THERE is a place in New South Wales called Cuddie Springs. You won’t find it
on any road map but you can see it from the plane as you fly over the
continent’s interior towards Sydney. If it has rained, you should spot a shallow
lake surrounded by saltbush scrub. If it’s dry, all you’ll see is a claypan in a
sea of coolabah and blackbox trees.
More than 30 000 years ago, when the lake was a more permanent feature of the
landscape, a group of people sat down on the shore to eat. Nothing strange about
that, except that what they were eating could help to answer two of the most
important questions about Australia’s ancient past. Did people have anything to
do with the disappearance of the gigantic animals that once roamed the
continent? And when did the early Australians head inland from the bountiful
coastal regions to colonise the less hospitable interior?
The main course at that lakeside dinner has provided the first
incontrovertible evidence that there were people around at the same time as some
of Australia’s extinct giants. The discovery of bones from long-dead megafauna
alongside bloodstained stone tools, charcoal and other signs of human activity
may provide the best clue yet to the fate of megamarsupials—the Australian
equivalent of Europe’s mammoths and giant elk, and the great bison and ground
sloths of the Americas.
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As a side dish, the diners ate porridge or “cakes” made from expertly milled
grass seeds, a type of food processing that is not supposed to have developed
for another 20 000 years—and then on the other side of the world. It shows
clearly that these people were able to make a reasonable living in apparently
hostile country from a very early stage. “Cuddie Springs is arguably the most
brilliant site ever found in Australia,” says Richard Fullagar, an expert on
stone tools at the Australian Museum in Sydney and one of the team excavating at
the lake. “It is the linchpin in lots of different arguments.”
The question of what happened to the world’s megafauna is a global one. By
the end of the last ice age, around 10 000 years ago, most of the giant species
of reptiles, birds and mammals had disappeared. After almost a century of debate
over their fate, there are two main schools of thought. One maintains that the
great cooling and drying of the climate that accompanied the last ice age made
most of the world uninhabitable for animals that needed prodigious amounts of
drinking water. The other argues that the arrival of that most effective of
predators, Homo sapiens, heralded an age of slaughter that soon saw off
the gentle giants.
Shrinking monsters
There are several variations on this theme: that diseases spread by the
incomers and their animals wiped out the megafauna, or that the deliberate
burning of overgrown scrub to promote new growth destroyed their habitats. Some
researchers believe that a combination of factors was probably to blame. In
fact, not all the great Australian beasts disappeared. Some shrank. Today’s red
kangaroos and Tasmanian devils, for example, are smaller versions of prehistoric
giants.
None of these explanations is wholly convincing. While climate change hit all
the continents at the same time, there are huge variations in the timing of
extinctions. In Australia, almost all the biggest animals appear to have gone by
about 35 000 years ago—well before the ice age reached its maximum. In the
Americas, they persisted for another 20 000 years or more—until well after
the ice retreated to the poles. Not only that, the last ice age was merely one
of 17 over the past 2 million years, and none of the others triggered such a
rash of extinctions.
The idea that people wiped out the great beasts within a few hundred years of
arriving on the scene poses an even bigger problem: there is no archaeological
evidence that humans systematically slaughtered the biggest animals. And in
Australia, there is no sign of hunting at all. Indeed, until Cuddie Springs was
excavated there was not one piece of unequivocal evidence that put people and
megafauna in the same place at the same time.
“Most of the discussion about people and megafauna so far has been based on
supposition from a few bits of bone and a few artefacts, but there have been no
complete bones and stone artefacts together,” says Judith Field, the
archaeologist at the University of Sydney who is in charge of excavations at the
site. “Cuddie Springs is it—where you have both together in undisturbed
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An expedition by the Australian Museum early this century retrieved a
collection of megafaunal bones from Cuddie Springs, but the archaeological
significance of the site only became clear in 1990, when a preliminary dig
revealed signs of human presence. In 1991 and 1994, Field carried out further
excavations with a team from the University of New South Wales, the museum and
the local Aboriginal community. They uncovered a series of layers of sediment
that records the comings and goings of animals and people, and documents with
rare precision the changing environment around the lake.
At the deepest, prehuman level lie the bones of a large number of species of
long-extinct animals, from the monstrous marsupial “tree feller”
Palorchestes, to the giant emu-like Genyornis. There were huge
reptiles too: horned turtles, crocodiles and a formidable predatory goanna.
These remains probably date back more than 100 000 years.
In a distinct layer above this ancient graveyard are the first signs of a
human presence, where animal bones are mixed with stone tools and charcoal from
camp fires. This layer, dated to between 30 000 and 35 000 years, includes
Genyornis and the wombat-like Diprotodon, the largest marsupial
ever. Above this is a layer 30 000 years old which is jam-packed with animal
remains and tools, including the first of many seed-grinding stones.
