AFTER THE BLACK BEARS raided my trash cart a second time, I got out my toolbox. With a power drill, an eyebolt, and a carabiner, I rigged up a lock that would, I thought, foil any creature lacking opposable thumbs. And I was right, more or less. When the bears visited a third time, they knocked over the cart, pried the lid open far enough to pull out a few paper towels, and then abandoned the effort and moved along.

I enjoy foiling the bears. I enjoy even more that they are around to be foiled. I live in a small city in the southern Appalachians with a large and growing bear population. My house lies a half-block from a four-lane road that carries 20,000 cars a day, but that doesn’t trouble the bears, and for the most part the bears don’t trouble the people. My neighbors and I swap notes on recent bear sightings, a bit self-satisfied in our tolerance. “We moved into their neighborhood,” one neighbor told me. “They were here first.”

That’s true, but it’s not the whole truth.

Here in western North Carolina, urban bears are doing better than rural bears. Cities offer a refuge from hunters and an abundance of garbage and bird feeders. It’s not so much that we’ve invaded the bears’ habitat. We are the bears’ habitat.

And the habitat for thousands (perhaps millions!) of other creatures as well, as I learned from reading two recent books: Rob Dunn’s Never Home Alone: From Microbes to Millipedes, Camel Crickets, and Honeybees, the Natural History of Where We Live, and Gavin Van Horn’s The Way of Coyote: Shared Journeys in the Urban Wilds.

Van Horn has written a collection of short essays based on his rambles through Chicago, where he observes coyotes, raccoons, falcons, and other weedy wildlife, concluding that “stupendous varieties of life can flourish in human-dominated landscapes.”

Van Horn, though, doesn’t know the half of it, and neither did I before reading Dunn’s Never Home Alone. Whereas Van Horn argues that to discover wildlife you need not leave the city, Dunn reveals that you don’t have to leave the house. Your home — yes, your home — is teeming with bacteria, viruses, fungi, spiders, flies, and more.

These two books share a message: open your goddamn eyes. The world is miraculous, the authors say, and they urge us to pay attention. In this attempt at persuasion, Never Home Alone succeeds extravagantly; The Way of Coyote less so. Their divergent paths offer some lessons in how to tell stories about wildlife, and how to make people care.

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Van Horn, who works for the nonprofit Center for Humans and Nature, takes his cues from the great naturalist and philosopher Aldo Leopold, presenting The Way of Coyote as “my effort to suss out an urban land ethic.” Leopold urged people to grant moral consideration to animals, plants, soils, and rivers, to live as if we are not rulers but common citizens of the natural world. This is hard enough in the woods. In a city, the task seems impossible. “Can people of the city learn to align themselves with nature’s cycles?” Van Horn asks. “Can we live as members of a larger-than-human community?”

To find out, he goes exploring, by foot and bike and train and kayak, and returns with some fascinating information. Many city creatures — and especially coyotes — are blessed with “behavioral plasticity, meaning they are adept at altering their behaviors to fit their environmental contexts.” Other animals take advantage of “habitat analogues,” which is to say that to a peregrine falcon a skyscraper looks a lot like a mountain cliff. Van Horn’s writing is at times lovely, with an earthy edge. Black-crowned night herons build their scraggly nests over well-used walking paths and relieve themselves without regard for the humans passing below, thereby “tarnishing our self-importance as well as our button-down shirts,” he writes. “Let us call this the virtue of night heron shit.”

The book works best when telling the stories of people like Sherry Williams, who combines a passion for African-American history with a love of pigeons, and Allison Sacerdote-Velat, a scientist who traps voles on a remnant patch of tallgrass prairie. “I love vermin,” Sacerdote-Velat says, charmingly, and suddenly I do too. Seth Magle, a wildlife ecologist with the Lincoln Park Zoo, has set up 120 motion-triggered cameras that have captured images of skunks, foxes, beavers, and flying squirrels. He guides Van Horn to a sliver of woods, wedged between a creek and the All-Foam Industries warehouse, that has become a dumping ground for old television sets. It is also home to a family of minks. This, to me, is astonishing, and I want to know more. How many minks? What do they eat? Where do they nest and raise their young? Are they poisoned by the toxins leaching from old cathode-ray tubes?

We never learn. The minks are introduced but quickly shuffled offstage so that Van Horn can soliloquize about Thoreau and describe the shattered TVs as “story boxes, decaying into soil while a deeper story persists in the nearby creek.” Van Horn claims that he and Magle are working toward the same goal, “him with a set of data points about urban wildlife, me with a set of stories about them.” He appears unware of a lesson that Aldo Leopold — who wrote in moving detail about the migration of geese and many other topics — never forgot: the best stories about wildlife are built on a foundation of data points. On the page, it is detail that conjures animals into life.

