The latest discovery out of Ethiopia is sure to add another arrow to carnists' quiver. An article in the New York Times sums up their announcement:
Scientists who made the discovery could not have been more surprised. They said the cut marks on a fossilized rib and thighbone were unambiguous evidence that human ancestors were using stone tools and sometimes consuming meat at least 800,000 years earlier than previously established. The oldest confirmed stone tools are less than 2.6 million years old, perhaps only a little before the emergence of the genus Homo.The evidence offered for their conclusion is a series of cutmarks and one percussion mark on two bovid bones. The authors run through a battery of microscopic tests to rule out other sources of the cutmarks, such as trampling by other animals, and conclude that the marks could only have come from australopiths using sharpened stones to scrape flesh off of the bones. If true, the discovery would substantially revise our understanding of australopith diet and behavior. The current consensus is that A. afarensis was largely herbivorous, thriving on fruits, seeds and tubers, with supplementation by insects and such, and perhaps a bit of meat-scavenging when opportunities arose. But this discovery could show that australopiths developed tool-use and pre-meditated meat-eating before Homo did.
Thankfully, the NY Times piece offers up the proper skeptical response from other scientists:
Still, the discoverers are already being pressed to defend their interpretation that the cut marks on the bones are evidence of stone-tool butchery. Tim D. White of the University of California, Berkeley, one of the foremost investigators of early human origins, said flatly that their “claims greatly outstrip the evidence,” and noted, “We have been working sites in this area for 40 years, and not a single stone tool has been found in deposits of this antiquity.”
Sileshi Semaw, a paleoanthropologist at Indiana University who was a discoverer of the oldest confirmed stone tools, from 2.6 million years ago, noted in an e-mail message from Ethiopia that researchers had often been misled by bone markings left by trampling animals and other natural causes. “I am not convinced of the new discovery,” he said.So, the jury is still out.
This touches on the issue of how vegans should handle the caveman argument. Many of us are tempted to strain credulity and torture the evidence to "prove" humans are "naturally" vegan. This is a trap, and one into which carnists (especially paleo-dieters) would love us to fall; the evidence isn't on our side. There's no doubt that hominids ate meat.
But, it should be remembered that this fact doesn't tell us very much about an "ideal" human diet, either. Paleolithic hominids were opportunistic feeders by ecological necessity, and a capability to do something does not imply either an obligation or a necessity to do it, circumstances being equal.
The argument for veganism has always been primarily ethical, and ought to remain that way. It's based on a concern for the future, not an obsession about the past.
So what if australopiths and early Homo ate animals? While interesting, it says little about what's right or wrong for Homo sapiens in the 21st century, confronted as we are by increasing resource scarcity, overpopulation, and biodiversity crises.
The problem I have with paleo-dieters isn't that they point out prehistoric meat-eating, but that they all seem to think a return to this style of living is both possible and ideal.
I'm skeptical of both claims; given what we know about the Pleistocene mammal extinctions and the impact of modern hunting, a return to the Paleolithic hunter-gatherer lifestyle is not sustainable. And from a nutritional standpoint, neither it nor veganism are "ideal"; the only "ideal" human diet is likely to be one of our own invention, in the future, borne of increased knowledge and practical application of biochemistry.
So this latest potential ammo for the carnists is much ado about nothing before it even ends up in their arsenal.
UPDATE: Paleoanthropologist John Hawks, writing about the same discovery, offers some interesting thoughts about its implications for the the expensive-tissue hypothesis:
A 2.6-million-year-old butchery tradition should already have refuted the hypothesis that meat-eating caused the expansion of brain size in Homo. But it was still possible to maintain that the initial Oldowan was insufficiently dedicated, or that the anatomical specializations (e.g., small guts) allowing brain expansion took time to develop, or that as-yet-undiscovered large-brained hominins would be found. Any of these are still possible, but the observations Braun points out pretty much demolish the 15-year-old story of "expensive tissue." Australopithecus seems to have had a small gut, and a bigger brain than chimpanzees. If there was a tradeoff, A. afarensis had already made it.