,” he said.

Patricio Meneses, Ph.D., the chair of the biology department, echoed the sentiment.

“Father Sullivan made me and every new faculty member feel at home from the first day,” he said.

“He was a true scholar, a great colleague, and a great friend.”

A wake for Father Sullivan will be held Monday, Nov. 25, from 3 to 5 p.m. and 7 to 8:30 p.m. at the Murray-Weigel Hall Chapel, Rose Hill Campus.

A Mass of Christian Burial will take place Tuesday, Nov. 26, at 11:30 a.m. at the Murray-Weigel Hall Chapel, Rose Hill Campus.

Notes of condolence may be sent to a cousin, Kevin Giuliano, 67 Sandburg Place, Pine Bush, NY  12566.

This simple observation, a team of researchers led by Fordham scientists has learned, is applicable in cities as diverse as Vancouver, Canada; New York City; New Orleans; and Salvador, Brazil. And it has implications for both how rats evolve and how we learn to cope with their presence in our midst.

In Urban rat races: spatial population genomics of brown rats (Rattus norvegicus) compared across multiple cities, a paper published last month in the Royal Society’s flagship journal Proceedings B, Fordham doctoral candidate Matthew Combs showed how genetic analysis of rats collected by teams in those four cities reveal the ways in which evolution is repeating itself in cities, thanks in part to the geographical features of urban areas.

Working under the direction of Jason Munshi-South, Ph.D., associate professor of biological sciences, Combs collaborated with researchers working in the three other cities who brought rat tissue samples they’d collected as part of separate projects to Fordham’s Louis Calder Center for analysis.

Same Species, But Subtle Differences

At least 150 rats were sampled from each city, and when researchers analyzed the results, they discovered that just as brown rats in Lower Manhattan have evolved to be distinct from their uptown brethren, (a discovery detailed in a 2017 paper) rats in those three cities differ from each other in discernable ways.

In Manhattan, the culprit is Midtown, with its relative paucity of shelter and food sources; in New Orleans, it’s the Inner Harbor Navigation Canal, which divides the Lower Ninth Ward neighborhood from the rest of the city. In both Vancouver and Salvador, major roadways were found to split disparate populations of brown rats.

Combs said previous studies had compared rats around the world, but none had incorporated such a robust number of specimens.

“In this case, we used hundreds of samples within each city to look at some very fine scale movements, and were able to get quite a bit more detail about these four cities, and ask questions about how the same types of landscape features were creating unrelated groups,” he said.

Munshi-South, whose lab has tracked the movement of rats around the world, said he was surprised that the level of differences among the rats was similar in all four cities, given that two are in temperate climates, one is sub-tropical, and one is tropical. All, however, are coastal cities located in the Americas, and are thus a “biological legacy of colonialism and migration.”

“They have a very similar level of genetic diversity in the rat population, and that may indicate a shared ecological and evolutionary history. These rats were likely introduced to these cities around the same time, and have been there for about the same amount of time,” Munshi-South said.

“Rats are really a reflection of human history. They don’t obviously have a recorded history that’s very good, but the genetics reveal a lot about how we move them around.”

Potential for Understanding Disease

Combs said the collaboration with the teams in the other three cities—some of whom were working on projects disease-related projects—was also noteworthy, because the technique the Fordham team uses to track genetic variations in species can be shared and used for other objectives as well.

“We can tell them about some of these genetic patterns, and they can tell us about disease dynamics and distribution, and hopefully we can put those two pieces of information together and start to understand how the movement of rats and the genetic patterns relate to the movement of disease, which is really what everyone’s worried about,” he said.

“I think there’s a lot of potential there.”

Munshi-South agreed, saying this study is a model for future ones in cities across the globe. The days of studying a single species in a single city are over, he said.

“One of the big hypotheses that’s out there is that urbanization drives the same ecological and evolutionary results over and over again,” he said.

“We’re trying to confirm that with these kinds of studies.”

The University Research Council and Office of Research presented the Outstanding Externally Funded Research Awards (OEFRA) to recognize the high quality and impact of the honorees’ sponsored research within the last three years and how their work has enhanced Fordham’s reputation—both nationally and globally.

