Tickle experiments prove rats’ ears look different when they’re happy

Rats can’t talk, but researchers say there is one easy way to tell if they’re happy: look at their ears.A group of Swiss scientists tickled rats to make them happy for science, in a delightful study published recently in the journal PLoS One. The researchers took photos of the happy rats and compared them to photos of the same rats when they were forced to listen to unpleasant noise. (Poor things!) And just as we smile and frown, happy rats do look a little different from miserable o