As a zoologist, I was, of course, intrigued at the prospect of documenting cases of non-human cannibalism. Looking back now, I can see that I’d started my inquiry with something less than a completely open mind. Part of me reasoned that since cannibalism was presumably a rare occurrence in humans (at least in modern times), it would likely be similarly rare in the animal kingdom.
Once I dug further, though, I discovered that cannibalism differs in frequency between major animal groups—nonexistent in some and common in others. It varies from species to species and even within the same species, depending on local environmental conditions. Cannibalism also serves a variety of functions, depending on the cannibal. There are even examples in which an individual being cannibalized receives a benefit.
In several instances, cannibalism appears to have arisen only recently in a species, and human activity might be the cause. In one such case, news reports informed horrified audiences that some of the most highly recognizable animals on the planet were suddenly consuming their own young. “Polar bears resort to cannibalism as Arctic ice shrinks,” reported CNN, while the Times of London echoed the sentiment: “Climate Change Forcing Polar Bears to Become Cannibals.” It was Reuters, though, that scored a perfect ten on the gruesome scale with an online slide show in which an adult polar bear was seen carrying around the still cute-as-a button head of a dead cub, the remains of its spinal cord trailing behind like a red streamer.
The real story behind polar bear cannibalism turned out to be just as fascinating, though it would also serve as a perfect example of how many accusations of and stories about cannibalism throughout history were untrue, unproven, or exaggerated—distorted by sensationalism, deception, a lack of scientific knowledge, and just plain bad writing. With the passage of time, these accounts too often become part of the historical record, their errors long forgotten. Part of my job would be to expose those errors.
I was also extremely curious to see if the origin of cannibalism taboos could be traced back to the natural world, so I developed a pair of alternative hypotheses. Perhaps our aversion to consuming our own kind is hardwired into our brains and as such is a part of our genetic blueprint—a gene or two whose expression selects against such behavior. I reasoned that if such a built-in deterrent exists, then humans and most non-humans (with the exception of a few well-known anomalies such as black widow spiders and praying mantises) would avoid cannibalism at all costs. Thus, the taboo would have a biological foundation.
Conversely, I weighed the possibility that the revulsion most people have at the very mention of cannibalism might stem solely from our culture. Of course, this led to even more questions. What are the cultural roots of the cannibalism taboo and how has it become so widespread? I also wondered why, as disgusted as we are at the very thought of cannibalism, we’re so utterly fascinated by it? Might cannibalism have been more common in our ancestors, before societal rules turned it into something abhorrent? I looked for evidence in the fossil record and elsewhere.
Finally, I considered what it would take to break down the biological or cultural constraints that prevent us from eating each other on a regular basis. Could there come a time, in our not-so-distant future, when human cannibalism becomes commonplace? And for that matter, was it already becoming a more frequent occurrence? The answers to these questions are far from certain but, then again, there is much about the topic of cannibalism that cannot be neatly divided into black and white. Likely or not, though, the circumstances that might lead to outbreaks of widespread cannibalism in the 21st century are grounded in science, not science fiction.
My aim was to stay away from the clichéd ideas about cannibalism that are already ingrained in our collective psyche and, with such a wealth of relevant material to explore, I quickly realized that this wouldn’t be difficult. Even the most famous cannibal stories, it turned out, had factual gaps that are only now being filled. In the case of the Donner Party, for example, I joined researchers whose scientific approach to the most infamous cannibalism-related event in American history had shed new light on this 19th-century tale of stranded pioneers.