What We Can Learn From Bones: Paleodiets, Early Hominins, and Mole Rats, Part Two

Before going further, let me remind readers of the purpose behind “What We Can Learn From Bones.” Creationists like to make two main claims about paleoanthropology. First, they claim that all we have are bone fragments and teeth, and by implication, that we can learn nothing from bone fragments and teeth. Second, they claim that paleoanthropology is a historic science and since humans were not around to witness the events in question we can never really learn anything about the past. The point of “What We Can Learn From Bones” is to show that we can gain a lot of useful knowledge from bone fragments and that there are a number of sophisticated methodologies that allow us to test our inferences about the past. Previous posts in “What We Can Learn From Bones” can be found by scrolling down my sidebar and clicking on the “Bone Fragments” category.
I am also departing, somewhat, from the outline I mentioned in the first part of “Paleodiets, Early Hominins, and Mole Rats” mainly because of several recent papers that are relevant to the issue (which I will get to later).

In 1955 Raymond Dart delivered a paper at the Third Pan-African Congress on Prehistory, at Livingstone, called The Makapansgat Australopithecine Osteodontokeratic Culture. In that paper Dart analyzed some 7,000 bones from Makapansgat and drew some remarkable conclusions about the behavior of australopithicines. According to Dart the australopithecines were highly efficient hunters who occasionally engaged in cannibalism and had a fondness for craniums. Here is the issue. Since we share a common ancestor with chimps some method of getting from chimplike behavior and diet to modern Homo sapien behavior and diet. A theory to explain this transition would also have to account for the origins of bipedalism, the growth and reorganization of the human brain, differences in the timing of growth and development, and, of course, culture. For Dart, hunting was the cause of these changes, the skill required to make tools, track down prey and dispatch them were a cause for the expansion of the human brain. The postures required for these activities was the force behind bipedal locomotion. Unexplained is how, given the bloodthirsty nature Dart gives australopithecines, the cooperation necessary for hunting could have developed, much less how a cohesive society could have developed. Dart’s ideas have long since been discarded, however, we shouldn’t be too harsh on him. As Brain points out in The Hunters or the Hunted? An Introduction to African Cave Taphonomy Dart’s analysis of the Makapansgat material represented one of the first attempt to analyze and interpret bone assemblages from African Caves. Later attempts to explain the change followed Dart in attributing the primary cause to either tool use, hunting, or both. Jolly’s seed eater hypothesis is something of an exception. Jolly identified a number of parallelisms between Theropithecus and early hominids which lead him to propose a two phase model of human evolution. In the first phase hominid species adapted to edaphic grassland enivironments and ate primarily grains, cereals and seeds of various types. This preadapted them for later human evolution – phase two for Jolly. In phase two an increased reliance on hunting with females still gathering grasses and seeds propelled hominid evolution – both biologically and culturally. What these hypotheses lack is, through no fault of their own, is evidence. Archaeologically, the first evidence of stone tool use comes from Gona and Bouri and dates to ~2.5 MYA. The first evidence, that I know of, for bone tools dates to ~1.8-1.3 MYA at Swartkrans and Sterkfontein in the form of bones used for termite foraging. Yet, many of the evolutionary trends of interest began before that. An added problem is that many of the tools used before then were likely to be expedient tools that were used once (or several times) then abandoned. The methodology for identifying these types of tools with certainty is presently, unavailable. A number of ways around this problem have been developed and in the next post I will take a second look at teeth and then lay the ground work for understanding stable isotope analysis.

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