Humans Were Actually Apex Predators For 2 Million Years, Study Finds

Were early humans really the "ultimate" omnivores? A team of researchers found that they may actually have been apex predators.

Humans were thought throughout history to be quite flexible in terms of their diet -- they were omnivores who were able to adapt to their ecological conditions. Some even think of these capabilities as the "core of human evolution."

However, a new study published in the Yearbook of the American Physical Anthropology Association found that the earlier humans were actually apex predators for two million years. It further claimed that it was the extinction of the large animals they preyed upon that led them to add vegetables to the mix gradually.

For their study, the researchers looked at about 400 scientific papers from various disciplines, including archaeology, paleontology, genetics and zoology. The idea was to see whether stone-age humans were, indeed, omnivores, a news release from Tel-Aviv University (TAU) explained.

Study co-author Dr. Miki Ben-Dor of TAU said most attempts to determine the diets of stone-age humans were primarily based on the diets of "20th-century hunter-gatherer societies."

"This comparison is futile, however, because two million years ago hunter-gatherer societies could hunt and consume elephants and other large animals — while today's hunter-gatherers do not have access to such bounty," Dr. Ben-Dor noted. "The entire ecosystem has changed, and conditions cannot be compared."

Multidisciplinary Study

From the hundreds of studies they looked at, the researchers found a total of 25 pieces of evidence that point to the stone-age humans being apex predators of the time. 15 of these are biological, while the rest are "archaeological, paleontological, zoological, and ethnographic," the researchers said.

One example Dr. Ben-Dor noted is the fact that the human stomach is particularly acidic even when compared to the stomach acidity in carnivores. According to Dr. Ben-Dor, this shows that humans consumed a lot of animal products because "strong acidity" provided protection from bacteria in meat.

Researchers also pointed out that humans' gut morphology, characterized by longer small intestines and shorter large intestines, is actually more typical in carnivores. Further, the structure of the fat cells in human bodies is rather similar to that of predators rather than omnivores.

As mentioned, researchers also found archaeological evidence of humans being predators. This includes the fact that stone tools related to plant food only appeared later on and increased toward the end of the Paleolithic era. Dental evidence also showed that caries teeth were quite rare during the Pleistocene, suggesting low carbohydrate consumption.

Humans Were Apex Predators

TAU explained that contrary to the common belief that humans' adaptability and dietary flexibility allowed them to survive and evolve, new findings show that it may actually be because they were apex predators of large animals.

Eventually, when many of the large animals were declining and going extinct, that was when they gradually changed their diets to incorporate more vegetables toward the end of the stone age.

"Many researchers who study the extinction of the large animals agree that hunting by humans played a major role in this extinction — and there is no better proof of humans' specialization in hunting large animals," Dr. Ben-Dor said.

"Archaeological evidence does not overlook the fact that stone-age humans also consumed plants," he added. "But according to the findings of this study, plants only became a major component of the human diet toward the end of the era."