Book Excerpt: How Coyotes Found a New Homeland in the East

By Hillary Rosner, a science journalist whose work has appeared in The New York Times and National Geographic, among other outlets. “Roam” is her first book. Originally published at Undark.

While so many animals’ habitats are shrinking across our human-engineered planet, a few species are actually expanding their ranges — managing to thrive in spite of, or even because of, human activity. Coyotes are one of them.

Back in 2004, researchers compared the contemporary and historical ranges for 43 North American species of carnivores (like foxes, badgers, and lynx) and ungulates (like pronghorn, moose, and mountain goat). They found that, in general, both had lost a lot of habitat, with bears, wolves, cougars, and wolverines losing significant chunks of their ranges. But raccoons and coyotes, by contrast, were thriving. Raccoons had expanded their territory by nearly 20 percent, and coyotes by an amazing 40 percent.

Scientists argue about the exact historic ranges of coyotes, but the most recent research — based on museum specimens, records of sightings, and fossils, bones, and other remains found during archeological excavations — shows that from 10,000 years ago through the late 1800s, coyotes lived across about two-thirds of North America, from California to the Mississippi River in the United States. They also likely ranged as far south as northern Costa Rica, and north into southern Canada. But they had never been found in the eastern U.S. In each decade since the 1900s, though, coyotes gained new territory: east across the U.S., south to Panama, and northwest across Canada all the way up into Alaska.

This continent-spanning coyote explosion was made possible by the very logging and fragmentation of forests that has made life so hard for other species, and by European settlers’ wholesale slaughter of wolves. Wolves outcompete coyotes for food and will even kill them in the competition. With the top-level predators missing from the food chain, coyotes flourished.

The coyotes found east of the Mississippi today are a recent creation. The eastern coyote, which can now be found from Florida to Newfoundland, is actually a hybrid of coyote, wolf, and domestic dog, with those in the northeast possessing the highest amount of wolf and dog DNA — between 8 and 25 percent wolf and around 10 percent dog, according to research by Roland Kays, a zoologist at North Carolina State University.

Kays estimates that these coyote-wolf mating events happened around a hundred years ago. “A century ago, wolf populations in the Great Lakes were at their nadir, living at such low density that some reproductive animals probably couldn’t find another wolf mate, and had to settle with a coyote,” Kays wrote in 2015.

The wolf genes made the coyote slightly larger, which likely gave it the ability to make dinner out of deer — a ready source of food in eastern forests, which allowed the hybrid coyotes to expand their historic range. “These animals thrived, dispersed east, and thrived again, becoming the eastern coyote,” Kays wrote.

The dog mating was more recent — roughly 50 years ago, by Kays’s estimate. “Nowadays,” he wrote, “eastern coyotes have no problem finding a coyote mate. Their populations continue to grow throughout their new forested range, and they seem more likely to kill a dog than breed with it.”

Unlike some other critters that have colonized new areas in the last century or so, like emerald ash borers or feral swine, both of which were brought by humans and caused havoc to ecosystems, coyotes evolved and adapted to exploit a human-altered landscape, taking advantage of new opportunities and then using their wits to survive.

In the 1980s, they made it as far south as southern Panama, and now only the dense forests of the Darién Gap separate them from Colombia and South America, where they have never existed before.

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Coyotes are generalists, meaning they aren’t picky about either food or lodging. This has helped them expand from grasslands into forests, suburbs, and cities. But they also benefit from their particular relationship to humans. Scientists use the term synanthropic to refer to a type of animal that thrives in urban landscapes — rats and pigeons, geese and foxes, raccoons and coyotes. A synanthropic species might actively choose to hang out in human-dominated places, moving into a new range, or it might simply be better equipped to survive in cities than other animals. Species that prefer instead to avoid humans, or that are harmed by urbanization, are called misanthropic.

The vast majority of carnivores that live on land are misanthropes; fewer than 15 percent are synanthropes. But scientists who have spent more than 20 years studying coyotes in the Chicago metro area believe that coyotes are a strange mix of both. In one study, those researchers put radio collars on 181 coyotes over six years and wound up, they wrote, with “a portrait of an animal that appears to benefit from the urban landscape through enhanced survival and possibly elevated population densities, while also exhibiting strong spatial and temporal avoidance of humans.”

The animals were avoiding more developed areas of the city and also becoming nocturnal. It’s a wily strategy: thriving in busy cities while steering completely clear of people. This status, which the scientists called “misanthropic synanthrope,” helps both individual animals and the species overall.

The same is true in New York City. Coyotes are thriving there — and scientists are on to them. Since 2009, a collaboration of researchers called the Gotham Coyote Project, or CGP, has been studying the ecology of the city’s coyotes.

I called up Anthony Caragiulo, a geneticist who worked on the project and also served as assistant director of genomic operations at the American Museum of Natural History’s Institute for Comparative Genomics. At the time, Caragiulo was analyzing DNA from coyote poop that volunteers collected in parks around the city and suburbs. “I don’t go out and collect anything,” he said when we spoke on the phone. “People just send me boxes of crap in the mail.”

