brazil pantanal wildlife caiman river

Courageous little butterfly !

The Julia butterfly (Dryas iulia, Júlia) has a very uncommon feeding strategy: 

by irritating a caiman's eye, the caiman's lacrimal glands produce a saline watery fluid to lubricate the eye surface. This fluid is rich in nutrients for the butterfly, which licks it up. This can be seen on many beaches along the rio Negro.