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- [Narrator] We are the paradoxical ape.
Bipedal, naked, large brained.
Long the master of fire, tools and language,
but still trying to understand ourselves.
Aware that death is inevitable,
yet filled with optimism.
We grow up slowly, we hand down knowledge,
we empathize and deceive.
We shape the future
from our shared understanding of the past.
CARTA brings together experts from diverse disciplines
to exchange insights on who we are and how we got here.
An exploration made possible
by the generosity of humans like you.
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- [Lyn] Activities involving the lighting and use of fires
separate hominins from other primates.
Indeed many of the innovations attributed to early humans
were dependent on pyrotechnology.
In a hunter gatherer context,
fire is mostly associated with domestic uses,
such as cooking, heating, social interactions
and protection from predators.
Importantly though, fire enables some technical tasks.
And products like ash were exploited
in a variety of ways from at least 300,000 years ago.
Fire gave humans the edge over other primates.
Where and when did this begin?
Fire simply obtained from burning branches
or coals originating in wildfires,
must first be distinguished from fire started from dry wood,
tinder, and some means of making sparks for ignition.
More than a million years ago, fire seems to have been
obtained expediently from natural sources, and then used
briefly at sites like Koobi Fora in East Africa,
and Wonderwerk and Swartkrans in South Africa.
The ephemeral burned layers in Wonderwerk
are in a dark area about 30 meters from the cave entrance.
All the evidence suggests that this fire
was transported from a natural source,
such as a lightning strike that set the grassland alight.
It was then used in the cave,
but the fire could not be curated and maintained for long.
Certainly, Homo erectus, the likely occupant of this cave,
seems not to have been able to make fire from scratch
and probably collected it from wildfires.
Nonetheless, we know that Homo erectus had an enriched diet
compared with earlier hominins, because relative to them,
Homo erectus had large brains but small teeth and guts.
This physique may have come about
through increased meat consumption
when hunting became efficient.
The occasional cooking of food
may have contributed to the new brain-gut ratio.
Perhaps this is so, but we don't have firm evidence yet.
Habitual use of fire is suggested
by the central placement of a hearth
in the late lower paleolithic site, Qesem Cave, Israel,
somewhere between 420 and 200,000 years ago
before the arrival of anatomically modern humans.
Not only were Qesem hominins cooking on fire,
but based on artifact use traces and botanical remains,
they seem to have used ash
as a preservative for various foods,
and perhaps also for hide preparation.
It appears that hominins were able to make
fire at will by this time.
Early Homo sapiens fossils date from about 300,000 years ago
at Jebel Irhoud in North Africa,
and slightly after that Florisbad in South Africa.
The start of the African middle stone age
coincides roughly with the appearance of Homo sapiens.
By 177,000 years ago,
Homo sapiens was found at Misliya Cave in Israel,
suggesting that the earliest Homo sapiens migrations
out of Africa may have began 200,000 years ago.
By that time, fire was a regular part of human technology.
Qesem is not the only example of early exploitation
of the byproducts of fire.
By 227,000 years ago at Border Cave, South Africa,
modern humans put ash to good use,
as I shall shortly explain.
Border Cave is large and it was extensively
excavated in the last century.
The present excavations sample small areas
exposed by previous archeologists.
Here in the 227,000 year old member, five White Ash,
there are several super-imposed ashy layers
implying repeated use of fire
and probably the ability to make it at will.
There are also femoral traces of silicified grass,
the grass is essentially fossilized.
In slightly younger members, we found burned rhizomes,
presumably from using fire for cooking.
And I shall discuss this shortly.
The plant material from the early bedding
was studied using a scanning electron microscope,
as well as phytolith analysis.
Both methods revealed anatomical features
like leaf blade structures,
and by lower bed, short cells, prickles, and stomata.
These identify the Border Cave plant fragments
as grass from the Panicoideae subfamily.
Panicum maximum still grows prolifically outside the cave.
Although the oldest bedding is a femoral now,
it may once have looked like better preserved grass bedding
in some of the younger occupations.
Within the stone age sequence of Border Cave,
people often placed grass on ash.
Occasionally, this ash was derived from older grass bedding
that may have been burned to clean the site,
but sometimes grass was placed on raked wood ash.
Chemical analysis of sediments can identify ash,
and sometimes its origin can be distinguished.
