Why Snakes Are So Mind-Boggling, and Why We Still Fear Them

I find snakes to be among the most fascinating nonhuman animals (animals) with whom I have fairly regular contact and I try as hard as I can not to let fear intrude into my attitudes about these magnificent alien beings. A good deal of my interest stems from deep concerns about the effects of misleading views about who these deeply emotional and sentient creatures truly are, for their well-being out in nature, and perhaps especially about what happens to them when they're kept in captivity as companion animals. These are among the many reasons why I was excited to learn about Stephen S. Hall's new book, Slither: How Nature's Most Maligned Creatures Illuminate Our World. I was pleased that he could take the time to answer some questions about his eye-opening, fact-filled book that offers a "naturalistic, cultural, ecological, and scientific meditation on these loathed yet magnetic creatures."

Marc Bekoff: Why did you write Slither?

Stephen Hall: I’ve always been fascinated by the beauty, agility, latent menace, and sheer Otherness of snakes. As a kid, I had a few snakes as pets, but it was never an obsession. As a science writer, though, I began to notice some really fascinating research articles on snakes in prominent journals like Science and Nature over the last decade or so: how they move, how they digest infrequent meals, how they sense their world. And I realized that some of the most remarkable traits of these animals were microscopic, molecular, indeed invisible to us for centuries. Given the undisputed fact that many people loathe and detest snakes, I thought it would be an interesting challenge to try to reconcile this hatred with the need to respect and preserve a class of animal that is routinely killed and in some cases faces extinction due to habitat destruction.

MB: How does your book relate to your background and general areas of interest?

SH: In all my books, I try to find narratives that show how new research technologies change our perception of biology in particular and of nature in general. In snakes, radio telemetry in the 1990s allowed researchers to track individual snakes in the wild, which allowed them to see unexpected behaviors: maternal care, sociality, temperament, habit, idiosyncrasy. Many researchers told me snakes have distinct personalities. Some rattlesnakes hang out with their “friends,” for example, and avoid other snakes they apparently don’t like. Rattlesnake moms sometimes use “babysitters” to look after their newborns while they go off to eat (gestating females may go nearly a year without eating).

With the advent of advanced genetics and genomics, snake scientists have also unearthed some mind-boggling metabolic tricks. Burmese pythons sometimes eat only one big meal a year: They may be the original intermittent fasters! And the meals are huge, equivalent to a roughly 140-pound human eating a 220-pound hamburger in one gulp. How do they process these huge meals? Snake scientists have discovered that almost from the instant they ingest food, these snakes turn on something like 2000 genes. They can enlarge their hearts to pump the “sludge” of fat-saturated blood. They enlarge the intestines to process all that food. And when digestion is complete, they molecularly pare away the cells that enlarged the heart, gut, liver, and kidneys. In other words, they can regenerate their own tissues on demand, in a kind of controlled proliferation that resembles cancer, then eliminate the cells, reverting to a metabolic state so low that it barely uses any energy to stay alive.²

MB: What are some of the topics you consider and what are some of your major messages?

SH: One of the major messages is that we can learn a surprising amount about human biology if we conduct research on snakes. One fascinating area of research is in the reproductive sphere. Patricia Brennan, a scientist at Mt. Holyoke College, has quantified sexual antagonism between male and female snakes by making casts of their genitalia (yes, a serpentine twist on the 1970s plastercasters!). Male snakes have two penises (the technical name is hemipenes), and in some species, the male organ almost resembles a medieval weapon—barbs, spikes, and protrusions likened to grappling hooks. Yet in other species, there’s no hardware; I saw a cobra hemipenis in Brennan’s lab, more than a foot long, that had fluttering, petal-like protrusions, almost like a foxglove plant. Her research has shown how genital anatomy can reflect either sexual antagonism or compatibility within a species, and she believes studying the female response to these male appurtenances may have implications for human health.

Another rich area of interest is research on the origins of fear of snakes. There is a strain of psychological research that hypothesizes the existence of a “fear module” in primates, including humans, that is specifically oriented towards serpents. One of the most provocative recent ideas is the so-called “Snake Detection Theory” advanced by Lynne Isbell of the University of California-Davis, which argues that in the early evolutionary history of mammals and then primates, the swift detection of snakes, a lethal predator, conferred a survival advantage—so much so that in order to hasten detection, evolution created two neural pathways, one subconscious and slightly faster than the other, which are preserved in modern primate brains, including ours. So we may be hard-wired to notice snakes, and Isbell believes the development of this neural system resulted in the huge visual system that distinguishes primates, including humans, from many other species. Fear may be partially innate, or at least associated with detection, but it is also acquired through culture, religion, and family.³

MB: Are you hopeful that as people learn more about snakes they will treat them with more respect?

SH: One of the things that surprised me in the course of the research for Slither is how much ancient cultures venerated snakes. It made me wonder: What did people in antiquity know that we don’t? Ancient cultures viewed snakes as intermediaries between humans and nature in all its manifestations. Serpents symbolized power and protection (to ancient Egyptians), health and healing (to ancient Greeks), agricultural fertility (to Mesoamerican cultures), and messengers to nature writ large in many cultures. These symbolic powers inspired reverence, and that reverence has been overtaken by fear and loathing in more recent times. If we respect them more (and protect their habitats), we might learn more about their unique biology and amazing physical capabilities in ways that might enhance human health.

And their metaphoric and symbolic power is profound. Like the sudden strike of a venomous serpent, snakes remind us of the unpredictability and fragility of life; in an age when algorithms and AI lure us into thinking that everything can be predicted, unpredictability may ultimately be more terrifying to us than any snake.

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