He wouldn't let go of my arm. I know he didn't pierce or took a chunk of me, but he wouldn't let go and he WAS still biting me when I had to hit his head so he would unlock. I never lay a hand on either of my dogs. He wasn't letting go of my arm.

If it would have been life threatening, as you put it, I wouldn't be trying to work with him still, I would have had to call animal control. I love him, I do, but I was being bitten, he wasn't letting go of my arm and I, as another animal (you seem to be forgetting humans have instincts too), did what I had to in order to defend myself.

Thanks for the nagging, but I was asking for suggestions on how to work with Estambres to make my home safe again, not just for us, but for Zeus as well. I don't see how your comment is doing any of that.

I know that maybe I'm assigning to many emotions to him. But I see that every single time we walk them and he is on a leash and Zeus is not, he will immediately become aggressive to Zeus. And this creates a gap between them. I really wanted them to have the same opportunity to run freely, but I see now that it might not be possible and that I was wrong about that

The golden, Estambres, is a he :P Thanks so much for this approach, I was so focused on trying to make them like they both have the same opportunities, that I forgot completely about them actually being different and needing me to treat them in different ways.

I've tried no to push him, I even stroke his mane first (in that specific time) to make him see I was being peaceful. He seems to respond well to the stimuli in the moment, always, but then he snaps for the littlest of things (Like me, telling him no when I get to the house with food and he jumps to take it from me. Not even touching him, just saying no) and let alone growl, but bites. So I guess that I'll need to try again with trainers and hope for the best.
If the goldie growls at me, the dobe will growl at him. And the goldie once tried to bite me when the dobe was around: immediate response, the dobe jumped on him, tackled him, and grabbed him by the neck. Zeus loves Estambres so very much (he will even let him always win the fights being twice as big and much stronger), but will always take my side and Estambres seems to know that.
This is so very helpful! I did not think of that at all. I'll make an appointment with the vet. Thank you!!

I do not understand what you mean by "so he would unlock". No dog of any breed has "locking jaws". And from the look of that wound he was not "biting" - he had just bitten. And not that badly at that. You said you were holding onto his collar? And that he bit you because maybe you were choking him by holding onto his collar. Well if you were then he reacted. Normally.

And you DID hit him. You hit him on his head.

Yes, I am fully aware that humans are also animals, as you say, and have instincts too, but I do not think I was nagging you therefore that comment was rather uncalled for.

"Working" with Estambres does not mean slapping him on his head if he does not do what you want, so reacts in the only way he knows, ie warning and then using his teeth when his warning is ignored.

But that was not a major bite and certainly did not warrant a hard slap on his head.

I think the OP is correct, it is a behavioral, not a physical problem.

Sounds like a dog with some bad tendencies that were not checked early, and have gotten engrained.

A few clips from the first post:

"he's very aggressive when he thinks he's not gonna get his way"

"He has some history on attacking us, but mainly just growling or come–and–go light bites when he gets nagged."

I don't think any of us could really diagnose this without seeing the dog and how he interacts with his family. But it sounds to me like the advice needed is behavioral. Maybe structure and training would help, with an established consistent routine that involves time out for any aggressive behavior, use of distraction when it seems like a bout of stubborn and potentially aggressive resistance is coming on. But those sorts of things are much better diagnosed and worked on in a hands on context.

From the description given, I think there is reason to fear someone is going to get hurt if things continue as they are going.

Oh, ouch. That looks wicked. But as others have said, the dog has been allowed to act growly etc. with you guys so now it has simply escalated. Also, labs and goldens here are generally far better behaved than many other breeds so them being prone to this issue not true at all imo.

Personally, if my dog bit me like that, as much as I love both my dogs, the dog would be gone the next day, never to return and so I'd never have this dilemma. Perhaps a behaviorist can be of help?

