AR0918NR297_rincon-del-socorro-boat-trip-catching-flies.jpg [© Last Frontiers Ltd]

Yawning caiman | A caiman (yaracé) in the Iberá wetlands stretches his mouth muscles. | The Iberá Marshlands (Argentina)

Filename: AR0918NR297_rincon-del-socorro-boat-trip-catching-flies.jpg (Nikki Ray)