I got my Male Maltese in Nov. 2011 at the age of 5 mos. He is relaxed and content, and perfect in every way. He has excelled at the top of both his training classes and behaves perfectly EXCEPT that he has become aggressive when people come onto our property or into our home. He barks, jumps and nips...so far. I've tried the commands, stepping on the leash, can of coins, sound collar, moving him to another room, etc. and nothing works (he cannot be trusted). After a visitor has been in our home for a little while, the dog calms down UNTIL that person MOVES! Then the dog barks, chases and nips. SO whenever we have company he doesn't know very well, I find it necessary to keep this 4 lb brat on a leash at all times.
He follows commands such as sit, stay, never begs at the table, is very quiet and sweet, is paper and outside potty trained, etc, and not at all crazy, except when visitors arrive. He's perfect at the vet and I can hand him over to anyone outside the home; but if someone reaches for him or for me, he becomes protective and aggressive...sometimes, not always.
I know it's about "his" property and "his" people. But, what can I do to stop this unacceptable behavior? Any suggestions at all would be welcome, since I cannot trust him, and that's very sad for both of us, as I am very social and would love to continue to take him out with me.
Thank you for your time.
Before we jump to territorial aggression, I wonder how many visitors he had in the home when he was just a puppy. You got him when he was 5 months old - already quite near the end of his socialization window to learn what things in life are normal and acceptable. So, do we know if he had loads of visitors in his home prior to coming to live with you? When he first arrived to your home, did you have loads of visitors to your home to meet him or just hang out with you? Did he always react this way, even at 5 months? It may be more about fear and lack of that early socialization than a true territorial aggression.
Example: my older dog, Chewie, went to work with me 5 days per week for the first 14 weeks I had him. (he was 5 weeks old when I got him, so right through his socialization window). And our neighbor and his two kids came over periodically to hang out. But we didn't have lots of visitors, we had no parties, we had no workers come over. I don't think we even ordered pizza during that fist few months he was with us. It wasn't intentional, it just didn't happen. The result - Chewie is pretty much a social butterfly and eager to meet all people when we're out in public, but barks and backs away and is nervous to be near any human he doesn't already know when they enter the house. He will settle, but if the person has been stationary for 20 minutes or longer (sitting and chatting), he will bark again when they get up. Just 5 minutes of actual interacting with him and he's fine with the new person, but his initial reaction is because I failed to help him learn that non-residents come to the house periodically and that this is normal and OK....
So, what to do with your dog in this situation - no matter the reason behind the barking... Well, the first and easiest thing to try (what works quite well in my home) is a Thunder Shirt. This is an anxiety wrap. It works on the same premise as weighted vests used with Autistic people. It creates a subtle, but constant external stimulation around the core of the body and in doing so, allows the dog to process other external stimuli without becoming so overwhelmed by it. So, while the dog may bark (woof, woof, woof) upon the arrival, he may settle much faster, rather than continue to bark for 5 or 10 minutes or longer. It also helps the dog be more comfortable with the movements of the visitor if they get up from sitting for a while.
It's not designed to be worn 24/7. In fact, the effect wears off after 30-90 minutes (depending on the dog). But it doesn't hurt to leave it on for a couple hours, just understand that the effect wore off a while ago. You can take it off for a few hours and then put it back on, reinstating the effect for another period of time. I've found, anecdotally, that wearing the shirt for an hour or two, twice per day for 2-3 weeks, no matter what's happening in the environment, and often specifically at meal times or other generally quiet times, helps to lower the baseline levels of stress hormones (cortisol and adrenalin), allowing the dog to better cope with stuff that normally triggers him. It's not 100%, he'll still trigger, but perhaps instead of freaking out just because the person uncrossed and recrossed their legs, he may not care unless the person actually walks towards him. By helping him to better cope, it gives you the opportunity to reinforce different behavior choices. Instead of barking/lunging/nipping, he may offer "softer" cut-off signals such as licking his lips, yawning, sniffing the ground, turning his head/averting his gaze, turning his back to the person, or even sitting down or looking to you for assistance. If he's further from triggering, then he's going to offer one or more of these other signals first, as the tension is building. Then you can praise and reinforce these softer cut-off signals by helping him get the distance/space he needs - perhaps calling him to you where he feels safer, or directing the person to go behind the couch, rather then directly toward the dog, etc.
Another tool that may prove helpful either on its own or in conjunction with the Thunder Shirt is called a Calming Cap. This is a piece of fabric that slips over his face and covers his eyes. He can still see, but it limits his vision, which can lower his reaction to visual stimuli that normally trigger him. You have to acclimate him to wearing it so that he's comfortable and not panicked by it, but I believe it comes with instructions. You would acclimate it the same way you'd acclimate a dog to wearing a muzzle (the steps are the same), so if you can't find YouTube video of acclimating to a Calming Cap specifically, you can turn to a few videos for how to acclimate a dog to a muzzle (positive reinforcement, using food to make the muzzle/cap a wonderful thing to interact with).
Also, giving him something to do while you have guests can help to calm him down. Chewing is a natural stress reducer, so giving him a Marrow Bone, antler, Bully Stick or a Kong that's stuffed with food and goodies could go a long way toward helping him feel better when faced with visitors. By providing him with this activity, and a place where he can enjoy it without interference (a bed in a corner, but with at least two escape directions), a crate or even another room, can help him learn a routine that when people come over, he can just settle in and enjoy one or more of these long lasting chew options. The rule is that guests never approach him while he's in that space. If he chooses to come over and greet them, that's fine. But the guests should never approach him in his safe place, so make sure you're not putting the bed/crate in the path to the bathroom or kitchen or front door so that your guests can be there for hours and never have to walk directly next to his safe space.
Finally, there are two books that I strongly recommend. The first is called On Talking Terms with Dogs - Calming Signals
, by Turid Rugaas. She explains a host of communication signals that dogs give, examples of circumstances when the dog might give them, how other dogs respond and what the purpose is of those signals. When you can read your dog's emotional state (because I promise you he's giving you a play-by-play all day long), you'll be better prepared to help him feel safer and more secure in these situations. You'll see his anxiety rising and you'll be able to intervene before he feels compelled to react with a harsher display.
The second book is by Grisha Stewart. It's called Behavior Adjustment Training: BAT for Fear, Frustration and Aggression
. This is a behavior modification protocol that helps dogs who are fearful, frustrated or aggressive learn that they can get their needs met (usually increased distance or discontinued interaction) by making choices other than barking/lunging/growling/biting.
She explains the whole premise to the protocol and then walks you through how to create set-ups so you can practice, as well as how to deal with real-world moments when you weren't actually planning to do specific training. Between these two books, I think you'll have a good start to get a handle on this. If you feel like you need more direct help, I encourage you to seek out a local professional who uses positive reinforcement methods and who is either already familiar with BAT or willing to read the book and learn about it.
I would avoid using scolding or shaker cans as these are likely to only escalate his behavior rather than help to calm him down.
I hope some of this proves helpful. Please feel free to followup if I can be of further assistance.
Los Angeles Behaviorist