Evolution: Hunting Began 1.5 Million Years Ago, Says Scientist

The child was only two years old, or maybe even younger, when many months of hunger took its toll. He or she finally collapsed and died, ending a short and difficult life.

The bones were slowly buried in desert sand, and nearly all the remains gradually disappeared. All the bones, that is, except a tiny fragment from the child's skull, about two inches long. It is a fragment that tells an amazing story.

The small piece of bone is 1.5 million years old, and it was found by an international team of anthropologists in Africa's fabled Olduvai Gorge in northern Tanzania, where scientists believe the human race began.

"It was immediately clear from the bone structure that this was one of our ancestors," anthropologist Charles Musiba of the University of Colorado in Denver said in a telephone interview. Musiba has made many trips back to Tanzania, where he was born, to dig through the hallowed grounds that have produced so many paleontological treasures.

But the bone he and others discovered on that day was unlike any others that he had seen. It bore the clear evidence of the disease that claimed the life of the 2-year-old. When they later studied the fragment under a microscope, they found tiny craters on its surface, indicating the child had suffered from anemia for months.

The child eventually died of malnutrition.

In a study published in the current issue of the peer-reviewed journal PLOS One, the scientists argue that the child belonged to a clan that depended on hunting for a major part of its diet. Hunting 1.5 million years ago is a surprise, since many scientists believe active hunting emerged much later in human evolution, possibly less than 100,000 years ago. Prior to hunting, our ancestors were scavengers, capturing small animals or eating whatever meat was left behind by other carnivores.

But the damage to the bone was found to be porotic hyperostosis, a disease caused by a lack of vitamin B12 and B9, so the child must have been accustomed to a diet rich in meat protein. Either the child, or its nurturing mother, must have suddenly been deprived of meat, causing anemia, malnutrition and ultimately death, the scientists contend.

Musiba said the meat the child depended on could not have come just from scavenging, because "you can't compete with hyenas and other scavengers and get enough meat to sustain yourself."

The finding is significant because of the major role hunting is believed to have played in human evolution. Hunting is more efficient as a group effort than when one tries alone, so early hunters formed clans, or cultures, the predecessors to modern civilization. And the nourishment in meat is rich enough that it allowed our brains to grow, setting us apart from all other animals.

Since the child who died of malnutrition was from a species that predated Homo sapiens, if these scientists are right, we have been hunters throughout human history.

However, some anthropologists, including the often-cited Lewis Binford, who died last year, have argued that the early stone tools found in digs around the world might have been adequate for harvesting a dead animal, but they were not suitable for hunting. Thus, some argue, humans remained scavengers and gatherers until relatively recently, more than a million years after that child died in Tanzania.

"Scavenging is very opportunistic," Musiba said. It depends on another animal making the kill, and then abandoning its own dinner. That would suggest that if our ancestors were used to meat, but dependent on others for the kill, they would probably have faced frequent and severe shortages. So many of the bones discovered in Olduvai Gorge should show vitamin deficiencies.

"We looked for that" in many other bones from that region, Musiba said, "but we didn't see it."

Musiba and his team, which includes anthropologists from Spain, South Africa, France and the United States, are currently studying the bones of animals recovered from the same site. They show the marks of tools, so they were obviously skinned and eaten by our ancestors, but were they also hunted?

Musiba thinks they were, partly because some marks show repeated blows, suggesting the animal was attacked while it was still alive. That research has not yet been published for other scientists to scrutinize.

"There is information which strongly suggests active hunting was prevalent by 1.5 million years ago," Musiba said.

It would not have been as difficult as might seem, even though the weapons – if they were weapons – were pretty limited. They didn't have spears, or projectiles of any kind, so they would probably beat a large animal over the head with a chunk of rock.

"Ambush is the best method," Musiba said. "You would know your landscape very well, and you would know where the animals would be congregating. It wouldn't be that difficult."

Still, the message in that tiny piece of bone is clear. For our ancestors, nothing came easy.

"The child had to have had a stressed diet for a long period of time, from three to six months, or even a year," he said. "Imagine dying at two years old of malnutrition."

It was not a life, he said, that any of us would want to live.