One of Borneo’s most elusive and enigmatic amphibians: the Bornean Lungless Frog (Barbourula kalimantanensis). Looking like the prize-winning stone from a rock-skipping competition, albeit with four webbed feet, this frog’s bizarre appearance is an adaptation for its aquatic life in fast-flowing rocky streams. Despite numerous expeditions to the region, less than twenty specimens have ever been found by biologists, making it one of the least known of all frogs. It is also the only frog in the world to be completely lungless, and is believed to absorb oxygen directly through its skin like the similarly-adapted lungless salamanders. West Kalimantan, Indonesia (Borneo).