|1936 to present
In the early 1990s,
Professor Henry Nix of the Australian National University's Centre
for Resource and Environmental Studies was intrigued by the frequency of
thylacine sightings, and decided to investigate how closely they coincided
with a computer generated map of where thylacines would most likely exist.
Nix developed a program called BIOCLIM, which
accurately predicts where an animal, plant or particular ecosystem should
Nix drew upon scientific
collections and official government records of where thylacines were shot
and trapped by farmers and bounty hunters from the late 1800s until the
early 1900s. From this data, he generated a map showing optimal,
sub optimal, and marginal areas of potential habitat.
He then compared sighting
records from 1936 onwards, and classified them into three groups based
on their reliability - e.g., reliable, less reliable, and unreliable.
Discarding the unreliable sightings, he used the remaining sightings as
independent data sets matching them against the BIOCLIM map. The
data sets matched the BIOCLIM predictions of where thylacines should occur
almost perfectly, with the greatest frequency of sightings clustering within
the areas of predicted optimum habitat. Statistically, the chance
that these independent data sets should so closely coincide is virtually
zero. Nix concluded: "These people really are seeing thylacines.",
and advised that a thorough search for living thylacines be made before
expending considerable resources in an attempt to clone the species.
Adherents to the 1936
extinction hypothesis argue that if the thylacine were still extant, then
a body would surely have been found or reported as road kill. Also,
prior to the appearance of Devil Facial Tumour Disease (DFTD), the devil
population was increasing, and this they state, indicates the removal of
the top predator. Both these points are valid considerations.
They also contend that
a small population of thylacines could not survive because of the problems
encountered with inbreeding. Thylacines and their cousins, Tasmanian
devils, have a low level of genetic diversity in comparison to other Australian
marsupials (Miller et al. 2009), consistent with a "founder effect".
In population genetics, the founder effect is the loss of genetic variation
that occurs when a new population is established by a very small number
of individuals from a larger population - this is true for many island
Inbreeding and the subsequent
loss of genetic diversity would certainly expose any remnant thylacine
population to an increased risk of extinction. This can be seen in
DFTD, where few devils show any natural resistance to the disease.
A DFTD Management Strategy Report produced by the Department of Primary
Industries, Water and Environment (February 2005) states:
"Research has shown
that due to the naturally low genetic diversity of Tasmanian devils, only
a relatively low number of founder animals are required to represent the
natural diversity of the species. Population genetic research suggests
that 25 individuals collected from a range of locations will be appropriate
to establish and maintain a captive population long term".
This is also likely to be true for the thylacine.
It is not the intended purpose of this section to provide detailed analysis
and comment on each and every sighting, as there have been literally hundreds
in the last 80+ years. Neither is it the museum's intention to argue
that all sightings are genuine, as that too is blatantly not the case.
Rather, we aim to provide evidence for the reader to at least question
the blank acceptance of the 1936 extinction hypothesis.
Post-1936 sightings do not appear to be area specific - rather, they have
been reported throughout the thylacine's entire historic range. A
number of the reported sightings were made by experienced bushmen who had
previously hunted the thylacine, or by park rangers, both of which are
highly unlikely to have made an error in identification.
Distribution of all
thylacine sightings 1936-1980. Source: Smith 1980.
Steven Smith (1981),
in his report "The Tasmanian Tiger - 1980", proposed a scale to
grade thylacine sightings. The Smith scale is divided into 4 divisions:
1. Observer's reliability
2. Circumstances of
3. Description of animal
4. Correlation with
other sightings since 1934
Each division is subdivided
further with marks awarded in an ascending scale concurrent with the level