Like many New Yorkers, coyotes were paying occasional visits to Manhattan but actually resided in the outer boroughs. In fact, they were thriving in the Bronx and continuing to expand their territory, moving across the East River into Queens and out toward the suburbs and rural areas of eastern Long Island. The researchers were trying to build a “genetic connectivity map” of all the coyotes, to understand who was related to whom, and where they had come from.

Caragiulo’s role in building the map was to extract the DNA from coyote poop he received in the mail. It was hard for me to picture: post office poop. “So, do people just, like, put it in a box and write your address on it?” I asked him. “They put it in a brown paper bag,” he answered. “And sometimes they throw in some silica beads, like the ones that come when you buy a pair of shoes.”

“And it just shows up in your mailbox at the museum?” I had spent a good part of my childhood in that building, and I still viewed it with the awe and reverence of a kid. If you’d asked me what I thought might arrive in the mailboxes of the museum’s venerable scientists, I’d have said exotic gemstones and the perfectly preserved vertebra of plesiosaurs. Definitely not coyote poop from the Bronx.

Caragiulo graciously invited me to see his inbox for myself, so one morning I met him at the museum’s basement entrance. It was a Tuesday in the fall of 2021, and because of pandemic-related staffing shortages, the museum was closed on Tuesdays. Other than security guards and some crews working on exhibit maintenance — and a public vaccination clinic underway in the lower-level lobby — the building was eerily empty.

We headed to a giant elevator and rode it up to the eighth floor. The hallways were deserted, and it felt vaguely apocalyptic. Because of the pandemic, most people were still working from home, he said, only coming in when necessary and allowed. The pandemic had also caused supply chain issues in the lab. Normally abundant items like pipette tips and DNA sequencing kits were taking up to three months to arrive. This had slowed down Caragiulo’s coyote work. The poop was piling up in his lab. “I’m the bottleneck,” he said.

He walked me over to an area of the lab where the shelves and surfaces were lined with cardboard boxes and precarious stacks of envelopes. At a station marked “Bench 3 — scat bench,” he opened a box that in turn was filled with small paper bags, lots of them. “Cedars Golf Course, Cutchogue,” read the hand-written info on one bag, from a scat collector named J. Murray, picked up on January 8. “Near goose carcass and possible vomit of goose feather & bones,” the notes stated.

I could see why Caragiulo preferred the lab to the field. Other bags had different people’s names on them — some scientists, some volunteers — as well as the names of various green places throughout Long Island: Quogue Wildlife Refuge, Kings Point Park. All had GPS coordinates.

Caragiulo donned a pair of blue latex gloves, spread a piece of tissue on the table, and opened up a paper bag. He retrieved a small bit of dried scat. It had no noticeable smell, and it looked like nothing more than a clump of mud. He shrugged. “This could be anything. I have no idea.”

Most of the samples he had analyzed over the past year, though, were definitively coyote. (A few domestic dogs, the odd fox.) By extracting and analyzing the DNA from the scat, he could quickly tell, first, whether it did in fact come from a coyote. Then, using so-called microsatellites — short, repeated segments of genetic code that are unique to an individual — he could examine which samples came from the same individual coyote, and which came from coyotes that are related.

He could also determine just how closely related they are. “The goal is to say, over five, 10, 15 years, which families were successful, where they colonized — to look at this web of movements that’s a snapshot in time.”

Carol Henger, a molecular biologist who worked with the GCP studied coyote DNA for her PhD research, said each park in the Bronx had its own distinct family group. The DNA from the scat of each individual and each family allowed you to see just who was moving where — like, “this coyote at New York Botanical Gardens is also related to Pelham Bay coyotes,” she said. “There was dispersal all around the city.”

From that genetic connectivity map, Henger and the Gotham team were also able to hypothesize how coyotes settled in New York City in the first place. The likely tale was that “they first settled in parks to the north of the city” — moving down from the suburbs of Westchester — “and their descendants have since colonized other parks and have their own family groups. The coyotes in Queens” — the newer arrivals — “were related to the coyotes in the Bronx,” Henger said.

It was, like many New York stories, a tale of immigration and survival.

Scientists are interested in this particular snapshot because they can now watch as coyotes move into a landscape where they’ve never existed before: Long Island, the 120-mile-long, vaguely crocodile-shaped spit of land that juts into the Atlantic Ocean east of Manhattan, anchored by Brooklyn and Queens at the western end.

“A lot of times we’ll say, ‘Oh, black bears are coming back, or bobcats are coming back,’” Chris Nagy, a cofounder of the Gotham Coyote Project, said, speaking about species whose populations are rebounding in places where they used to exist before humans caused their numbers to plummet. “But coyotes are showing up for the first time.”

Nagy marvels at this. “When I talk to people about this stuff, I say the city thing is cool, but they’re also in Alaska all the way to the tropical rainforest in Central America. They’re figuring out ways to make a living wherever they can.”