Australian
Screen

Teacher’s notes

provided by

This clip shows examples of the Lake Eyre dragon, a small lizard that lives in Lake Eyre, the driest part of the Australian continent. The opening scenes show the vast expanses of the salt lake as the narrator speaks of its soaring temperatures. Next, a Lake Eyre dragon is seen hunting ants and using body language to intimidate rival dragons. In the final scene a dragon walks on its heels and feeds on ants. Sounds of wind blowing and orchestral music accompany the commentary, with the music often imitating the movements of the dragons.

Educational value points

• The Lake Eyre dragon (Ctenophorus maculosus), so tiny it fits in the palm of the hand, is Australia’s most salt-adapted vertebrate. Living for up to six years, it finds shelter among the cracks in the salt, digging deeper when necessary. Its eyesight is excellent, with spiky scales around the eyes acting like a sun visor against the glare off the salt. Its scientific classification is Phylum: Chordata, Class: Reptilia, Order: Squamata, Suborder: Iguania, Family: Agamidae.

• Lake Eyre, shown here, a 9,324-sq-km flat salt lake floating on a sea of mud, is the world’s biggest expanse of salt. The evaporation of floodwater over thousands of years has created a crust that is up to 50 cm thick in some places. The Lake has filled to capacity only three times in the past 150 years and when it does it can harbour water nine times as salty as the sea.

• As seen in the clip, the dragon forages for food on the lake margins, walking on its heels with its toes off the ground when the salt is too hot and feeding on the tiny harvester ants that nest in the salt and survive on seeds and dead insects blown onto the surface. The dragons also compete with the ants for windblown insects. They themselves are prey for hawks and falcons.

• Harvester ants are important for Lake Eyre dragons, not only as a source of food but also as builders of anthills. The clip illustrates how male dragons use the anthills as lookouts. One scientific study has shown that males with higher densities of lookout sites have larger territories, and males with larger territories have more mates (Olsson, 1995, http://cat.inist.fr).

• Visual signalling, mostly based on the body movements shown in the clip, allows the lizards to test out their dominance, identify territories and make courtship displays using combinations of push-ups, arm waves and head bobs. Some scientists believe that this body language may allow even more complex communication. Many female dragons display bright colours during the breeding season, perhaps to indicate when they are not sexually receptive.

• Images of the Lake Eyre dragon such as those shown here had not been seen by Australian audiences until the release of Nature of Australia, and the clip reveals the award-winning skills of nature documentary team David Parer and Elizabeth Parer-Cook. The couple spend a lot of time in the wild, producing many reels of footage using a wide range of shots. Here, detailed close-ups and commentary present the viewer with a 'real-life’ experience of the dragon.