From Tropical Topics newsletter, No. 78 June 2003,
produced by Stella Martin at the Queensland Environmental
Protection Agency. Download the PDF to read the whole issue.
Acknowledgements to Russell Best, Queensland Parks and Wildlife
Service and Tony Griffiths, Key Centre for Tropical Wildlife,
Charles Darwin University.
Dragons | Frilled lizards | Gilbert’s
dragon | Two-lined dragons |
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Photo: Greg Calvert
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There are about 60 species of dragon lizards in Australia (330
worldwide). They are active during the day, although some in hot
arid zones may come out at night. With well-developed limbs they
are good runners, climbers and, in some cases, swimmers. Dragons
are able to change colour, becoming dark when absorbing heat and
lighter when trying to cool down. Males become more colourful at
mating time.
This lizard is found throughout the forests and woodlands of
northern Australia, is the only lizard in the world with a frill
— a thin, but wide, scaly ruff. When not in use, it is folded
loosely over the lizard’s upper body, but when the animal is
called upon to defend itself, it opens its mouth to unfurl the
frill into a circular ruff which would have been the pride of an
Elizabethan courtier.
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Although the frilled lizard is coloured with muted tones of
browns and black, which camouflage it well in its dry woodland
home, the frill, when erect, is brightly coloured with patches of
yellow and orange. Its owner is now aiming to be seen and with
mouth gaping, it lashes its wiry tail at the enemy. If bluff fails,
the lizard takes off, running along the ground on its hind legs to
the nearest tree. Although probably primarily used in defence, the
frill, which has numerous blood vessels, may also help with
temperature regulation. The frilled lizard spends 90 per cent of
its time in the trees. It is a ‘sit-and-wait’ predator
which surveys the ground, leaping on food such as ants, termites
and other invertebrates when they show themselves.
Studies have shown that in the dry season, when food is scarce,
a frilled lizard will climb up into the canopy of a tree and stay
there for up to three months as its metabolism drops by as much as
70 per cent. The lizard is aestivating—the equivalent, in a
hot climate, of hibernation. By dropping its energy requirements,
it can thus survive a period of food shortage. To lower its
metabolism rates the lizard must also keep cool so, instead of
basking in the sun it keeps in the shade, shifting around the trunk
of the tree if necessary to avoid the sun.
This impressive lizard is one of Australia’s largest
dragons, growing to 95 cm in total length.
This dragon is a common and relatively large lizard (52 cm total
length) with a long thin tail almost three times the length of the
head and body combined. It is found across the savannas, except in
eastern Cape York Peninsula. Often seen in pairs, some males have a
white streak on the side of the head. It likes to perch on any
elevated object — trees, termite mounds, posts and so on
— especially near water. It feeds on ants and any other
lizard which it can subdue.
These animals live on the ground or in low vegetation. They are
named for the two pale lines along their backs. There are several
species, but the northern two-lined dragon (Diporiphora
bilineata) is one of the most widespread, found across northern
Queensland and the Northern Territory. They prefer savanna
woodland, sclerophyll forests and sandy country. Well camouflaged,
they perch on low branches, looking out for insects to ambush.
