No study of our primitive human-like ancestors is complete without knowing something about the
environment in which they lived. Because we are primarily concerned with the ‘unknown’ Stone-Age past of pre-Aboriginal Australia, we shall confine ourselves to our part of the world.
As the authors have evidence to hand pointing to a Miocene-Pliocene primate/ancestral
hominid fossil record within Australia, linked to a new theory involving the continental break-up in
geological times, and which we shall turn to in the following chapter, we shall here confine ourselves to
a picture of life in those times…
Throughout the Tertiary Period, which began around 65 million years ago and covered the next
six epochs, as discussed in the next chapter, Australia was invaded by the sea. It had retreated during
the previous Oligocene epoch, but advanced again shortly before the beginning of the Miocene epoch.
The most extensive flooding took place in the southern part of Australia. Elsewhere rainforests were
gradually replaced by more arid-adapted woodland and savannah expanses. The Mammalian fauna at
this time included grazing diprotodontians: at least four genera of Marsupial Lion; the Thylacine; giant
flightless birds such as Dromornis australis and other megafauna.
The coming of the Pliocene period around 7 million years ago saw a recession of the sea and
intense volcanicity over a wide area of eastern Australia. At the same time our growing marsupial fauna
saw diprotodontian marsupials [which included possums and wombats] evolving quite ‘modern’
features. There was a lush environment with much permanent water. Certain fossils about to be
discussed in the next chapter suggest that primate species, particularly the earliest ground-dwelling
forms, were present in Australia during the Miocene.
They were joined by the beginning of the Pliocene
by ancestral hominids as suggested by the Bega skull endocasts.
Our fossil evidence for Miocene primate presence is sparse at present, but the environment of
the time would certainly have been favourable to these animals. As these ancient primates would have
been herbivores [folivores], they would have routinely consumed significant amounts of insects on the
leaves that they ate. As we humans are primates this information is relevant! Primate diets tend to be
highly variable on a month-to-month basis in the wild.
We cannot say whether the owners of the primate feet and hand slate fossil impressions [see
next chapter] were entirely herbivorous. They might have been omnivorous feeders and therefore
might have displayed predatory behaviour towards other animals, even their own kind. As Harding
[1981] reports, there is widespread evidence of predatory behaviour and meat consumption among
non-human primates.
“It is now clear that several primate populations make regular and substantial use of precisely the type of food
[animal flesh] which the early theories described as instrumental in the emergence of hominids”.
Carnivorous feeding habits in our primate ancestors led to the use of the first crude weapons
such as jagged bones and stones and broken tree limbs used as clubs, which in time led to the
development of crudely flaked stone tools and sharpened saplings for spears etc, as our primate
ancestors began to progress to a more near-human evolutionary stage.
It is argued by the authors that, at the time these events were transpiring, Australia and New
Guinea were part of a great land shelf joined to mainland Asia during Pliocene-Pleistocene times and
that an offshoot land shelf joined New Zealand [then a single landmass] to New Guinea.
By the dawn of the last great Ice-Age, the Pleistocene period, around 2 million years ago,
following the close of the Pliocene period, and which was to last until about 10,000 years ago, a wide
variety of unique species had evolved in Australia. Unlike the harsh conditions of the northern
hemisphere, Australia did not experience extensive glaciation, this being confined to the Victorian-New
South Wales Alps and also Tasmania.
The rest of Australia experienced a warm and temperate climate, the interior being a land of
richly vegetated plains, forests, lakes and river systems. This environment supported a vast population
of marsupial, bird and reptilian life, and they in turn provided an endless supply of food for our Stone-
Age hominids.
Rex Gilroy
Australian Yowie Research Centre,
Katoomba, NSW
Monday 25th June 2007
