P200 Introduction to Prehistoric Archaeology
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The Archaeology of Human Origins, Part II
Which hominid was responsible for making and using the earliest stone tools, between 2.5 and 2.0 million years ago? There were at least two genera of hominids alive at the time: robust australopithecines lived in East Africa (A. boisei) and South Africa (A. robustus), and at least one species of early Homo (Homo habilis) was present in both areas at the same time. Bones of both australopithecines and Homo have been found associated with early tools... but this is just circumstantial evidence.
Could the australopithecines have made stone tools? Yes, their hands had a dexterity very similar to modern humans and their brain sizes were as large or larger than living apes, such as chimpanzees, that make and use a wide variety of tools today. But did they NEED tools? Perhaps not, since their extremely large cheek teeth, robust jaws and large chewing muscles suggest that they were adapted for eating a large volume of coarse or hard vegetable foods. On the other hand, recent bone chemistry research on South African australopithecines published in the January 15 1999 issue of Science suggests that they may have included at least some savanna animal or insect foods in their diet.
Could early Homo have made stone tools? Yes, their hands had a dexterity very similar to modern humans and their brain sizes were significantly larger than living apes, such as chimpanzees, that make and use a wide variety of tools today. Their small teeth and chewing muscles suggest that they were adapted to chewing fairly soft foods, perhaps prepared with tools.
Meat Eating and Human Evolution?
Larger brains are metabolically costly, requiring a steady source of both calories and high quality protein... suggesting that the ability to use tools to acquire high quality plant foods, like nuts, and soft animal foods (such as meat or marrow) would have been adaptive for early Homo. So... was the ability to use tools to access animal foods a selective advantage for early Homo, distinguishing them from other hominids? A number of early archaeological sites in East Africa, such as sites at Olduvai and Koobi Fora, Kenya, are large concentrations of stone artifacts (simply flaked cores and flakes) associated with fragmentary animal bones. Can we demonstrate that early stone tool makers (perhaps Homo) ate the meat off the bones (or the marrow within them)? Key types of evidence include:
- cutmarks made by stone tools on the bones
- hammerstone percussion marks on the bones
But, as featured in the video we saw in class, Pat Shipman, Rob Blumenschine and others have demonstrated that carnivores have also damaged alot of the bones at many of these early sites. How can archaeologists decide who got to the bones first, the carnivores or the hominids? In other words, were hominids hunters, or scavengers? Or both? Chimpanzees certainly hunt today, so hominids probably would have had the strategic intelligence to do so. But chimps only hunt small, forest animals. The animals at the archaeological sites are very different. Shipman noted a few examples of cutmarks overlapping toothmarks on a few bones, but there are thousands of others at the sites. Blumenschine has argued that sites include many bones that would have been accessible to hominids through scavenging. On the other hand, Henry Bunn has argued that there are many cutmarks on meaty limb bones of small animals support a hunting hypothesis.
Fossils of a new species of Homo are found in Rift Valley sites in East Africa starting over 1.8 million years ago. This species is often called "early Homo erectus" (many anthropologists put it in a separated species called "Homo ergaster"). It is distinguished from all earlier hominids by:
- larger brain (850-1000cc)
- narrow birth canal and altricial young
- small, human-like face and teeth
- large stature and tall, thin, frame adapted for trekking in hot, dry country
This is the first hominid species to be found outside of the African continent, and was associated with archaeological evidence that suggests several technological innovations and behavioral changes that we'll talk about next time. No matter which hominids species you think made the earliest stone tools, before 2 million years ago, it is certain that Homo erectus was a tool-maker, because tool making continues even after all the earlier australopithecines and other species of Homo have gone extinct, and H. erectus is the only surviving hominid.
Want to learn more about chimpanzees?
- online lecture about chimp diet from my 1998 P380 course
- online paper by Craig Stanford about chimpanzee hunting
- Great NEW web resource!! African Ape Study Sites by Jim Moore, UC San Diego
- Jane Goodall Institute
- The Jane Goodall Center for Excellence in Environmental Studies
Jane Goodall at Gombe National Park, Tanzania
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Last updated: 31 January, 1999
Copyright Jeanne Sept 1998 : do not cite without permission