They may not have the ability to speak our languages directly, but over thousands of years of domestication, dogs have likely developed certain'signals' to help them communicate with humans. When they're confronted with an angry face, a new study has discovered that dogs tend to their lips as an immediate response – and, this was more often the case when a human was involved, instead of another dog. Animal behaviour researchers say this may be linked to the dogs' perception of human emotions, acting as a way for them to communicate in response to visual cues of anger. In the study, dogs were shown two facial expressions (one positive and one negative, from the same individual). When they're confronted with an angry face, the researchers discovered that dogs tend to their lips as an immediate response Historically, animal's facial expressions have been considered to be inflexible and involuntary displays, which reflect an emotional state rather than active attempts to communicate with others.

Oxytocin, a hormone involved in social bonding, influences what dogs see and how they experience the world around them, a new study has found. Normally, dogs focus on the most remarkable aspect of a situation, for example threatening stimuli in scary situations - an important skill for survival. But the new study found that dogs under the influence of oxytocin were more likely to focus on smiling human faces than angry ones. Pictured top left are examples of two images shown to the dogs treated with oxytocin during the experiment. Left is an angry face, and right is a happy face.

On a recent Saturday morning, my wife, Susan, and I slipped into the city to visit the Metropolitan Museum of Art, a place we hadn't gone together since before our sons were born. The crowds hadn't yet descended and for an hour or so we wandered around and absorbed the cavernous hush of art. We separated for a bit, together but apart; while Susan roamed among the Manets and Van Goghs I slipped into a small side gallery, not much larger than a subway car, that held a series of glass cases with small bronze sculptures by Degas. There were a few busts and several horses in stride and the figure of a woman stretching, a small bronze rising to her feet and curling her left arm upward as if waking from a long nap. At the end of the gallery, in one long case, were two dozen ballerinas in various states of motion or repose.