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214 IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007

The Atherton Tablelands is a 700–900-m high plateau in North Queensland, Australia. Prior to European settlement, the region was
covered largely by upland rainforest interspersed with areas of more open sclerophyll forest. Large-scale clearing for agriculture began in
the early part of the 20th century and continued for a number of decades. Logging was in decline by the time most of the remaining
rainforest was incorporated into the Wet Tropics World Heritage Area in the late 1980s.

FREEMAN AND FREEMAN



IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 215

Chasing Big Snakes

The ping from the receiver indicated the Amethystine
Python (Morelia kinghorni) was very close; judging by the

volume it was less than two meters in front of me. Once again,
I am amazed at how these large snakes manage to “melt” into
the forest floor. After some frustration and muttered curses, like
a switch coming on in my head, I see him. Stretched out in the

leaf litter is the large muscular predator right where I had been
looking for the last minute or so. At 3.5 m, this male is larger
than average, which is slightly less than 3 m in length (A.B.
Freeman, unpubl. data; Fearn et al. 2005). We have been follow-
ing him for over two years now and he has become like an old
friend. He watches me cautiously as I quietly withdraw a short
distance to start data collection. Five minutes later, he decides

Giants in the Rainforest:
A Radiotelemetry Study of the Amethystine

Python in North Queensland, Australia
Alastair Freeman and Amanda Freeman

School for Field Studies, Center for Rainforest Studies, Yungaburra, Queensland 4883, Australia
(Alastair.Freeman@epa.qld.gov.au)

Photographs by the senior author except where indicated.

AMETHYSTINE PYTHON IN NORTH QUEENSLAND

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Amethystine Pythons (Morelia kinghorni), such as this large male, appear to “melt” into the forest floor.



216 IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 FREEMAN AND FREEMAN

that I am no threat and turns to continue on his way. After two
and a half years and many hours spent studying these magnifi-
cent animals in the wild, the sight of this large reptile moving
over the forest floor still gives me a buzz of excitement.

We started the radiotracking project in April 2004. For the
preceding two years, we had been collecting roadkill data and
incidental records for this species on the Atherton Tablelands in
North Queensland. We came to the conclusion early that radio-
tracking individuals would be necessary to really understand
more about the ecology of this species in the wild. In particular,
we had become interested in how this large predator uses a land-

scape that is highly modified by land clearance and agricultural
development.

Where and How Do You Study Big Snakes?
The Atherton Tablelands is a mid-elevation plateau (700–900
m), situated southwest of the city of Cairns in North
Queensland, Australia. Prior to European settlement, the region
was covered largely by upland rainforest interspersed with areas
of more open sclerophyll forest (Winter et al. 1987). Large-scale
clearing for agriculture began in the early part of the 20th cen-
tury and continued for a number of decades (Winter et al.
1987). Logging was in decline by the time most of the remain-
ing rainforest was incorporated into the Wet Tropics World
Heritage Area in the late 1980s. Today, the area is a mosaic of
pasture, crops, and small towns. Interspersed among these are
rainforest fragments ranging in size from a few trees to 600 ha,
many dissected by major and minor roads. Small areas of sec-
ondary growth are common, particularly along riparian corri-
dors. Large areas of continuous forest are confined to the slopes
of hills that surround the Tablelands. Our study area is situated
on the eastern edge of the Tablelands, centered on the School for
Field Studies Centre for Rainforest Studies. In the immediate
vicinity are all of the main habitat types known to occur in the
Atherton Tablelands, everything from cattle pastures to World
Heritage rainforests that have never been cleared.

The Amethystine or Scrub Python is the largest snake in
Australia. It is also arguably the largest terrestrial carnivore in
Australia. Surprisingly, very little is known about its ecology in
the wild. Most accounts of this species have been observations
of specific events (Fearn and Sambono 2000; Turner 2001;

Catching a large python is often a collaborative effort. Here the authors
chase a telemetered snake. 

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The Amethystine or Scrub Python (Morelia kinghorni) is the largest snake and arguably the largest terrestrial carnivore in Australia. Surprisingly,
very little is known about its ecology in the wild.



