|
Boyd’s Forest Dragon
Photo: Courtesy of Damon Ramsey
BSc.(Zool) Biologist Guide
Boyd’s Forest Dragon (Hypsilurus boydii)
Markings:
- The forest dragon is very distinctive with large pointed scales on a crest behind
the head, pinkish flat-topped conical scales on the cheeks and a deep mustard yellow pouch
beneath the jaw line.
- Despite its ornate structures and bright colouration it is cryptic in its
tropical rainforest environment where it camouflages well.
Habitat:
- The forest dragon is restricted in area from just south
of Cooktown (located north of Cairns), and the Atherton Tableland region
and south to Paluma near Townsville.
- It spends most of its time in trees and due to its
camouflage it is often very hard to see and thus tends to go unnoticed.
However they can more easily be spotted basking in the sun on the sides of
roads and walking tracks where it may be lying on the ground to absorb
some of the heat radiating form the surface.
- Forest dragons are territorial with the larger male
territory usually containing one or more small female territories.
Sometimes lizards have one or two favourite trees within their territory
to which they will regularly return. (Source:
Environmental Protection Agency)
- Sunlight is not always available in the rainforest;
the thick canopy blocking most of it. Hence several lizard species have
abandoned basking in favour of a lifestyle known as 'thermoconforming'.
This is where the lizard's body temperature simply conforms to that of
the air around it. (Source: Environmental
Protection Agency)
Diet:
- Their diet consists of insects and other
invertebrates with ants the most common prey item.
- They will also take beetles, grasshoppers and have a
special fondness for earthworms. Although they may occasionally eat
rainforest fruits, this seems to be rare.
(Source: Environmental Protection Agency)
Size:
- The forest dragon grows to a length of about 15cm but
its tail adds much to the overall length.
Egg-laying/Mating:
- Stormy weather in December has been shown to
encourage mating and egg laying behaviour in Boyd's Forest Dragon.
- Mating attempts have been viewed on the forest floor
with the larger male giving no attention to decorous behaviour.
- The female digs a shallow hole, about 10cm in depth,
to deposit three or four eggs into. She then covers them for incubation.
Viewing Opportunities:
Additional
Information:
-
A
Boyd's forest dragon is only found in the rainforests of north eastern
Queensland. The male has a home range of about 1000 square metres. Female
ranges are slightly smaller. Home ranges of the same sexes do not overlap
but larger male territories often contain one or more female territories.
Movements within the territories vary with season with dragons travelling
100m or more during summer days but relatively little in winter.
-
These lizards spend much of their time perching on the side of tree trunks
just one or two metres from the ground waiting to ambush prey. They
sometimes have favourite trees to which they will regularly return. They
eat beetles, spiders, crickets and lots of ants. They also love
earthworms. Although they may occasionally eat rainforest fruits, this
seems to be rare.
-
The male is larger than the female and can be distinguished by its larger,
blockier head. Both sexes have a large yellow dewlap below their chins
which they can erect using a bone called the hyoid. The dewlap is used for
displaying to each other and to scare off predators.
-
The breeding season is late spring and early summer. At this time female
dragons in the cooler uplands often move in search of open sunny spots,
such as roads. They tend to sit on
the roads, presumably using the
warmth to help speed development
of the eggs (a risky. habit ). Despite their fairly large size,
forest dragons produce
relatively small clutches, laying only one to six eggs at a time
in a shallow hole. Unfortunately
upland dragons often lay them in
warmer areas at the sides of roads where they are vulnerable to
vehicles. Lowland dragons lay on
the forest floor.
-
The lizards mature at about 1-3 years of age. They may live for about five
or ten years but this is uncertain.
-
In general the forest dragon relies on its superb camouflage to escape
predators. It will usually stay very still, only moving when it is sure it
has been spotted. Then it slowly folds in its arms and legs and slides
around the back of the tree, keeping the trunk between itself and its
observer.
-
The best way to spot a forest dragon is to carefully scan the sides of the
trees at about head height, while slowly walking through the rainforest.
Examine any large bump – it may well turn out to be a lizard.
-
Boyd's forest dragon belongs to a South-east Asian group of lizards,
although our species (Hypsilurus
(Gonocephalus) boydii) is endemic to the Wet Tropics region of North
Queensland.
-
For more information on these lovely animals look at Nature Australia
Vol 25 No 8 Autumn 1997 for
an excellent article entitled Forest Dragons by Boyd’s specialist
Geordie Torr
This extra information was supplied courtesy of The Queensland
Environmental Protection Agency.
Additional Information:
Boyd's Forest Dragon:
Hypsilurus boydii
The 'Boyd's Forest Dragon' (Hypsilurus
boydii), is one of the Daintree region's most spectacular examples of
this family. It is an exquisite medium sized lizard coloured an olive brown,
with brighter patches of yellow, black and white, spines, a dewflap and
white 'stones' embedded on the cheeks (right). It is often found perched in
the first few meters height of a slim rainforest trunk. Their still stance
is also a way of avoiding detection by predators, and if spotted, they
slowly move themselves around the other side of the trunk out of sight. They
are common at Mossman Gorge and at Marrdja, especially at warmer times of
the year, but due to their capacity for camouflage, they can be hard to
spot.
Script:
Courtesy of Damon Ramsey BSc.(Zool) Biologist Guide
Additional Boyd's
Forest Dragon Photos
|
