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References and readings:
R Gilroy, 1980. “Why yowies are fair dinkum.' Australasian Post, August 7, 1980. p 12-14. Gilroy's description of yowies.

J Lytton, 1979. "The great Australian yowie hunt.' People, August 16,1979, p 38-39. Cast of yowie track andGilroy's "fossils" illustrated here.

Anonymous, 1979. A register of "monsters". North West Magazine, December 17,1979, p.6. Gilroy quotedregarding partial carcases of yowie.
the Yowie-Ocalypse
Revelation in the Age of Bigfoot
A Naked Yowie Project Initiative
 General articles about yowies:
The Evidence for the Yowie

by Ralph MoInar
The Skeptic Vol 2, No 4
June 1994
as we have evidence the immigrants were either (i)
flying forms, (ii) small forms or (iii) carried in boats.
These considerations suggest that large non-human
primates in Australia are unlikely. However, this
matter needs to be pursued further.

Let us look in greater detail at how the immigrants
arrived. Marsupials and monotremes seem very likely
to have been here from the beginning, having inhabited
this portion of Gondwanaland before it broke into
modern southern continents. Bats arrived doubtless
by flying, rather soon after the break up of
Gondwanaland, being here by the middle of the
Miocene some 20 million years ago. Rodents arrived
later, at the beginning of the Pliocene (some five
million years ago), and the evidence suggests that they
made their way from southeast Asia via Indonesia and
New Guinea and spread south through Australia from
Cape York. Humans arrived even later, presumably
from Indonesia (where human remains date back well
over a million years) and were established in Australia
probably by 50,000 years ago. Dingoes were the last
to arrive, undoubtedly accompanied by humans, only
about 7,000 years ago.

Very likely all of these immigrants arrived from
Asia via Indonesia, and at least in one case, New
Guinea. During the Pleistocene much of the world's
water was stored in the polar ice caps, and hence the
sea level was lower than at present, perhaps by as
much as 200 metres. While this is enough to transform
Indonesia from an archipelago into a broad peninsula
(Sundaland), it is not enough to join Indonesia to
Australia. Thus only those creatures that could cross
the two remaining sea gaps, each 50 to 100 miles wide,
between Sundaland and Timor and between Timor and
the Australian shelf (Sahulland) reached Australia.
Rodents presumably drifted on floating vegetation, and
humans in boats. So far as I am aware none of the
great apes has exhibited much ability to cross sea
barriers, so we might conclude that it is unlikely that
an ape invaded Australia from Indonesia.

The finding of a yowie, of course, would disprove
this. Thus we would theorize, were a yowie to be
discovered, that it had somehow crossed these sea
gaps. But we cannot reverse this process and say that
because such a potential route to Australia exists, that
yowies exist. After all there are the gaps and a fair
amount of chance seems involved in both crossing
the gap and in establishing a population on the other
side. We cannot say which animals will make this
crossing (with the exception of humans with their
boats, and of flying forms), and which will not. Many
of the Indonesian animals, such as tigers, rhinoceroses,
etc., were not able to make this crossing. So
biogeography suggests that yowies are unlikely, but
does not prove them impossible.

We may also ask how yowies would relate to the
Australian environment, specifically would the yowie
fill an otherwise vacant niche? Unfortunately niche
theory is, so far, difficult to use predictively. We know
that vacant niches do occur, for sometimes an
introduced animal can move into an environment
without much disturbing the already existing forms -
although admittedly this seems the exception rather
than the rule. The eastern coastal rain-forests of
Australia would seem to have a vacant niche for an
ape or ape-like form, just as many of the Australian
terrestrial environments seem to have a vacant niche
for a large carnivorous mammal. However just
because a given type of animal is absent from an
apparently appropriate environment does not mean
that the niche is actually vacant. There may well be
reasons why that type of animal would not survive in
that environment, such as inadequate carrying capacity
(i.e. insufficient resources to support the animal), or
even too small a geographic area. So niche theory
doesn't seem to help much.

