Frilled lizard, Frilled dragon, Frillneck lizard
The Frill-necked lizard (Chlamydosaurus kingii) is a species of lizard native to northern Australia and southern New Guinea. Its common names come from the large frill around its neck, which usually stays folded against the lizard's body. Frill-necked lizards, or 'frillies' as some call them, are relatively large lizards and are kept as exotic pets.
The Frill-necked lizard has a particularly large and wide head; a long neck to accommodate the frill; long legs and a tail that makes most of its total length. The species is sexually dimorphic, with males being larger than females[ and having proportionally bigger frills, heads and jaws. The corners of the frilled lizard's eyes are pointed and the rounded nostrils face away from each other and angle downwards. Most of the lizard's scales are keeled, having a ridge down the centre. From the backbone to the sides, the scales alternate between small and large. The distinctive frill is a flap of skin that extends from the head and neck and contains several folded ridges. When fully extended, the frill is disc-shaped and can reach over four times the length of the animal's torso in diameter. Otherwise, it wraps around the body. The frill is laterally symmetrical; the right and left sides are attached at the bottom in a V-shape, and cartilage-like connective tissue (Grey's cartilage) connects the top ends to each side of the head near the ear openings. The frill is supported by rod-like hyoid bones, and is spread out by movements of these bones, the lower jaw and Grey's cartilage. This structure mainly functions as a threat display to predators and for communication between individuals. It can also act as camouflage when folded, but this is unlikely to have been a consequence of selection pressure. The frill may be capable of working like a directional microphone, allowing them to better hear sounds directly in front of them but not around them. There is no evidence for other suggested functions, such as food storage, gliding or temperature regulation. Frilled lizards vary between grey, brown, orangish-brown, and black dorsally, the underside being paler white or yellow. Males have a dark belly but a lighter chest. The underside and lateral sides of the species are sprinkled with dark brown markings that merge to create bands on the tail. The colours of the frills vary based on range; lizards west of the Ord River have red-coloured frills, those living between the river and the Carpentarian Gap have orange frills, and those east of the gap have yellow to white frills. New Guinean frilled lizards are yellow-frilled. The more colourful frills have white patches which may add to the display. Colouration is mainly created by carotenoids and pteridine pigments; lizards with red and orange frills have more carotenoids than those with yellow and white frills, the latter two are also lacking in pteridines. Yellow colouration has been linked to higher steroid hormones. Among western lizards, the amount of red or orange colouring correlates with success in display competitions between males of similar size.
These lizards occur in northern parts of Australia as well as southern New Guinea. Their Australian range stretches from the Kimberley region of Western Australia east through the Top End of the Northern Territory to Queensland's Cape York Peninsula and nearby islands of Muralug, Badu, and Moa, and south to Brisbane. In New Guinea, they live in the Trans-Fly ecosystem on both the Papua New Guinean and Indonesian sides of the island. These lizards live in savannahs and sclerophyll woodlands. They prefer highly elevated areas with good soil drainage and a greater variety of tree species, mostly Eucalyptus species, and avoid lower plains with mostly Melaleuca and Pandanus trees. Frilled lizards also prefer areas with less vegetation on the ground, as they can then better spot prey from above.
The Frill-necked lizard is a solitary hunter. This lizard is an arboreal animal, spending most of its time quietly camouflaged on trees and coming down only at sunrise and sunset in order to feed or mate. The Frilled-neck lizard is a very territorial animal. When threatened, the frill extends, intimidating the rival and making the lizard look much larger than it is. In addition, they use the frill as a means of communication. These lizards are most active by day while in the morning, they are often seen sunbathing. When sunbathing, the frill of the lizard extends, allowing the animal to get a large amount of heat in a short amount of time. When finished, the lizard climbs back onto the tree. Being a cold-blooded animal, this reptile has to maintain its body temperature at a suitable level.
Like many of their relatives, these lizards are carnivores (insectivores). They primarily feed upon insects such as moths and butterflies as well as consume beetles, termites, and cicadas. They will also eat spiders, mice, and even, other lizards.
The Frill-necked lizards are polygynous. Mating season lasts from September to November, during which the males compete with each other for their mating rights. After mating, the female lays 1-2 clutches of 12-18 eggs. The eggs are laid in a small underground burrow and incubated during 50 -90 days. The sex of future breeds depends on the temperature inside the burrow: higher temperatures yield males while cooler temperatures usually bring females. Parental care is not common among the frilled-neck lizards, and the hatchlings are fully independent. However, they remain together for the first 8-10 days of their lives. The young are able to frill and hunt as soon as they are hatched. Reproductive maturity is reached quite early - at 18-20 months old.
One of the major concerns, threatening their population, is the pet trade. The Frilled-neck lizard is presently an extremely popular pet species due to its extraordinary frill and running style. A large number of them live in captivity while many are kept by amateur owners and raised inappropriately. Another notable threat is the loss of habitat. These animals dwell on dry trees, which are currently chopped down in large numbers, leading to a sharp loss of their habitat. The Frilled-neck lizard is also threatened by predators throughout its range. They are easy prey for a number of predators in the area due to not having defensive weapons except camouflage.
According to IUCN Red List, the Frill-necked lizard is locally common throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.