Fearn 2002), valuable in themselves but far from the detail
needed to get a complete picture of this species’ ecology.
Scientific studies have been few and far between (Martin 1995;
Fearn et al. 2005).

The radio transmitters are surgically inserted into the body
cavity of the snake near the vent. Because of the body shape of
snakes, this is the only practical way one can “attach” a transmit-
ter to them. After about 9–11 months, pythons are recaptured
and the transmitter is removed or replaced before the batteries
expire. Over a period of 27 months, we have radiotracked six
individual pythons for varying lengths of time. The snakes are
located on average twice a week. When located, detailed notes
are made of the habitat in which they were found, their exact
locality is recorded using a handheld GPS, and air and ground
temperatures and a range of behavioral variables are recorded. If
at all possible, we try to visually locate the snakes, but many
times, particularly when they are in the canopy and emergent
layers of the forest, they are impossible to see.

IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 217AMETHYSTINE PYTHON IN NORTH QUEENSLAND

Map of the Atherton Tablelands in North Queensland, Australia.

Today, the Atherton Tablelands of North Queensland, Australia is a mosaic of pasture, crops, and small towns. Interspersed among these are rain-
forest fragments ranging in size from a few trees to 600 ha, many dissected by major and minor roads. Small areas of secondary growth are com-
mon, particularly along riparian corridors. Large areas of continuous forest are confined to the slopes of hills that surround the Tablelands.



Some Preliminary Results
The tracking so far indicates that Amethystine Pythons on the
Atherton Tablelands are strongly but not exclusively forest
dwellers. The majority of sightings of radiotracked snakes
(around 75%) have been in forest habitats, either rainforest or
rainforest regrowth, with around 20% of sightings of animals in
clearings or along the forest edge. The remaining sightings are
in sclerophyll forest. One of the most interesting findings to
emerge from the study is knowledge of the snakes’ behavior dur-
ing the cool misty winters of the Tablelands. Radiotracking has
shown that during the coldest part of the year, Amethystine
Pythons spend most of their time in large epiphytic basket ferns
(Drynaria sp.) in the canopy and emergent layers of the forest.
Similar behavior was documented on the Atherton Tablelands
in the late 19th century by the explorer Carl Lumholtz, who
described how in winter his Aboriginal guides would climb high
into ferns to catch pythons for food. Although he referred to
those snakes as Morelia variegata (Lumholtz 1889), judging by
their size, they could only be Amethystine Pythons. Studies in
Neotropical rainforests have shown that temperatures are signif-
icantly higher in the canopy and above it than below it
(Madigosky 2004). These very large epiphytes (most are larger
than 1 m in width) in the canopy and in emergent trees there-
fore serve as ideal basking platforms.

Far from being a big, slow sluggard of a snake, the
Amethystine Python can move far and relatively quickly when

necessary. In many ways, these pythons, with their gracile bod-
ies, long tails, and slender necks, are built more like an arboreal
colubrid or treeboa than a large python.

One of the males has a home range of over 200 ha, whereas
another male moved over 800 m in a 24-hr period. They seem
to apply both “sit-and-wait” and “active-foraging” strategies for
prey capture. During the warmer months, we have come across

218 IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 FREEMAN AND FREEMAN

Although most frequently encountered lying motionless on the forest
floor or in the canopy, one male Amethystine Python (Morelia king-
horni) had a home range of over 200 ha, and another male moved over
800 m in a 24-hr period.

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Radiotracked snakes were located on average twice a week. Detailed notes document the habitat in which they were found. Here the senior author
is radiotracking the snake visible on the ground. 



IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 219

individual snakes displaying what can only be called active
“exploratory” behavior in the middle of the day. In one case, a
large male was observed moving systematically over the forest
floor, his tongue constantly flicking, pushing his head into holes
and then withdrawing it. Active foraging by Amethystine
Pythons, while seldom observed, is fairly well known because of
the number of pythons that are trapped in chicken coops after
eating their fill and then being unable to squeeze back out
through the wire mesh. More commonly, these pythons have
been found in a sit-and-wait foraging stance, often next to obvi-
ous mammalian trails through dense grass or undergrowth.

