Does he maybe just want to play? I just got a new dog, a fixed, 4 year old golden retriever/collie mix. He'll see the cat, walk over to it and either stand or sit in front of it whining. Doesn't snap, growl or show his teeth. I noticed once when he did it he blocked the cat when it looked like it may dart around one side of him. Could this mean he could get aggressive towards the cat?