The frilled-neck lizard is so called because of the large ruff of skin which usually lies folded back against its head and neck. The neck frill is supported by long spines of cartilage which are connected to the jaw bones. When the lizard is frightened, it produces a startling deimatic display: it gapes its mouth, exposing a bright pink or yellow lining; it spreads out its frill, displaying bright orange and red scales; raises its body; and sometimes holds its tail above its body. This reaction is used for territorial displays, to discourage predators, and during courtship. The lizard is a relatively large member of the agamid family, growing up to 85 cm (2.79 ft). It is capable of bipedal locomotion. The frilled-neck lizard does not have a standard colour, but its body is darker than its frill.
Distribution and Habitat Edit
The frilled-neck lizard is found mainly in the northern regions of Australia and southern New Guinea. The lizard is also, on rare occasions, found in the lower desert regions of Australia. The lizard inhabits humid climates such as those in the tropical savannah woodlands. The frill-necked lizard is an arboreal lizard, meaning it spends a majority of its time in the trees. The lizard ventures to the floor only in search of food, or to engage in territorial conflicts. The arboreal habitat may be a product of the lizard's diet, which consists mainly of small arthropods and vertebrates (usually smaller lizards). However, the trees are most importantly used for camouflage. There is not one standard colour: rather, colouration varies according to the lizard's environment. For example, a lizard found in a dryer, clay filled environment will most likely have a collage of oranges, reds, and browns; whereas a lizard found in a damper, more tropical region will tend to show darker browns and greys. This suggests they are adapted to their habitats; their colors are a form of camouflage.
Like many lizards, frill-necked lizards are carnivores, feeding on cicadas, beetles, termites, and mice. They especially favour butterflies and moths, their larvae even more so. Though insects are their primary source of food, they also consume spiders and occasionally other lizards. Like most members of the agamids (dragons), frill-necked lizards employ an ambush method of hunting, lying in wait for their prey. When the lizards eat, they eat in abundance; these binge periods usually occur during the wet season, when they ingest hundreds to thousands of alate (flying) ants or termites.
The frilled-neck lizard is ectothermic and maintains its body temperature by basking for up to 30 minutes to achieve an average of 2–3 °C above the surrounding temperature. Weather conditions, including sunlight, are the main factors regulating the lizards’ temperature. This basking period usually occurs in the morning to early afternoon. During the basking period, the lizard will be found near the bottom of a tree and out from under the forest canopy. This ensures maximum exposure to sunlight. However, the lizard's final internal temperature depends mainly on the ambient temperature of the surrounding environment. The lizard's frill is thought to aid in thermoregulation.
Reproduction and Sexual Dimorphism Edit
The frilled-neck lizard is sexually dimorphic; meaning that there are physical differences between male and females. This dimorphism is apparent in the length of the lizard; the male is generally larger than the female. There is little to no dimorphism in the color of the lizard. Frill-necked lizards breed in the early wet season from September to October. Adult males fight for mates, displaying their frills and biting each other. One to two clutches of 6–25 eggs are laid from early to mid-wet season from November to February. The eggs are laid in a nest 5–20 cm below ground, and usually in sunny areas. Incubation takes two to three months. Gender is partly temperature determined, with extreme temperatures producing exclusively females, and intermediate temperatures (29 to 35 °C) producing equal numbers of males and females. Their eggs are soft-shelled.