The Australopithecines lived in Africa between 4.1 million and 1.4 million years ago. This means there were several species of bipedal primates with chimp-sized brains walking through the forests, woodlands, and savannas of Africa for nearly 3 million years (remember, Ardi lived 4.4 Mya). There is also evidence of bipedalism going back 7 million years that includes Orrorin tugenensis and Sahelanthropus tchadensis.
Obviously, this new experiment in bipedality was a huge success. Seven species of Australopithecines have been discovered in addition to the earlier species of Ardipithecus, Orrorin, and Sahelanthropus. Moreover, new discoveries are always looming on the horizon, which begs the question: why did bipedal primates go extinct?
Several hypotheses have been advanced, including climate change, shrinking supplies of essential fallback food, too much competition with other species for limited resources, natural disasters, disease, predation, even tribal warfare. Currently, scientists don’t have enough evidence to support any conclusions.
Evolution dramatically teaches us that all species die. Anthropology professor, David S. Strait, concluded in his excellent article, “Evolution–Education and Outreach”:
“The australopiths are gone, but in much the same way that birds are dinosaurs, we are australopiths in that we are almost certainly descended from one of them. It is possible that the australopiths on our direct lineage are not yet known to science, but it is highly unlikely that australopiths represent an entirely distinct clade whose evolutionary history is completely independent from ours. Interestingly, members of our own genus (Homo) appear to have succeeded by abandoning the adaptations that made australopiths successful (e.g., large jaws, massive cheek teeth, huge chewing muscles). In their place, early members of the genus Homo may have become behaviorally flexible by evolving large brains, more dextrous hands, and advanced tool use. This strategy evidently proved to be more successful in navigating the vicissitudes of the Pleistocene.” (Strait, 2010)
Whether the Australopiths went out with a whimper or a bang has yet to be determined. Nevertheless, the treasure trove of fossils and scientific data prove that they were a highly successful genus that flourished in Africa for nearly 3 million years. (to be continued in next post)