25 June 1998

Deep Thought - Science à GoGo talk to Phillip Tobias


When researchers announced earlier this month that Mr Ples, a relative of early humans, had a smaller brain than previously expected, the scientific world was thrown into a tizzy. We didn't know as much about brain evolution as we thought we did, it was revealed, and the skull of Mr Ples seemed to mock us with australopithecine laughter. Who was this elusive hominoid who'd made fools of the anthropologists? Science à GoGo went straight to Phillip Tobias, Director Emeritus of the Palaeonthropology Research Unit. He discovered Mr Ples' skull in South Africa in 1989, and feels almost like a father to him. Here he tells us in his own words about the late, great Mr Ples, including his hobbies, sexual behaviour, and chances of winning Wimbledon...


By 1989 the late Mr Alun Hughes and I had been excavating in a cave site not far from Johannesburg, rejoicing in the name of Sterkfontein (this means "Strong Spring": this does not refer to the nature of the vehicles which, originally, we needed to negotiate what passed as Pleistocene pathways, but to a fresh water spring in the stream, a few hundred metres from Sterkfontein). We were digging a trench and our drilling operations happened to intersect a fine skull. It was very similar indeed to that of the skull which had earlier been called "Mrs Ples" (pictured) and so, as our new one was obviously a male of the same kind of creature, we called it Mr Ples.

When Robert Broom and John Robinson found Mrs Ples in 1947, they named the creature to which it belonged "plesianthropus". It seems that certain of the media people had great difficulty in wrapping their tongues or their quills around the word plesianthropus, so it was shortened to Ples. As Broom and Robinson were convinced that the 1947 cranium was female, they called it Mrs Ples. But why, do I hear you cry, Mrs and not Miss? (This was before the era of Ms). Well the old dear had lost all of her teeth and so Broom felt it more justified to call it Mrs than Miss.


Our skull was the first good example of a male of the same kind and it was natural for us to call it Mr Ples. These odd creatures walked the face of Africa between 3.5 and 2.5 million years ago, going on two legs rather than on four legs. Thus, they were human in their posture and gait. Also, instead of large fangs, usually shown dripping gore, they had neat and petite canine teeth, just as human beings do. So they were human in their teeth. But they would have worn a very small size hat - if they had worn hats - if there had been hats! The bone size was approximately one third of the average size in modern human beings. But their pelvic bones showed very clearly that they were adapted to uprightness as we are. So we are confronted with the very sobering realisation that we were human in our backsides before we were human in our brains.

The first of all of these creatures had been found in South Africa by my predecessor as Head of the Department of Anatomy at the Witwatersrand University Medical School, a wild and exuberant young Australian called Raymond Arthur Dart. The little child of Taung, which fell into his hands in 1924, was recognised through Dart's anatomical insight and imaginative flair as a true "missing link". Because Taung was a little child of 3-4years when it died, nobody wanted to believe Dart, even although "the child is father to the man". "Give us an adult," they cried, "and then we may be prepared to talk turkey with you!" It was from Sterkfontein that the first adults came.

Well, Sterkfontein has proved the richest site in the world for this kind of creature, the strange, upright-walking but small-brained creatures which most scientists believe provided a population which was to evolve into human kind.


Their main hobby was probably eating, or looking for food, although sexual activities may have occupied quite a large part of their time and energy, exactly as in bonobos or "pigmy chimpanzees" in middle Africa today. Food is sometimes spoken of as an aphrodisiac - so you can take your choice between the food-gathering activities and the sexual activities. When they were tired of both of these, it seems that they enjoyed tree climbing, just as the African apes do today, and very possibly, they might have slept in trees where they would at least have had some security from the prowling big cats of Africa.


Brain size is not everything: quality does count for something. So we would be very wrong to think of Australopithicus (as Dart first called these creatures) as a dim-witted lowbrow. For we must face the fact that they were able to hold their own, despite the challenges to survival in Africa, for probably several million years. We know that life was cheap, because about a half of all of the apeman fossils that we find belonged to individuals that did not live long enough to reach adulthood. Many of them died as children and adolescents, before ever their wisdom teeth had erupted.

But one does not need wisdom teeth to reproduce. Very probably the business of baby-making started at a young age, as it does in many societies today. So the species survived even with a small brain.

Very probably they lived in a somewhat sheltered environment. We know today that this part of Southern Africa was well watered, wooded and even forested at the time when these first bipeds walked the face of the earth. It was only when the climate and conditions of Africa underwent severe deterioration about 2.5 million years ago that the struggle for survival became intensified and many of the species that had lived before that time did not make the grade. On the human line, it is at that moment in time that the first of the bigger brained early ancestors came into the picture - a species which the late Louis Leakey, John Napier and I named Homo habilis - the first handyman. We called him this by a name which Dart had suggested to me, because there was evidence to suggest that these creatures with a 50% bigger brain size were able to make tools and this must have greatly helped in the survival stakes.

Back to Mr Ples and his brain: it is unlikely that either Mr or Mrs Ples could speak and perhaps they wouldn't have had very much to speak about. But when Africa changed at 2.5 million years, new species appeared, old species disappeared, change was everywhere apparent, tool-making became a new dimension in human survival - and if you couldn't teach your children which stones to choose and how to break the stones and to shape them, then this new invention would have been a flash in the pan and of no evolutionary significance. But they could teach their children and they did: and that is what evolution is all about - save the children, not save yourself.

So our new evidence is one more piece of testimony that these apemen of Africa were still very chimpanzee-like in their brain size. They had not yet begun to show that remarkable splurge of brain enlargement which became the hallmark of mankind. Brain enlargement, it seems, was in the rearguard - other things were in the vanguard of human evolution, like teeth and hands and feet.

We have managed to get our new results on the brain size of Mr Ples by applying modern technology such as the marvellous imaging techniques of CAT scanning, to very old remains. This interface is a meeting of the very new and the very old. Who knows what new technologies may produce in the coming century, when they are applied to the study of old rocks and their contents? We have come a remarkably long way in the hundred-odd years that we have been studying human evolution, but it is only a fraction of what is to be expected in the second hundred years of paleo-anthropology. Even when I started as a young student, first visiting Sterkfontein just over 50 years ago, all dating of rocks was guesswork. When I brought the first fossil baboons back from Makapansgat, about 300km north of Johannesburg, when I was not yet out of my teens, one of my mentors, Robert Broom, published an account of them in the daily press under a screaming headline: "Students Discover 300 000 Year Old Secret". But that was sheer guesswork and, with new techniques of dating today, we now know that the layer from which those baboons stemmed was approximately 3 million years of age.

Some of these exciting new developments will be discussed next week when the biggest ever gathering of anthropologists will take place in South Africa. It will be a meeting of the living and the dead, people who are steeped in the study of human biology, largely of living human kind, meeting together with people who are studying the deep time dimension in human development. From this meeting of minds, we expect exciting developments to ensue. The meeting will be held at Sun City, 200 kms north west of Johannesburg, from 28th June to 4th July 1998. Some 700 people will be attending from 74 different countries - possibly the most internationally representative gathering of its kind ever held anywhere in the world.


If Mr Ples appeared on the Centre Court at Wimbledon, I don't think anyone would look twice at his appearance - if he wore a hat. His leg action on the court may be quaint, if not cool, but certainly not as eye-catching as the bowling action of the South African spin bowler Paul Adams.