Why do dogs look sad?

A paper published today in the Proceedings of the National Academy of Sciences found that dogs’ faces are structured for complex expression in a way that wolves’ aren’t, thanks to a special pair of muscles framing their eyes. For the study, a team at the University of Portsmouth’s Dog Cognition Centre looked at two muscles that work together to widen and open a dog’s eyes, causing them to appear bigger, droopier, and objectively cuter. The retractor anguli oculi lateralis muscle and the levator anguli oculi medialis muscle (mercifully known as RAOL and LAOM) form two short, straight lines, which connect the ring of muscle around a dog’s eye to either end of the brow above.

Source: www.theatlantic.com