What Did Dart Tell Us About Evolution? The Case of a Collective Man-Ape in South Africa, 1926-2005

These are not trivial revisions. They point out important questions about the evolution of an unusual life-history stage, namely childhood, and the related changes in brain size.

On 7 February 1925, Nature published an article about a curious fossil unearthed in South Africa1. ‘Australopithecus africanus: The Man-Ape had been sent in by an Australian palaeoanthropologist, Raymond Dart, who was then at the University of the Witwatersrand. In his memoirs, Adventures with the Missing Link (1959), Dart notes that he was dressing for a wedding when he was distracted by the delivery of two large boxes of rocks, containing the face of Australopithecus and the braincast (known as an endocast) — an internal cast of the braincase formed from sediment — that fitted into the skull, like a ball in a baseball pitcher’s mitt.

Dart’s report of the fossilized skull and matching endocast — an internal cast of the braincase formed from sediments that had accumulated in it — was published2 in Nature on 7 February 1925. Both the discovery and Dart’s insights deserve to be celebrated. There were also things that Dart didn’t know and things that he misconstrued. Questions about human evolution are still being raised a century later.

Researchers who study the evolution of growth and development in part by evaluating dental and brain growth in an expanding record of hominin babies have been revising Taung’s age at death since the mid-1980s. We now know that Taung was around 3.8 years old when it died, with a brain of near-adult size and developmental maturity beyond that of a human of the same age6. Some scientists think Taung was female because the best estimates of its adult cranial capacity is less than female australopithecines. Taung has been found to be 2 million years old, which is within the range of 3 million to 6 million years ago for all of the Australopithecines found in South Africa.

Most ape infants can cling onto their mothers’ bodies actively by a few months after their birth, whereas human babies are slower to mature and remain dependent on their parents or carers for much longer. Most apes don’t have a childhood, a period in which individuals who are weaned still have the support of their elders.

Childhood is probably a crucial innovation in human evolution because it creates the opportunity for offspring to learn much more from their nurturing elders than would otherwise be possible. In fact, the emergence of a prolonged period of dependency or ‘helplessness’ in human ancestors is widely thought to have produced conditions conducive to cognitive evolution.

Trenchant criticism came thick and fast. The children of humans and other apes were similar, so it is easy to say that Australopithecus was a non-human ape. They could have been irked by Darts comments on the jaw of an ancient creature. The brains of humans used to be thought to have evolved before the rest of the skeleton. An upright ape with a small brain and a humanlike jaw went against the grain.

Although things have changed, the field of palaeoanthropology10 has been slow to recognize the contributions of the many women, including Salmons, and African scholars who made key discoveries. One of the greatest observers of human origins was Kamoya Kimeu, who died in 2022. His successors are leading research today. The collections aim to show how many people contributed to this part of the human story. The people might have changed, but Africa remains the heart of human origins.

Ethiopia was by then on the palaeoanthropological map. Some of the key fossils found in Africa would soon join it. And Nature was there to document every new bone and tooth. West Africa is in the spotlight for new and exciting discoveries.

Nature, together with Nature Africa, Nature Communications and Nature Ecology and Evolution, is publishing two collections to commemorate this anniversary. The first includes 100 papers that charted this journey and reveal the part that this journal has played in documenting it. The second delves into the field of palaeoanthropology from the perspective of African scientists today.