Not many creatures dare to get too close to the face of a crocodile, but butterflies and bees have an unexpected reason to fly right in. Evidence suggests that crocodile tears offer these flying insects scarce minerals and a boost of protein, in what basically amounts to a harmless parasitic relationship. Unlike the relationship between the crocodile and the plover, which is symbiotic, the croc isn't getting much out of letting insects land on its eyes. Plovers pick meat from the predators' teeth, offering a meal to the bird and a free tooth cleaning for the croc. Egrets pick parasites from the fur of all sorts of animals. Similar relationships can be found deep under the surface of the sea, as well.
The crocodile-butterfly-bee tear-drinking phenomenon was noted in 2013 when a boat carrying students, photographers and aquatic ecologist Carlos de la Rosa slowly passed a spectacled caiman relaxing on the banks of the Rio Puerto Viejo in northeastern Costa Rica. "It was one of those natural history moments that you long to see up close," said de la Rosa, the director of the La Selva Biological Station for the Organization for Tropical Field Studies in San Pedro, Costa Rica. "But then the question becomes, what's going on in here? Why are these insects tapping into this resource?" Doing a little research, de la Rosa found that seeing butterflies hovering around the eyes of crocodiles is fairy common – it's just hard to catch on camera. Sometimes, it's just a matter of being in the right place at the right time. "Those are the kinds of things that, you know, you don't plan for them, you can't plan for them," de la Rosa said. "You just keep your eyes open and have curiosity, and when you see something that doesn't seem to fit, dig."