Faculty were honored in five separate categories, and were presented awards by University Provost Stephen Freedman, Ph.D.:

Humanities: Nina Rowe, Ph.D., Associate Professor of Art History and Music in the Graduate School of Arts and Sciences

Rowe, an expert in the art of northern Europe in the high and late Middle Ages, recently received a $4,000 grant from the American Philosophical Society and fellowships totaling $95,000 from the National Endowment for the Humanities and the American Council of Learned Societies. She used the awards to fund research for her current book project, From Adam to Achilles to Alexander: World Chronicles and the Anecdotal Past in the Late Medieval City.

Interdisciplinary Research: Chun Zhang, Ph.D., Professor of Curriculum and Teaching at the Graduate School of Education 

Zhang has worked with colleagues at Columbia University and New York University to investigate workforce development in universal preschool programs in New York City. At Fordham, she has collaborated with Yi Ding, Ph.D., associate professor of school psychology, and Tiedan Huang, Ed.D., assistant professor of educational leadership, administration, and policy, to secure research funding. Her efforts have netted awards and grants totaling more than $2.8 million for studies that will impact the lives of children with special needs and their families.

Junior Faculty Research: Jordan DeVylder, Ph.D., Associate Professor at the Graduate School of Social Service

DeVylder, who joined the Fordham faculty in 2017, has a keen interest in preventive mental health, with an emphasis on psychosis and suicide. He is currently conducting a randomized trial to test an intervention to improve detection of untreated psychosis by community social workers. The trial is being funded by a $680,000 National Institute of Mental Health grant. DeVylder also recently won an $85,000 grant from the American Foundation for Suicide Prevention.

Sciences: Jason Munshi-South, Ph.D., Associate Professor of Biological Sciences

An expert in the burgeoning field of urban ecology, Munshi-South was awarded a $600,000 research grant from the National Science Foundation in 2015 to study the evolutionary biology of wild rats. Since then, the NSF has granted multiple sub-awards , some of which have involved bringing undergraduates from other campuses to work with him during the summer. The NSF has continued to increase this award annually; its total is expected to reach over $672,000 this year. In total, Munshi-South has received more than $1 million in grants from the NSF, the National Institute of Health, and other foundations and organizations.

Social Sciences: Yilu Zhou, Ph.D., Associate Professor of Information Systems at the Gabelli School of Business

Zhou is the first faculty member from the Gabelli School of Business to be awarded a National Science Foundation grant, for her research project, “Can You Trust Apps Age Recommendations? Inconsistent and Unreliable Maturity Ratings on Mobile Platforms.” An expert on human-computer interactions and social media mining, she received two awards totaling $245,000 from the NSF for the project.

George Hong, Ph.D., chief research officer and associate vice president for academic affairs, touted the fact that from July 1, 2017, to March 31, 2018, Fordham faculty submitted 116 new grant proposals—an increase of 142 percent over the same period last year—and that faculty has received 82 awards in the past nine months.

Joseph M. McShane, S.J., president of Fordham, commended the winners for the example they set for their students.

“I wanted to congratulate all of you for renewing the heart of the University, in a really significant way, and giving all of our students inspiration, hope, and great pride,” he said.

Organized by the Office of Research and the University Research Council and sponsored by the University Research Compliance Council and the Office of Sponsored Programs, the daylong event included a workshop devoted to compliance awareness, a forum of humanities researchers, and a keynote speech by Jennifer Saak, Ph.D., managing director of Traliance. 

At the Louis Calder Center, scientists explore ecological mysteries and study society’s impact on the natural world.

To the casual observer, Fordham’s Louis Calder Center might seem to be just another quiet tract of Hudson River Valley forest. But for natural scientists, it abounds with opportunity. Explore the 113-acre biological field station in Armonk, New York, and you’ll find a bounty of ecosystems and animals, from the four-legged to the microscopic. At the heart of the preserve is a 10-acre temperate lake teeming with a diversity of aquatic life. Go high enough and, way off in the distance, you can see another big player in the preserve’s ecology: New York City, which begins only 16 miles away.

