I have a 1 year old "intact" black lab/shepard mix. We got him when he was 4 months old, and he's been socialized at puppy class and dog parks since then. He was always very friendly and playful......
Lately he's been showing signs of dominance/aggression. Both with humans and other dogs.
He's started barking excessively during the day at any noise in the house. I used to garden/have coffee out front with him on a leash, now he barks and snarls and darts towards anyone that passes.
The other day I had a guest over, and let him sniff/say hello to the guest before taking him off his leash, and giving him a bone to run and chew. He took the bone upstairs to his crate, chewed on it a bit, then came down a few minutes later, sat calmly on the floor between me and the guest, and the guest started petting him, remarking about how calm he was now. Then out of nowhere, the dog snarled, lunged towards him and nipped him in the arm!!!He didn't draw blood, but it was hard enough to leave some teeth indents in his skin! Needless to say, we were both very thrown off, because he's never been anything but playful with people before!!!!
Then yesterday at the off-leash dog park, he was very "humpy".... essentially humping a bunch of other dogs. He didn't show any aggression.... so I'm not sure if it was sexual or dominance...... but then today at his dog class, he got into a dog fight where he was showing aggression for the first time towards other dogs (and they were all off-leash.... I know sometimes they can react aggressively when on-leash). The trainer ended up leashing him back up because she thought he was unsafe to have off-leash!!! He's been going to that class since Dec, why all of a sudden is he acting out!?!
He is going to get neutered on Tuesday...... hoping that helps? We were told by this trainer not to neuter him for a year to allow his bones to form correctly........ (although I've never heard anyone else say this, so maybe we were lead astray?).....
Anyways, has anyone had this happen before around the 1 year mark? Does it get better or worse? Should I be worried that he is going to hurt someone???? Will he grow out of it, or am I looking at a serious problem here?