A frog swallowed her eggs and gave birth through her mouth

The gastric-brooding frog shut down her stomach acid, swallowed the fertilised eggs, raised the young in her stomach, and opened her mouth to let froglets out. Both species are extinct.

Rheobatrachus silus, from a few streams in south-east Queensland, was described doing something no other frog was known to do. The female swallowed the eggs or the early tadpoles. For weeks her stomach stopped being a stomach: acid and digestive enzymes were suppressed, and the tadpoles developed in a chamber that had been digesting food the week before. They grew. She did not eat. When they were froglets, they came up and out, and a birth was a mother sitting with her mouth open while finished animals climbed from it. A second species, R. vitellinus, was found farther north and did the same thing.

Both are extinct. The last confirmed sightings were in the early 1980s. Chytrid fungus, which has emptied many streams of frogs, is the leading suspect, not a complete proof of the last day. What remains is the record, including film, of a reproductive system that used the one organ a vertebrate cannot spare at dinner. Turning it off for a month, completely, and turning it back on, was the trick. No living frog is known to have kept the trick. The stomach, in this library, is a vat of acid. In this one animal it was, for a season, a room.