These levels are capped by a stone pavement that represents a long dry period
around 28 000 to 19 000 years ago when the sediments were blown away. “The
pavement is so dense with bones and stones that you can’t get a trowel between
them,” says Field. After this, the megafauna disappear, but grinding stones are
present all the way to the surface.
Pollen preserved in the layers, along with the nature of the mud and silt
particles, document the changing climate and vegetation. When the first people
arrived, Cuddie Springs was a swamp with abundant freshwater fern that grows
only in still, shallow waters. By 30 000 years ago, the climate had begun to dry
out and people were camping on the claypan floor of the lake, and would probably
have had to dig for water in dry years. The lake then entered a prolonged dry
phase as the ice age tightened its grip on the world, and by 19 000 years ago,
at the peak of the ice age, the saltbush had more or less given way to
grassland.
The finds at Cuddie Springs put people and megafauna in the same place at the
same time, but they don’t prove that people were killing the animals. The bones
show no obvious signs of butchering. But as Field points out, recent experiments
have shown that it is possible to cut up a carcass with stone tools and leave no
mark.
Butcher’s tools
The tools have yielded more information. Their design generally provides some
clue to their function: hammerstones were for smashing joints, sharp-edged
flakes could be used for cutting or scraping meat from bones. Field and
Fullagar’s analyses of the microscopic patterns of wear on the tools from Cuddie
Springs—and the residues of blood, hair and other tissues—lead them
to believe that those from the lowest levels were used mainly for stripping meat
off bones and processing soft tissue. “This is compelling evidence for a
relationship between people and megafauna—because if they weren’t
butchering these animals, what were they butchering?” says Field.
Tom Loy, a molecular archaeologist at the University of Queensland in
Brisbane, is convinced that some of the traces of blood on the tools from Cuddie
Springs are from megafauna, or at least from Diprotodon. Loy has spent
more than a decade studying blood, fat and other remains on dirty tools,
borrowing techniques from pathology, immunology, molecular genetics and forensic
science. Red blood cells are often visible under the microscope. Hairs have a
characteristic pattern on the outside and collagen looks like a rope
unravelling. “They are all pretty distinctive,” says Loy.
There is surprisingly little degradation of blood, says Loy. “We don’t know
how much of it disappears over time but what’s left is very recognisable as
blood.” Anything that looks like a bloodstain is tested: first with an Ames
Hemastix, a dipstick that turns from yellow to green in the presence of minute
traces of the blood protein haemoglobin. The test, more familiar in hospital
labs where it is used to check for blood in the urine, is a cheap and easy way
of deciding whether further investigation is worthwhile. Field and Fullagar have
used Loy’s techniques to test for blood on hundreds of artefacts from Cuddie
Springs, confirming that most of the greasy marks and spots that look like blood
under the microscope really are what they seem.
The next step is to narrow down the origin of the blood with an antibody
test. The antibodies staphylococcal protein A and streptococcal protein G bind
to immunoglobulin G, an important protein in mammalian blood. If the test is
positive, the blood came from a mammal. And if it was a mammal, the
million-dollar question is which one? One way to find out is to grow haemoglobin
crystals from the blood sample. The size and shape of the crystals are
suggestive of a species, says Loy. The technique is difficult and the crystals
don’t last long, yet it provided what Loy believes was the first, fleeting
glimpse of megafauna on a tool from Cuddie Springs. “We tested a tool taken from
among the bones and found a few Diprotodon-like crystals,” he says.
“Then they disappeared.”
Loy is close to perfecting a more reliable means of identifying the source of
the blood—by sequencing fragments of DNA retrieved from the residues. With
a PCR machine, which can accurately replicate the fragments millions of times
over, Loy can generate enough DNA to work with. He looks at a stretch of DNA
about 100 base pairs long from a gene called 28S rRNA, which has a role
in assembling ribosomes, the protein factories found in every animal cell.
The first section in the sequence is common to all animals. “Then there is a
bit that’s diagnostic of mammals,” says Loy. “And then there’s a variable bit
that depends on which mammal it is.” Before you can identify an animal, however,
you need something to match it to—in this case sequences from known
species of extinct animals. So Loy is building up a reference library of
sequences with DNA extracted from bones held in collections and museums.
“Fortunately there are heaps of diprotodons,” he says.
Loy has tried to sequence DNA extracted from residues on two of the Cuddie
Springs tools. One produced a match with the hairy-nosed wombat, a species that
is not present in New South Wales today. The second produced something partway
between a wombat and a Diprotodon.
