It’s not that uncommon to find out your ancestors once did something rather dubious that you’d prefer was left in the past. Finding out our ancient human ancestors were not only more cannibalistic than we had realized, but they did it because frankly it was much easier to hunt people thanks to their abundance, is something we can collectively feel conflicted about.
Homo antecessor is a controversial species of hominid that lived in Western Europe in the Lower Paleolithic, around 1.2 million to 800,000 years ago. It is debatable where H. antecessor falls on the human family tree, but its discoverers propose it to be somewhere between Homo erectus (1.9-1.4 million years ago) and Homo heidelbergenisis (700,000-200,000 years ago) – arguing it may be the best candidate for the common ancestor of Neanderthals and Homo sapiens.
We know that many of our archaic ancestors dabbled in anthropophagy (cannibalism), but butchered H. antecessor bones dating back 800,000 years found in Spain represent the oldest known instance of it.
A new study from Spain’s National Research Center on Human Evolution (CENIEH), and published in the Journal of Human Evolution, analyzed why H. antecessor may have indulged in this behavior.
There are several reasons why cannibalism may occur, ranging from social and cultural rituals to simple survival. Using the Optimal Foraging Theory (OFT) as a jumping off point – the strategy that foraging animals, when confronted by several options, calculate what provides the most benefit for the lowest cost, energy-wise – they posed the question could this explain H. antecessor’s behavior?
By calculating and comparing the cost/benefit of "obtaining and processing" the large animals available at that time to doing the same to humans, they found cannibalism was a more profitable survival strategy, and likely occurred much more frequently than we had thought.
“Our analyses show that Homo antecessor, like any predator, selected its prey following the principle of optimizing the cost-benefit balance, and they also show that, considering only this balance, humans were a 'high-ranked' prey type,” co-author Jesús Rodríguez announced in a statement.
“This means that, when compared with other prey, a lot of food could be obtained from humans at low cost.”
Rodríguez and team think this may be because, despite the low nutrients of human flesh, humans were more easily available compared to animals.
“For Homo antecessor, it was easier to encounter a human than another animal,” co-author Ana Mateos said. However, “One of the possible explanations for this high encounter rate between humans could be that the cannibalized cadavers were those of members of the group who had died from different causes.”
This ties in with the findings of a 2017 Ig Nobel-winning study by Dr James Cole that worked out the calorific significance of cannibalism and concluded humans wouldn’t make a great staple diet. However, Cole suggested that as a lack of evidence indicated whether cannibalism in the Paleolithic era was common or not, it’s possible our ancestors ate humans who died from natural causes, saving them the hunting effort.