Our rescue collie is 4 years old and we have had him for a year. Lately he has been exhibiting growling at other dogs when they come near him. We have another dog, who is 13 and stays over the other side of the room when he is in there. We also have a cat that is frightened of him. Tonight he was sat under the table whilst we had dinner, he went to sleep for about 10 minutes, when he woke up he dived at me snarling, I was terrified.We have taken to leaving him out when he growls at someone/something as this appears to be the only thing that calms him down. Yesterday we had a thunder/lightning storm and he was irrascible, we could not leave him outside and so had to have him growling inside. We are at our wits end, can anybody help!