Happy faces - sheep style

Can animals draw information from faces in the way we can? The evidence seems to suggest that, to some degree, they can.

Many animals are social and being able to identify individuals and pick up social cues from them would seem to be highly advantageous. Smell is used by many animals, such as mice, to identify individuals. Elephants can keep track of up to 30 individuals on the basis of smell. Primates, though, seem to rely on vision.

One animal studied intensively is sheep. They have surprisingly sophisticated face recognition systems that appear very similar to those of humans. They can detect emotional states of other animals - the flared nostril is a give-away. They can also spot the difference between different human expressions - they prefer happy faces to sad ones.