Does Thor have a clue?

Our little dog, Thor, is a good pup. He loves Jeff to death and generally puts up with me and loves on me when Jeff is busy with other things. I've noticed though that since we've been further along in this pregnancy that Thor has taken somewhat more of a liking to me. He cuddles up in my lap more, hops up in bed with me when I go to bed early and seems to just like attention from me.

The other night when I was jiggling my belly to see if the girls would move I noticed that Thor didn't seem to like it. Then today when Jeff and I were sitting down together on the couch I did it again to see if they would move and Thor got mad. He started barking at me and play biting at my hands. I laughed and pushed him away a little but he was right back defending. I don't know if he thought I was hurting myself (he doesn't like it when Jeff and I play fight either and will "protect" us from one another) or if he actually has a clue that there are little ones growing in there and didn't want me to hurt them. It was interesting anyway and made me wonder a little. I hope he adjusts okay when they are born. We've read and heard things about pets having a hard time with it and want to keep him happy still.