What made ancient hominins cannibals? Humans were nutritious and easy prey.

Pedro_P

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An ancient human relative namedHomo antecessorpreferred eating its own kind over other animals, a new study finds. These skull bones — fossils ATD6-15 (frontal bone) and ATD6-69 (maxilla) — belong to the "Boy of Gran Dolina."
Credit: José-Manuel Benito
▼ Around 900,000 years ago in what is now Spain, the human relativeHomo antecessorhunted and ate others of their kind, leaving behind the oldest known evidence of cannibalism.
And new analysis of these ancient remains hints that these hominins were cannibals because human flesh was nutritious — and that humans were easier targets than other types of large prey.
Bones of sevenH. antecessorindividuals at the Spanish archaeological site Gran Dolina displayed distinctive signs that they were cannibalized: human tooth marks, cut marks, and fractures to expose the marrow, researchers reported in a new study. Those bones were mixed with bones representing nine other mammal species; 22 individuals that also had been butchered and eaten.
H. antecessorseemingly had plenty of prey to choose from, so why were humans on the menu? To find out, the researchers used computer models to calculate how many caloriesH. antecessorwould require per day. Then, they estimated the caloric payoffs of various animals — including humans — and the energy that would have been needed to catch them. They speculated thatH. antecessorhunters would choose their prey based on a balance: the most calories for the least effort.
Counting calories
Previous studies showed that while humans provided a moderately nutritious meal, there were other animals that packed far more calories per bite, the scientists reported. But if hunters had to spend less energy to catch human prey, they would benefit even if the caloric count of human flesh was lower, according to the study.
The researchers found that while human bones were the most represented, they accounted for less than 13% of the hunters' caloric requirements; most of which came from rhinos, deer and horses. But unlike humans, those animals come at a very high energy cost.
"Our analyses show thatHomo antecessor, like any predator, selected its prey following the principle of optimizing the cost-benefit balance," lead study author Jesús Rodríguez, a researcher with the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), in Spain, said in a statement.
"Considering only this balance, humans were a 'high-ranked' prey type. This means that, when compared with other prey, a lot of food could be obtained from humans at low cost," Rodríguez said.

► This article was originally published here: Source