The Frill-necked Lizard, Chlamydosaurus kingii, also known as the Frilled Lizard or Frilled Dragon, is found in southern New Guinea, the
Kimberley and across northern Australia. It primarily inhabits savanna woodlands, but may also be found in tropical to warm temperate forests. It also is found where there is an open scrub or tussock grass under story.
The term frilled is in reference to the large ruff of skin which usually lies folded back against its head and neck. The frill is supported by long spines of cartilage, and when the lizard is frightened, it gapes its mouth showing a bright pink or yellow lining, and the frill flares out, displaying bright orange and red scales. The frill may also aid in thermoregulation.
These lizards are usually gray, brown, or reddish-brown. They may grow up to 40 inches in total length. Males are significantly larger than females. They often walk on its hind legs when on the ground. When frightened they begin to run on all-fours and then accelerate onto its hind-legs where it can reach some quite impressive speeds. It is semi-arboreal, and hunts in the trees for small arthropods (including caterpillars and cicadas), and on the ground for ants and termites, spiders, or small vertebrates.
During breeding season adult males fight for mates, displaying their frills and biting each other. One to two clutches of 4-23 eggs are laid in a nest 2-8 inches below ground, and usually in sunny areas. Incubation takes two to three months. Sex is partly temperature determined, with extreme temperatures producing exclusively females, and intermediate temperatures (29-35C) producing equal numbers of males and females.