What about population biology? We often hear,
particularly in regard to the Loch Ness "monster" and
such, that for a species to persist there must be a
sufficiently large population for breeding. It is then
assumed that a sufficiently large breeding population
is a numerically large population, and that with such
numbers of individuals it should be reasonably easy
to find one, if the beast actually exists. The conclusion
drawn is that the "monster" does not exist or else we
would already have found specimens. I think that this
is not a very convincing argument, as it does not take
into account fluctuations in population size. This is
also relevant is assessing whether a species may have
become extinct, as mentioned previously in connection
with the desert hare-wallaby and the Moonie River

It may be that for large mammals the populations
do not fluctuate much in the undisturbed state, but we
do not yet know this. Certainly for smaller mammals
great fluctuations may occur, and a prime example of
this is the desert rat-kangaroo, Caloprymnus
campestris. Caloprymnus was originally discovered
in 1843 and was known from only three specimens. It
was not seen again for over 85 years, but in 1931 it
unexpectedly appeared in reasonable numbers. Since
1935 it has not been seen again. Now admittedly this
is a desert animal, living in regions of low human
population density, but nonetheless it does
demonstrate that a population can be very low for a
long period and then become reasonably common,
only, in this case, to disappear again.

This kind of thing should make us wary of the kind
of argument mentioned above in regard to the Loch
Ness monster. On the other hand, it must be admitted
that a creature reported as often as is the yowie (or
the Loch Ness monster for that matter) would be
expected to have a reasonably large population size,
after all apparently no one saw (or at least reported)
Caloprymnus for 80-odd years. I wonder if "unknown"
animals very rarely reported are actually more likely
to exist that those often reported.

The various bodies of biological theory are not as
helpful as might be wished - they suggest that yowies
are not likely (from biogeography) but they do not
prohibit the possibility of their existence. Indeed, when
first reported the platypus was judged less likely to

There is no reason to say that yowies do not exist,
but likewise no convincing evidence to say that they do. In theory, Mr. Gilroy and others who believe in yowies have a simple task, to produce one - however
this task is never as simple in practice as in theory.
The important thing that the case of the platypus
showed in this regard is that when specimens of an
alleged animal becomes available all of us, scientists
and laymen alike, will accept its existence. Obtaining
the specimens is often no easy task, but its very
difficulty shows why we are sceptical.

The difference here between believers and sceptics
is in the value given various kinds of evidence. And
this, in turn, is based on the basic beliefs and values
of the individual. Go through almost any scientific
magazine and you will find evidence no better than
any here mentioned, accepted without examination
when it supports the political and social beliefs of the
editors. Much depends on what we choose to be
sceptical of I wish Mr Gilroy and others who would
discover the yowie every success, but I will wait until
I see it to relinquish skepticism myself.

Cryptozoology is the study of animal species not generally recognised as existing in the real world, but which are not inherently implausible phenomena. Unlike many paranormal and pseudoscientific beliefs, the discovery of a Loch Ness Monster or a Yowie would not overturn any fundamental scientific principles. New species of animals are regularly being identified, and although these tend to be smaller animals, such as insects, there is recent evidence that a previously unidentified large ungulate may exist in Vietnam.

Where cryptozoology differs from regular zoology, and where it falls within the parameters of a pseudoscience, lies with its treatment of sketchy or non-existent evidence as the basis for unwarranted and often highly fanciful speculation by its more avid Proponents.

While the discovery of a Yowie is possible, though highly improbable, many of the characteristics attributed to it by believers are absurd.
One sighting reported to the Museum lasted not
longer than three seconds according to the witness
and was made through heavy scrub, so that at no time
was more then a small portion of the beast visible.
The Nerang sighting was reported to have lasted less
than three seconds, Mr Gilroy reported this sighting
to have been a matter of seconds, and even the events
of the Kilcoy sighting may well have lasted less than
a minute, even though no duration was given to my

Even when no durations are quoted in the reports,
it is often clear the seeing condition were far from
optimal. A report from Dunoon mentions the sighting
took place in dense scrub, one from Springbrook in
bushes, one at Murgon just before dusk, and that at
Coomera Valley around midnight.

