Washington DC: A new study has revealed how diet helped shape our evolution.
The Tel Aviv University research found that "Ice age diet," wherein Neanderthals consumed high amounts of protein from large prey, accounted for their anatomical differences, namely a larger ribcage and a wider pelvis, from Homo sapiens, the ancestor of modern humans.
Neanderthals, who were heavyset and had larger rib cages and wider pelvises than the more modern and advanced Homo sapiens, lived on Earth until some 40,000 years ago. Neanderthals were quite similar to Homo sapiens, with whom they sometimes mated, but they were also different, being shorter and stockier.
According to the research, the bell-shaped Neanderthal rib-cage or thorax had to evolve to accommodate a larger liver, the organ responsible for metabolizing great quantities of protein into energy. This heightened metabolism also required an expanded renal system (enlarged bladder and kidneys) to remove large amounts of toxic urea, possibly resulting in a wide Neanderthal pelvis.
Researcher Miki Ben-Dor noted that during harsh Ice-Age winters, carbohydrates were scarce and fat was in limited supply. But large game, the typical prey of the Neanderthal, thrived. This situation triggered an evolutionary adaptation to a high-protein diet, an enlarged liver, expanded renal system and their corresponding morphological manifestations. All of these contributed to the Neanderthal evolutionary process.
Prof. Ran Barkai said, "We found that, in the case of the Neanderthals, an acute shortage of carbohydrates and a limited availability of fat caused their biological adaptation to a high-protein diet."
According to the researchers, the total dependence of Neanderthals on large animals to answer their fat and protein needs may provide a clue to their eventual extinction, which took place at the same time as the beginning of the demise of giant animals or "Megafauna" in Europe some 50,000 years ago. The team is now researching this subject.
The study appears in American Journal of Physical Anthropology.