While we have never observed an animal “in the act” of
swallowing prey, we have obtained some information on diet in
the study area from droppings, regurgitated samples, and the con-
tents of one dissected stomach. So far, the Amethystine Pythons
have shown a preference for Bandicoots (Isoodon macrourus and
Parameles nasuta) and Red-legged Pademelons (Thylogale stigmat-
ica). The former are small marsupial omnivores similar in appear-
ance to a large rat; the latter is a medium-sized forest macropod.
Other food items that we have recorded from pythons in the
study area and elsewhere include Spectacled Flying Foxes
(Pteropus conspicillatus), rats (Rattus sp.), cats (Felis catus), and
birds. The most unusual item we have found is reptilian eggs that
were in the droppings of one of the radiotracked females. How

these came to be in the snake we have no idea, and we have yet
to identify the species to which the eggs belong.

Sadly, we have collected almost no data on reproductive
behavior. No observations have been made of fighting behavior
in males or of mating, and none of the three tracked females has
attempted to brood a clutch.

AMETHYSTINE PYTHON IN NORTH QUEENSLAND

Rainforest canopy from below. During the coldest part of the year, Amethystine Pythons (Morelia kinghorni) spend most of their time in large epi-
phytic basket ferns (Drynaria sp.) in the canopy and emergent layers of the forest.

Amethystine Pythons (Morelia kinghorni), such as this female, can
move far and relatively quickly when necessary. In many ways, these
pythons, with their gracile bodies, long tails, and slender necks, are
built more like an arboreal colubrid or treeboa than a large python. 

B
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Other Reptiles in the Study Area
In addition to the Amethystine Python, another boid present in
the area is the smaller and more common Carpet Python (M.
spilota). Two subspecies of this species are thought to occur on
the Atherton Tablelands: the specialist rainforest-inhabiting
“Jungle Carpet” and the more widespread “Coastal Carpet”
(Barker and Barker 1994). However, from roadkill and inciden-
tal data that we have collected, no consistent pattern of habitat
use differentiates the two supposed subspecies (Freeman and
Bruce 2007). Consequently, we believe that the presence of two
subspecies on the Atherton Tablelands is unlikely.

Other snakes that have been observed in the study area
include Brown Treesnakes (Boiga irregularis), Common
Treesnakes (Dendralaphis calligastra), Yellow-faced Whipsnakes
(Demansia psammophis), Small-eyed Snakes (Cryptophis
nigrescens), Eastern Brown Snakes (Pseudonaja textilis), and the
impressive Red-bellied Black Snake (Pseudechis porphyriacus).
However, perhaps the most spectacular and unlikely sighting in
the area was of a Coastal Taipan (Oxyuranus scutellatus). This
species is generally thought to be a snake of dry open areas. One
of us (ABF) came across a 1.8-m animal on an old logging track
in thick rainforest. This highly venomous species tends to have
a bad reputation among the general public, but, in this case, the
snake sat quietly for 30 seconds or so while it was photographed
before moving off into the forest.

Lizards in the study area include a number of Wet Tropics
endemics. The Chameleon Gecko (Carphodactylus laevis) and
spectacular Northern Leaf-tailed Gecko (Salturus cornatus) are
regularly observed at night during the warmer months, while the
more secretive Boyd’s Forest Dragon (Hypsilurus boydi) is less fre-
quently seen. The skink fauna numbers eight species, ranging
from the diminutive Saproscincus tetradactylus with a SVL of 33
mm to the impressive Pink-tongued Lizard (Cyclodomorphus ger-
rardii) with head-body lengths to 200 mm.

Other more widely distributed species that occur in the area
include Eastern Water Dragons (Physignathus lesueurii lesueurii)
and the imposing Lace Monitor (Varanus varius). This large
varanid can reach lengths of 2 m elsewhere in Australia, and we
have observed individuals over 1.5 m in our study area.

