1 yr old male suddenly showing aggression

[Sarah~]

My puppy just turned 1 year old on valentine's day, and it's like a switch has gone off or something... he's suddenly reacting to things that have never bothered him before.

Just this month there have been 3 separate incidents where he's barked and lunged at people in our house, people he's known for some time. The first time it was when one of my roommates was messing around, play fighting with us and he grabbed my arms, shoved me down on the couch and Eko barked and lunged at my roommate. My roommate backed up and the dog was fine. The next time was when my roommate's girlfriend slapped my roommate on the arm, he did the same thing as he had done before, barked, lunged, then was fine.

This last time was the most worrying to me, he's always been wonderful at greeting people at the door, but just a few days ago my boyfriend's cousin and his girlfriend, who the dog already knows and has had no problems with before, knocked at the door and Eko started barking furiously. He NEVER, not one time, has EVER barked more than once when someone knocks at the door. And when I opened the door, he kept barking, it took all I had to drag him away from the door and hold on to him. She asked if petting him would calm him down and I told her not to try and touch him right now just in case he did try to bite her.

Nothing's happened since then, and I DO want him to be protective of us and the house but only when it is needed.

[KZoppa]

You need to make it clear to him that YOU decide when he needs to be protective. He needs to know the difference between playing and an actual threat. If you're not already, get involved with a trainer who likes and knows GSDs and can help "harness" this behavior so its done appopriately. He's issuing a warning that from the sounds of things is not necessary but he feels it is. The people he cares about are in danger as he views it. Sounds like he's thinking he needs to take charge because nobody else did... Hopefully others will chime in soon.

How has his behavior been up to this point? How's his socialization? Training?

[Sarah~]

He's been very well socialized with people, we have people coming over all the time so he is very used to it. We allow him to bark once when there is a knock at the door, then we say "enough", and he is quiet. He does try to stick his head out of the door before it's fully open, we are still working on that. But once they are inside he's all over them, rubbing on their legs and giving kisses. Very friendly to people on the walk as well, always approachable, loves to be pet.

That's what's so crazy about it, he's always been so friendly to everyone and everything, so this behavior shocked everyone. We have never seen it from him until now. He has had basic training, he knows sit, down, stay, come, leave it, shake, the basics and a few tricks. With dogs we haven't been able to socialize him as much as we wanted but he was raised with a dog for the first 6 months and has been friendly to the few dogs he's met since then.

He's not very good with cats, he chases them and snaps at them if they get near his food when he's eating. But any person could stick their hand in his bowl while he eats and he will stop eating and sit.

[KZoppa]

Originally Posted by Sarah~

He's been very well socialized with people, we have people coming over all the time so he is very used to it. We allow him to bark once when there is a knock at the door, then we say "enough", and he is quiet. He does try to stick his head out of the door before it's fully open, we are still working on that. But once they are inside he's all over them, rubbing on their legs and giving kisses. Very friendly to people on the walk as well, always approachable, loves to be pet.

That's what's so crazy about it, he's always been so friendly to everyone and everything, so this behavior shocked everyone. We have never seen it from him until now. He has had basic training, he knows sit, down, stay, come, leave it, shake, the basics and a few tricks. With dogs we haven't been able to socialize him as much as we wanted but he was raised with a dog for the first 6 months and has been friendly to the few dogs he's met since then.

He's not very good with cats, he chases them and snaps at them if they get near his food when he's eating. But any person could stick their hand in his bowl while he eats and he will stop eating and sit.

one thing I would suggest is teaching him a place command and enforcing a stay on it. It will help with the poking the head out the door too. Beyond that, without witnessing the behavior, I really don't feel comfortable recommending much else beyond the place command and stepping up obedience in all situations. I'll check back later and see if anyone else has responded. Like i said earlier, it sounds to me like he suddenly thinks he needs to warn in all situations whether appropriate or not. This needs to be corrected obviously.

[Mick_21]

My male shepherd did not show any signs of aggression or protectiveness until about 12 months as well. After a little while he will learn to differ between a threat and company but he will still bark when someone knocks on the door. I don't think you have any problems unless when you say enough and he doesn't listen and is aggressive towards people you let in. Then you should seek professional advice. When my girlfriend first started coming over my male would separate us if she got to close not with aggression but mainly jealousy, now they cuddle up on the couch. I think when your dog lunged he may have wanted to play as well...but there is a possibility that he was scared for you and felt the need to protect you. As he gets a little bit older he will stop doing this. When you let someone in you should let them pet him as he will like it and will soon realise that your friends are okay, but i doubt he would let them in if you are not there.

[gsdraven]

Stop the wrestling around your dog, it is confusing him. Work on your control with him especially around the door behavior. The door does not get opened until he is calm for the sake of your guests. I'm sure they won't mind waiting a bit until you get him under control.

[Sarah~]

So... This morning, not 10 minutes ago as I was feeding him breakfast I put my hand over his bowl like I have before while training him, but he showed teeth at me and growled. I immediately said NO bad dog and made him sit while I picked up the food bowl. When I gave it back to him I put my hand down again and everything was fine. He's laying on my lap right now being the sweet puppy he normally is like nothing happened. I will speak to my roommates about not wrestling with him anymore because something needs to be done before this gets any worse...

[Mrs.K]

Why do people feel the need to CONSTANTLY mess with their dogs food.

How would you like it if someone was putting their hand over your food, take the plate away and then reach onto your plate to pick up your food and then put it back in front of you, everytime you get a meal.

Just leave the dog and the food alone!

[msvette2u]

Originally Posted by gsdraven

Stop the wrestling around your dog, it is confusing him. Work on your control with him especially around the door behavior. The door does not get opened until he is calm for the sake of your guests. I'm sure they won't mind waiting a bit until you get him under control.

This.
He is a dog, not a robot.
It sounds like he kind of just lives there as a community pet with no active training really, and that's going to have to change.
And yes...stop messing with his food. You will create problems by doing that.

[Mrs.K]

Originally Posted by gsdraven

Stop the wrestling around your dog, it is confusing him. Work on your control with him especially around the door behavior. The door does not get opened until he is calm for the sake of your guests. I'm sure they won't mind waiting a bit until you get him under control.

One easy way to do that is to teach him crate games initially. Makes it much easier to get that kind of self control.