Its proximity has never been more relevant. “Humans and our cities are the most dominant forces of contemporary evolution now,” says Jason Munshi-South, Ph.D., a Calder-based biology professor who recently co-authored a paper in the journal Science on how species are evolving within cities. Other scientists at Calder study invasive species that arrive via big-city commerce. And they tackle many other mysteries: why some animals survive new threats while others don’t, how nutrients flow beneath the soil, or how insects transmit disease.

The center was born 50 years ago when the land was given to Fordham by the Louis Calder Foundation, named for the paper and pulp magnate who maintained a summer home on the property. Today, that home is Calder Hall, one of several buildings in which students and professors analyze DNA samples, inspect plant and animal specimens, hold classes, and generate knowledge.

Among many other public services, the Calder Center supports the nation’s longest-running study of ticks and Lyme disease, and its scientists work to illuminate society’s impact on nature at a time of growing concern about biodiversity and climate change.

It is also a crucial training ground: “The most important thing we do here is make scientists,” says Thomas Daniels, Ph.D., an expert in tick- and mosquito-borne diseases who has served as the center’s director since 2014.

On a sparkling autumn day late last October, FORDHAM magazine tagged along as undergraduates, graduate students, professors, and visiting scientists went about their work—gently probing, collecting samples, and explaining the science behind their work and its potential impact.

Evolution in the Big City

In recent years, Fordham biologist Jason Munshi-South, Ph.D., and his team of graduate and undergraduate students have become known for their studies of urban wildlife and pest species, most notably rats.

“The initial idea was to understand what a New York City rat is, from all ecological and evolutionary angles,” he says of one project, which grew to a global scale and has public health implications. “We’re using DNA to understand how they move around the city and how they’re related to other rat populations.”

In a first-floor lab in Calder Hall, doctoral student Carol Henger uses similar methods to study coyotes, animals that only recently moved into the city for the first time, Munshi-South says. She’s looking at DNA markers from coyote scat collected in Pelham Bay Park and elsewhere to infer how individual coyotes are related, what they’re eating, and how they’re dispersing.

Meanwhile, Nicole Fusco, another doctoral student in Munshi-South’s lab, sequences DNA to study gene flow among populations of salamanders.

Biodiversity and Climate Change

In the Calder Center’s Lord & Burnham greenhouse, constructed on the property nearly a century ago, doctoral student Stephen Kutos has been growing pairs of potted trees and studying how they pass water and nutrients back and forth via subsoil networks of fungus.

“Tree stumps have been found that are still alive hundreds of years after the tree was cut down, quite possibly because surrounding trees send them nutrients,” he says. With further study, he adds, it may be possible to restore the wild population of one type of tree he’s growing, the American chestnut, which was eradicated from the wild 100 years ago by blight.

Restoring the tree could help combat climate change, scientists believe, because the American chestnut can absorb and store carbon quickly.

In an adjacent greenhouse, several researchers work on an evolutionary study initiated by Fordham biologist Steven Franks, Ph.D., and focused on Brassica rapa (field mustard). As Franks demonstrated in an earlier study, the annual plant evolved earlier flowering within just five years to cope with drought conditions in California.

The Mystery of the Red-Backed Salamander’s Survival

Late in the morning, undergrads Dan Khieninson and Erin Carter and doctoral student Elle Barnes enter Calder forest in search of red-backed salamanders.

“You can find them anywhere in the forest as long as the soil’s moist,” Barnes says before the group navigates a steep decline to the forest floor.

She indicates several flat, weathered pieces of wood she’s left behind. “You’re more likely to find them under here.” The three researchers crouch down and soon locate several specimens.

They’re trying to discover why red-backed salamanders are not affected by the chytrid fungus that is devastating other amphibian populations.

“It’s not enough to just study the ones that are going extinct,” Barnes says. “There are solutions in the ones that will survive. What do they have that other amphibians are lacking?”

