It can be easy to tell how dogs are feeling but new evidence suggests they're also trying to communicate.
Scientists are beginning to link animal facial expressions to emotions, making it possible for us to understand how they feel.
If you're looking online for new love, a new job or just to meet up with new friends, then a lot rests on the face you present to the world.
What happens when the face is no longer the primary means of expression?
Just a few hours after birth, infants show a preference for human faces. Over the next few months, they learn from facial expressions.