Shane Campbell-Staton is showing the world how human activity is shaping evolution right now
Shane Campbell-Staton, assistant professor in the Department of Ecology and Evolutionary Biology at Princeton University.
One night back in 2016, Shane Campbell-Staton couldn’t sleep. Doing what any person who feels inexplicably restless at 3 a.m. might do, biologist Campbell-Staton embarked down a YouTube rabbit hole. A few videos deep, he came across a clip about the tuskless elephants who live in Gorongosa National Park in Mozambique.
Much of Campbell-Staton’s career up to this point had revolved around the study of small green anole lizards native to the southeastern United States. Specifically, he was studying how the reptiles adapt to changes in temperature, especially when faced with human-made changes to their environments. But the phenomenon of elephants rapidly evolving without tusks to adapt to human activity such as poaching resonated with Campbell-Staton’s research interests.
He became so curious about the tuskless elephants that he reached out to some scientist friends to see who — if anyone — was researching them. On the email chain was Princeton professor ecology and evolutionary biology Rob Pringle, who happened to be planning an expedition to Mozambique as part of a long-term study on the ecology of large mammals in Gorongosa National Park. Pringle invited Campbell-Staton along. By 2018, Campbell-Staton, who was then an assistant professor at the University of California-Los Angeles, was driving around Gorongosa in search of tuskless elephants from which to collect genetic samples.
The accidental foray into elephant tusk research was one of many unusual paths that anyone who knows Campbell-Staton, who joined Princeton as an assistant professor in the Department of Ecology and Evolutionary Biology in 2021, might expect him to take. He’s a researcher described by colleagues as a rising star. “Right now, he’s full throttle,” said Pringle. “Every time we talk, he’s got a new idea.”
His latest endeavor: hosting "Human Footprint," a six-part PBS science and travel show about how people have transformed the planet. The series began airing on Wednesdays this summer.
Campbell-Staton imagines that his career likely will be filled with exciting twists and turns akin to the path leading him to work with elephants. “What attracts me to projects are stories that I find fascinating, mysteries that I find fascinating,” he said. “Chasing those mysteries and trying to understand the questions that go along with the stories and the answers to those questions leads me down all sorts of unexpected roads.”
When following Campbell-Staton’s research, it’s best to expect the unexpected. From looking for tuskless elephants in Mozambique, to studying how urban lizards in Puerto Rico adapt to rising temperatures, to joining a collaboration to investigate radiation’s impact on the wolves of Chernobyl, Campbell-Staton’s interests take him in many directions. (This story originally appeared in Discovery, a magazine from Princeton's Office of the Dean for Research that highlights research at the University across disciplines.)
A biologist begins
Ask a biologist how they got into the field, and they’ll probably recount a story about encountering salamanders while hiking through the woods or splashing around with anemones in tidal pools off the beach. Campbell-Staton isn’t one of those biologists. “I grew up in the ’hood in South Carolina,” he said. “My pathway into science was actually through television.”
A self-described latchkey kid, Campbell-Staton said he spent a lot of time at home, taking care of his little sister while his mom worked shifts up to 72 hours long as a taxicab driver. “I didn’t have a whole lot of experience with the outdoors at all,” he said. During these afterschool hours, he spent time watching crocodile hunter Steve Irwin and biologist-slash-television host Jeff Corwin. TV introduced Campbell-Staton to the amazing animals and incredible places of planet Earth.
The love he found for the natural world led Campbell-Staton to the University of Rochester, where he completed his bachelor’s degree in ecology and evolutionary biology. It was here that he began blending his interest in genomics and lizards. In the laboratory, Campbell-Staton used DNA sequencing to trace the evolutionary origins of bearded dragons. After completing an honors thesis on the subject, Campbell-Staton went on to pursue his Ph.D. at Harvard. Again he studied lizards, but it wasn’t until toward the end of his Ph.D. that Campbell-Staton had the opportunity to explore the phenomenon that would become the hallmark of his research: how human activity can impact evolution.
