Culture and Society
PUBLISHED
New research has modeled the long-term effects of cannibalism, finding that the practice of consuming fellow humans is damaging to health and society. In extremely rare circumstances, however, it can have some benefits to those forced to practice it.
Cannibalism is one of the most widespread taboos out there. Humans, in normal or stable circumstances, do not like the idea of consuming fellow humans, and have developed a stronger aversion to it than even consuming hot pockets.
And yet we have found plenty of evidence for the practice around the world, with it repeatedly emerging in a wide array of human populations throughout time.
"This coexistence of recurrent practice and persistent prohibition raises a fundamental question: when does cannibalism become adaptive, and why is it typically suppressed?" the authors of a new paper ask. "We address this problem using a formal model that treats cannibalism as a potential food source subject to energetic benefits and multiple sources of cost."
We don't want to be the site saying "cannibalism has its upsides", but the one obvious benefit of consuming humans is that we are made of meat. Studying the practice, the team suggests, can to a certain extent be done in the same way as evaluating another food source. This involves looking at the risks and energy rewards of consuming human flesh like it was chicken wings or a nice flan.
Seeing the potential risks and rewards could help reveal why taboos around the practice developed so consistently.
Archaeological evidence has shown that human bodies are sometimes processed in similar ways to other prey. This suggests that human meat may be subject to the same kind of analysis as other food sources. Humans, however, are a poor source of energy when compared to other animals.
"We looked at the human body as a potential food source, analyzing both the energy benefits and the hidden costs," Dr. Michał Misiak, lead author of the study, explained in a statement. "From a caloric perspective, a human being turns out to be an average meal, especially considering the difficulty of obtaining one."
As well as being more difficult to hunt and/or farm, consuming human flesh comes with a significant increase in risk.
"The key problem lies elsewhere: the risk of infection," Misiak added. "Pathogens have an easier time because they enter a body with an almost identical physiology."
The team attempted to model this effect by looking at the benefits of consuming human flesh, which is primarily that it keeps you alive for a time, and comparing that to the massive downsides, through the spread of things like highly deadly prion disease.
This involved providing a rough estimate of the calories in a human body, which the team placed at 32,376 calories of edible muscle (although if you add in all the bones, gristle, and organs then this figure comes out at an impressive 143,771 calories).
This would break down into around 65 portions of 500 kcal, or roughly two pints of lager beer. The team also estimated the cost of hunting a fellow human, and the task of cooking the meat.
They found that under certain circumstances – when the meat came from a person who had died from natural causes, for example – the consumption of a human would only "cost" around 5,691 calories in terms of food preparation.
"Under these conditions, the model predicts that cannibalism remains energetically viable until expected caloric intake from alternative food sources exceeds 116,479 kcal per month (equivalent to 3,882.63 kcal/day)," the team writes.
When hunting was involved, however, the energy cost was roughly the same as what would be returned by consuming the hunted human. This would make it significantly less worth the effort, unless you're really into the flavor (or, for example, you are hoping to annihilate a clan of enemies).
The real downside, though, was not the energy cost of hunting humans, but the spread of disease within society.
The team found that this problem gets more significant the longer cannibalism continues, and very quickly outweighs any benefits. On top of this, the risk of infection significantly increases if the victim of cannibalism had themselves been a cannibal. The team suggests that the taboo around cannibalism may have therefore arisen as a result of these risks.
"The taboo acts as an evolutionary safety net," Dr. Misiak explained. "Our results suggest it's a biologically justified response to the growing risk of epidemics. Societies that didn't curb cannibalism simply didn't survive."
The team says that their research highlights why we should be skeptical of any claims of widespread cannibalism.
Throughout history European colonizers, such as those who reached what was to become the USA in the 1600s CE, have accused Indigenous People of widespread cannibalism, often as a way to make them look barbaric or to justify violent actions against them. This study suggests that widespread cannibalism is too risky to be sustainable, and so we should be especially skeptical of such claims.
"A central interpretative implication of the model is that cannibalism is inherently high-risk and therefore unlikely to be practiced regularly over long periods," the team adds. "This suggests that claims of widespread or habitual cannibalism should be treated with caution, particularly when such practices are inferred during periods of relative abundance rather than starvation."
In short, humans can be used as food, and there is a calorific benefit to it under very specific circumstances where other food sources are scarce and human meat is free. However, societies which adopt it as a more widespread practice would soon find themselves with more human steaks than they could handle, thanks to all the disease and death it would generate.
The team argues that this likely led to the development of the taboo around cannibalism found right around the world.
In short, stick to chicken if you can't bring yourself to try tofu.
The study is published in PNAS.
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