About how far back hunting and meat eating might go... Our closest living relatives, chimpanzees, hunt - do you think that this provides a clue about how far back in prehistory hunting may have been a part of life for our ancestors?Indeed, I think it does. So does the paleo-diet crowd. But in their eagerness to claim the mantle of science for their fad diet, the "paleos" draw exactly the wrong point from this fact.
If you will indulge me in a brief bit of jargon, I'll illustrate the point.
In paleontology, we talk a great deal about ancestral traits vs. shared derived traits and/or unique derived traits. An ancestral trait, or plesiomorphy, is one possessed by a most recent common ancestor (MRCA) and all of its descendants; put another way, it's a trait modern organisms inherited from a distant common ancestor, and thus not a trait that defines the modern organism. Plesiomorphies, because they are so common, are not terribly useful for defining relationships between groups of organisms (taxa, sing. taxon).
Shared derived traits, or synapomorphies, are found in two or more taxa who form the tips of a cladogram, a branching "tree" diagram used to illustrate evolutionary relationships. Synapomorphies are the only traits actually used to arrange organisms into monophyletic groups (clades which comprise a single common ancestor and all its descendants).
Unique dervied traits, or autapomorphies, are found in only one species on a cladogram. They are not useful for reconstructing evolutionary relationships between taxa, but can be used to define a taxon.
Now, paleo-dieters talk a great deal about meat "making us human," often waxing poetic and engaging in more than a touch of magical thinking about the benefits of animal flesh. Often, this talk is absurdly focused on big game and ignores the prominent role that bug-eating likely played in early hominid, and even modern human, diets. All told, it's a claim that meat-eating made us what we are; that is, that meat-eating is an autapomorphy for H. sapiens, something that defines us.
Oddly, to justify this position, paleos will often point up the same observation that Therese does: namely, that hunting is found among many primates. This, they say, is further proof that meat-eating is something essential to our humanness.
And it's right there that the paleo-diet shell game gets revealed; for in saying that primate hunting is evidence that human meat-eating is something special, the paleos are actually contradicting themselves. And none of them seem to realize it.
This justification changes hunting and meat-eating from autapomorphic status (i.e., something only Homo sapiens does) to synapomorphic (i.e., it's something all primates do), thus making it less "special" to humans. If paleos truly understood evolution, they'd see the contradiction right away, and realize that the logic of their argument implicitly disproves what it explicitly asserts.
Now, if it were possible to say that no other mammals engaged in hunting or meat-eating, the paleos might have a point, for that would make these traits autapomorphic -- that is, unique -- to primates. But, too bad for the paleos, it is not possible to say anything quite so ridiculous.
Faunivory is ancestral for all mammals, since we spring from an insectivorous common ancestor. All mammals -- even cows and deer -- retain some capacity to eat and digest other animals (or, to be more specific, to efficiently digest calorie-dense nutrient sources). In short, it's nothing special, and pretty much useless when trying to define a species.
If you want to know what makes, say, primates, or ungulates, distinct when compared to other animals, you have to look at their synapomorphies and autapomorphies; that is, at the the traits they developed that take them away from the mammalian ancestral condition. In the case of ungulates, that would be herbivorous specialization (among many other traits); among primates, it would be frugivory.
The problem with paelo-diet gurus is they treat meat consumption as something special about our evolutionary heritage, when in fact, it's quite the opposite.
It's this imprecise and misleading use of scientific concepts -- this all-over-the-map intellectual fuzziness masquerading as erudition -- that makes the paleo-diet pseudo-science. Pointing out that hominids eat meat isn't nearly as profound as the paleos wish it were. What it tells us about human evolution amounts to barely more than nothing, and they want it to be everything.