The answer lies in their microbiome, Barnes says. She, Carter, and Khieninson use cotton swabs on the salamanders’ bodies to collect samples of microorganisms that they can test against chytrid fungus in the lab. The impact of their research could extend beyond conservation biology, Barnes says: “The discoveries we make about disease and microbiomes can be applied to multiple systems, including humans’.”

A Closer Look at a Ubiquitious, Ecologically Valuable Species

Michael Kausch, a doctoral student in aquatic ecology, rows a boat out on Calder Lake to take some water samples he can later test for cyanobacteria at the lakefront McCarthy Laboratories. Meanwhile, inside the lab, his fellow doctoral student Stephen Gottschalk is working with their Fordham supervisor, John Wehr, Ph.D. Gottschalk is studying green algae in the Characeae family.

“They’re an important food source for birds, a habitat for insects, and they support fisheries,” he says.

So far Gottschalk has collected samples in nine U.S. states, and he’s been working at the New York Botanical Garden under the supervision of Kenneth Karol, Ph.D., to examine his samples on a molecular level.

He’s finding that what scientists once thought were just subtle differences among green algae are in fact ecologically important distinctions. “They’re designated as one species,” Gottschalk says, “but what it looks like to me so far is these are very regionally distinct.”

Mosquitoes, Ticks, and the Pathogens They Carry

Insect-borne diseases are a big part of the research focus at Routh House, the vector ecology lab at the Calder Center that’s jointly run by Fordham and the New York state health department. Inside the lab, scientists study samples of various species, such as the aggressive and potentially disease-carrying Asian tiger mosquito. Outside, they collect specimens and conduct surveillance projects.

“We set up mosquito traps all around the lower Hudson Valley,” says Marly Katz, a state employee and Fordham doctoral student. “All the mosquitoes end up here, where I identify them, and then we send a bunch [to the state health department]for disease testing.” She and her colleagues are also collaborating with Columbia University scientists to “map the Asian tiger mosquito,” she says, and determine if changes in climate are affecting its migration patterns.

While Katz checks a mosquito trap, research technician Richard Rizzitello collects ticks by dragging a white cloth across the ground and then pulling them off with forceps (he uses a lint roller to collect any larvae).

One Calder scientist, Nicholas Piedmonte, displays egg-to-adult samples of the blacklegged tick, which can carry the bacterium that causes Lyme disease.

“These are great for education and outreach,” he says, particularly in central New York, “where ticks are kind of a new problem.”

View a timeline of the Calder Center’s history. And watch a July 2017 video celebrating the center’s recent golden anniversary.

“Traditionally, we’ve thought about evolution as a long-term process that happens in relation to natural environmental features and the interactions between species. But now there is one phenomenon that is rapidly changing many other species, which is how they interact with humans and our built environment,” said Jason Munshi-South, Ph.D.

“Humans and our cities are one of the most dominant forces of contemporary evolution now.”

In “Evolution of Life in Urban Environments,” a paper by Munshi-South and co-author Marc T.J. Johnson, Ph.D., published today in the journal Science, the researchers cite direct evidence of evolutionary change among more than 100 species living in cities around the world.

Munshi-South, an associate professor of biological sciences based at Fordham’s Louis Calder Center, and Johnson, an associate professor of biology at the University of Toronto, came to this conclusion after examining the findings of 192 studies that documented evolutionary change due to urbanization.

While it has been observed since ancient times that certain animals—rats, pigeons, bedbugs, roaches, and mosquitoes, for example—adapt to the presence of humans, the number of recent studies confirm this phenomenon is widespread among species. A majority of the studies that Munshi-South and Johnson examined have been published in just the last five years.

From Isolation to Divergence

Their research reveals that a significant number of species have become isolated in cities, in either pockets of habitat that have survived or in other spaces they’ve adapted to. Urban species have diverged from other populations through multiple evolutionary processes such as genetic drift and natural selection. They have also become different not only from populations in the more rural surrounding environments, but from other urban populations of the same species.

Munshi-South said the studies raise more questions than answers, but they also hint at some intriguing possibilities.

