Is Your Rat Happy?!

We’re all convinced that our pets show emotions, and it’s true that it’s easy to see when your dog or cat is happy or somber or scared. But what about your pet rat? A recent study shows that yes, indeed, rats can show happiness and it’s less about the eyes and mouth and more about their ears!

Luca Melotti, a researcher and animal behaviorist at the University of Bern in Switzerland, ticked rats repeatedly and then photographed their faces to find similarities. That’s right, Melotti pulled what every aunt and uncle does and tickled until the rats giggled. And we know that rats love tickling because of a different study (seriously, did I miss the job fair flyer that said I could tickle rats all day?!). What Melotti found was that happy rats tend to have relaxed ears; that is, their ears hang low and dangle to the sides. Their ears also tend to be more pink than anxious rats, but that could just be excitement and increased blood flow from all that tickling.

Melotti’s is the first study of it’s kind to focus on the expressions of happy rats: previously, studies had been done to see if they had angry faces or faces that indicated that they were in pain. (That’s why I could never be a researcher). All of these studies have an overall purpose, however, which is to show common expressions across all mammals. For example, both hippos and seals (in addition to humans) have open mouths when playing – we just call it laughing. And it turns out that rats can laugh too, it’s just too high pitched for humans to hear. And if that isn’t the most adorable thing you hear all day, then I want your life!