Visitors that dare to venture deep into the Western Amazon rainforest often encounter a strange sight - groups of butterflies hovering above yellow-spotted river turtles that are basking in the sun. What's even stranger is why they are there - To drink the tears from their eyes! And it's not because the beautiful insects are trying to comfort the reptiles, but because the tears contain the one ingredient that is lacking in their diet - sodium.

According to Phil Torres, a biologist who has been exploring the Amazon for many years, the forest lies 1,000 miles away from the primary source of salt - The Atlantic Ocean. This together with the fact that rain strips the atmosphere of any mineral particles it contains before it reaches the forest, makes the area extremely lacking in sodium, which is vital for the good health of all living beings.

While carnivores like turtles, get their required quota from meat, which contains a sizeable amount of the mineral, herbivores have to devise innovative ways to obtain theirs. In the butterfly's case it means leaching off the sodium from muddy riverbanks, puddles and . . . . turtle tears!

Though Torres is not completely sure, he believes that the butterflies who absorb the salt by placing their proboscis on the salt-laden tears are not hurting the poor reptiles that have no way of fending for themselves. They do however obstruct their vision, which makes the turtles more susceptible to predators.

Not surprisingly, the Amazonian butterflies are not the only insects that have figured out this easy source of sodium. Torres has seen bees doing the same. According to the researcher, they seem to annoy the reptiles a lot more - whether it's because of their buzzing or the fact that they may not be as gentle as the butterflies, is anybody's guess!

And if you think that is amazing, how about this? In December 2013, Carlos de la Rosa, an aquatic ecologist and director of the La Selva Biological Station in San Pedro, Costa Rica, was leading a group of tourists down the Puerto Viejo River, when he noticed the same scenario - except this time around, the butterfly and bee were drinking the tears off a mighty crocodile, who appeared as helpless and resigned to the parasites as the turtles were!