“In some of the more recent studies on selection that have looked at the same organism in multiple cities, there seems to be this tantalizing pattern of correlated changes across cities,” he said.

“We see cities as these amazing evolutionary experiments. Some species occur in many cities all over the world, and all of those populations may be evolving in the same direction. It implies that there is some directionality and repeatability to the evolution process. There haven’t been good ways to study that outside of the laboratory or [some]small islands in the Caribbean.”

Munshi-South’s own research on rats in New York City has shown that rats living in lower Manhattan are genetically different from their relatives further uptown—likely because traveling through the habitat of midtown skyscrapers is more difficult for the colonies. Urban white-footed mice found in places like the New York Botanical Garden or Central Park also exhibit genetic changes for digesting fats and carbohydrates, compared to their rural counterparts.

White Clover and Evolution

Johnson studied the white clover plant, which produces cyanide as a defense against feeding animals, but which is poisoned by its own cyanide if the plant freezes. Survival depends on a cover of insulating snowfall in the winter. In North American cities where there is less snow cover to insulate the plants, however, Johnson found that white clover has evolved to produce less cyanide than its rural counterpart.

The researchers suggest in their paper that urban planners embrace management and design practices in cities, such as “green belts,” to help native species thrive and to mitigate disease-carrying pests.

Munshi-South said the large number of urban evolutionary biology studies that have come out recently proves that the field has become a coherent discipline in its own right.

“It started out with people, like Mark and me, studying organisms that were living near our urban universities. We started noticing changes—some small, some significant—right in the back yards of our labs,” he said.

“And they seem to be driven by changes happening in the city.”

Where do they come from, and how do they get around? Fordham biologists produce the world’s first in-depth genetic study of brown rats, and investigate the mysterious, wily ways of New York’s biggest scourge.

New Yorkers love to hate their rats, shuddering whenever a pointy nose or a scaly tail peeks from behind a trash can or subway rail. So visitors to the First Street Green Art Park on New York’s Lower East Side were surprised one Saturday this past May when they came upon five street artists painting larger-than-life murals celebrating the city’s most reviled rodent—a rat giving the peace sign, a rat snuggled contently amid a vegetable ratatouille, a rat with an NYC baseball cap and a spray can, rats looking, well, cute.

The unusual project, “Street Art for Street Rats,” was intended to bring attention to the research of Fordham biology professor Jason Munshi-South, Ph.D., and his graduate students, who have spent the past four years trying to understand the species that, perhaps more than any other, has adapted itself to live side-by-side with humans in the urban environment.

“You’d think rats are so common, we’d know all about them, but in fact we don’t know very much about their ecology or evolutionary biology,” Munshi-South says.

Biologists don’t even know how many rats live in New York City. Estimates range from 250,000 to 2 million. Yet, argues Munshi-South, rats are as important to study as any other species, if not for their extreme resilience and adaptability, then for the insights into how we can fight back against the damage they cause and diseases they spread.

With the help of $670,000 in funding from the National Science Foundation, Munshi-South and his students have helped lift the veil of mystery to reveal the inner workings of New York’s rat population.

“The initial idea was to understand what a New York City rat is, from all ecological and evolutionary angles,” says Munshi-South. But the project soon expanded globally to examine where rats were coming from and how they got to New York. The lab put out a call to labs across the globe, and dozens of researchers from as far away as Japan and the Galápagos Islands sent in the genetic signatures of the rats in their neighborhoods—more than 300 samples in all. “It grew into an effort to understand the evolutionary history of rats all over the world,” he says.

A Long Global Journey

Other animals have adapted to live in cities—birds, mice, wild turkeys, and coyotes, for example, have moved into urban green spaces across the country. But rats may be the most successful at exploiting the human environment, says Matthew Combs, a Ph.D. student in Munshi-South’s lab. They’re also highly social animals that, once they establish a colony, reproduce and expand rapidly, learning from one another where to find the best sources of food—and which danger spots to avoid. “They are able to take advantage of all the resources we provide, even in the face of all our attempts to eradicate them,” Combs says.

