Why Butterflies Drink Turtle Tears (and Yes, Turtles Make Tears!)

Butterflies are more hardcore than you might think. While some animals drink the blood of their enemies, butterflies prefer to drink the tears of other animals. This strange behavior is known as lachryphagy and is mutually beneficial between a butterfly and a turtle. This video by @BBCearth shows just how symbiotic this odd relationship can be.

Turtle Tears Are Surprisingly Nutritious

Many insects benefit from the waste or excretions of other animals. Some of these relationships are harmful, such as parasitic interactions. However, symbiotic relationships like this neither hurt nor hinder the turtle in this video. It may even benefit the turtle, who gets a free tear duct cleaning. At the very least, their interaction is considered commensalism, meaning this turtle is entirely unharmed.

Butterflies need sodium to make up part of their diet. Anyone who has ever cried and tasted their own tears knows how salty they can be. Butterflies have found ways to benefit from the natural occurrence, which is commonly seen in the Amazon. There, butterflies congregate around freshwater turtles, taking turns landing on their heads to drink their tears. This provides adequate sodium that would be difficult to find elsewhere. Butterflies in this region struggle to find minerals like this, hence their unique means of obtaining salt.

Why Turtle Tears?

You’re not alone if you’re wondering why turtles are the lucky recipients of butterfly kisses. As it turns out, turtles have more tears than most reptiles. As tear ducts produce tears to lubricate the eye, butterflies feed as they would from a flower. It’s minimally invasive for the turtle, if they notice at all, apart from the slight annoyance of being momentarily blinded. The butterflies take so little liquid that it barely affects the turtle’s tear production.

Experts surmise that butterflies could also be getting other nutrients from turtle tears. Amino acids are prevalent in this liquid, and depending on the turtle’s diet, its tears could hold more nutrition beyond sodium. Butterflies don’t depend on turtle tears alone and may feed on mud, feces, or even blood in the Amazon. They’re not the only ones seeking out sodium, though. Bees have been known to buzz around turtles in the Amazon but cause more of an annoyance than butterflies.

Don’t Worry, Turtles Aren’t Sad

Despite their high tear production, turtles aren’t actually crying. They produce a high volume of tears due to salt excretion. Their tear glands are located just behind their eyes and are relatively large. This produces plenty of saline that turtles don’t need but is the perfect source of sodium for butterflies. In the Amazon, turtles also use their tears as lubrication. Saline protects their sensitive eyes from sand, dust, and other airborne irritants. Even so, butterflies don’t drink enough of their tears to negatively impact saline production. Turtles aren’t the only ones with significant tear production, though. Butterflies have also been known to drink crocodile tears.