Outside the Evanston Public Library, Van Horn pauses to look up at the third floor, hoping to catch a glimpse of nesting peregrines. He writes, “People hurry past me, not looking up, not even looking at the odd man on the sidewalk looking up.” He is pleased with his own supposed oddity, critical of the rushing crowds. He displays, in other words, a touch of the smugness that too often mars nature writing. For a book ostensibly about wildlife, the creature we learn most about is Van Horn himself. One morning he rides his bike to Lake Michigan, sits down in the shallows, and begins to weep: “The rising sun that warms my back as I cry. Cry because I feel like one thing with the lake. The lake holds me. A mourning dove calls.” The scene is so overwrought that it could be rescued only by an incontinent night heron passing overhead. Alas, the bird stays in its nest.

Here’s some advice for those who wish to persuade people to appreciate nature: don’t scold us for staring at our phones. Instead, give us a reason to look up: entice us into the natural world by showing us that it is more fascinating, more alluring than the stories on our screens.

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That is a skill at which Rob Dunn excels in Never Home Alone. An ecologist with both North Carolina State University and the Natural History Museum of Denmark, Dunn has done field work in Costa Rica, Australia, and Ghana, but he came to realize that he could find “the same kinds of discoveries and joys I associated with the rain forest in other realms,” including kitchen counters and damp basements.

For decades, doctors and scientists — with a big assist from those selling cleaning products and insecticides — urged us to see the creatures in our homes as pathogens and pests: “Anything that wasn’t worrisome wasn’t of much interest,” Dunn writes. But the viruses and bacteria that make us sick are rare. Most are benign or even helpful.

Take tap water. Municipal authorities assure us that it is free of pathogens, but that doesn’t mean it’s sterile. Drinking water contains bacteria, amoebae, nematodes, and even a few crustaceans. And that’s before it gets to your house and encounters new environments. When you finish a shower and turn off the tap, warm water pools in the shower head, providing ideal conditions for bacteria and other microbes — “many trillions of individual organisms” — to grow together in a slick mat, where they feed on one another and on fresh microbes delivered by the tap water. Predatory bacteria latch onto other bacteria, bore holes in them, and eat them. Protists eat the predatory bacteria, and nematodes eat the protists. “This is the food web that falls upon you as you bathe,” Dunn writes.

We needn’t worry about that pipe-dwelling ecosystem unless it harbors certain species of mycobacteria that can cause lung infections. Many assume that the solution to this threat lies in a heavier dose of chlorine in the water, but that turns out to be wrong. Mycobacteria are rare in water systems that use no biocides, more common in those that do. That’s because chlorine kills off most of the living things in water, allowing only the toughest and most dangerous — including the bad mycobacteria — to survive.

Never Home Alone is, among other things, an argument for biodiversity. Taking a scorched-earth approach to microbes — by bleaching the water supply or killing off our internal microbiomes with antibiotics — generally does not end well. “[W]hen you kill species but leave the resources upon which they feed, the tough species not only survive but thrive in the vacuum created by the death of their competition,” Dunn writes. His book presents a photo of an amphipod, a tiny crustacean that, if present in tap water, means that the system draws upon a healthy underground aquifer that is unlikely to contain pathogens. So if you examine your drinking water with a microscope and discover a translucent creature vaguely resembling a shrimp, the proper response is: Down the hatch.

The larger creatures in our homes are mostly harmless as well, which is a good thing because there are a lot of them. When Dunn realized how little scientists knew about domestic arthropods, he organized a census, starting with his own home in Raleigh, North Carolina. At his direction, a team of experts trooped through his front door “like some kind of entomological circus,” laden with jars, nets, aspirators, hand lenses, microscopes, and cameras. They found one hundred species of arthropods, 10 or 20 times the number they had expected, and other homes turned up similar results. A typical house might be home to freeloader flies, fungus gnats, black scavenger flies, dung flies, wolf spiders, and ghost spiders, as well as an assortment of beetles, wasps, bees, millipedes, and aphids.

These creatures for the most part hurt each other, not their human roommates. Certain wasp species prey only on cockroaches. Spiders eat house flies (to our benefit, since the house fly is the rare household insect that does spread pathogens). Household spiders almost never bite humans. What about the large number of people who complain to their doctors about spider bites? “[N]early all of these ‘bites’ are instead actually cases of infections due to resistant Staphylococcus bacteria (MRSA) misdiagnosed by patients and doctors alike,” Dunn writes. And MRSA, of course, are bacteria that thrive where antibiotics have wiped out the competition. The lesson: Worry about MRSA and leave spiders alone.

Never Home Alone is a thumping good book that raises alarm and offers reassurance in roughly equal measure. And it is funny. After testing bacteria from various areas of the home, he observes that the “samples from pillowcases and toilet seats are different from each other, but perhaps not as different as you might hope.” On a related note: “German cockroaches can carry pathogens, it is true, but not any more so than your neighbors or children carry them.” Researching industrial applications for his work, he has trouble finding bacteria hardy enough to digest a highly alkaline waste product of paper manufacturing. “Imagine eating wood chips while submerged in a bath of lye, and you have the idea,” Dunn writes. “The dinner is unpalatable and then your skin falls off.” I even laughed while reading the acknowledgments (“Erin McKenney provided critical insights about food and feces, as she often does”) and the endnotes. Chapter 12, note 13 explains that refrigeration slows but does not eliminate bacterial growth in packaged foods: “This is what the ‘best by’ labels should really say: ‘Not totally thick with microbes until January 4.’”

