Australian green tree frog

White's Tree Frog ( Litoria caerulea)

The White's tree frog ( Litoria caerulea), often referred to only briefly coral finger, is an indigenous to Australia and New Guinea Froschlurch from the genus of Australian tree frogs ( Litoria ). The English surgeon John White has this kind described in 1790 for the first time scientifically. For a climbing tree frog of the finger coral is comparatively large and bulky. The animals are considered relatively tame, and often live near human settlements. Because of their seemingly smiling appearance and their sedate nature to White's tree frogs particularly popular when people are enjoying. The antibacterial and antiviral properties of their skin secretions make them also interesting for pharmacology.

Taxonomy

In his book, Journal of a Voyage to New South Wales John White described the way first. However, since the preparation which he sent to England, go changed his color, White's Tree Frog was classified ( according to the Latin words for " frog " and "Blue" ) as Rana caerulea. The green color of the frog actually based on blue pigments, which lie on a yellow layer. However, the latter vanished during preparation of the sample so that the conserved animal appeared blue. ( It can also happen actually living blue copies, which is also missing the yellow dye! )

Later the way for a long time under the scientific name Hyla caerulea within the subfamily Hylinae was performed, ie, among others, in the same genus as the European tree frog (Hyla arborea ). Finally, a separation of the 127 species of Australian tree frogs ( Litoria ) from the genus Hyla ( Actual tree frogs ) has in the zoological systematics but enforced, which is especially biogeographic to justify less morphologically. Together with the genera Cyclorana and Nyctimystes they are now classified in the frog subfamily Pelodryadinae.

Your German trivial name has changed the way because of their sometimes ( " coral " ) pink stained hands; but often this is not the color description.

Dissemination

The original distribution area of ​​coral finger form the northern and eastern Australia (particularly Queensland and the Northern Territory ) and New Guinea ( especially its south in layers below 200 m above sea level ). Its habitat includes areas with a warm, humid, subtropical to tropical climate. In the warm temperate south-east Australia, it occurs only where there is no cold season is " wintry " available, such as in the lowlands of the state of New South Wales. By giving people the kind was used as neozoon also in parts of New Zealand and the United States. So, in two regions of Florida smaller, propagating populations. The New Zealand once existing animals have not been sighted since the 1950s.

Features

Coral fingers are big, clumsy tree frogs that can be ten to twelve inches long ( the females are slightly larger than males ). The very broad head has a short, round snout and slightly upswept corners of the mouth give the animals a seemingly smiling facial expression. Behind the eyes, which have a silver or goldmetallischfarbene iris with horizontal pupil, runs above the highly visible eardrum to the edges each have a beaded, gland- rich skin thickening. This is reminiscent of the parotid glands of toads and complies with these also. Her smooth top alternates in color from green and brown ( rarely blue ), which is inter alia dependent on the temperature of the surroundings and their mood. Occasionally, the animals have irregular white and dark -rimmed or gold-colored stains maximum diameter of five millimeters on the flanks, which are more in old age. The gekörnelte abdominal skin is whitish, the throat of the female also. In the males this is brownish - yellow and wrinkled, as there is their vocal sac.

The inner sides of the rear legs have a brownish- red color. The long, broad fingers and toes that are forward up to one third and on the hind legs connected to two-thirds over webbed together, end in eye-catching, round - flat adhesive discs. These can be up to five millimeters wide in adult animals. They work like suction cups and allow the frog to climb trees, and even easily on vertical glass surfaces to run up (See: European tree frog ).

The White's tree frog can be infrafrenata (Giant tree frog ), among others confused with two other species of its genus, Litoria splendida and Litoria. From the first it differs by the Drüsenwulste at the back of the head while he may be differentiated from the second by a missing white stripes on the lower jaw.

Although frogs have lungs, they cover in addition much of their oxygen demand over the skin surface, so it must be moist. However, a constantly moist skin environment has the disadvantage that pathogens such as bacteria, fungi or viruses can penetrate more easily. To counter the risk of infection, including the skin secretion of frogs peptides that can kill these germs. The White's Tree Frogs, these are Cearine, a group of antibacterial and antiviral peptides. Also contains the secretion Caerulin that has the same physiological effect as cholecystokinin. Some peptides from the skin secretions are, as laboratory tests have shown also to be capable of destroying HIV without harming healthy T- cells.

Lifestyle and behavior

The frogs behave fairly quiet and sedate; also they are fairly sedentary. The day she slept in the vegetation and on cool, damp places to perk up in the early evening and go until late at night to catch prey. In rainier spring and summer in the Southern Hemisphere their cries are heard; in the dry season in the winter they insert a period of inactivity.

