May 28, 2014 -- Mr. G the goat was feeling baaaad until being reunited with his best bud, a burro named Jellybean.

The two were separated for six days after being rescued from an animal hoarding situation in Southern California. Once the staff at the Animal Place Sanctuary in Grass Valley, California, realized how much Mr. G missed his friend, a volunteer agreed to drive 14 hours to bring the two together.

Mr. G sure seemed mopey and down in the dumps during his separation from Jellybean. But do animals really get depressed?

Possibly, but scientists don’t like using the word depressed when talking about animals, Olivier Berton, an assistant professor of neuroscience in psychiatry at the University of Pennsylvania, says.

“We prefer the term depression-like behavior,” he explained.

Berton, who studies social behavior in rodents and sheepishly admits that he has no experience with goats, says it’s hard enough to pin down a definition of depression in humans let alone animals because it’s such a subjective emotion.

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Animals can’t communicate what they’re feeling so it’s difficult to say why they behave as they do in certain situations, he explained. The only thing researchers can do is observe their behavior and then make inferences about what their furry subjects might be going through.

In Berton’s studies, when rats and rodents are isolated, separated from their social group or forced to live with larger animals that bully them, they stop exercising and eating -- just like their human counterparts. While they’d normally do just about anything for a taste of something sweet, they’re no longer willing to press a lever or run through a maze to gain access to junk food treats.

Berton’s work also shows that the brains of rodents who exhibit depression-like symptoms shrink in the areas associated with pleasure and reward and grow in areas associated with negative emotions and stress.

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As for goats, Deanna Clark, who raises milking goats on her farm in Boring, Oregon, and is known around town as “The Goat Expert,” says the bearded beasts do have the capacity to feel blue.

“They are highly intelligent animals that bond strongly with each other, other species and sometimes even inanimate objects like rocks or wheelbarrows,” she said.

Clark says you really can’t have a solo goat. In a case like Mr. G’s, she might have tried to introduce a buddy goat to cheer him up.

Professor Berton pointed out that vets often put dogs and cats that show signs of depression on antidepressants. Treatment does seem to help, he said, but more large-scale studies need to be done to know for sure.