In order to trace the journeys of rats around the world, the biologists in Munshi-South’s lab have availed themselves of recent advances in genetic research and data analysis.

“Anytime a population undergoes major changes, when it shrinks or expands or mixes with other lineages, it leaves a residue in the genome,” explains Munshi-South, who has been teaching at Fordham since 2013. To detect those residues, the lab uses a “big data” approach. Rats have some 2.7 billion base pairs in their genome. Using techniques developed for the Human Genome Project, the researchers are able to show through successive subtle gene variations which rats are related to which others, tracing their progression across both time and space.

The New York rat is known by many names, including the common rat and the brown rat. But its official name, the Norway rat (Rattus norvegicus), is a misnomer. Emily Puckett, a postdoc in Munshi-South’s lab who analyzed more than 300 rat DNA samples from 30 countries, discovered that the species actually originated in Mongolia, transitioning from forests to farms to villages as they adapted to human food sources—probably thousands of years ago, with the advent of agriculture. From there, they expanded both east to Japan and western North America, and west to Europe, where in the 1700s they stowed away on British ships bound for the bustling port of New York.

A Feisty, Unwelcoming Breed

To examine the history of rats closer to home, Munshi-South and Puckett got permission from the American Museum of Natural History to extract DNA from 100-year-old rat skulls and skins as a supplement to the samples they gathered from all over the city. They published their findings, the first in-depth study of its kind, in Proceedings of the Royal Society B, the flagship biological journal of the U.K.’s Royal Society.

While Munshi-South expected to see evidence of many waves of rat immigrants mixing in New York over time, mirroring the story of its human immigrants, that turned out not to be the case. In fact, all of the rats of New York can be traced to that initial wave in the 18th century, with little mixing with new arrivals since.

“We think that once rats get established and build big, healthy colonies, it’s hard for new rats to integrate and breed into the population,” he says. In other words, New York’s rats are so aggressive they fight off any newcomers. “That’s good news” for humans, he continues. “We are not at risk of novel diseases from a lot of new rats mixing with the local population.”

Combs has picked up the trail from there, looking at how rats are moving within New York. On any given day, he can be found setting and checking traps in every ZIP code of Manhattan, a difficult task given how adept rats are at avoiding danger. So far, he and his colleagues have caught more than 550 rats and produced genetic data for 250 of them since the start of the study.

“Most of the rats I trap are juveniles, only a couple weeks or a couple months old,” he says. “Those are the only ones foolish enough to walk into my traps.”

To find his quarry, Combs targets out-of-the-way spots behind trash cans and in the corners of parks, looking for telltale signs of burrows, pellets, or the greasy smudge marks from sebum, oil of their fur that marks well-traveled pathways. He often receives help from residents hanging out on sidewalks or stoops who are only too happy to tell him where the rats live in their neighborhoods—sometimes even letting him into their backyards to trap them.

Once he traps the rats, he brings them back to the lab where he extracts DNA samples and analyzes them for differences. So far, his research has revealed rats to be creatures of habit, rarely venturing more than 30 to 150 meters from their colonies. When they do stray, they tend to head north and south, possibly following the long, unobstructed paths of sewers and subway lines. As a result, a subtle north-south genetic gradient exists along the island, with a break in midtown.

“There seems to be an uptown group of rats and a downtown group of rats, with less movement around the midtown region,” says Combs. That break may be due to the neighborhood’s lack of residential buildings and green space, impeding their progress.

The next step in the research is to use computer models to ask what environmental attributes—such as water sources, open soil, sewers, and subway lines—determine how rats are distributed within the space. In addition, Combs will look at demographic patterns of rats’ human neighbors to see if, for example, rats are more prominent in socioeconomically depressed areas, as some research suggests.

Controlling Threats, Debunking Myths

In addition to its intrinsic value in understanding a species that lives so closely with humans, the project has public health implications. Rats can be a menace, damaging infrastructure and spreading diseases such as salmonella and leptospirosis to dogs and humans. If city officials are better able to understand where rats are coming from and how they get around, they can better control how they spread. Munshi-South has been collaborating with the New York City health department to help officials refine their strategy for exterminating rats. While much of that work remains confidential, Munshi-South says that part of the project is locating major reservoirs of rat colonies from which the rats might be spreading.

