Aggressive Lab/Chow/Border Collie mix
My dog Bear is 2 years old, we've had him since he was 2 months old. We were told he was a black German Shepherd, but he seems to me to be more of a Black Lab, Border Collie, Chow mix. Maybe there's some German Shepherd in there.
In the last year, but especially so in the last 4 months, Bear has begun to show aggression towards people, and some dogs. He appears to be very protective of us, and is very territorial. He has always barked and growled in the house anytime someone walks by on the street, talks outside of our yard, or basically does anything. Sometimes he seems even afraid, and I can't tell why he is so nervous. When people enter our yard, he barks and runs up to them to smell. Usually people who enter our yard are friends, and Bear immediately turns into his happy, friendly self. However, the barking goes on throughout the day, with people, and with dogs in the surrounding yards.
He's snapped at a number of people in the last few months, including children. This makes me very nervous because we have a 10-month old (he has never shown aggression towards her, and is nice to her, but still I don't trust him). We also bring him to family events where there are children, and bring him out into public where there are a lot of strangers. Yesterday he ran snarling at a girl walking close by us at the beach, so it seems his aggression is getting worse!
I am concerned because it's getting to the point that I'm nervous to take him out of the house without some sort of muzzle, but I don't want to muzzle him. Generally he listens to my commands, though it is difficult to get him to listen once he gets going. He listens to my husband even less.
What do I do? He's a really friendly dog and is great at the dog park, but I'm worried he's going to really attack someone!