Dining With the Chimps

Somehow I got caught up in a debate about scavengers. It began with critiquing a recent article suggesting that early hominins ate grasses (see last post). In response to a Facebook post on the matter, a friend replied that she thought early people were scavengers. She led me to a paper by Craig Stanford, an anthropologist from USC, “The Predatory Behavior and Ecology of Wild Chimpanzees” (no date), that had some provocative information in it. If you thought chimps were meat eaters before, this paper makes it shockingly clear how much meat they eat:

“At Gombe, we now know that chimpanzees may kill and eat more than 150 small and medium sized animals such as monkeys, wild pigs and small antelopes each year.…

“The amount of meat eaten, even though it composed a small percentage of the chimpanzee diet, is substantial. I estimate that in some years, the 45 chimpanzees of the main study community at Gombe kill and consume more than 1500 pounds of prey animals of all species.”

I was under the impression that they primarily ate bush babies (Galagos) but Stanford asserts,

“Although chimpanzees have been recorded to eat more than 35 types of vertebrate animals (Uehara 1997), the most important vertebrate prey species in their diet is the red colobus monkey.”

Thirty-five types of vertebrates? Once again, I am astounded. These guys are bigger hunters than I thought. I do know that they count leopards among their prey. Yup, leopards. Their prey.

Killing by chimps is anything but incidental. Stanford observes:

“Jane Goodall has noted that the Gombe chimpanzees tend to go on ‘hunting crazes,’ during which they would hunt almost daily and kill large numbers of monkeys and other prey (Goodall 1986).”

He went on to assert,

“Chimpanzees may be among the most important predators on certain prey species in the African ecosystems where they live.”

Nonetheless, he still maintains a distance from meat-eating humans. He opines, “Since neither humans or chimpanzees are truly carnivorous —most traditional human societies eat a diet made up mostly of plant foods —we are considered omnivores”; a claim which is disputed somewhat. There are people who classify humans among the carnivores, but it’s indisputable that we’ve always had a large herbivorious component to our diet. The notion that “most traditional human societies eat a diet made up mostly of plant foods” is somewhat disingenuous. That depends largely on what one means by “traditional society,” a term he does not define. There are, in the main, two kinds of societies one might call “traditional.” There are those traditional elements of all modern societies, all of which are post-agrarian revolution and, hence, much more dependent on plant matter than a traditional hunter-gatherer society. Those pre-agricultural societies that survived into the modern age did so because they lived on marginal lands and don’t necessarily represent the norm for pre-agrarian societies. Nonetheless, it’s hard to imagine claiming the Inuit, for example, “eat a diet made up mostly of plant foods.” So, while it’s true that we’re omnivores; it’s by no means established that pre-agrarian societies ate, primarily, plant food. It’s those kinds of unwarranted assumptions that cloud one’s interpretation of data. The assumption makes it more likely that we had a vegetarian past, something the PC (politically correct) world would dearly love to be true. The brutal truth is, we certainly were as significant predators as chimps, and we certainly became more so once we were upright.

The author asked the question:

“Many researchers now believe that the carcasses of large mammals were an important source of meat for early hominids once they had stone tools to use for removing the flesh from the carcass (Bunn and Kroll 1986). But the evidence for stone tool use dates to only 2.5 million years ago. For the 3 or so million years of human evolution prior to that time, did our ancestors eat meat?”

Classic blunder. It’s not “evidence for stone tool use,” it’s evidence for flaked-stone tool use. All the difference in the world. By not mentioning the inevitable millions of years of un-shaped tool use that we must have had, he leaves the impression that we didn’t start using stone tools until we miraculously learned how to shape them. If we hadn’t already been using stone tools before we learned to shape them, how did we ever come up with the idea? It makes the question, “For the 3 or so million years of human evolution prior to that time, did our ancestors eat meat?” sounding like he didn’t read what he’d just written. Does he think we would have given up eating meat for those intervening years? Surely, he doesn’t. It’s an unfortunate slip of logic.

And it obviates the idea that we could have ever been scavengers. I know of no instance where a species turned from predator to scavenger, not to mention back again. That would be stunning, unprecedented. In the end, scavenging turned out to be one funny idea.