My friend and I were walking our (small) dogs this evening. They had all just responded to us telling them not to chase the nice jogger person (!) so my friend asked all three dogs to sit and give a paw and she gave them all a treat. Another dog, a large lab, only vaguely known to us, bound over and muscled in amongst our three and grabbed treats from my friends hand. At this point my sweet gentle little Ted (age 9mths) growled horribly and snapped at the lab! He didnt make contact but it really shook me up. The owner said it served her greedy dog right but I felt awful! Ted happily shares treats with more familiar dogs and this was a first. He eats with our other dog and our many cats and has never shown any possesiveness. Does this mean he is actually prone to aggression? How should I deal with this?