Cannibalism, suggests the biologist Bill Schutt in his entertaining but slightly unorganised account, is an “enduring aspect of life” that leaves none of us “untouched”. At this point, the reader may be checking his or her neck for bite marks. But Schutt clearly means that we are touched by cannibals in some kind of all-encompassing but non-literal sense. From the child-eating hag of “Hansel and Gretel” to Hannibal Lecter, Schutt argues that cannibals are central to human stories.

In many single-topic books, there is an element of special pleading. It’s an understandable form of salesmanship in a market of too many books and not enough readers. Whether the book is about cod or clocks, the author attempts – sometimes more convincingly than others – to persuade us that this tiny sliver of life on earth is more pivotal than anything else. As someone who wrote a book suggesting honeybees are – in multiple ways! – the key to human civilisation, I am not the person to criticise such writing. On the other hand, it can go too far. Schutt’s final paragraph tries to make the case that cannibalism is highly underrated. Maybe it’s even the key to everything:

Far from being the nightmarish aberration we tell ourselves it is – in films, novels and tabloid sensationalism – cannibalism has woven itself into our myths and legends, formed the basis of miracle cures, ancient and modern, helped discipline naughty children (and entertain good ones), popped up in the Bible, fascinated anthropologists, zoologists and biologists and – sadly – played a significant role in colonialism, conquest and war.

Cannibalism, in other words, is even better than cod.

It’s surprising Schutt felt he had to plead that his subject is worthy of our attention. We recoil from a book on cannibalism not because the subject doesn’t interest us but because it bites us, right in the viscera. I’m not aware of anyone ever reproaching cannibals for being boring. They have been accused of many horrible things – eating other people being the main one – but then, they are guilty of those.

Take Armin Meiwes, currently serving a life sentence in Germany for eating engineer Bernd Brandes, who answered a chatroom request looking for someone who actually wanted to be consumed. With Brandes’ consent, Meiwes killed and dismembered him and sauteed him with “salt, pepper, garlic and nutmeg”. He said the flesh tasted a bit like pork.

Such psychopathic cannibals are not, however, the main focus of Schutt’s book, as he wisely remarks that he wanted to avoid giving “acclaim” to real-life Hannibals. Schutt is more interested in cannibalism as a cultural and biological phenomenon. In a series of fascinating chapters, he examines the circumstances under which different forms of cannibalism are adopted by either human or animal societies.

Facebook Twitter Pinterest Armin Meiwes, the German man jailed in 2006 for eating Bernd Brandes – despite having his consent. Photograph: Epa European Press Agency/EPA

In anthropology, there are two basic kinds of cannibalism. Exocannibalism means eating someone from outside your social group, perhaps as a form of ritual tribute or warfare. The Caribs apparently consumed enemy prisoners “to transfer desired traits, like strength or courage, from the deceased enemy to themselves”. Endocannibalism, by contrast, means eating someone from within your family or group, and it can be an act of love or respect. For the Amazonian Wari’ tribe, eating a small piece of a deceased relative mixed with bone meal and honey is believed to help with the grieving process.

A more extreme form of endocannibalism is the filial variety once practised in China. Key Ray Chong, author of Cannibalism in China, recounted that “children would cut off parts of their body and make them into soup to please family members, particularly their parents”. It most often occurred in medieval times between sons and fathers. Part of one’s own thigh or upper arm might be removed and thoughtfully cooked for an ailing parent in a congee rice porridge.

In the Wari’ tribe, eating a small piece of a deceased relative is believed to help with the grieving process

Eating human body parts, Schutt reminds us, has not always involved violence or slaughter. The most obvious example is the tradition of new mothers eating the placenta after a baby is born as a way to replace nutrients lost during birth. In Texas, Schutt meets Claire Rembus, founder of a company called Your Placenta, which sells an array of placenta-based products. Rembus and Schutt share a meal of placenta osso bucco cooked with tomatoes, garlic and onion. It reminds him of chicken gizzards, with the texture of veal: “firm, but tender”.

Human meat is a taste few will ever share. For all our talk about cannibalism, there are very few human cultures where it actually happens, apart from in extreme circumstances such as the Uruguayan flight disaster of 1972, when 16 survivors on a remote, snowy mountain collectively – and reluctantly – decided to eat some of their dead comrades. But non-survival cannibalism is extremely rare. Schutt argues that this is partly because there is a strong western taboo against it. In Freudian terms, cannibalism is one of those unthinkable actions that we forbid to hide the fact that we have a deep and primitive urge to do it. But there are strong signs that most humans have an even stronger urge not to eat other people. It isn’t pleasant to think of ourselves as meat.

Many animals, on the other hand, have no such compunction. In nature, as Schutt writes, cannibalism comes with “no grey areas, no guilt and no deception’. The best and most vivid parts of the book describe some of the extraordinary forms of cannibalism that take place in non-human societies. For animals, cannibalism can offer evolutionary advantages to deal with problems that Schutt summarises as “too many kids, not enough space, too many males, not enough food”. Firstborn eagles may consume rival siblings and even hamsters may be driven to eat their young in conditions of stress, but perhaps the goriest of all cannibals are to be found in various spider families. The female redback spider munches on the abdomen of her male partner as they copulate, before wrapping him in silk as a nourishing meal to enjoy later. Male redbacks, Schutt notes, weirdly benefit from being eaten because it gives them the chance to pass on their genes. For redback spiders, cannibalism really is the key to everything.

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