One of the strangest frogs ever studied, a species that carries its eggs in its stomach and then spits out hatchling tadpoles, has disappeared two years after being discovered in the subtropical rain forest of an Australian national park.

The species seems to have vanished as mysteriously as did a smaller species of gastric brooding frog that was discovered in 1974 in the same park and which disappeared in 1979.

There is fear that both species were wiped out by scientists and others who collected too many of the animals for study in the laboratory.

The disappearance was reported by Keith MacDonald, a wildlife ranger in the Queensland national park.

The frog's behavior is so odd that its discovery was rejected as a hoax by a leading British scientific journal.

Eventually scientists were convinced that the frog really did eat its own eggs as soon as they were laid and hold them in the stomach for several weeks until they hatched. It was also determined that the animal did not eat during this period and that the female's digestive juices were suppressed.

The behavior is thought to be an adaptation for survival in the frog's habitat, swiftly running mountain streams that could easily wash away the jelly-covered eggs if they were simply plastered on a rock or vegetation, as is the more common practice of frogs.