At the same time, Munshi-South’s lab has continued collaborating with researchers in other cities. Just as humans have built different urban environments, so too might rats adapt to them differently, following different patterns of movement in the open spaces of New Orleans, the parks of Vancouver, or the favelas of Salvador, Brazil. Researchers from all three cities have recently visited Fordham to compare notes and research techniques that will help tease out the ecological differences of rats, which may be just as pronounced as the cultural differences of the humans they live with.

The recent “Street Art for Street Rats” event was conceived by Combs as a way to help educate the public about the ecology of rats in all its complexity. The spark came when he ran into Jonathan Neville, a friend from his undergrad days at Hamilton College, who is a co-founder of the Centre-fuge Public Art Project, which works to “transform neighborhood eyesores” with vibrant murals.

While the artists were painting, Munshi-South, Combs, and others from the lab were on hand to teach passersby about how they use genetics to trace the journeys of rats around the city. And they debunked some common myths, such as the misconception that there are more rats than people in New York (actually, they say, there are 250,000 to 2 million rats, compared to 8.4 million humans) or that rats are able to squeeze their skeletons flat (though they can fit in tight spaces). Even so, they realize there are limitations to the average New Yorker’s tolerance.

“A lot of people do respect them and think they are fascinating,” says Combs, who likes their feistiness and adaptability. “But if someone thinks they are a scourge and is just interested in getting rid of them, I won’t try and change their mind.”

—Michael Blanding is a journalist and the author of two books, including The Map Thief (Avery, 2014).

You won’t likely see them during the day, of course, but on Saturday, May 20, rats will be front and center at “Street Art for Rats,” an afternoon of art and science.

The event, which takes places from 1 to 5 p.m., will feature five artists recruited by the Centre-fuge Public Art Project to paint panels at the park.

It’s being organized by Fordham biology doctoral student Matthew Combs, who is researching rats for his dissertation under the supervision of associate biology professor Jason Munshi-South, Ph.D. Combs and others will be on hand to answer questions and will have on display rat bones, skins, skulls, and assorted rat-related paraphernalia.

The event is part of a $500,000 National Science Foundation grant that Munshi-South received in 2015 to map the city’s “ratscape.”

Combs actually got the idea to partner with Centre-fuge after he ran into a friend who works there while he was out trapping rats a few years ago. The group enlivens mundane scenes like construction trailers with art, and has mounted numerous exhibits in the park before.

“I think street art makes a lot of sense. The medium is very much created in the city and has that a setting of coming straight out of the urban environment,” he said.

Three artists have been confirmed so far: New York City-based Denton Burrows, and Belarus natives Yu-Baba  and Key Detail.

In conversations with the artists, Combs said he’s stressed that rats should be the main focus of the murals, but the art should help the public understand them in the context of the larger urban environment. Some of the questions he expects to answer are how many rats are in the city (estimates range from 250,000 to 2 million), and whether it’s true they can flatten themselves out to squeeze through cracks (yes, but not as much as some assume).

He’s excited to see how the artists choose to represent them because rats evoke such strong reactions.

“Every New Yorker has a rat story, or has their own ideas about what drives New York City rats and where they come from. So by letting each artist take ideas and run with them, I think we’ll end up with some really interesting creations,” he said.

In a study published on Oct. 19 in the Royal Society’s flagship journal Proceedings B, scientists from Fordham reveal the complex routes that Rattus norvegicus has taken over the last several centuries, and where different lineages have settled and occasionally mixed with each other.

Global population divergence and admixture of the brown rat (Rattus norvegicus) was authored by Emily Puckett, Ph.D., postdoctoral associate at Fordham’s Louis Calder Biological Field Station, along with 17 co-authors. The study is the first large-scale genomic analysis of brown rats around the world, using 314 specimens from 76 locations that were submitted over the last three years to the lab of co-author Jason Munshi-South, Ph.D., associate professor of biology.