Most reports are made by city dwellers, rather than
people living on properties. We can all appreciate that
under conditions in the bush, often at least unfamiliar
to city folk, it can take well over a minute to recognize
an animal, even if it is large. This is notably true when
the light is poor, the foliage thick, or even in good
light if there is marked contrast between the light and
the shade. In such cases, where it is difficult to see an
entire animal, a mistaken impression may easily be
gained from a short observation of the back of a beast
disappearing into the bush.

Even greater than the problem of recognition, is
that of memory. We are accustomed to thinking of
memory as a record like a film or a book, that preserves
just what we perceive and thereafter as long as we
live it is indelible. There may well be such a memory,
as the research of Wilder Penfield has shown, but if
so it is not the day-to-day kind of memory involved in
reports of yowies and such. That memory has been
shown to be very mutable indeed. It appears that only
certain abstract features of an event are stored, the
rest being conjured in some fashion from the
imagination to provide a "memory". This memory may
well be influenced by factors attendant upon its recall,
such as the questions asked by investigators. In one
well-known experiment two groups of subjects were
shown a series of coloured slides depicting an
automobile accident that occurred after the vehicle
had passed through a stop sign. One group was queried
as to the happenings after the vehicle had passed
through the stop sign, and the other after it had passed
through the Yield (ie Give Way) sign. A substantial
proportion of the later group later remembered the
vehicle as having passed through a Yield sign and not
a Stop sign, because they were asked about a Yield
sign and not about a Stop sign.

Thus while we may fairly say that reports of unusual
things made under unusual conditions may well be
accurate, we cannot assume this accuracy without
extensive independent supporting evidence. This is
why science chooses to deal with phenomena that can
be repeated (or repeatedly observed) under controlled
(although not necessarily laboratory) conditions. In
the case of the yowies there is supporting
circumstantial evidence, although even an ardent
believer would be hard pressed to call it extensive.
Neither is it independent, as we have seen. But as
Sherlock Holmes reportedly remarked:

"Circumstantial evidence is a very tricky thing. It may
seem to point very straight to one thing, but if you
shift your own point of view a little, you may find it
pointing in an equally uncompromising manner to
something entirely different." Certainly such is the
case with the evidence for yowies as one shifts from
belief to disbelief (or the reverse).

Convincing independent circumstantial evidence is
lacking as even Mr Gilroy admits. Mr Gilroy's alleged
fossil tooth of a yowie (as well as all of his alleged
fossil bones or implements illustrated in the news
media) viewed from any point other than that of
absolute faith dissolves into merely a suggestively
formed pebble - rather like the fairy treasure of old
tales dissolved into dry leaves in the light of day. Thus
sightings are unreliable as evidence as the reader is
doubtless aware.

What would then constitute evidence, or better,
proof? I would accept only two items: a live beast, or
a carcase (or a substantial portion of one). Neither of
these has yet appeared. Mr Gilroy has mentioned a
portion of a carcase but, as inevitably seems to happen
in such cases, it is reportedly jealously held by the
finder, and not available for general inspection. Mr
Gilroy also claims to have some fossil material which
I will comment on later fossil material it must be noted
does not constitute proof of the existence of a living
animal. There are other reports of carcases of yowies
or yahoos (some in Joyner's booklet), but always
removed twenty or seventy years into the past.
In fairness I must admit that the non-existence of
skeletal or other remains does not, contrary to what is
often thought, constitute evidence that yowies do not
exist. There are indeed Australian (and other)
mammals, although none so large as yowies are
alleged, that are known only from very sparse remains.
The most extreme example, Lagorchestes asomatus,
the desert hare-wallaby, is known only from a single
skull collected in 1932. It is generally assumed that
this beast is now extinct. There are others almost as
sparsely known: the Moonie River (Queensland)
wombat, Lasiorhinus gillespiei, is known from only
three incomplete carcases, all found before 1891. We
usually assume that animals so sparsely known are
extinct or very close to it, but there are some examples
that suggest that this need not be so, notably the desert
rat-kangaroo, discussed later in a somewhat different

In the absence of compelling evidence for the
existence of yowies can we rationally evaluate their
plausibility? First let us examine that the witnesses
have in fact seen just what they have reported seeing.
There are several bodies of biological theory that
might be of assistance here: biogeography, niche
theory and population biology. The most obvious,
evolutionary theory, is not very useful. Fortunately
(or unfortunately) there is nothing about yowies as
reported that seems implausible in light of modern
evolutionary theory. Some modern evolutionists, such
as SJ Gould, feel that evolutionary theory ought not
to be used to make any kind of predictions at all and
hence would argue that no such reported beasts as
yowies can be said to be implausible because of
evolutionary considerations. Other evolutionists, such
as R.Riedl, I think would disagree.