That opportunity arrived after a winter storm passed through Texas where Campbell-Staton had been studying several different populations of lizards. “I decided to go back and look at how these populations responded to the single extreme weather event,” he said.
What he found astounded him. The lizard populations experienced a number of shifts in gene expression that allowed them to better tolerate the cold, much like their northern counterparts. “Typically, when you think about evolution, you think about it playing out over thousands or millions of years,” explained Campbell-Staton. “The idea of being able to track selection in real time became fascinating for me.”
“Shane has a really great ability of seeing things in a different way than other people see things,” said Kristin Winchell, who collaborates with Campbell-Staton and is an assistant professor at New York University. “He can identify these big picture ideas and problems and envision how he would test them very clearly.”
Chasing the story around the globe
From living vicariously through the adventures of conservationists on-screen, Campbell-Staton now gets to experience Earth’s extraordinary habitats firsthand. His work has taken him to Puerto Rico, Australia and South Africa. The trip to Mozambique to study tuskless elephants in 2018 was his first excursion to continental Africa.
If you’d asked Campbell-Staton five years ago whether he’d ever be interested in studying the tooth development of elephants, he’d have answered with a resounding, “No, not particularly.” Pringle, however, who invited Campbell-Staton to research elephants alongside him, was less surprised at the latter’s move from lizard thermal biology to tusks.
“My own research program is sprawling,” said Pringle. “I think that’s one of the reasons that Shane and I can collaborate so well, because we both have this sort of expansive sense of what’s possible.”
Campbell-Staton’s task was to collect fecal samples from tuskless elephants to extract and test their DNA. Upon arriving in Mozambique, Campbell-Staton said he drove around for three weeks in search of elephants — and encountered none at all. Luckily for Campbell-Staton, Pringle and his team had arranged a helicopter to track down and tranquilize elephants to collect their blood, which ultimately provided the crucial DNA.
In 2021, Campbell-Staton, Pringle and colleagues published a paper in the journal Science drawing a connection between the relatively large proportion of female elephants born without tusks following the 20-year Mozambican civil war and the genes associated with tusklessness. During the war, elephant populations declined 90% due to poaching for their valuable ivory tusks.
The study provided evidence for the role of poaching in tuskless-elephant survival and population growth. If studying how animals adapt in the face of human activity is the body of Campbell-Staton’s research, then his collaboration with other scientists is the beating heart. “Shane cares about the people he collaborates with,” said Winchell. “And I think when you place the people as a priority in your scientific collaborations, that leads to better science.”
The human impact on the tree of life
When Campbell-Staton is not traveling for his research, he spends his time in his laboratory at Princeton, typically at a computer completing statistical analysis. He described his graduate students and postdoctoral fellows as the “boots on the ground” — in the work they do preparing DNA samples for sequencing and carrying out genomic studies.
“My role is to provide these young, ambitious scientists with as many opportunities as possible,” said Campbell-Staton. “And to help them think of the coolest, craziest stuff that could possibly be done to get at some of these really important and pressing questions.”
His experience with studying rapid evolution in Texas lizards as a Harvard graduate student bloomed into a collaboration with Winchell, who at the time was pursuing her doctorate across the river at the University of Massachusetts, Boston, while also visiting a laboratory at Harvard. Campbell-Staton heard about her research with lizards in urban environments and their partnership grew from there.
In 2021, Winchell worked as a postdoctoral researcher in Campbell-Staton’s Princeton laboratory, and then began her position at New York University as an assistant professor. She continues to study how anoles adapt to city living. “I think of [urban environments] as both relevant to conservation in a changing world and also as an evolutionary testbed to understand fundamentally critical questions of evolutionary processes,” she said.
Campbell-Staton and Winchell agree that urban environments are crucial for understanding biodiversity. Winchell’s dissertation research concluded that lizards in urban areas had adapted to develop longer limbs and larger toe pads. These genetically based shifts allowed the lizards to better navigate their urban environments.