Understanding the evolution and ecology of Rattus norvegicus is important because they cause billions of dollars in damage annually around the world, and significantly degrade the quality of life and health of city dwellers.

The Fordham study determined that 13 evolutionary clusters have followed five routes out of China and Mongolia. The first expansion traveled southward into Southeast Asia, and then moved east, toward the Pacific coast of Asia.

Over time, two groups headed west to North America—one via Alaska’s Aleutian Islands, and another towards the Pacific Coast of North America. Meanwhile, another group ventured west, making it through Western Asia and the Middle East, and into Europe, where they split into two subgroups in Western Europe and Northern Europe.

Brown rats were then able to colonize eastern North America, South America, Africa, and New Zealand via ships originating from European colonial powers.

For Americans, Puckett said this study in phylogeography is useful because it illustrates how Rattus norvegicus arrived on the continent via different routes, and with different genetic makeups. Further study will examine how individual populations vary genetically, with the aim of determining the best way to control diseases that rats spread.

For instance, the study found that in New York City, the rats that arrived from Western Europe, most likely on British ships, have to this day remained the only brown rat lineage to establish itself. In contrast, some rat populations on the west coast exhibit evidence of colonization from both Europe or eastern North America, and Asia.

Even for rats, New York City is a tough place to make it as an outsider.

The Tecan EVO liquid-handling robot arrived at Calder in December, thanks in part to a National Science Foundation grant. The machine is helping biologist Jason Munshi-South, PhD, process DNA being used to study the rodent and coyote populations in New York City. It is queued to work on other research projects, too.

Its Liquid Handling Arm (LiHa) has eight pipette “fingers” that distribute liquid into tubes, and its Remote Operated Machine Arm (ROMA) moves things onto a heating or shaking mechanism to prep DNA for analysis—all of which give Kylo’s human counterparts more time for research and analysis.

“It doesn’t take breaks, doesn’t get shaky, and can work through the night,” said graduate student Matthew Combs, who works in Munshi-South’s lab. “Learning how to use it will be a great skill for students.”

Normally such an exclamation would be a bad thing, but not for Jason Munshi-South, PhD, associate professor of biology. On April 20, the National Science Foundation awarded Munshi-South’s laboratory at Fordham’s Louis Calder Center a $600,000 grant to further study the evolution of rats in New York City.

The funding relates to his ongoing research of brown rats, also known as Norway or sewer rats—a species that can cause significant damage to human health and infrastructure. One of the major aims is to understand how rats move throughout the city, and, as a corollary, how that movement influences their genetic structure.

Munshi-South said that his research has already shown that there are genetic differences among rats in different parts of the city. His efforts were the subject of a New York Times Magazine spread this past weekend.

The new research will continue to collect rat DNA from every Manhattan zip code, as Munshi-South’s team did last summer. Biologists will then focus on differences between genomes. With this information in hand, they can then attempt to construct mapping models of how the rats move.

Other models will be based on special patterns of infrastructure, such as subway tunnels that run north and south.

By using the genetic codes, the team expects to be able to distinguish north and southbound rats from crosstown travelers. Other models will trace sewer routes and map populations in green spaces.

“We’re also going to build models based on human socioeconomic status,” said Munshi-South. “We’ve constructed the city [venues]in such a way [as to determine whether]socioeconomics may drive the way rats move around.”

The project, “Cityscape Genomics of Rats,” will also look beyond New York City. Genomic data from more than 300 rats from 25 cities will be examined to see in which ways they relate to New York City’s rats.

The city’s American Museum of Natural History has granted the team permission to extract DNA from 100-year-old rat skulls and skins to measure evolution’s hand in the game. And there is another $15,000 set aside for artists to portray the “human-rat experience.”

“Some of our work is about what makes a New York City rat a New York City rat—where did they come from, and what makes them different,” said Munshi-South. “But the greater implication is if we understand how they move, we can possibly intervene to change how they move.”

— Janet Sassi