Turning to biogeography, we note that, roughly
speaking the native mammalian fauna of modern
Australia consists of two groups. There are those that
have evolved in Australia since the end of the
Mesozoic, the time of the dinosaurs, and those that
have migrated to Australia probably during the past
40 million years (since the early Miocene times). The
former group includes marsupials and monotremes,
and the latter group the placental forms, such as bats,
rodents, humans and dingoes. Both bats and rodents
are forms that have demonstrated the capability for
wide dispersal over water, as of course have humans.
So their appearance in Australia should not cause any
conceptual difficulty. Presumably dingoes came with
humans, who very likely arrived in boats. Thus so far
To anyone used to the mammals of Europe or North
America, Australia is the land of unique, unfamiliar
and exciting mammals: the marsupials and
monotremes. Indeed there are many other unusual and
interesting organisms in Australia, the result of a long
period of isolation while the rest of the world was
changed. Australia has also produced reports of beasts
that, if true, would make it a land of even more unusual
animals. The most widely known and popular of these
reported beasts is the yowie, once called the yahoo.
The yowie, as most of us are aware, is supposedly a
large, furry or hairy, ape-like creature reported largely
from eastern New South Wales, with some reports
from eastern Victoria, and recently, south eastern
Queensland. Much, but certainly not all, modern
information about yowies comes from Mr Rex Gilroy,
who pictures yowies as giant (up to 3 metres tall)
hominids related to the supposedly giant
Gigantopithecus and Meganthropus of eastern Asia.

In spite of the large jaws and teeth of these two forms,
there is no evidence that these latter animals were any
larger than modern apes.

The older yahoos indicate a beast somewhat
different from the Gilroy conception. Many of these
reports have been republished verbatim in a little
booklet "The Hairy Man of South Eastern Australia",
by Graham Joyner of Canberra. These reports, dating
from 1871 to 1912, indicate an ape-like beast about
the height of a man. Some reports say that it was
shorter than a man, and some that it was as tall as a
tall man. In some reports there is also some suggestion
that it resembled a bear or a wombat and at least one
witness reported it in a tree. The modern yowie reports
are usually interpreted in terms of the popular
conceptions of the North American bigfoot
or the Asian yeti. These older reports, however, do
not indicate a creature as large or as human-like.

Evidence for yowies falls into four major categories:

(i) Miscellaneous unusual nocturnal noises;
(ii) Scratches and other markings of tree bark,
including torn bark;
(iii) Casts or photos of footprints;
(iv) Reports of sightings.

The noise category is most difficult to deal with, as
many native animals make loud and startling nocturnal
calls, for example, owl screams, the cries of grounddwelling
birds, possum territorial calls, feral pig
snuffles and grunts and koala mating cries. For any
person not used to all of these, and most citydwellers
are not, they can be difficult to identify with certainty.
Since no recordings of alleged yowie cries are
available, and since the descriptions given are rarely
detailed, we can really conclude nothing from this type
of report.

Torn bark and scratches on trees are unimpressive
as evidence for these are rarely pictured clearly or
described in detail and there are many possible
mundane causes to be eliminated. Gliders leave
characteristic scratches in bark, while cattle, deer and
such introduced animals may scratch or gore tree bark.
Lightning also can shred bark in long lines down the
trunk, and one report telephoned to the Queensland
Museum was due simply to peeling bark of a gum.
Unless sources such as animals or lightning can
definitely be ruled out, and this is often much more
difficult than usually thought, these reports really leave
nothing to go on.

