The Nature of Fear: Survival Lessons From the Wild by Daniel T. Blumstein Harvard University Press
ink illustration of terrifying bat with fangs and claws
Matt Huynh

If you grew up in a land of potentially dangerous animals, as I did, much of your outdoors education might have entailed learning to recognize and avoid the settings in which you were most likely to encounter them. Dawn after a streak of hot, rainless, overcast days? Shark weather, according to the local wisdom. A smooth clearing in otherwise tangled bushland, its topside granulated like cane sugar? A telltale sign of Australian bulldog ants below, prickling with venom. The wisest way to flip a rock: Reach over and pull the farthest edge up toward you. Now anything coiled beneath it escapes in an away direction. Coming to understand oneself as, if not prey, at the very least a legible target for other creatures’ defensive instincts was a timeworn rite of passage. Still, shrewd (and possibly life-preserving) though it was to jump back from a shiver sliding through the long grass, I remember being most afraid of animals that posed little immediate threat to my life or well-being. What terrified me—and in this, I feel sure I am not alone—were bats.

For context, let me describe the Nocturnal House at the Perth Zoo, a brown-brick outbuilding tucked behind bamboo in a far corner of the grounds. On entering, a person leaves daylight behind, passing through a blackened corridor into a space flooded with red light. I know now that the lighting design has less to do with macabre theatricality than with the zoologists’ intent to display nighttime animals at their most wakeful: The large-eyed mammals and birds inside, aglow in crimson, are not spooked by the low, red luminance of the space, and so they behave as they might under cloak of darkness. But absent this explanation, the ambience did much to transpose the fauna of the Nocturnal House into a child’s gathering nightmares.

As I remember it, the bats hung in pairs, like velvety boxing gloves, from a grate in the roof of their enclosure. These were ghost bats, a carnivorous species, colonies of which cluster in caves and disused mine shafts in the north of Australia. True to their spectral name, the bats are an ashy white and have transparent wings laced with red veins so that, while roosting, each encloses itself in a caul of its own ticking blood work. When they chittered, you both heard and felt it, like a trickle of ice water running down the back of your head. The bats’ mouths were full of needle-fine teeth. Their long ears—thin as glassine paper—made me think of a bishop’s miter. Their noses were lobed, their chins were cleft; the light made all of this worse.

In the wild, ghost bats favor the flesh of the native budgerigar, an endearing parakeet that many households keep as a pet. After one fatal bite to the bird’s neck while it sleeps in a tree, the bat will carry it off to eat—starting with the head—as it hangs by its claws from a rock face. And perhaps it is this very invertedness—the silver bat in the black night, returning to its stony underworld to chew on feathers upside down—that makes you believe, however fleetingly, that every animal in the world might be accompanied by its own, bespoke devil. The colorful, trilling budgie above. Belowground, a ghost bat. Looking to nature, who doesn’t begin compiling these sorts of binaries? Here, the hunted; there, the hunters. Animals that fear; animals to be feared. Serendipitous symbols partitioned from cursed ones. If the bats in the Nocturnal House turned and quivered, surely that was because they recognized the fright skittering in your eyes and were pulled—by some predatory impulse within—to beat against the wire, hungry to meet the fear.

I kept coming back to the memory of those ghost bats, their trembling and my own, while reading a new book by Daniel T. Blumstein, an ecologist at UCLA. In The Nature of Fear: Survival Lessons From the Wild, he offers a natural history of an emotion. Looking at how different animal populations apprehend and respond to alarming stimuli in their environment (the paw prints of a rapacious meat eater, say), Blumstein argues that fear itself represents an evolutionary high-wire act. To thrive, animals need to be adequately alert to perilous dangers, but not so terrified that their foraging, rest, and social relations are unduly impaired.

Foolhardy animals perish, but overly trepidatious individuals can likewise fail to pass on their genes, because of starvation, stress, and isolation. The ability to identify the right things to be afraid of is a heritable trait in some species. Across the animal kingdom, Blumstein emphasizes, the experience of being afraid shares physical commonalities, including chemical pathways in the body and muscular reflexes. Terror makes wildlife of us all: Adrenalized, with pupils dilating and the midbrain trained on escape, we share with other mammals the heiliger Schauer, or “holy shiver,” of prey that has fallen into a predator’s line of sight.

Clearly, The Nature of Fear is a book for this moment. Dread is all around, manifold and constant during the coronavirus pandemic, of course. But a particular theme of our escalating anxieties comes to the fore with Blumstein’s book in hand: the fear of belonging to nature. City dwellers we may be, denizens of culture and technology, and envoys of the economy, but SARS-CoV-2 undoes the illusion that we live elevated lives, disconnected from the planet’s animals and the subtending universe of microbes sprinkled within and around them. We transmit the virus by virtue of being warm-blooded hosts—vulnerable, as animals, to one another. As the pandemic brings into focus our biological fragility, the time seems apt to examine the nature of human fear through the lens of, well, nature.

In recent months, many more people than me have come to fear bats for a new reason. SARS-CoV-2 is a “zoonotic virus”—which is to say, a virus that emerged from contact with animals—and is widely theorized to have arisen from a kindred coronavirus circulating in groups of horseshoe bats, perhaps those in the southwestern Chinese province of Yunnan, or elsewhere, in Myanmar, Laos, or Vietnam. Though the genetic pathway of the virus seems highly likely to have devolved from a specific, ancestral bat virus, SARS-CoV-2 mutated before being transmitted to humans—to date, no bat has been found carrying the virus that infects people.