Together, Winchell and Campbell-Staton are exploring how lizards respond to the urban heat island effect — when urban environments tend to be several degrees warmer than forest environments. In addition to gauging how the reptiles tolerate hotter environments, the researchers also are testing how their physical performance differs at higher temperatures. For example, the researchers put the lizards on racetracks to see if they’ve adapted to run faster when experiencing hotter conditions.
Across all systems and scenarios studied by the researchers in Campbell-Staton’s lab, a common theme comes up again and again. “Life is both incredibly fragile and incredibly resilient,” said Campbell-Staton. “And it plays out every single day.” Species are plummeting to extinction due to human activity, and at the same time species are finding unique and strange ways to adapt and survive.
“Everything we do — whether it’s intended or unintended — has cascading consequences,” he said. Campbell-Staton says his research shows how deeply rooted we are to the tree of life, even when we humans may think of ourselves as separate from the animal kingdom. “We have become a force of evolutionary change in a lot of different ways, and we’ve also become a force of evolutionary change for ourselves,” he said.
The theme of human-induced evolutionary change is present throughout all the animal populations Campbell-Staton has studied. While the research is fascinating, it’s also heartbreaking, said Campbell-Staton.
The most difficult challenges he has faced in his research career have been emotional, rather than technical. “There is inherent value in trying to understand our human footprint, but the reality is our human footprint is not a pretty thing,” Campbell-Staton said.
He recalled observing a sedated elephant in Mozambique and realizing he was looking not just at a study subject, but at a matriarch of a herd. And not only was the elephant a matriarch, she had survived the Mozambican civil war, during which 9 out of 10 members of her species died within a 15-year period. And throughout all the stress, the elephant had gone on to have her own offspring and grandchildren.
The fragility and resilience of life also plays out in the animal populations still living in Chernobyl after the 1986 nuclear accident, one of the worst in history. Campbell-Staton recently started collaborating with postdoctoral research associate Cara Love at Princeton to study the wolves that hunt in the Chernobyl exclusion zone. Love brought the research idea to Campbell-Staton, and they are working on their first paper. Despite the chronic radiation in the Chernobyl exclusion zone, wildlife, including wolves, has returned to the area. The animals are not just surviving — they appear to be thriving.
With funding from the Pew Research Center, the Princeton Branch of the Ludwig Institute for Cancer Research, the Princeton Catalysis Initiative and the therapeutics company Genmab, Love and Campbell-Staton are asking how the wolves of Chernobyl have adapted to dangerous levels of radiation. Their ultimate hope in studying the wolves is to understand cancer biology, and, in this way, potentially find “novel therapeutics for cancer using the solutions that natural selection has come up with,” said Campbell-Staton.
Just as he followed the story about tuskless elephants all the way to Mozambique, Campbell-Staton’s move into cancer biology is in line with his ever-growing range of research interests. “I am not a cancer biologist by any means whatsoever,” he said. “But again, it’s one of those things where the story requires questions and those questions lead you down all sorts of scientific pathways.”
Expanding horizons
Over the past year, Campbell-Staton has continued to travel frequently, both for field work and for the filming and production of "Human Footprint," a science-travel series that's a fitting turn for a biologist who found his own passion for science by watching others on screen.
Campbell-Staton says it's his collaborations with others, like Pringle, Winchell and Love, that have been integral to the creativity that pushes forward his science. The researchers each bring their own expertise, and by working together they can expand the horizons of scientific understanding.
“As scientists, it’s our job to stand on the horizon of our collective human knowledge and look out into the darkness that is the unknown,” said Campbell-Staton. From anoles to elephants to wolves, there is one thing that is certain about his future as a scientist — Campbell-Staton will be found at the edge of that darkness, finding ways to illuminate new knowledge.
A team of conservationists and scientists gathers around an elephant to help steady it as they turn it on its side to attach a collar as part of a continuing study about the evolution of tuskless elephants in Gorongosa National Park, Mozambique.
