The Southern Gastric Brooding Frog is native to southern Australia, and because of its strange breeding habits, has been subjected to intense scrutiny.

Southern Gastric Brooding Frogs, also known as Platyus Frogs or more simply as Gastric Brooding Frogs, are mainly aquatic. They live under rocks or in other hiding places, or sit submerged in water with only their eyes visible above the surface. Generally, these unusual frogs are found along the edges of eucalyptus forests in rocky creeks or shallow pools. Southern Gastric Brooding Frogs eat insects, which they catch in water or on land. After catching their prey, they push them into their mouths with their forelegs. Southern Gastric Brooding Frogs are not speedy on land and could make potential prey items themselves. However, they secrete a mucous substance, which allows them to slip more easily from the mouths of predators. In the water, however, they are strong, agile swimmers. Southern Gastric Brooding Frogs are neither nocturnal nor diurnal in their routines. Their major predators are eels and herons. In captivity, Southern Gastric Brooding Frogs are reported to struggle when handled and usually cannot be tamed.

The eyes of the Southern Gastric Brooding Frog are situated on top of their heads, so they can sit underwater but remain aware of their surroundings. They are dull slate gray in color, with lighter and darker patches of color over their backs. Their bellies are often white with cream patches. A brown superocular bar is also seen. Generally, females are about 2 inches (51 millimeters) and males are about 1.5 inches (38 millimeters). Tadpoles live off their yolk sac and do not have mouths or coiled intestines.

First noted in 1972, the Southern Gastric Brooding Frog is now thought to be extinct in the wild. A sighting of one of these creatures has not been reported in the wild since 1981. The only known ranges it inhabited were the Blackall and Conondale mountains of southern Australia. The population depletion was suspected to have been due to drought, pollution, or over-collection. It is possible that the Southern Gastric Brooding Frog can become helpful in patients suffering from ulcers, since they have the ability to shut off the hydrochloric acid production in their stomachs.

Because the skins of Southern Gastric Brooding Frogs are so sensitive, any harsh chemicals in the water in which they are kept easily affects them.

The Southern Gastric Brooding Frog usually reaches sexual maturity at two years of age. Their breeding behavior makes them unique among frogs, and the breeding process is not fully understood. The female Gastric Brooding Frog gives birth to her young from her mouth. They brood their young in their stomachs, hence their names. The Gastric Brooding Frog can actually stop producing hydrochloric acid while carrying its young, which it swallows in egg form. The eggs probably remain in the stomach of the Southern Gastric Brooding Frog for about eight weeks, and the Southern Gastric Brooding Frog hatches her young simply by opening her mouth. The other amazing thing about the Southern Gastric Brooding Frog is that it can carry about 30 young in its stomach. The average clutch size is 18 to 25, and the eggs are colorless when swallowed. The mother Southern Gastric Brooding Frog stops eating while hatching her eggs, and the tadpoles developing in her stomach have no teeth. Most breeding occurs in spring and summer.