I don't ever advise taking a dog by the collar unless it's absolutely needed. Certainly doing this while trying to teach recall isn't a good idea. Frankly we are not pack members, but dogs are expected to do what I tell them (get down, come here, drop it, sit, etc ) in my household without question so I do think that implies I am over them in a sense.

I never suggest trying to deal with a dog that has bitten the owner without professional guidance as it can be dangerous.

I don't know how many retrievers you have dealt with, but sadly NO breed is better behaved naturally than any other. It is a myth that Labrador & Golden Retrievers are naturally well behaved believe me, I seen too many failed guide dogs of both breeds & their crosses to believe this. There were even the classic dog fight between litter mates on Blue Peter from the litter of Goldens they bred in which ALL(including the mother)were involved except the dog that had been puppy walked on the actual program. These were not badly bred dogs coming from bloodlines that had produced 100s of excellent working guide dogs. Also a colleague I worked with had severe problems with her yellow Labrador guide dog & biting-the dog was retired at 2 1/2 & was PTS shortly afterwards. When I lived near a breeding kennels belonging to & run by the GDBA I was in contact with way too many failed dogs that had temperament problems, escalated by the training they had received.

This dog needs to be trained using positive methods & the OP needs to be guided by a professional qualified behaviourist or trainer

I don't think that those breeds are better behaved than other breeds always. In America, unlike the UK labs and golden are no where to be found on bites lists etc. But Doberman are pretty high. I agree that the dog needs professional help. Guide training and other types of extremely focused training for dogs is unnatural and often backfires. I gave up on it with my dog because of that. It's just hard for dogs and goes against their nature. Any dog that is allowed to growl and snap at people can end up like her Estambres, unfortunately.

Really so you stop your dog from growling then ??

It is an instinctive WARNING behaviour that should be read as the dog indicating that it is uncomfortable in the situation it is in. If you stop it growling & punish the dog(either mentally or physically)for growling you will end up with a dog that goes to the next stages of snapping & biting without any WARNING as you have conditioned the dog that growling is punishable.

Why do you think dominance based trainers end up getting bitten ?? because they stop the dog being able to use it's instinctive warnings & forcing it to bite to get it out of the situation, they usually end up saying "I didn't see that coming" because they haven't the faintest idea about natural dog behaviours & fail to read the dogs body language.

I've worked with so many dogs who have learnt to show aggression to force itself out of a bad situation because that have been conditioned NOT to growl by their ignorant owners/previous owners

No I don't tolerate any growling and as many dogs have come through here none have made the likely fatal mistake of biting or trying to bite me. So I can't say that dogs who are not allowed to growl will always bite. Why should I accept a warning from a dog? Though a growl comes before a bite, a growl comes before a bite and I'll have none of it. I do not strike dogs unless I am being bitten or someone else or another animal is being bitten. But if one bit me badly, like latched on like she claims her dog did, he'd feel my ultimate wrath and if he ever got another home(assuming he survived my defense), he'd think twice before ever trying it again.

Positive reinforcement is great but I'm not going to be nice to a dog that threatens me. He will find out just what a bad idea that is. I do not strike, hurt , or hit dogs. I do not use prongs etc either. But a dog that growls at me will know in no uncertain terms that it will not be tolerated. I am not scared of any dogs and what I say goes, and the dogs know this.

With rescue dogs that are adults it can be a tad more difficult, but I used to foster and though a few of those dogs growled at me, it did not happen more than a few times. Dogs are not stupid and they usually choose their battles wisely. I'm not the one. Train your dogs how you like, but I'm not being nice to a dog I feed, care for etc that dares to threaten me in my own home.

Mind you, I do not go about advising people to stand up to growling dogs, because it is dangerous and can be counterproductive but it works for me all these years and I'll wager it will keep working. It's hard to not be scared of a snarling aggressive dog, but I'm sure as crap not and the dog has a very short time to cut that out in this home. And if he doesn't? He's gone, simple as that... temperament is not right for my family.

I love positive reinforcement, but I draw the line at threatening family members in any form. My choice and it works for our dogs and our family.