Let me start off quickly by addressing the elephant in the room: littermate syndrome is not a real syndrome. It is more of a ‘complex’, I suppose.
It was discovered by researchers wanting to know whether guide dog puppies could be raised together in a guardian home (good ones are really hard to come by, so it would be prudent to see if you could get one home to take two puppies and essentially double their value to the program). To cut a long story short, they found that both puppies – even if they tested the same at 8 weeks – would have issues down the track with one another and in general. One would often be overtly confident, the other extremely timid. One would often pass, the other would fail. They couldn’t get both puppies to pass.
This research mirrored what many dog trainers were seeing not only in families that bought two puppies at the same time, but in families that bought another dog as ‘company’ for their current one. This is another reason why the name is inaccurate; it is not dependent on the dogs being in the same litter, being related at all, nor even being the same age.
So, what’s the issue, why does this happen?
When we buy a puppy as company for an adult dog, or when we buy two puppies together/similar in age for the sake of halving the work (or whatever reason), what we’re essentially doing is ensuring that they form a strong bond with one another.
This sounds sweet, doesn’t it? Sure!... Except when one needs to stay at the vet for a few days, or you try to take one for a walk without the other one, or when one dies, or heck even if you just want to practice some control and obedience with them! And that’s if they like each other. Issues relating to aggression, intense resource guarding, bullying and fighting are very common also. Particularly in multi-dog situations involving similar-sized dogs and those of the same gender.
I digress, some dogs can do perfectly well and do not form dysfunctional relationships with one another without our interference. But many more do, and when they do it’s one of the most stressful and labour-intensive processes to work through. In some cases, one of the dogs needs to be rehomed for their own mental health.
So, you think your dog is lonely and you want to get him a companion? This doesn’t make any sense to me… You bought your dog as a companion for yourself. If you’re working long hours just make the time you spend with your dog awesome. Meet their needs in the time that you have. Hire a dog walker if you must. Adding another dog to the mix will probably just create different issues for your household. Our dogs exist for human companionship and that is where they best fit in. They need to get the most value from their people and not other dogs.
If you want to add another dog to your family, or if you want to bring home siblings, how can you go about it to prevent this dysfunctional co-dependent complex? Well, it’s damn hard! In an attempt to halve the work, you’ve really just tripled it! All of their best times need to be spent separated from one another. Training, walking, playing, all need to be done with you.
They can come together when they both consistently choose to engage with you over each other. Sounds hard? It is! You might be separating your puppies 90% of the time until they’re passed adolescence.
It’s crazy making, so why would anyone put themselves through that?
Do the smart thing; get one puppy. Raise and train to a high standard before you add another, and do the exact same with that one so that you end up with two adult dogs that think you’re the best thing since sliced cheese.