Footprints are something else. Often considered as
hard evidence, they are in fact little better than reported
sightings, especially if casts or photos are involved.
The actual footprints in place can be examined to
determine whether or not they are genuine,
independent of the witnesses' reports, and hence
constitute independent evidence. Although footprints
may be faked, notably by making and wearing on the
feet snowshoe-like models, footprints are more easily
checked than either casts or photos. Both casts and
photos of footprints can be faked. Their evidentiary
value depends entirely upon the reliability of the
witness. Because footprints can be faked, they do not
constitute good evidence, either alone or in
combination with reported sightings.

The published photos of yowie tracks and of casts
made of the tracks range from those which appear to
represent tracks (although whether of yowies or of
models cannot be determined) to those which seem
most peculiar. Those reported with the Kilcoy (Qld)
sighting of 1979 are odd in two respects. First they
are quite elongate, more than those of any known large
primate and second they show only three toes. Because
they are so narrow there is no question of toes having
been lost, as say from injury, for there is simply no
room for them.

In addition, as illustrated in the newspapers, these
tracks had no debris - leaves, twigs, etc - in them,
although made in grassy and wooded country. They
appear to have been cleaned by some agency, certainly
not what one would expect from an animal whose
alleged weight should impress leaves and twigs into
soil soft enough to retain tracks. I have not seen the
original tracks, but the newspaper photos do not
indicate anything other than suggestive depressions
of the soil carefully cleaned out. Some of Mr Gilroy's
tracks appear much more ape-like, and certainly could
not have been made by the same kind of animal as

those at Kilcoy. However, even the casts made by Mr
Gilroy could be of faked tracks, made by models as
mentioned previously. Although such fakery may seem
unlikely, in the attempt to establish the existence of
an otherwise unknown animal, only such evidence as
absolutely cannot be faked is admissible.

When we turn to an examination of the reports
things become more tenuous. The sightings, both those
reported in the newspapers and such as have been
telephoned to the Queensland Museum, are based very
largely on fleeting glimpses, often under poor
References and readings:
General articles about yowies:
R Gilroy, 1980. “Why yowies are fair dinkum.' Australasian Post, August 7, 1980. p 12-14. Gilroy's description of yowies.

J Lytton, 1979. "The great Australian yowie hunt.' People, August 16,1979, p 38-39. Cast of yowie track andGilroy's "fossils" illustrated here.

Anonymous, 1979. A register of "monsters". North West Magazine, December 17,1979, p.6. Gilroy quotedregarding partial carcases of yowie.
Newspaper reports of yowies.
Gold Coast Bulletin, August 25,1978, p7. Nerang report.
Ibid, October 18, 1978, p16. Coomera Valley report.
Ibid, March IQ 1979, p& Springbrook and other reports.
The Telegraph (Brisbane), October 2,1979, p14. Murgon report.
The Courier-Mail, January 4,1980, pl. Kilcoy report.
The Sunday Sun (Brisbane), April 24,1981, p32.
Dunoon report GO Joyner, 1977. “The Hairy Man of SouthEastern Australia” (privately published, 27 pp.) A compendium of old newspaper reports of the yahoo.
General information about Australian mammals:
WDL Ride, 1970. 'A Guide to the Native Mammals of Australia' (Oxford University Press, 249 pp). Includes details of very rare Australian mammals mentioned.
Information on the reliability and otherwise of memory:
EF Loftus, 1979. *The malleability of human memory American Scientist, 67, pp312-320.
MJ Tyler, ed, 1979, 'Me Status of Endangered Australian Wildlife' (Royal Zoology Society. S. Australia, 212 pp).More details of very rare Australian mammals.
General information about problems of perception and recognition:
G Reed, 1972. 'The Psychology of Anomalous Experience' (Hutchinson).
HE Ross, 19174, 'Behaviour and perception in Strange Environments" (George Allen & Unwin).
JE Rodgers, 1982. ‘The malleable memory of eyewitnesses’, Science 82, June, pp32-35.

Dr Ralph Molnar was Curator of Mammals at Queensland Museum and is a member of the Queensland Committee of Australian Skeptics.