Never smile at a crocodile—or sit on its face and drink its tears. Yet that’s exactly what ecologist Carlos de la Rosa spotted a butterfly and a bee doing this past December as he boated down Costa Rica’s Puerto Viejo River. In one encounter (pictured above and caught on video), the spectacled caiman (Caiman crocodilus) placidly sunbathes on a fallen tree trunk as a Julia butterfly (Dryas iulia) and a solitary bee (Centris sp.) flutter around its face and taste its tears. The brave bugs’ tear-sipping behavior likely provides salts and proteins scarce in the tropics, de la Rosa writes this month in Frontiers in Ecology and the Environment. Scouring online photographs snapped by amateur photographers and other researchers, de la Rosa was surprised to find ample evidence of insects supping tears from crocodiles and other reptiles such as tortoises. He now thinks the practice may be more common than scientists once thought—just rare to witness.

See more ScienceShots.