I appreciate the additional feedback....and as for the play growl I don't think that its that. Gus does have a distinctive play growl and this is different. This is a lower growl. The last time that this happened I do remeber him backing away from the people that were petting, like he was a little uncomfortable. As I have thought about this A LOT, I am starting to think that it is just an overstimulation issue. I also remember that on more than one of these occassions that it happened he has came back and sat on my foot right after the growl. Just after I posted this the other day it happened again with a teenage girl, this was totally my fault we were in an area that was way to overstimulating; and the girl asked to pet him. He growled a little at her, and she backed away and said it was OK that she had dogs and understood. I told her that I thought he was a little uncomfortable. I felt bad for putting him in that position. He was really tired, and had been sleeping in the car, and then when we got out of the car, there were lots of people, noises, and tons of distraction. I just hope that some of this remedies when we work with him. He is so good natured, and good around adults! Hopefully as he gets older, and gets more confident this will subside a little. I totally don't think that its aggression, to me it appears like he is insecure in certain situations.