“These two tools were relatively small and unspecialised and were unlikely to
show much, yet we turned up these sequences,” says Loy. So the chances of
finding a definite Diprotodon look pretty good. “We have concentrated
on diprotodons because people want to know about them. They were so weird and so
big that they capture the public imagination,” he says. “But now we need to look
at giant kangaroos such as Sthenurus and get some Genyornis
samples to work on.”
The DNA might prove beyond a doubt that people were butchering
Diprotodon and its contemporaries, but it won’t show whether they hunted
them or scavenged from a dead or dying animal. Some palaeontologists believe
that the first hunters did not pursue large animals because their weapons
weren’t good enough or because they were not prepared to take the risk.
Direct evidence for hunting is hard to find. The early Australians made their
spears and arrows from wood, which is rarely preserved. But, as Loy points out,
the risks of attacking Diprotodon might not have been that high.
Although it was enormous, weighing in at around 2 tonnes, Diprotodon
had a tiny brain and was probably a slow and shambling beast. “They weren’t very
bright,” says Loy. “And the arrangement of their shoulder blades meant they
would have had a cumbersome gait.” If Loy finds the blood of the faster-moving
and more agile giant kangaroos, the team can be more confident that people were
hunting them.
Whether the lake people were hunters remains unproven, but they were
certainly millers. Field has excavated 33 fragments of grinding stones from
Cuddie Springs, 21 of them dating from the same time as the megafauna. Fullagar
suggests that the polished surfaces of these stones, and plant material still
sticking to them, show that they were not used to process energy-rich roots and
tubers, as you would expect at that time, but grass seeds, a foodstuff that
requires a lot of hard work for far less reward. “Seed grinding was thought to
be a late development in human history linked to the development of agriculture
and settled societies,” says Fullagar. Before this, the earliest known seed
grinding stones came from the Middle East and date from around 12 000 years ago.
“It pushes the date for this technology way back,” he says.
Shiny stones
Some of the Cuddie Springs grindstones show evidence of “wet milling” of
grass seeds, a technique in which seeds are first ground dry, and then water is
added and the mixture ground again to make a floury paste which might be eaten
raw or cooked in the fire. “Wet milling produces a distinctive gloss on stone,”
says Fullagar. “It’s the effect of silica [from plant tissues] on stone. It
smooths the stone at the molecular level to produce a mirror-like shine.” Wet
milling was previously thought to have developed only 3000 years ago.
As with butchery, processing plants leaves telltale residues on stone tools,
including starch grains and phytoliths, the silica skeletons of plants.
“Phytoliths are the key to identifying which plants were being processed. Tubers
don’t have them. Grasses do,” says Fullagar. Starch grains and phytoliths have
such distinctive forms that they should eventually help in identifying the
species of grass. Some archaeologists argue that seed grinding is a very
recent innovation, developed after the ice age as part of a “dietary
revolution”. Once they had adopted grasses as foods, people would be better
equipped both to live in marginal country and to deal with changes in climate
and food supply. In Australia, there has been much debate about whether people
had to begin milling grass before they could inhabit the arid
interior—which would have put a late date on their movement inland. The
evidence from Cuddie Springs suggests that early Australians had the means to
survive in an arid landscape 30 000 years ago.
Field argues that people may have milled grains occasionally, but only began
to rely on seeds as the climate dried out in the last ice age. “Perhaps Cuddie
Springs is where seed grinding developed. It’s difficult to say,” she says.
There may have been compelling reasons why people wanted to stay despite the
worsening climate. And if they wanted to stay they needed to switch to new types
of food. The lake might have been an important ceremonial site: the team has
found a conical stone or “cylcon”, which possibly had some ritual function.
Cuddie Springs is part of an Aboriginal dreaming track, and there is a dream
time story that provides an explanation for the presence of the bone deposits
there.
Whatever their reasons for staying, the residents of Cuddie Springs do not
fit the traditional image of a small band of people scraping a meagre living
from the inhospitable land of Australia’s interior. Even in the face of dramatic
climate changes and the dwindling supply of large animals, these people had the
means to support a thriving group. But did they—and their counterparts
across the continent—have any impact on the megafauna?
“Cuddie Springs won’t answer the question of whether there was a Pleistocene
overkill. Nor will any one site do that,” admits Loy. If people hunted
Diprotodon, then it was probably just one of many animals they killed. But
it is possible that people played some part in the demise of the large animals
in the immediate area, suggests Field. “Only a handful of megafaunal species are
found in association with artefacts at Cuddie Springs. So maybe the megafauna
were already in decline.” It might have been a case of hitting a large animal
when it was already down.
- Further reading:
The Future Eaters by T. Flannery (Secker and Warburg). - Archaeology of the Dreamtime by J. Flood (Collins).
- Pleistocene seed-grinding implements from the Australian arid zone
by Richard Fullager and Judith Field, Antiquity, vol 71, p 300 (1997)