A new paper recently published in the National Academy of Sciences by Dr. W. Andrew Barr, Dr. Probiner, John Rowan, Andrew Du, J. Tyler Faith et.al details a new multi-year study where the dietary habits of early Pleistocene hominins were examined. They found some surprising results, which may change the way we view how we got our modern bodies, brains, and even cultures. For decades now, since Dr. Richard Wrangham’s theories on the use of fire and meat consumption detailed in his 2009 book “Catching Fire”, we have long believed that H. erectus began a new habit of meat consumption that would lead to many biological and cultural changes within the homo lineage. Many people believe that the advent of more effective stone tools and new behaviors led to a more active hunting lifestyle, also in part to their adapting anatomical bodies. Soon they were hunting, not just scavenging as all hominins were believed to do before. This new source of food, and mass amounts of proteins and nutrients, led to many things, as Dr. Wrangham explains.
Cooking allowed for the need for less mastication, our jaw muscles got smaller, our skulls changed shape to be home to these newly shaped muscles. Our brains were able to grow to larger sizes than ever before, double the size even. Due to all of this, when we see evidence of individuals being taken care of and surviving near-fatal injuries, we at first began to think we saw the start of a culture, a culture that would be recognizable to us as something different than those of the natural world. Something more human. But, this has all been put into question by this new paper. Let’s find out why.
So what does the new study say? Well, let’s break it down. Basically, what the hypothesis was, is that H. erectus was not more of a meat eater than any other hominin, it was not more carnivorous. Which, at this point, I would like to say no hominin is or has ever been a carnivore, I do not agree with the usage of the term, as all hominins are omnivores.
Anyway, the idea that erectus was not hunting any more than it ever had, started to become clear. The reason for this, the team believed, was because there was such a drastic focus on finding signs of meat-eating among them. Such a periscope focus that other signs and clues to the diets of these early hominins disallowed for other ideas and views to come to light. Generally, scientists are very agreeable with the former hypothesis for humans eating cooked meat at higher rates starting around 2.5 mya. But what if we started to look at the greater picture? What would we find?
Studying around 59 different sites, dating from 2.6 to 1.2 mya (well within the range of H.erectus). What was shown was that as the abundance of modified bones and the number of zooarchaeological sites all show an increase in the activities of erectus the increase was mirrored by a corresponding rise in the way in which samples were searched for and the intensity of which they were discovered. So changes in human behavior, the way we act, and the reason we do the things we do, could be the cause, rather than an increase in the pure consumption of meat.
There are alternative methods as to why we have the body designs that we have today, and our brains are as they are today after a long trail of evolution and random, successful progress. But here is the thing, the point that I personally would really like to get across to anyone reading this article. Humans, most primates in general (not all) are not herbivores, they are not carnivores, they are omnivores, and they are opportunistic. So what does this mean? Well, we will eat any, and everything that we come across. We are survivalists, it is how our genera have survived for so long, and through such drastic circumstances, we do not turn our noses up at what we eat (save maybe in this day and age). Our species and all of our ancestors ate whatever they could get their hands on so that they and their families could survive.
As most things in evolution occur, what we came by to eat would have been by chance, what we ate, how nutritious it was, and what we decided to do with it, all added to the nutrients that were consumed. What was consumed led us to be who we are today, and our diets continue to drive our lives? Bad diets lead to unhealthy, unhappy lifestyles, we have proven this. Healthy diets make healthier, happier people. It’s our circumstances that bar us from all having fresh, healthy food. But it is what our bodies crave. A wide variety in diet is important for our brain health and growth.
With this new challenge to the “Did Meat Make us Human” hypothesis, we may have a new light shined on the way our brains and bodies developed. It changes long-held thoughts on how Homo erectus lived, survived, and adapted. What was the change between habilis and erectus? The changes may not be as clear now as we once believed, and as always the lines in paleoanthropology become blurrier and blurrier each day, while other aspects become more clear.
What we will find out as new studies continue to be published, and new ideas are explored, we will see which hypothesis stands the test of time. It seems we may not know exactly how we got here is yet another aspect.
But isn’t that fun?
See you next time, and never stop learning!
Seth Chagi
World of Paleoanthropology 