Sussman's research is based on studying the fossil evidence dating back nearly seven million years. "Most theories on Man the Hunter fail to incorporate this key fossil evidence," Sussman says. "We wanted evidence, not just theory. We thoroughly examined literature available on the skulls, bones, footprints and on environmental evidence, both of our hominid ancestors and the predators that coexisted with them."
Since the process of human evolution is so long and varied, Sussman and his co-author, Donna L. Hart, decided to focus their research on one specific species, Australopithecus afarensis, which lived between five million and two and a half million years ago and is one of the better known early human species. Most paleontologists agree that Australopithecus afarensis is the common link between fossils that came before and those that came after. It shares dental, cranial and skeletal traits with both. It's also a very well-represented species in the fossil record.
"Australopithecus afarensis was probably quite strong, like a small ape," Sussman says. Adults ranged from around 3 to 5 feet and they weighed 60-100 pounds. They were basically smallish bipedal primates. Their teeth were relatively small, very much like modern humans, and they were fruit and nut eaters.
But what Sussman and Hart discovered is that Australopithecus afarensis was not dentally pre-adapted to eat meat. "It didn't have the sharp shearing blades necessary to retain and cut such foods," Sussman says. "These early humans simply couldn't eat meat. If they couldn't eat meat, why would they hunt?"
It was not possible for early humans to consume a large amount of meat until fire was controlled and cooking was possible. Sussman points out that the first tools didn't appear until two million years ago. And there wasn't good evidence of fire until after 800,000 years ago.
Contact: Neil Schoenherr
Washington University in St. Louis