The mating calls of males that they generate with their throat permanent vocal sac, are a deep, slow and permanent croaking. The vocalizations, including the females are a little quieter capable, but serve not only the partner determination. Outside the mating season, usually after a rain, give the frogs by their reminiscent of a hoarse barking croak their location known - often high up in trees and eaves, at night or near floor level. Just make it, for example, the small relative, the European tree frogs in late summer. The purpose of this behavior is not yet clear - it could be an expression of well-being is simple. In addition, the animals of possible danger a penetrating Schreckruf of itself, for example, when a predator approaches them or, as when a person steps on a hollow log in which a frog lives.

Depending on the habitat preference of coral fingers different habitats. Your typical whereabouts are treetops near quiet waters. You can also live in the reeds of wetlands or grasslands in temperate climatic regions. Synanthropic they have to make a living in the immediate vicinity of man. So coral fingers are known to water containers to and use in houses. They are found in water tanks, drainage pipes and eaves, because they are wet and slightly cooler than the ambient usually. Sewage pipes and water tanks are apparently therefore visited by them with a preference for mating season because their sounds carry further here. Similarly, one can observe in the evening the frogs on windows, where they hunt small animals, attracted by light.

White's tree frogs eat mainly insects and spiders, and occasionally of smaller frogs and mammals. The prey has to be moving for it to be recognized. Since their teeth are not able to divide food, frogs can only take bite-sized bite to eat, which are swallowed whole. Unlike many other species of frogs, White's tree frogs use but no spin tongue, but pounce on their prey, they pack with their jaws and stuff them into their mouths with their hands.

Among the natural enemies of the species there are several species of snakes, birds, and lizards. With the colonization of Australia by European immigrants were added yet dogs and cats. Frog's life expectancy in captivity up to 16 years; lifespans are separated reports of 20 years. In its natural environment, the life expectancy is certainly less.

In the dry season this tree frogs can use condensation effect to absorb more moisture and not to dry up. Thus, they can cool off strong in cold nights and then search for example a warm tree hollow, where the humidity settles as condensed water on her skin. The condensed water is absorbed by the frogs through the skin.

Reproduction, individual development

Shortly before the pair phase in the summer rainy season the males grow a brownish Bruns Wiele sealed on the inside of each of the first finger. This rough calluses help them to be able to lay hold on the back of the females during amplexus, so the Umklammerungsphase. After the animals have been found, the calls, the pairing is usually in stagnant water. While the female releases her eggs into the water, this ride- on males are inseminated with sperm. A relatively large spawning bales from 200 to 300 brown, each 1.1 to 1.4 millimeters in size, and surrounded by the transparent jelly eggs is released into the water. There, the clumps sink to the bottom or attaches itself to below the water surface objects located. The Amplexus may take up to two days, with multiple spawning bales are stored with a total of 2000 to 3000 eggs.

After three days of embryonic development in warm water hatch about eight millimeters tadpoles. To ensure the survival and development budget, the water temperature between 28 and 35 ° C must be and have the water a depth between 5 and 50 centimeters. The external appearance of tadpoles changed during their ontogeny. Upper hand, they are mottled brown, from which developed the later brown or green coloration of the adult animals. The underside is initially dark and brightens with time. The tadpoles grow in the course of two to three months zoom up to a length of about 44 millimeters before they complete the metamorphosis into a frog. Sexual maturity begins at the age of two years.

Endangering

Since the Environment Protection and Biodiversity Conservation Act 1999, the White's Tree Frogs, like all endemic Australian species under protection. The earlier momentum -like export for the pet trade is strictly regulated. As hazardous turns out that much was destroyed by the people from the natural habitat of the species. Also deadly fungal infections have been (see: chytridiomycosis ) observed in single copies.

In addition, the fact that it is possible to determine a general decline in the populations since the 1950s, concern. Due to the relatively long lifetime of the individual coral finger but accurate conclusions about the population trends are still uncertain, as is not so much affect a short-term decline in the rate of reproduction at a longer-lived species must be like a kind of low life expectancy. For now, the type of the IUCN is regarded to be not at risk.

Animal husbandry

When coral finger is one of the world's most popular pet species among the frogs. This is ensured by his tame behavior and be sympathetic look that is reminiscent of the typical frog in the cartoon. In species-appropriate, hygienic housing and care he is less prone to diseases than many other Terrarium. However, he needs enough space, climbing, humidity and heat, as well as live prey animals. Overfeeding can be a problem, since captive coral fingers - unlike in the wild - for lack of movement have no opportunity for sufficient energy combustion and as often show an excessive corpulence.