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A few years ago, an elephant calf named ZhuangZhuang made headlines and broke hearts when photos of the baby animal crying made the rounds online.

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But was ZhuangZhuang really crying?  What about animals in general?  Do they cry?

The answer is yes.  If you're asking whether or not animals emit moisture from their eyes, both humans and most land mammals need tears to keep their eyes healthy. 

They keep our corneas moist and, more importantly, clean.  When dirt or dust gets stuck in there, we make more tears to wash away all the gunk.

So yes, animals can and do cry.  And since ZhuangZhuang was emitting moisture similar to human tears, technically he was crying.

But the real question here is - was ZhuangZhuang crying emotional tears?

For a long time, scientists thought animals cried emotional tears, but the evidence was all anecdotal.

Charles Darwin even wrote a book on the topic - Expression of Emotions in Man and Animals.  He included an entire chapter about a weeping Asian elephant that he was convinced was showing human-like emotion.  

And Darwin wasn't the only scientist who saw animals that looked sad on the outside and assumed they were sad on the inside too.  

Some have analyzed crying Rhesus Monkeys that were separated from their mother or lost dogs weeping for example.

But, many animal behaviorists today think animal crying might be a hard-wired response to lack of contact or stress, and not an emotional reaction.

So while scientists don't rule out the possibility that animals might cry emotional tears, they're hesitant to say that just because an animal looks sad, it is sad.

This whole thing would be a lot simpler if we could just ask an animal if it's feeling down don't you think?  Well that's what neuroscientists are doing...sort of.

By performing brain scans on animals like monkeys, dogs, and rodents, a group of animal behaviorists are trying to figure out if animal brains look like human brains when those human brains are feeling certain emotions.

So far, results show that animal brainwaves do look a lot like human brainwaves when we're experiencing fear, anger, or joy.  And in 2013, a study in Japan found that chimps exhibit the same brain patterns as humans when they look at emotional images.  So even though they can't say what they're feeling, they might actually be feeling something.

We may never know for sure what animals are thinking and feeling, and whether or not crying is one way they express how they're feeling, but it's possible that similar brain patterns might be linked to similar physiological responses.  In other words, emotional tears.

So, that Darwin guy...maybe he's onto something.

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