Au. africanus was anatomically similar to Au. afarensis, with a combination of human-like and ape-like features. Compared to Au. afarensis, Au. africanus had a rounder cranium housing a larger brain and smaller teeth, but it also had some ape-like features including relatively long arms and a strongly sloping face that juts out from underneath the braincase with a pronounced jaw. Like Au. afarensis, the pelvis, femur (upper leg), and foot bones of Au. africanus indicate that it walked bipedally, but its shoulder and hand bones indicate they were also adapted for climbing,
History of Discovery:
The Taung child, found in 1924, was the first to establish that early fossil humans occurred in Africa. After Prof. Raymond Dart described it and named the species Australopithecus africanus (meaning southern ape of Africa), it took more than 20 years for the scientific community to widely accept Australopithecus as a member of the human family tree.
How They Survived:
The hunter or the hunted?
No stone tools have been discovered in the same sediments as Au. africanus fossils; however, for a long time researchers believed Au. africanus was a hunter. Raymond Dart created the term ‘osteodontokeratic’ culture (osteo = bone, donto = tooth, keratic = horn) in the 1940s and 1950s because remains of this species were found alongside broken animal bones. Dart assumed these broken animal bones, teeth and horns were used by Au. africanus as weapons; however, in the 1970s and 1980s, other scientists began to recognize that predators such as lions, leopards, and hyenas were instead responsible for leaving these broken animal bones. These predators even ate Au. africanus individuals, too.
Despite the carnivorous preferences of their contemporaneous predators, Au. africanus individuals had a diet similar to modern chimpanzees, which consisted of fruit, plants, nuts, seeds, roots, insects, and eggs.
How do we know what they ate?
Scientists can tell what Au. africanus may have eaten from looking at the remains of their teeth---tooth-size, shape, and tooth-wear can all provide diet clues. Dental microwear studies found more scratches than pits on Au. africanus teeth compared to a contemporaneous species, P. robustus. This pattern indicates that Au. africanus ate tough foods but also had a very variable diet including softer fruits and plants.
Evolutionary Tree Information:
Many scientists consider either this species or Au. afarensis of East Africa to represent a viable candidate for the ancestor of the genus Homo.
We don’t know everything about our early ancestors—but we keep learning more! Paleoanthropologists are constantly in the field, excavating new areas, using groundbreaking technology, and continually filling in some of the gaps about our understanding of human evolution.
Below are some of the still unanswered questions about Au. africanus that may be answered with future discoveries:
- Au. africanus is currently the oldest known early human from southern Africa. Where did it come from? Was it a descendent of Au. afarensis from Eastern Africa?
- Is Au. africanus part of the lineage that led to our own species, Homo sapiens?
- In 1994, scientist Ron Clarke found four left early human foot bones while searching through boxes of fossils at Sterkfontein, a site in South Africa where most Au. africanus fossils come from. He dubbed this fossil "Little Foot", and has since found that it comes from a 3.3-million-year-old partial skeleton, most of which is still embedded in the cave sediments. When this fossil is completely excavated, it will shed light on several questions about this species (if it is designated as an Au. africanus individual): How big was it? What did its post-cranial skeleton look like? How does it compare to STS 14, another partial skeleton of Au. africanus?
Dart, R., 1925. Australopithecus africanus. The man-ape of South Africa. Nature 115, 195-199.
Other recommended readings:
Berger, L.R., Clarke, R.J., 1995. Eagle involvement of the Taung child fauna. Journal of Human Evolution 29, 275-299.
Clarke, R.J., Tobias, P.V., 1995. Sterkfontein Member 2 foot bones of the oldest South African hominid. Science 269, 521–524.
Lacruz, R.S., Rozzi, F.R, Bromage, T.G., , 2005. Dental enamel hypoplasia, age at death, and weaning in the Taung child. South African Journal of Science 101, 567-569.
McHenry, H., 1998. Body proportions in Australopithecus afarensis and A. africanus and the origin of the genus Homo. Journal of Human Evolution 35, 1-22.
Scott, R. S., Ungar, P.S., Bergstrom, T.S., Brown, C.A., Grine, F.E, Teaford, M.F., Walker, A., 2005. Dental microwear texture analysis shows within-species diet variability in fossil hominins. Nature 436, 693-695.