It can be hard enough to read fellow humans' body language, let alone another species.

It's probably closer to some Terminator vision flowchart. Do I see something? If so, do I eat it, fight it, or have sex with it?

I do hope they have some happy times. Their lives seem very hard. Perhaps they get exhilarated from a good hunt or when they find a perfect roost with prime offensive views and good camo, or have twitchy little dreams like dogs/cats.