Butterflies drink turtle tears in a behavior scientifically known as lachryphagy, or "tear-feeding," to obtain vital sodium, amino acids, and other dissolved minerals. While nectar provides butterflies with abundant sugars for energy, it severely lacks essential salts necessary for their metabolism, muscle function, and reproductive health.

Turtles, especially carnivorous river species, ingest far more salt in their diets than they require. To naturally flush out excess salts, irritants, or bodily waste, turtles excrete this high concentration of minerals through their tear ducts. Basking in the sun, turtles relax with moist eyes, providing a convenient and highly concentrated salt lick for nutrient-deprived butterflies.