My name is Briana Pobiner, and as an evolutionary anthropologist in the Smithsonian’s Human Origins Program, I study how our early human ancestors learned to survive and adapt to a changing world, especially through what they ate. I’m especially interested in when meat-eating became important in our evolutionary history. How did our ancestors find their food? Did they hunt or were they scavengers? How did they compete with big carnivores, who ate the same kinds of animals they did? Clues from the Earth’s fossil and archaeological records help scientists find the answers to these questions.
Fossil evidence for early humans eating meat and marrow dates back to at least 2.6 million years ago in the form of butchered animal bones. Ancient tools from this same period suggest that our ancestors used simple stone knives and rounded rocks to slice meat off of animal bones and pound them open to access the fat and calorie rich marrow inside. But at this time, early humans were barely over three feet tall and hadn’t developed hunting technology like spears or bows and arrows. So how did they take down large, dangerous animals like elephants and hippos?
Perhaps they didn’t… do it themselves.
To test the hypothesis that early humans could have scavenged meat and marrow from the remains of kills of carnivores, I spent several months in a modern nature preserve in central Kenya called Ol Pejeta Conservancy, following large carnivores around and watching them hunt. After waiting for predators like lions and leopards to finish consuming their prey, I found that most carcasses were abandoned with at least some meat that an early human could have scavenged. Some of the carcasses were left with a lot of meat still on the bones – especially those of the bigger prey animals. In fact, the leftover meat from just one zebra kill made by lions could have provided almost 6,100 calories for our early human ancestors – that’s the entire daily caloric requirements of almost three adult male Homo erectus individuals, or just over 11 Big Macs. Not bad for a “lowly” scavenger!
Based on these findings, waiting for larger predators to abandon their kill would have been well worth the trouble for early human species like Homo erectus, which evolved almost 1.9 million years ago and were up to 6 feet tall. They could have stuck around until after the lions were completely finished eating their prey before slicing some of that meat off of the bones and gaining access to the marrow. Plus, waiting could have reduced their risk of being eaten by the lions themselves.
Other researchers have suggested that our ancient ancestors may have scavenged from the kills of sabertoothed felids, which were around during the time that early humans started to eat more meat. Some of these extinct big cat species were even bigger than modern lions and tigers. They were likely solitary, and would have left a lot of excess meat on their prey if there was only one of them eating from the big animals that they killed.
While scientists are still trying to unravel the dietary habits of early humans, scavenging from carnivore kills seems to be one feasible method, especially in habitats with lots of big cats. For more information about this research, read my new publication in the Journal of Human Evolution.
By Dr. Briana Pobiner, Human Origins Program, Smithsonian’s National Museum of Natural History