Vegetarianism proved literally hard to swallow for early humans, according to new research that bolsters evidence our ancestors likely veered from this lifestyle around 2.6 million years ago in favor of eating raw red meat and starch-rich plants.
The study, published in the journal Nature, suggests that meat and tools, and not the later advent of cooking, freed early humans to evolve smaller chewing-related features, such as smaller teeth and smaller, shorter faces. These, in turn, might have paved the evolutionary way for improved speech, thermoregulation and even the development of a bigger brain.
"No one knows for sure why hominins started to eat more meat around 2.6 million years ago, but there is abundant evidence for this behavior, including stone tools and cut marks on bones," lead author Katherine Zink of Harvard University's Department of Human Evolutionary Biology told Discovery News.
What Did Prehistoric Humans Eat?
"The most common explanation is climate change," she added. "During this period, Africa became more open grassland, with more antelopes and other herbivores."