At Border Cave, Marine Wojcieszak
conducted onsite FTIR analysis,
and we could therefore be certain that ash was indeed
used underneath grass bedding.
Ash provides a clean, dry insulating surface,
but ethnographies report further, that ash repels
crawling insects and various parasites.
Ash supposedly blocks their breathing
and biting apparatus and dehydrates them.
The two images at the top of the screen
show how the grass bedding may have been made.
The two images below this
show how we experimented with 30 brown ticks,
placing them in a circle of ash within a sealed container.
Those ticks that reach the ash wall were smothered
in the powder and moved with difficulty.
Ash may thus have some efficacy in preventing bites
from parasites that endanger people's health.
Border Cave people seem to have employed several techniques
for keeping pests away.
Sandra Lennox used the wood anatomy of charcoal
found on the 227,000 year old bedding
to identify the camphor bush, Tarchonanthus.
The smoke from this aromatic species
is used by modern rural communities to repel insects.
Maasai herdsman in East Africa
still make bedding from Tarchonanthus leaves
and also burn its wood.
We found more than 60 charred rhizomes of underground plants
in Border Cave occupations
dating between 170 and 120,000 years ago.
Some rhizomes were presumably buried and lost
while being roasted in hot ash.
They were all from the same species
and their morphology matched that of a small Hypoxis.
Cooking makes food more digestible
and easier to chew than when raw.
It facilitates peeling rhizomes and it enhances
the glucose availability of starchy plants.
Hypoxis was identified largely
from the anatomy of the rhizome.
We found raphides which are calcium oxalate crystals
and Xylem vessels, particularly useful
for identifying the rhizomes.
People dug the rhizomes in the field,
then transported them and fire wood
along the steep cliff back to the cave.
They could easily have prepared and eaten the rhizomes
where they were unearthed, but they did not.
The cooking of rhizomes in the cave was a planned activity
with the reward deliberately delayed,
presumably in order to share the food at the home base.
The process tells us something about the social practices
and the cognitive attributes of these early humans.
At Klasies River in the Southern Cape,
quartzite rocks may have been used to aid cooking
because they were ridden by repeated heating and fire.
Unidentified underground storage organs
were cooked here more than hundred thousand years ago.
Other aspects of pyrotechnology are surprisingly early.
By 164,000 years ago, people appear to have discovered
the transformative power of heating certain salacious rocks.
Careful heating of some rocks and minerals
makes them especially suitable for napping.
Heat treatment is particularly beneficial
for pressure flaking.
At Pinnacle Point, silcrete was heated
from the time of the earliest occupations.
Heat treatment was also observed at Blombos,
where bifacial points were carefully crafted from silcrete.
An aspect of pyrotechnology that has absorbed
much of my research time has been the production of glue,
a single component product and adhesive compound product.
The success of manufacturing fixative pastes
is dependent on controlled heat.
Something that can be achieved
by understanding the properties of various woods.
Raman and EDS spectra revealed hematite and carbon
in the adhesive, on a Sibudu point 72,000 years old.
The adhesives on 64,000 year old tools
comprise plant resin and ochre powder compounds,
gas and liquid chromatography, identified coniferous resin,
while Raman confirmed the presence of hematite.
I wanted to know whether the recipes were created
with knowledge of the properties of the ingredients.
I therefore manufactured some glues and adhesives
with and without powdered ochre,
and heated them gently to dry them.
They were used to join wooden strips
that were later pulled apart by a universal testing machine.
Compound adhesive containing a mixture of ochre and gum
is stronger than gum alone.
This suggests that people knew that ochre
was a successful loading agent,
and they did not simply choose the ochre for its color.
People at Blombos made ochre rich paint
a hundred thousand years ago.
Probably by using the same sort of technology
demonstrated for adhesive manufacture.
Sibudu's occupants created a type of tempera paint,
thousands of years later.
As shown in this brief review that favors African examples,
fire technology was already quite well developed
before 200,000 years ago.
Close to the origin of our species,
people could produce fire at will
and they used fire, ash and smoke from medicinal plants
to maintain clean pest free camps.
Modern hunter gatherer camps had fires as focal points.
People regularly sleep alongside them
and perform domestic tasks in social contexts.
The earliest Homo sapiens groups
seem to have behaved similarly.
Among the tasks they performed around fires
were some fairly sophisticated creations
of compound mixtures to enable the assembly
of composite tools and weaponry.
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