The Australian Green Tree Frog, simply Green Tree Frog in Australia, White's Tree Frog, or Dumpy Tree Frog (Litoria caerulea) is a species of tree frog native to Australia and New Guinea, with introduced populations in New Zealand and the United States. The species belongs to the genus Litoria. It is physiologically similar to some species of the genus, particularly the Magnificent Tree Frog (Litoria splendida) and the Giant Tree Frog (Litoria infrafrenata).
The Green Tree Frog is a large species compared with most Australian frogs, reaching 10 centimetres in length. The average lifespan of the frog in captivity, about sixteen years, is long in comparison with most frogs. Green Tree Frogs are docile and well suited to living near human dwellings. They are often found on windows or inside houses, eating insects drawn by the light.
Due to its physical and behavioural traits, the Green Tree Frog has become one of the most recognisable frogs in its region, and is a popular exotic pet throughout the world. The skin secretions of the frog have antibacterial and antiviral properties that may prove useful in pharmaceutical preparations.
Anatomy and morphology
The Green Tree Frog can grow up to 10 centimetres (4 inches) in length. Its colour depends on the temperature and colour of the environment, ranging from brown to green; the ventral surface is white. The frog occasionally has small, white, irregularly shaped spots on its back, up to five millimetres in diameter, which increase in number with age. The frog has large discs at the end of its toes, of about five;millimetres in diameter at maturity. These help the frogs grip while climbing and allow them to climb vertically on glass. The eyes are golden and have horizontal irises, typical of the Litoria genus. The fingers are about one-third webbed, and the toes nearly three-quarters webbed. The tympanum (a skin membrane similar to an eardrum) is visible.
The tadpole's appearance changes throughout its development. The length of the species' tadpoles ranges from 8.1 millimetres (once hatched) to 44 millimetres. They are initially mottled with brown, which increases in pigmentation (to green or brown) during development. The underside begins dark and then lightens, eventually to white in adults. The eggs are brown, in a clear jelly and are 1.1–1.4 millimetres in diameter.
Although frogs have lungs, they absorb oxygen through their skin, and for this to occur efficiently, the skin must be moist. A disadvantage of moist skin is that pathogens can thrive on it, increasing the chance of infection. To counteract this, frogs secrete peptides that destroy these pathogens. The skin secretion from the Green Tree Frog contains caerins, a group of peptides with antibacterial and antiviral properties. It also contains caerulins, which have the same physiological effects as CCK-8, a digestive hormone and hunger suppressant. Several peptides from the skin secretions of the Green Tree Frog have been found to destroy HIV without harming healthy T-cells.
Distribution
The Green Tree Frog is native to northern and eastern regions of Australia and to southern New Guinea. Distribution is limited mostly to areas with a warm, wet tropical climate. Eastern Australia, although cool in winter, species. It is found in the southern Australian state of Victoria, but the frog cannot survive southern Victoria's cold winters and is therefore restricted to the north. In New Guinea, the Green Tree Frog is restricted to the drier, southern region. Its range spans from Irian Jaya to Port Moresby, and is most abundant on Daru Island. There have been isolated records in northern New Guinea, however this is thought to have been through introduction by humans.
The species has been introduced to both the United States and New Zealand. In the United States, it is restricted to two regions within Florida, where it was possibly introduced through the pet trade. Only small populations have been found in Florida, and it is unknown whether they have caused any ecological damage as an invasive species. In New Zealand, a population was once present; however, there have been no sightings since the 1950s
