The remains of the "first Europeans" discovered at an archaeological site in northern Spain have shown that these prehistoric men were cannibals who preferred the flesh of children.
"We know that they practiced cannibalism," said Jose Maria Bermudez de Castro, one of the co-directors of the Atapuerca project, a UNESCO World Heritage Site.
A study of the remains revealed that they turned to cannibalism to feed themselves and not as part of a ritual, that they ate their rivals after killing them, mostly children and adolescents.
"It is the first well-documented case of cannibalism in the history of humanity, which does not mean that it is the oldest," he said.
The remains discovered in the caves "appeared scattered, broken, fragmented, mixed with other animals such as horses, deer, rhinoceroses, all kinds of animals caught in hunting" and eaten by humans, he said.
"This gives us an idea of cannibalism as a type gastronomy, and not as a ritual."
The Atapuerca caves were first discovered in the late 19th century, when a tunnel was blasted through the mountain for a railway line.
"But at the time in Spain, there was not enough scientific knowledge to begin research," said the other co-director, Eudald Carbonell.
The first excavations did not take place until 1978, then "in 1984, we found 150 human remains.
In 1992, they found a complete intact skeleton, and two years later, they discovered remains dating back more than 800,000 years.
Those remains probably correspond to the first humans who reached Europe, known as Homo antecessor, after the Latin word for pioneer or explorer.
Homo antecessor, who lived before Neanderthals and Homo Sapiens, probably came to the caves of Atapuerca after a long migration from Africa and through the Middle East, northern Italy and France.
It is a particularly good site for human settlement, at the confluence of two rivers with a comfortable climate and rich in fauna and flora, de Castro said.
They found water and food in abundance, could hunt wild boar, horses, deer, "which means that they did not practice cannibalism through a lack of food. They killed their rivals and used the meat," he said.
"We have also discovered two levels that contain cannibalised remains, which means that it was not a one-off thing, but continued through time," he said.
"Another interesting aspect ... is that most of the 11 individuals that we have identified" as victims "were children or adolescents".
"We think that there are also two young adults including a female, which indicates that they killed the base of the demographic pyramid of the group."
Atapuerca, situated on the edge of Eurasia, allowed Homo antecessor to develop in an isolated and more distinct way, with characteristics that were both archaic and modern.
In addition to hunting, they also made tools.
The area at the time was heavily forested, with oaks, chestnut trees and junipers, and abundant with bears, lynxes, panthers, foxes and hyenas.