Meat may play a major role in holiday meals, but new research suggests the preparation and consumption of animal products may have had a major impact on human evolution as well.

Chewing meat may have played a significant role in the evolution of speech, researchers declared. They speculate that the action of gnawing at flesh may have driven evolution to favor small jaws and teeth.

The act of cutting flesh apart into smaller pieces before chewing also likely saved time and energy in early hominids compared with other primates. Together, researchers speculate, these two changes could have favored those with features favorable for complex speech. This may explain one odd fact about human evolution.

Homo erectus, a species of human ancestor that first evolved around 1.8 million years ago, exhibited a larger brain and body than its predecessors. These required a greater amount of energy than earlier species, necessitating a greater intake of calories.

Yet, Homo erectus was seemingly less-capable than other higher primates at consuming energy from food. These human ancestors had a smaller gut than before, jaw muscles were weaker than other species and teeth were smaller.

Some paleontologists theorized the adoption of cooking may explain this apparent paradox. However, the earliest evidence for cooking is from one million years ago, and the practice did not become common until 400,000 to 500,000 years in the past. This development was far too late to explain changes in H. erectus.

Volunteers in a detailed study of chewing gnawed away on raw goat flesh, a tough meat similar to wild game. The flesh was only minimally prepared, in manners similar to those that may have been employed by our oldest-confirmed ancestors. This included slicing the meat with instruments composed of ultra-sharp obsidian, a volcanic glass.

"The stone flakes that we strike off rocks are sharper than any knife we have — maybe not super-expensive knives, but better than the average knife in a kitchen drawer," said Katherine Zink of Harvard University.

Chimpanzees spend roughly half their waking hours chewing their food, using up significant time and energy. Humans are among the most proficient chewers in the animal kingdom, and the results of the study were consistent with the hypothesis of favored traits.

Research into the role meat preparation and consumption may have played in human evolution was profiled in the journal Nature.

Photo: Naotake Murayama | Flickr