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Dunn is good company not only on the page but also, apparently, in person. Science is a social enterprise, he argues, dependent upon relationships of trust and respect that allow for easy communication, “the kind of shorthand conversation upon which discovery depends.” He is forever wandering across campus to talk with colleagues and postdocs and graduate students, or batting around ideas via email, or — to cite the experiment I’m most sorry to have missed — gathering fellow scientists and master bakers from around the world in Belgium to drink beer and study the microbiology of bread.

Dr. Dunn’s science club sounds really fun. And the best part is, we’re all invited. Dunn has distributed kits that allow children to gather samples of the ants in their backyards and submit them for analysis; as a result, two eight-year-olds helped determine how far the Asian needle ant had spread across the United States. People sent in swabs from their shower heads so he could test how water system microbes varied across cities and continents. Others emailed photos of their resident camel crickets, those pale, leggy creatures that reside in basements. There are native species of camel crickets in the United States, and scientists had assumed that those crickets sometimes moved into people’s homes. But the photos submitted by citizen-scientists revealed that household camel crickets were, in fact, members of two species native to Japan.

The camel cricket research exposed gaps in our knowledge and in our perception. “If you aren’t a scientist and you see a camel cricket in your house, you assume scientists know what it is,” Dunn writes. If you are a scientist but not an entomologist, you assume the entomologists know. Entomologists, meanwhile, assume the camel cricket experts know. “Meanwhile, just two people on Earth specialize in the study of camel crickets,” Dunn writes, “and neither of them happens to live in a house where the Japanese species is present.” So no one noticed, or no one cared. Camel crickets are vermin, and most of us do not love vermin.

Never Home Alone is an expert’s exploration of the limits of expertise. Experts are crucial, of course. We need them to do the PCR analysis and to spend a lifetime classifying moth flies so they are prepared to identify the specimen we find in a spider web. But the world is a big place, and the experts can’t do it all.

That’s where you come in. “When you see a species in your home, you should study it,” Dunn writes. “Don’t assume someone else has already figured everything out. Take pictures. Make drawings. […] Then send a letter to a scientist.” You just might find something no one has noticed before. “[D]iscoveries lurk among the animals in our homes,” Dunn writes. In fact, “they are especially likely there.”

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Both Never Home Alone and The Way of Coyote encourage “rewilding,” the process of allowing wild creatures to colonize our cities and homes. Both Dunn and Van Horn want us to open our eyes and our hearts to the world around us. Van Horn’s motivations are ethical. “[O]ther creatures are worthy of our quiet respect,” he writes, and when we grant that respect, we help both the animals and ourselves: “[T]he dynamism of the human imagination, the empathic reach of our thought, finds fullest expression in understanding and meeting the needs of those who are not human.” He is counting what we’ve lost in our disconnection from nature, and urging us to restore our souls.

Dunn doesn’t express much interest in our souls, though spending time in his lively company is certainly good for one’s spirits. His motivations are varied. By understanding the wildlife of our homes, he suggests, we can cultivate biodiversity and keep pathogens at bay. We might also discover useful things: cutting devices modeled on the mandibles of grain beetles, 3D-printer nozzles inspired by the silk-sprayers of spiders, new strains of brewer’s yeast harvested from wasps. These are all fascinating ideas, but you can tell they aren’t Dunn’s true inspiration. “The beauty and sublimity” of the creatures around us, he writes, “is reason enough to care about them.”

What makes Never Home Alone so compelling is a sense of wonder and delight that encompasses all sorts of creatures and all sorts of science — black mold lurking in drywall, armpit bacteria on the International Space Station, the link between schizophrenia in humans and the cat parasite Toxoplasma gondii. And anyone can contribute to science, simply by carrying a magnifying glass over to the windowsill or taking a swab from a toilet seat. The book opens with the story of the Dutch merchant and microscopist Antony van Leeuwenhoek, who in the 1670s trained his lens on a glass of water and found, to his astonishment, that it was teeming with life. Even 350 years later, mysteries remain. Dunn urges each of us to become, like Leeuwenhoek, “an astronaut of the miniature,” exploring new worlds right under (perhaps even in) our noses. Next time my trash cart gets knocked over, perhaps I’ll take a few samples to see what types of microbes the black bears leave behind.

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Mark Essig is the author of Lesser Beasts: A Snout-to-Tail History of the Humble Pig(Basic Books) and Edison & the Electric Chair(Walker & Co). He lives in Asheville, North Carolina.