Do Puppies Actually Dislike Their Siblings? What To Know About Littermate Syndrome

If you've been around puppy siblings — or better yet, adopted them — it's probably warmed your heart to see them play together. But what about when they're a little naughty and jealous?

Some pet parents attribute this to littermate syndrome. But is it really a thing? Or is the behavior tied to something else?

You shouldn't put so much stock in the idea, explains Kathrine Christ, certified dog behavior consultant (CDBC), executive director of the International Association of Animal Behavior Consultants Foundation and owner of Hands Full Dog Training, who explained why you shouldn’t put so much stock in the idea of littermate syndrome.

Littermate syndrome is a label given to behaviors seen in puppy siblings who are raised together but don’t exactly get along — but it’s not backed by science, just anecdotal evidence.

“In situations where problems do occur with housemate dogs, the logic is circular,” Christ told The Dodo. “The ‘syndrome’ is defined by its apparent symptoms, which are then credited back to the fact that the animals are littermates, without any alternative causes considered for the problem behaviors.”

Since there’s no actual scientific link between siblings and behavior, littermate syndrome is more of a myth, especially because puppies who don’t live with their siblings can also be particular with other pups.

“No evidence exists that indicates littermates have a higher rate of behavior problems than any individual dog or other two dogs raised together,” Christ said.

According to Christ, we should instead be associating behavioral issues with biological and scientific causes.

If your dog has a little disagreement (or seems not to like another pup), it could be for many reasons, such as his environment.

“Attributing problem behaviors solely to the presence of a littermate is disingenuous and not science-based,” Christ said.

Some may identify these behaviors as symptoms of littermate syndrome:

But it’s not exactly fair to call them symptoms of littermate.

After all, there’s no actual scientific information to back the idea, and there are a lot of causes for these behaviors that have absolutely nothing to do with living with a littermate.

According to Christ, you should instead be assessing those behaviors based on each dog as an individual and not the fact that he’s living with his sibling.

The myth of littermate syndrome can be a problem because difficult behavior is so frustrating for many pet parents — and it's best to get to the real source of it.

“When a pat explanation is offered and when the problem is viewed as inevitable or not modifiable, people may choose to give up on one of their puppies instead of working through any issues that arise,” Christ said. “Or worse, re-home one of their pets before any issues even begin.”

According to Christ, you should consult a dog behavior professional if you notice siblings having issues.

“Hiring someone with credentials independently assessed by a third party provides you with a level of assurance that they are educated and qualified to be providing advice on your dog's behavior,” Christ said.

Socializing your puppies is so important because that’s what helps them develop positive associations with people, objects and other animals.

“Puppies should be trained and socialized both separately and together, and they should be taught how to be comfortable when they are separated both from humans and from their housemates,” Christ said.

So if you’re noticing your puppies aren’t getting along, don’t just chalk it up to littermate syndrome, because it misidentifies the cause and can keep your BFFs from getting the help they need to be happy and comfortable.