Though recent studies have shown that rodents express emotions with their face, whether emotional expression in rodents has a communicative function between conspecifics is still unclear. Here, we demonstrate the ability of visual recognition of emotional expressions in laboratory rats. We found that Long-Evans rats avoid images of pain expressions of conspecifics but not those of neutral expressions. The results indicate that rats use visual emotional signals from conspecifics to adjust their behavior in an environment to avoid a potentially dangerous place. Therefore, emotional expression in rodents, rather than just a mere 'expression' of emotional states, might have a communicative function.
So, what are we going to do with this new discovery? There are non-animal alternatives.
Researchers, including those who cause pain in rats, are not surprised by this finding, and neither am I. Combined with what we've previously learned about the rich and deep emotional lives of rats, we need to ask, "Why are rats still unprotected by animal welfare legislation and why are they continually abused in research?" Dr. Jeffrey Mogil, a neuroscientist at McGill University in Montreal, Canada, is one of those who intentionally causes rats to suffer in his research program conducted in his Pain Genetics Laboratory. He claims: