This reminds me of when my DD-11 was 6 months old & just learning to sit up. She was sitting on her blanket with my DH, and my Sheltie brought the ball to play catch. My DH proceded to play catch w/the dog & my DD started to giggle, hard. In fact she giggled so hard that there was a couple of times we weren't sure which way her emotions were going to go - laughter or tears. I hurried & got the camcorder going & was able to tape her infectious giggle at the dog chasing the ball. She never giggled again like that at the dog, so that is a very precious tape.