I find the animal/dog thing really interesting, because it's something that's come up with ds1 recently.
I used to be a dog trainer pre dcs and was really interesting in canine communication, body language etc. I often play with my dogs by emulating their body language as best I can - for a bi-ped. 
Ds1 was watching me goading my lurcher to play by averting my eyes and play-bowing and was fascinated - mainly because the bonkers dog was having a complete mad one, charging around the room and play-bowing back - cue much hilarity from all three dcs.
Suddenly ds1 said "Why is he doing that Mum? What's making him do it." I explained that it was me that was making him do it and he said "But how? You aren't doing anything."
I explained to him that I was copying the dog's own body language and that if a dog wants another to play they avert their eyes, so that they don't seem threatening, then lower the front end of their body onto their elbows. Ds watched me for a few more minutes, then pointed out that I was sitting on the sofa and not lowering myself onto my elbows, so how did the dog know what I meant. I explained that all I had to do was avert my eyes, extend my hands, lower them and dip my head for our pup to understand what I meant - the movement was subtle, but clear enough. The more I wanted to wind the pup up, the bolder I had to make the body language. So I sat on the floor and bounced on my arms - at which point the loopy great lump of a dog completely lost the plot and jumped on my head.

We then had a really good talk about why dogs need clear body language because they don't have much in the way of verbal communication skills and that people use both, verbal and non-verbal communication skills.
Ds is now noticing some non-verbal stuff, but pretty much always gets it's meaning wrong. So, say I am concentrating on something - he will ask why I am cross or if I am thinking/pondering about something - he will ask me why I am sad. However this is progress, having come from place where he didn't even seem to notice non-verbal signs.