The Pseudis Paradoxa is the Benjamin Button equivalent of the amphibian world. The paradoxical creature starts off as a 25-cm-long tadpole and shrinks as it grows. ending up as a small tropical frog, about a quarter of its original size.

When biologists discovered the paradoxical frog in the South American wild,they were understandably confused. At first, they thought the adult frogs were actually the babies, which later grew into giant tadpoles, exactly the opposite of how every other frog species in the world develops. They later figured out that the 11-inch tadpoles were indeed the juveniles, but still couldn’t explain the bizarre phenomenon.

Photo: Imgur

Luckily for Pseudis Paradoxa females, they don’t give live birth. Instead, the lay normal size eggs which later hatch into tadpoles that grow continuously for four months. As they morph into froglets, the giant babies lose their tales, which make up most of their overgrown bodies. Adult paradoxical frogs measure around 2.5 inches, pretty standard for tropical frogs.

Photo via Curious Creatures

The green frog with dark green stripes is a species of hylid frog from South America. It inhabits ponds, lakes and lagoons from northern Argentina through the Pantanal, Amazon, and the Guianas, to Venezuela and Trinidad.

Photo: Trinidad Expedition 2013

Pseudis Paradoxa feed on larvae, small insects, and tiny invertebrates. As nocturnal creatures, they spend most of their lives in water. Their croaks supposedly sound like pigs’ oinks, adding to their paradoxical nature.

Sources: Mentalfloss, Wikipedia