Yes, the 'theory of mind' is a pretty old philosophical discussion. It does seem bizarre to adopt this towards other humans (thus avoiding solipsism), and not other animals, especially as they exhibit proto-morality, social interaction, feelings such as fear and aggression, courtship, rearing of young, and so on. I noticed the other night on TV, some animal researcher talking about the importance of gaze in some animals - if you meet a wolf in the wild, for God's sake, don't look at in in the eyes, or it will impute aggression to you. Actually, this is true of some dogs and horses, see horse whispering.