Getting two dogs at the same time seems like a great idea. They look great together, and after all, don’t they deserve to be with their sibling? Two puppies can entertain each other and keep each other company. So, what is the problem with bringing home two puppies at once?

When given the chance, Veterinarians and professional trainers would advise against bringing home two puppies at the same time. Unfortunately, while we offer pre-purchase or pre-adoption counseling, it is rare for us to get this opportunity unless we have a relationship with you from your previous pet. Most of us get caught up in the moment and spend very little time discussing the companion we are about to spend 10+ years with.


Puppies are already demanding, but what we like to focus on at Banderas Pet Hospital, is the total picture. Meaning I want to spend as much time of physical health as I do socialization and mental health of my patients. This means less behavior issues, less rehoming, and less heart ache all around.

Since puppies’ brains continue developing until they hit sexual maturity (and even a bit beyond that), and there’s some convincing research out there that bringing two puppies home at the same time prevents one of the puppies from reaching his or her full potential.

But Doc, how can you say that? My siblings love each other so much…. Say it ain’t so….

Well, since we are focused on evidenced based medicine – we are lucky that this has been researched already by a group who knows all about creating behaviorally sound puppies: guide dog organizations. One of the biggest problems that guide dog organizations run into is that puppy raising takes time and dedicated volunteers – how great would it be if you could move two puppies at the same time?!

A guide dog organization ran just this experiment – Group one was given TWO puppies to raise, the second group were given just ONE puppy to raise. All puppies were temperament tested prior to placement and tracked thereafter the puppy rearing was complete. This is what they found: two puppies put in the same household always caused one puppy to become temperamentally unsuitable for work, even when both puppies started off as perfect candidates.

When two puppies are placed together, they learn to rely on each other. One of the puppies always becomes shy, even when both puppies started off as bold and outgoing. This is a huge problem, since it means that the shy puppy never reaches his or her potential as a service dog. In fact, this was such a major issue that they discontinued the study and separated puppies.  The “bold” puppy starts to get its confidence from the litter mate, and ultimately, they are using each other as a ‘guide’ dog of their own. The puppies frequently become incredibly co-dependent, exhibiting heartbreaking anxiety when separated from one another. They often fail to bond to their human family as strongly as they otherwise would, or sometimes at all.


The kicker for me, is at social maturity, these puppies may begin fighting with one another, sometimes quite severely. This happens because there is no clear winner. The closer in age, sex, and breed two housemates are, the harder it is for them to determine who is in charge. This results in more repeated attempts at determining a ‘winner’ between the two dogs. This occurs not just with littermates but again, any two similarly sized, looking and sex of dogs.

Can littermate syndrome be prevented?

Potentially yes, but in real life, this is hard.  Remember, even the experienced guide dog puppy raisers were not able to keep this at bay.  Ultimately, it means managing them separate as much as possible.

Here is what you can do:

  • Crate them separately
  • Feed them separately
    • (I had two litter mates that I fed separately, but they could see each other. One dog would growl and not allow the other to eat until he finished.  Of course, this was during vet school and now I know this was a bad idea – separation and avoidance of adverse activity can be key).
  • Walk them separately
  • Bring them to classes separately
  • Spend more one-on-one time with them than you think is necessary
The bottom line is that if you find yourself bringing two cuddly puppies home, YOU ARE NOT ALONE! This happens all – the – time.  You just need to be aware of what is happening between them, the dynamic it creates for your family, how they are looking to each other as a source of comfort and confidence.  It will just be more important to divide and conquer their experiences and training and starting early is going to be key.

If you find yourself in this situation, please reach out so we can help you through this process – we have experience we would like to share.

Alternatively, if you just got a puppy and are thinking of getting or adopting a companion for that puppy, let’s set up a pre-adoption consultation to discuss how best to go this process.

As always, In love and health,

Dr. Jenna Cooper