Where to from Here?
The radiotracking is about to finish, the last two snakes will be
caught soon and their transmitters removed before they are
released back into the wild. While the radiotracking will finish,
we will continue to collect feeding observations for this species.
Also, some circumstantial evidence suggests that Amethystine
Pythons may suppress the densities of browsing folivores such as
opossums and tree kangaroos in some rainforest fragments.
Perhaps that will be our next research project.

220 IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 FREEMAN AND FREEMAN

Coastal Taipans (Oxyuranus scutellatus) are generally thought to be
snakes of dry open areas. This highly venomous species tends to have
a bad reputation among the general public, but, in this case, the snake
sat quietly for 30 seconds or so while it was photographed before mov-
ing off into the forest.

Amethystine Pythons (Morelia kinghorni), such as this female, use both
“sit-and-wait” (seen here) and “active-foraging” strategies for prey capture.

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Bandicoots, small marsupial omnivores similar in appearance to a large
rat, are favored prey for Amethystine Pythons (Morelia kinghorni).

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IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 221AMETHYSTINE PYTHON IN NORTH QUEENSLAND

Acknowledgements
A number of people have assisted with this project. Rick Shine,
Sydney University, and Andrew Krockenberger, James Cook
University, provided radiotransmitters. Wendy Bergan and Carol
Esson provided veterinary assistance with insertion and removal
of transmitters. Radiotracking equipment was made available by
the Queensland Parks and Wildlife Service Threatened Species
Group. Logistical support was provided by the School for Field
Studies Centre for Rainforest Studies. Financial assistance was
provided by Australian Geographic. A special thanks goes to all
the students and staff at the School for Field Studies Centre for

Rainforest Studies, particularly Maggie Vinson, Pierson Hill,
and Kyle Pias.

References
Barker, D.G., and T. M. Barker. 1994. Pythons of the world. Volume 1. Australia.

Advanced Vivarium Systems, Lakeside California.

Fearn, S.L. 2002. Morelia amethistina (Scrub Python). Diet. Herpetological
Review 31:58–59.

Fearn, S.L. and J. Sambono. 2000. Some ambush predation postures of the
Scrub Python Morelia amethistina (Serpentes: Pythonidae) in north east
Queensland. Herpetofauna 30:39–44.

Fearn, S.L., L. Schwarzkopf, and R. Shine. 2005. Giant snakes in tropical
forests: A field study of the Australian Scrub Python, Morelia kinghorni.
Wildlife Research 32:193–201.

Freeman, A.B. and C. Bruce. 2007. The things you find on the road: Roadkill
and incidental data as an indicator of habitat use in two species of trop-
ical pythons, pp. 152–165. In: R.W. Henderson and R. Powell (eds.),
Biology of the Boas and Pythons. Eagle Mountain Publishing LC, Eagle
Mountain, Utah.

Lumholtz C.S. 1889. Among Cannibals: Account of Four Years Travels in
Australia, and of Camp Life with the Aborigines of Queensland. J. Murray,
London.

Madigosky, S.R. 2004. Tropical microclimate considerations, pp. 24–48. In:
M.D. Lowman and H.B. Rinker (eds.), Forest Canopies. 2nd ed. Elsevier
Academic Press, San Diego.

Martin, R. 1995. Field observation of predation on Bennet’s Tree-kangaroo
(Dendrolagus bennettianus) by an Amethystine Python (Morelia ame-
thistina). Herpetological Review 24:74–76.

Turner, G. 2001. Fatal ingestion of a large prey item in the Scrub Python
(Morelia kinghorni). Herpetofauna 31:112–115.

Winter, J.W., F.C. Bell, L.I. Pahl, and R.G. Atherton. 1987. The distribution
of rainforest in northeastern Queensland, pp. 223–226. In: G.L. Werren
and A.P. Kershaw (eds.), The Rainforest Legacy: Australian National
Rainforest Study: The Nature, Distribution and Status of Rainforest Types.
Vol. 1. Australian Government Publishing Service, Canberra.

Wet Tropics endemic Northern Leaf-tailed Geckos (Salturus cornatus)
are regularly observed at night during the warmer months.

Adult Lace Monitors (Varanus varius) are seen regularly in the study area. These large varanids can reach lengths of 2 m.




