Litoria caeruleaAustralian Green Treefrog

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Geographic Range

The White's (or Dumpy) Treefrog is native to Australia and southern New Guinea. It can be found both in the northern and eastern parts of Australia (Badger 1995). More specifically from the coast to the drier interior of north western Austrailia, Northern Territory, Queensland, SA, and NSW (Cogger 1983).

Habitat

These treefrogs have adapted to seasonally dry or wet habitats. They prefer moist forested environments, but have skin that can adjust to drier situations (see above). Some scientists believe that these amazing animals can control how much water is evaporated through the skin, and thus have ability to control their body temperature (Duellman 1986). This frog's adaptability allows it to share suburban and agricultural areas with humans. They have been found in lavatories (where they have been known to leap onto people's laps), water tanks, and city reservoirs. During the hot summer months they can appear on the verandas of people's homes, or actually enter people's homes, while looking for moisture (Badger 1995).

Physical Description

This treefrog has many unique factors that set it apart from other hylids. It is a rather large treefrog in general, ranging in length from 3 to 4.5 inches (7 to 11.5 cm) (Badger 1995). Females are usually slightly bigger than the males. An average female specimen is about four inches in length, whereas their male counterparts are more likely to be in the 3 inch range (Mattison 1987). These frogs tend to be light bluish green to emerald green dorsally, with scattered white or gold spots on the side and occasionally on the back from the angle of the mouth to the base of the forearms. As with many treefrogs, this species is capable of some color change. The ventral surface is a milky white and rough in texture. The dorsum and throat are smoother to the touch. Vomerine teeth are prominant between and behind the choanea. These treefrogs have enormous toe pads. Fingers are partially webbed, but the toes are almost completely webbed. There is a distinct tympanum present. The second finger tends to be longer than that of the first (Cogger 1983). The eye has a horizontal pupil whereas other hylids tend to have a vertical pupil. The fatty ridge over the eye is a very distinct trait of the White's Treefrog. The skin is covered with a thick cuticle that allows it to retain moisture as an adaptation to arid areas. Males are more slender in appreance than females and have a grayish wrinkled vocal sac that is located underneath the throat region. The females are white on the throat (Mattison 1987). The waxy blue-green color and rolling skin folds of fatty material have earned the frog the nickname "dumpy" (Badger 1995).

Development

Reproduction

Breeding takes place in the summer rainy season. It often occurs in very moist places such as drainage systems, water tanks, or grassy semi-permenant water systems (Badger 1995). The female expels her eggs with such a force that they go through the deposited sperm cloud and stop up to half a meter away. The female's clutch of eggs can contain from 150 to 300 eggs. Once fertilized, they sink to the bottom of whatever water system they are in. The eggs range in size from 1.1mm to 1.4mm in diameter. During the mating season, males grow a black pad on their thumb to help in gripping the females during amplexus, which can last for days while the female lays her eggs (Walls 1995). The eggs take about one to three days to hatch (Badger 1995), and metamorphosis can occur in two to three weeks under good conditions. Young frogs mature in about two years.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)

Lifespan/Longevity

Behavior

These frogs are very tame in nature and are have little fear of humans. They are can be active in day or night (Duellman 1986). The male Litoria caerulea calls year round from high positions in the trees, but at night he comes down to call from slightly elevated larger rocks. During the dry season they cover themselves in a cocoon of sloughed epidermis and mucus and burrow to keep moist. During the summer rainy months they feast for a few days then start to breed. When threatened they emit an ear piercing distress call (Duellman 1986).

Food Habits

Reports on the food habits of this species in the wild are rare, but they are largely insectivorous, and eat moths, locusts, roaches and other insects.

Economic Importance for Humans: Positive

Scientists have discovered that skin secretions from this animal can destroy the staph bacterium that is responsible for the cold sore absesses involved in Herpes Simplex infections. The same secretions have been also known to lower the blood pressure in humans (Badger 1995). These frogs are commonly bred for the pet trade. These hardy frogs have an average life span of 16 years (Duellman 1986), but one is recorded to have lived 21 years. They are said to be good pets for children, as they are hardy and easily maintained (Walls 1995).

Conservation Status

Reportedly this species is still common in parts of its natural range.

Other Comments

The scientific name "Caerulea" means blue in Latin. This is interesting because they are not usually seen as blue, but as a bright green color instead. However, their skin is actually a mixture of blue and green pigments with a yellow layer over top of it. When the yellow layer eventually wears off the frog appears blue (Walls 1995).

Some authorities place this species into the genus Pelodryas

[See Savage, Proc. Biol. Soc. of Washington, 99(1):42-45].

Contributors

Tami Bruin (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

References

Badger, D. 1995. Frogs. Stillwater, MN: Voyageur Press, Inc..

Cogger, H. 1983. Reptiles and Amphibians of Australia. Sanibel, Florida: Ralph Curtis Books.

Duellman, W., L. Trueb. 1986. Biology of Amphibians. Baltimore, Maryland: McGraw-Hill Publishing Company.

Mattison, C. 1987. Frogs and Toads of the World. New York, NY: Facts on File Inc..

Walls, J. 1995. Fantastic Frogs. New Jersey.: T.F.H. Publications, Inc..