There are a few reasons why it may seem a good idea to take 2 pups at the same time or from the same litter home. Keeping each other company is the first one that comes to mind. But is it really a good idea?
Commonly people say that littermate puppies will bond to each other, and not to you (some call this ‘littermate syndrome’), and that they can develop anxiety when separated if not taught to be independent from each other. While this can be true, it can also happen between any dogs of the same household.
There seems to be different information around, so let’s have a look at what the experts say…
Is There Evidence That 'Littermate Syndrome' is Real?
There doesn’t appear to be any objective evidence that litter mate syndrome is real according to Drs Hetts and Estep from the Behaviour Education Network. They say that attachments can form between any two dogs of the same household, and the main issue with adopting littermates is the time and effort it takes to train two puppies at the same time (Estep & Hetts 2017).
Development and Aggression
Dogs in the same household can have scuffles, but we do see it, anecdotally, more commonly in littermates, or at least dogs of the same sex, same/similar age and same/similar size. They are reaching the same developmental stages at the same time, so dogs that are pushing boundaries, or becoming socially mature can often become bullies, or even resort to fighting to get what they want.
Well known applied animal behaviourist Patricia McConnell says to avoid purchasing or adopting littermates for a few reasons, one being that she more commonly sees bullying and aggression between littermates (McConnell 2014).
Puppies’ brains continue developing until they reach sexual maturity (and even a bit beyond that), and there’s some convincing research done by Guide Dog Organisations that bringing two puppies home at the same time prevents one of the puppies from reaching his or her full potential (Reusche 2012).