October 4, 2012
Skull Fragment Shows Earliest Evidence Of Human Meat Consumption
Lawrence LeBlond for redOrbit.com - Your Universe Online
New evidence indicates that early humans were meat eaters, based on a 1.5-million-year-old skull unearthed in Tanzania by Spanish researchers. The skull, that of a child, shows signs of anemia, suggesting a regular diet of meat in early hominids. The finding sheds new light on the evolution of human physiology and brain development.
The skull was found in the Olduvai Gorge in Tanzania and showed signs of nutritional deficiencies commonly caused by a lack of meat in the diet. This finding suggests early man needed meat to thrive, and leads researchers, led by Manuel DomÃnguez-Rodrigo from Complutense University, Madrid, to believe our ancestors began eating meat much earlier in history than previously believed.
Previous studies have shown that early hominids ate meat, but whether it was a regular part of their diet or only occasionally consumed was not known. Dominguez-Rodrigo and his team suggest the bone lesions present in this skull fragment provide support for the idea that early humans needed to maintain a meat-diet or anemia would set in. The bone lesions observed in the child skull fragment shows signs of vitamin-B deficiency.
Nutritional deficiencies, such as anemia, are most common during weaning, when the diet of children change drastically. The authors suggest that the child possibly died at a time when he/she was beginning to eat solid foods lacking meat. And, if the child was breastfed, it is possible the mother may have been nutritionally deficient as well.
Both cases imply that “early humans were hunters, and had a physiology adapted to regular meat consumption at least 1.5 million years ago,” the authors noted.
“Meat eating has always been considered one of the things that made us human, with the protein contributing to the growth of our brains,” said Charles Musiba, PhD, associate professor of anthropology at the University of Colorado Denver, who helped make the discovery.
Musiba said evidence in the child´s skull fragment shows deficiency in vitamin B12 and B9, indicating meat was cut off during the weaning process. “He was not getting the proper nutrients and probably died of malnutrition,” he said.
The study offers insights into the evolution of humans, said Musiba, adding that the movement from early plant-eating scavengers to meat-eating hunters may have provided the protein needed to grow our brains and give us an evolutionary kickstart.
“Meat eating is associated with brain development“¦the brain is a large organ and requires a lot of energy. We are beginning to think more about the relationship between brain expansion and a high protein diet,” Musiba explained.
Humans are one of the few surviving species with such a large brain compared to body size. Chimpanzees, our closest living relatives, eat very little meat and have far less brain capacity than we do, added Musiba.
“That separates us from our distant cousins,” he said. “The question is what triggered our meat eating? Was it a changing environment? Was it the expansion of the brain itself? We don't really know.”
The study was published Wednesday in the peer-reviewed journal PLOS ONE.