Nonetheless, the Humane Society International reports that in Australia, “paramedics are being overwhelmed by calls about bats during the COVID‑19 crisis,” as people mistakenly perceive native flying foxes as a viral hazard. Indonesian authorities have gassed and burned caged bats in markets. Bats in India have been dislodged from their roosts. Likewise, they’ve been culled in Cuba, while in Kigali, Rwanda, government workers have trained water cannons on colonies of straw-colored fruit bats, intending to drive them away. Bats have been demonized. Little wonder, given their storied, superstitious past (see: vampires, Halloween, and Macbeth’s witches, mixing “wool of bat” with eye of newt in their hexing cauldron). Bat-fear already had a template.

Where does the line fall between instinctive fears and those acquired via culture? In one fascinating chapter of The Nature of Fear, we discover that certain shapes and objects sharpen attention and arouse innate fears in a variety of animals, even if the distinct threats represented by those contours have never been encountered. Humans pick out the serpentine squiggle of a snake from fuzzy images, for example, far more accurately than they can pinpoint other camouflaged creatures. Other primates can be born watchful of snakes even if they spend their entire life in a laboratory. And some species of arboreal frog are so finely attuned to predatory snakes that if their eggs are jiggled by the unique vibrations of a snake slithering along a bough, the spawn will spontaneously hatch, in a matter of seconds, to give the underdeveloped tadpoles the chance to scatter. These amphibian fears are embryonic.

Reading all of this put me in mind of Rorschach blots, a now outmoded psychological test wherein subjects are shown a series of ambiguous ink spots and asked to characterize them. The first and fifth ink blots in the series are typically seen as bats, or black butterflies; Hermann Rorschach considered these “normal,” unconscious associations. But isn’t our fear of bats largely rooted in how well they elude our sight? At night we can’t follow a small bat zipping to and fro; we perceive it as a blurred flitter, or else identify the creature from its sounds, faint squeals on the edge of human hearing. Bats huddle away from scrutiny in the shadowed corners, the highest archways.

A layered horror: The realization that our vision can scarcely seize upon a bat in the gloom suggests, more broadly, that the nighttime world, as bats apprehend it, is concealed from us. Likely they make us out with an acuity greater than what we bring to our perception of them. We do know that much of what bats hear, we cannot; some are able to pick up ultrasonic sound. Their ears, like orchids, come in a staggering array of shapes, ornamented with curls, frills, and ribbing, delicate and monstrous. Yet if what we deem a monster hinges on grotesque anatomy—a body freakish to our eyes—then science suggests that one definition of the monstrous might merely be an animal that navigates a sensory world that is different from the one we inhabit.

As to the bats themselves: Do we know if they would startle and feel instinctively scared if they were shown ink-blotted silhouettes of people? Who can tell what human-focused terrors lie in the heart of a bat? Though no one has yet been able to run that test, as far as I know, Blumstein leads me to ask whether all the fear in the Nocturnal House was circulating on my side of the glass.

Whatever feelings bats may have toward people, humans have used bats’ other fears against them. The Royal Botanic Garden in Sydney, concerned about swarms of flying foxes destroying heritage-listed trees, has smeared python excrement on branches and deployed a device called the Phoenix Wailer to generate reverberant, discomfiting sounds in order to drive off the bats. As Blumstein notes, certain sounds consistently panic a variety of species, including humans. Acoustically, “noisy” sounds are the most frightening; their dynamics are chaotic, and, to us, they seem raspy and discordant, with rapidly fluctuating frequencies. Distinct from volume, it is this dissonance (called “nonlinearity”) that brings on wide-eyed alarm in our kind and appears, likewise, to distress some other animals. One day, as Blumstein is holding a baby marmot captured as part of a study, the pup emits a “nonlinear” scream. The scientist writes that in decades of fieldwork, he’d “never heard such a horrible sound.” That the bloodcurdling pup scream is utterly unlike the marmots’ customary chirps and chucks intensifies the shock. When animals make dissonant noises, they can seem possessed of voices that don’t quite come from nature at all.

Though the Phoenix Wailer at the Royal Botanic Garden may not alarm us as it does bats, the sound is audible to both of us—and its deployment is occasioned by a newfound mingling that unnerves us humans. The reason the Royal Botanic Garden found itself trying to ward off flying foxes: In the past 20 years, flying-fox populations in Australia have become urbanized, as major brush fires and agricultural clearing have erased more and more of the animals’ habitat. Flying foxes are not shy cave dwellers. Weighing up to two pounds, the bats’ bodies are as big as milk cartons, and their wingspans can be more than a meter. Today they roost by the tens of thousands in city parklands. Usually we think of environmental degradation leading to shrinking animal populations, but accumulations of displaced flying foxes in cities are another result.

If people fear bats most en masse, as a darkening cloud, might it be because large groupings of bats sometimes gesture to a change in the ecology? Whatever the source of the unease, at a point when the pandemic has heightened fears of bat encounters, more Australians are seeing more bats—and those bats have been more distressed because of summer heat waves. Earlier this year, a rescue helicopter headed for a hospital in Queensland had to be diverted because thousands of mobbing bats made landing too difficult. Stressed bats are known to shed more viruses, perhaps as a strategy to challenge the species they compete with for food and habitat. A fear of the bat not in the sky but nearby may indeed serve some evolutionary purpose.

“As if terrified and fleeing from itself,” the poet Rainer Maria Rilke wrote of the bat, “it zigzags through the air, the way a crack runs through a teacup.” Rilke’s evocation of an animal scared of itself could easily have been the epigraph to Blumstein’s book. Fear is very close during the pandemic. Yet the time is also at hand to reflect on what it means to be, in a very real sense, one another’s environment. Right now, to be walled off from one another is not an expression of fear, but of our connectedness to one another, and to animal life.

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