At my university, the secretary in my office was a woman who had previously served in the army. She was young, strong, and tough but let her find a spider, however small, anywhere in the office and she would freak out, rushing to my office to tell me to get rid of it while she stayed as far away as possible. It was no use my saying that spiders are harmless and that they are actually helpful in getting rid of other insects that are actually harmful, like mosquitoes. She didn’t want to hear it. She wanted it gone and I had no choice but to comply.

But spiders are ubiquitous so arachnophobes have a tough time because there is no habitable place on Earth where you are free of them. This article in the February 17 & 24, 2025 edition of The New Yorker by Katheryn Schulz, a self-described arachnophobe, reviews a lavishly illustrated book The Lives of Spiders by Ximena Nelson that takes a comprehensive look at the immense variety of spiders who occupy pretty much the entire world. The statistics are staggering.

To date, we know of some fifty thousand spider species, though, like this magazine, they are hard to keep up with, since new ones pile up every week. Scientists suspect the true number is at least double that, while the number of individual spiders likely clocks in somewhere north of fifteen quadrillion. These are not evenly distributed across ecosystems, of course, but you cannot escape them anywhere except Antarctica. Like us, spiders are geographically intrepid. They thrive across rain forests, cloud forests, boreal forests, grasslands, wetlands, deserts, savannas, steppes, caves, mountains, marshes, and bogs. One species, the diving-bell spider, builds its web beneath the surface of lakes and ponds, attaches an air bubble to it for breathing, and lives out its days underwater. Within these diverse environs, spiders distribute themselves the way Manhattanites do, crowding in at every level from garden apartment to penthouse. In your average patch of Eastern woodlands, there will be spiders burrowing beneath the soil, scuttling through the leaf litter, crouching in the bushes, dangling from the tree limbs, and spinning webs high up in the canopy. If your reaction to this is to vow to spend more time in the great indoors, you underestimate your nemesis; one recent study of private homes in North Carolina found spiders in one hundred per cent of them.

Spiders are carnivores and their diet is quite varied.

Also, all spiders are predators. There is one partial exception to this rule, Bagheera kiplingi, a largely herbivorous spider native to Mexico and Central America. Some other species will occasionally nibble on a plant, technically making them omnivores, but, on the whole, what distinguishes the spiderly appetite is its stunning carnivorousness. Collectively, spiders eat at least half a billion tons of meat per year, more than the amount consumed by human beings.

What exactly do these voracious flesh-eating creatures consume? Insects, of course. Also: fish, tadpoles, frogs, lizards, and the occasional vertebrate—mice, shrews, voles, bats. The largest spider, the Goliath birdeater tarantula, does, in fact, eat birds. One spider, Evarcha culicivora, which lives in Kenya and Uganda, feeds almost entirely on us, although, thank goodness, indirectly: its preferred diet is mosquitoes engorged with human blood.

Another thing spiders eat with great gusto is one another. Every known variety of spider can engage in cannibalism, and some do so with particular enthusiasm, most often during or immediately after copulation, with the female almost always doing the eating.
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If I were a spider, in short, I would still be afraid of spiders. As an order, they possess a whole suite of lethal characteristics and abilities, capable of ambushing, snaring, swarming, or deceiving their prey.

But while all spiders are venomous, few are lethally so and fewer still attack humans.

Far be it from me to question the legitimacy of any spider-based phobia, but I am duty bound to report that the fear of their bites is largely ungrounded: fewer than 0.5 per cent of spider species possess venom that is toxic to humans.
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Before you call the exterminator, however, consider these reassuring figures: worldwide, somewhere between three and seven people die of spider bites each year, putting the odds of meeting your maker that way at significantly worse than one in a billion. That doesn’t prevent people from routinely showing up in emergency rooms seeking help for spider bites, ninety to ninety-six per cent of which turn out not to be spider bites at all.

Schulz tries to figure out why, despite their harmlessness to humans, spiders provoke such intense fear in some people.

One might reasonably wonder: If spiders almost never cause us real harm, why are so many people afraid of them? Between three and fifteen per cent of the population suffers from full-blown arachnophobia, making it not only one of the most common animal phobias but one of the most common phobias over all, up there with heights and flying and ahead of needles and crowded places. Those numbers do not reflect the far larger share of people whose aversion to spiders does not quite rise to the level of pathology.

While various theories have been proposed to explain this, evolutionary ones can be ruled out, since spiders are not harmful to humans and indeed are helpful so there is no reason to think that our ancestors evolved to fear them, the way we fear snakes.

The source of this broad anti-arachnid sentiment seems unlikely to be evolutionary. For one thing, arachnophobia is prevalent in places with no dangerous spider species whatsoever; for another, even before modern medical interventions, spiders did not pose a significant threat to human beings. If anything, they are good for our health, since they carry no known diseases but are voracious consumers of insects that do, including tsetse flies and malarial mosquitoes.

She suggests that it is the fact that spiders are so very different from us, in their morphology, their hairy legs and googly eyes, in their unusual mode of their locomotion, and in the grisly way that they feed on their victims, is what creeps many of us out, not to mention the way that they are so frighteningly (and unfairly) portrayed in the media.

I suspect that this is the key to why so many of us find spiders creepy: it’s not their legs, per se, but the fact that they are dramatically unlike us in almost every respect. Consider their eyes, which are as round and globular as fish eggs, often disproportionately large (but not in the dewy, Walt Disney way), variable in size even on the same spider, and arranged in such bizarre ways that it’s hard for our brains to even parse them as eyes, let alone determine where the spider is looking, to say nothing of what it is thinking. Consider, too, their penchant for postcoital cannibalism. Consider their disgusting table manners and their grisly practice of wrapping their prey in winding sheets. What with one thing and another, spiders are all but indistinguishable from the countless horror-movie creatures they have inspired.

On top of this, and speaking of horror movies, spiders suffer from terrible reputation management. Their depictions in literature, film, and folklore run a short gamut from icky to deadly, and the small handful of exceptions aren’t potent enough to tip the balance.

This may be more than you ever wanted to know about spiders. But arachnopphobes among this blog’s readers can be thankful that I did not post any photographs of them because even that can give some the heebie-jeebies. For those who would like to see some images of them, you can check out some pages from the book.