“You are what you eat,” nutritionist Victor Lindlahr once famously declared. That certainly turned out to be true for the ill-fated Fore tribe in the highlands of Papua New Cannibalism A Perfectly Natural HistoryGuinea, who until fairly recently engaged in ritualized cannibalism of their deceased relatives in a rite of honor that unknowingly condemned hundreds of them annually to a devastating and ultimately fatal disease called “kuru” that was—due to its bizarre symptoms—popularly known as the “laughing death.” This story of the Fore and how their consumption of the brains of family members transmitted a peculiar epidemic is just one of the fascinating tales in Cannibalism: A Perfectly Natural History, by Bill Schutt, a well-written, entertaining but occasionally flawed account of a topic that is often as much taboo as it is irresistible.

Indeed, there is something that is equal parts enthralling and horrifying about the subject of cannibalism that attracts an audience that nevertheless wants to shrink away from it. For many, The Road is Cormac McCarthy’s most memorable and disturbing novel—rather than his far more nuanced excursion into man’s inhumanity to man, Blood Meridian—precisely because people are not simply slaughtered, but devoured.  The most unforgettable serial killers—both real and fictional—remain Jeffrey Dahmer and Hannibal Lechter, respectively.  There’s a good reason why people who know almost nothing about American history still seem to know something about the whaleship Essex and the Donner Party.  For us, cannibalism is a rare and horrid deviation from the norm.  To that conclusion, Bill Schutt would say: not so fast!

When I was a small child, I was really excited when my pet gerbil gave birth, then horrified when in short order she methodically ate her own young. The image of scattered pink and furless baby gerbil parts littering the terrarium remains seared into my memory. My distressed gerbil was engaged in something called filial cannibalism, but the practice of one member of a particular species consuming all or part of another of the same species is hardly aberrant in nature, as the spoiler in the subtitle—A Perfectly Natural History—suggests. In fact, as the author reveals, it is remarkably prevalent, occurring for a variety of reasons under a whole host of various conditions, and much less often linked to starvation desperation than might be supposed, although far less common among mammals than creatures such as insects and mollusks, for instance.

In the first third of the book, Schutt—professor of biology at LIU Post and research associate in residence at the American Museum of Natural History—takes the reader on a tour of this peculiar habit among fauna both familiar and foreign. Schutt treats us to some great tidbits along the way. It turns out that everything we thought we knew about sexual cannibalism with Black Widow spiders and praying mantises is wrong, not because it does not occur but because, like almost everything else in the universe, there is a great deal more complexity to the phenomenon.

But things get really interesting when Schutt gets around to higher life forms. Apparently, cannibalism often occurs as a reproductive strategy—termed heterocannibalism—as when lions that take over a pride eat the cubs sired by another male. An evolutionary adaptation has played a weird trick on male spotted hyenas to deter them from similar behavior: female spotted hyenas produce high levels of testosterone, their vulva seals to form a pseudoscrotum, and they develop a bizarre elongated clitoris that becomes a pseudopenis that violently ruptures when large full-term hyena fetuses pass through it during birth.  Female hyenas are the tough guys on the block; no males would dare to eat their babies. [p65] But there are no such obstacles to similar practices by sea lions, polar bears and—our closest living relatives—chimpanzees. And there are tantalizing clues that cannibalism may have once took place among some species of therapod dinosaurs.

After leaving the animal kingdom behind, Schutt turns to the human experience, and here is where things get a bit uneven. Among humans, cannibalism—known as anthropophagy—assumes many forms and is naturally a thornier subject. The unfortunate Kore practiced what is known as endocannibalism, a ritualized consumption of relations driven by honor and respect.  A variation of that once occurred in other aboriginal groups when they ate the bodies of their enemies in order to capture their strength and spirit; that is one form of exocannibalism. But exocannibalism also encompasses the more familiar desperate measures taken to ward off starvation.  Much of the rest of the book serves as a platform for the debate about how wide of a net can be cast for anthropophagy.  Is gnawing on your fingernails a form of cannibalism? Some actually think so. That’s one extreme.  Another is voiced by an expert “denier” who argues that the vast majority of reports of cannibalism are examples of hyperbole or downright fiction.

There are many roads unfortunately not traveled. Early on, the author informs us that he does not want to stoke sensationalism by dwelling on serial killers like Dahmer and the like, but a deeper discussion of why people who are not starving—other than aborigines guided by tribal custom—would choose to eat other people is largely absent. Apparently, there were incidents of cannibalization-for-sustenance of American POWs by their Japanese captors in World War II, but—more intriguingly—also cases where their livers were served up as delicacies to Japanese officers, a fate only narrowly avoided by downed pilot George H.W. Bush. Schutt references Bush’s bare miss, but fails to train the lens on the dynamic that nearly put him on the menu, which seems like a missed opportunity of some significance.

There are others. A now famous case of starvation cannibalism followed the 1820 sinking of the whaleship Essex that left survivors stranded on whaleboats, where they proceeded to eat the dead, then drew lots among the living for who would serve as the next course. This episode has been chronicled at length in book and film, but it is less well well-known that this was a very common—although essentially unadvertised—practice among shipwrecked sailors, euphemistically termed the “custom of the sea.” I kept hoping Schutt would probe this macabre maritime tradition with such a storied history over several centuries, but I was left disappointed. Instead, a very long chapter is devoted to a blow-by-blow account of the Donner Party incident, which has been done to death for mass consumption (puns fully intended!) in so many venues that here it inspires little more than impatient yawns.

Still, despite sins of omission, Schutt’s Cannibalism remains well worth reading. His strength as a scientist shines through and mitigates some of the weaknesses in the total product. Most importantly, he is also an excellent writer whose well-crafted prose neatly carries this fascinating narrative.