Dog Behavior: Getting Along with Other Animals
SOURCE: Can We Help You Keep Your Pet? (Link: http://www.wonderpuppy.net/canwehelp/1others.php)
Adding another dog to the household can upset the pack order, and might cause dominance issues between the pets. A dog approaching adolescence may feel the need to test his place in the pack order. Some growling and skirmishes can be expected between dogs while they sort this out. There is not really any problem as long as one dog does back off or roll over, and the other does quit pushing it at that point. It should be completely bloodless, just a lot of canine 4 letter words and some pushing around while the new or maturing dog tests his position in the pack. It can sound quite scary. Sometimes the original dog will end up subordinate, sometimes not. That’s not a bad thing as long as each dog accepts his place in the pack, whatever it is.
If, hopefully, you are top dog of the pack, then you do have some control over how they treat each other too, at least while they are in your presence. If the original dog wants to be dominant and is worried about his place in the pack, continue to give the original dog his full share of attention as much as you can. Or at least a bit more then the new dog. The less dominant dog can get a bit less if necessary, it doesn’t have to be equal, they don’t necessarily expect it to be. This will assure the dominant dog that his place is secure, and he is less likely to challenge the other dog. Things like feeding the dominant dog first, petting him first, etc., shows that you respect his position in your pack, and encourages others to do so too.
Please note: Realize that this isn’t always necessary, and you will sometimes be able to continue to give your original dog all the attention he’s come to expect without problems even if he is subordinate to the new dog – don’t let it dissuade you from trying a second dog. The new dog sometimes DOES seem to understand that his subordinate is your favorite, and your beta (second in pack position), and can often accept it – in relation to you. It is not necessarily a true ladder of pack positions, one always above the other in all respects. This is the case in my own home. My original dog, Leilah, a 3 year old female, always backs off in respect to my new dog, Copper, a 9 year old male, as far as food, water, going through doors, etc…, in any relations just between them. But Copper does not compete with her for position in relation to me. Leilah is in a beta position to both Copper and me. He is the dominant between THEM, he is secure in that since she’s never challenged it. If she bounces on him too much in play, I let him tell her off, as is his right. That they are opposite sexes does help. I just don’t want people to think there will be a problem automatically upon getting a second dog, the information here is for POSSIBLE problems, and problems already occurring.
Spaying and Neutering might help also. They won’t be taking out sexual frustrations and tensions on each other if they don’t have the frustrations and tensions to begin with.
If other species are involved or there’s a large size disparity, problems can be caused by prey drive. While training is sometimes effective, complete separation at all times when the animals are not strictly supervised is the safest thing to do, this is not something that might resolve itself in time like a pack order spat.