This article about the first barbecue was written by Christina Scott for the Science in Africa Magazine. Return to home page.

First barbecue. In the heat of our prehistoric past - when was the first braai (barbecue)?

The use of fire is one of the key tools that marked the difference between early ape men, and their primate cousins. Fire also marked the start of mankind's long march from being a common snack for predators to being the world's most successful predator.

Not just any old fire would do. A random lightning strike, setting the long grasses smouldering in the dry season, didn't count. But when an early man (or woman) used his or her developing brain to think about the possibility of capturing some of that fire safely, perhaps on a long branch of white stinkwood or another tree, maybe even with one end dipped in water for safer handling, and carried that fire to a communal living area - well, that was controlled fire, and control of such a valuable tool has made all the difference to our history.

"Without the controlled use of fire it would not have been possible to develop rocket technology," says Francis Thackeray of the Transvaal Museum in Pretoria, South Africa. "Without a rocket it would not have been possible for humans to have traveled to the moon." And it would not be possible, without fire, for Americans to consider a mission to Mars.

The first barbecue. Burnt bones from Swartkrans
cave in the Cradle of Humankind

Now a team of scientists – two South Africans, two Americans – have confirmed that fire was first utilised on the African continent, not elsewhere. Through the expensive technology of the modern age, and in particular electron spin resonance, their results lead them to believe that the first small, tentative technological steps that eventually led to the giant leap of lunar exploration began in southern Africa more than 1 million years ago.

Swartkrans is a dark cave in the Cradle of Humankind, about a kilometre west of Sterkfontein. (Sterkfontein is where the rare, virtually complete Little Foot skeleton was discovered, and the Cradle of Humankind is one of the richest palaeontological sites in the world).

In 1984 a treasure trove of more than 250 ancient burnt animal bones was discovered at the site by Dr Bob Brain, then the Director of the Transvaal Museum. These fossilised remains of antelope, at least one million years old – and in some cases more than one million year old – were discovered in a section identified as Member 3, in which the brescia - the deposits containing the fossils - has been eroded into decalcified sands. As it erodes, the brescia returns from a rock-hard type of cement back into its original sand. The problem is, decalcified sand can make it more difficult for scientists to date accurately the material found within it.

These antelope bones appeared to have been braaied - or to use a word more commonly understood outside South Africa, the hominid bands sheltering in these caves seemed to have enjoyed regular antelope barbecues. Brain worked with Dr Andy Sillen, a chemist in the archaeometry laboratory at the University of Cape Town, which specialised in the chemical detective work required to analyse these frequently minute shards from both archaeological and palaeontological deposits. Sillen and Brain recognised that the fossilised bones had been burnt by undertaking chemical analyses (looking at ratios of carbon, nitrogen and hydrogen), as well as by studying the structure of bone affected by heat. But how hot? And how long ago?

Brain burnt modern bones of domesticated animals in a kiln at known temperatures and compared them to the fossilised bones from Swartkrans. Histological results – that is, the microscopic analysis of bone sections – suggested that the heating temperatures experienced by the fossils had been similar to those in campfires, and well above the temperatures experienced in naturally-occurring grass fires which burn at relatively low temperatures (about 200 degrees Celsius). If confirmed, this would place the earliest controlled use of fire between one million years ago, and one and a half million years ago. (Previous to this, the earliest controlled use of fire was thought to date from only about half a million years ago, from a site in China.)

But some palaeontologists questioned the validity of their claim. Many agreed that the bones had been heated but some suggested that the fossils weren’t over one million years old. So when newer technology presented an opportunity to re-examine the issue of the heat, the scientists jumped at the chance.

"We decided to re-examine some of the Swartkrans bones to see if electron spin resonance could serve as a palaeothermometer," explains Dr Thackeray. The bones had been kept in storage in the Transvaal Museum. Dr Anne Skinner of the Department of Chemistry at Williams College in Maryland in the USA flew to South Africa to obtain a selection, which then accompanied her to the USA. The electron spin resonance was done at Williams College.

"Preliminary results confirm that the bones fall into three general categories: unheated, slightly heated, and calcined" says Dr Skinner. (Bones may start off white, then progress to brown and black as they are burnt, but in intense heat they return to a white colour and become very brittle. This is what is meant by the term calcined.) "The presence of manganese in the fossils makes comparisons with modern heated bone difficult, but there is some evidence that the manganese electron spin resonance signal depends on temperature, which would then provide a second measure of the degree of heating."

Swartkrans is in fact named after the dark manganese deposited naturally there, and is the Afrikaans word for a black hillside. Another problem facing the first group of scientists was that manganese was being dissolved out of hill and back into the deposits all the time. How to tell if the darker bones were simply affected by manganese, or by fire? The new work by Anne Skinner, Joan Lloyd and colleagues, using electron spin resonance, confirms the ideas of Brain two decades earlier. These bones have gone through intense heat.

They found that the palaeotemperatures associated with many of the bones exceed 500 degrees Celsius, which is the kind of temperature associated with controlled fires in confined areas. 500 degrees Celsius is hot enough to change both the structure and the chemistry of bone.

Whether you are heating organic materials such as bone or inorganic materials such as rock, the heat produces free radicals, atoms which are temporarily available for a chemical reaction to take place because they are not already bound in a chemical marriage in a molecule. These molecules can be detected by electron spin resonance. This process has been to look at heated flint, for example, and stone. It has seldom been used to date bone. The type of free radicals formed depends on the heating temperatures, with higher temperatures resulting in simpler radicals. That particular group of free radicals is then embedded in the bone as it slowly turns into a fossil, and has remained there undetected until now. More tests are planned within the next year to get the particular temperature for particular bones.

The burnt bones from Swartkrans are still thought by Thackeray and Skinner to be between 1 and 1.5 million years old, although the electron spin resonance technique was not used for dating. There is always difficulty in dating palaeontological deposits in South Africa, which lacks the extremely useful volcanic deposits in East Africa, which can be precisely measured. The figure of one million years and greater is derived from the fossilised fauna found side by side with the burnt antelope bones in the same layer of decalcified sand. These animals can be matched with other members of their species in ancient sites uncovered in Kenya and Tanzania.

Thackeray cautions, "we do not claim that distant human relatives such as Homo ergaster or Homo erectus were making fires, but at least they were probably using fire in a controlled manner. They could have collected burning branches of trees that had been set alight by lightning after dry winters on the highveld".

Whoever first used controlled fire had no thoughts about what this discovery would unfold over the centuries. Indeed, whoever first used controlled fire probably was hungry, infected with insects and desperately afraid of the big cats and hunting hyenas which prowled the region. But out of a need for safety comes the technologies which shape our lives, even today.

"Africa as a continent can be proud of the prehistoric technology which contributed to the development of space age technology," says Dr Thackeray. And if you want to touch base with some of humanity’s own history of technological innovation, there are some burn fossilised antelope bones on public display at the Transvaal Museum in Pretoria. It’s rather appropriate that the off-white fossil
fragments share a display cabinet with a piece of the moon. Without the first fire, there would have been no moon rocket – and no moon rock.

Author: Christina Scott.

Reproduced with permission Science in Africa Magazine.
Article remains copyright of Science in Africa.
www.scienceinafrica.com

Return to top of first barbecue.