Littermate Syndrome: Everything You Need to Know

The Airvet Collection
3 min readMay 10, 2021


In the market for a new puppy…or two? It might seem like a good idea to adopt sibling dogs-they already have a special bond-but you might want to think again. Most pet parents have never heard of littermate syndrome. By the time you find out about it through a Google search, it’s probably too late. Read on to find out why this close bond between puppies can sometimes be a little bit too close-and downright problematic.

What is Littermate Syndrome?

Littermate syndrome is when the intense bond-or hyper-attachment-between two puppies from the same litter hinders their ability to connect with others and develop as individuals. Puppies with littermate syndrome can exhibit behavioral issues like fearfulness of unfamiliar people and other dogs, separation anxiety, difficulty learning basic obedience skills, fighting, and even bullying.

Cohabitating siblings can also become so emotionally dependent on each other that they can’t bear to be separated-even just a few feet apart. Littermates have been known to exhibit excessive whining, crying, and destructive, aggressive behavior when separated. Some littermates even refuse to eat alone. Littermate syndrome can also lead to impaired coping mechanisms later in life.

Not only is it a nightmare for you to wrangle two out-of-control pups, but littermate syndrome can prevent both puppies from growing and thriving as individual adult dogs. Littermates often get so carried away with each other that they have a hard time bonding and communicating with the human family. Littermate syndrome can affect dogs of any breed and even unrelated puppies who are raised together.

How to Avoid Littermate Syndrome

What if it’s too late for your littermates? Breeders and employees at adoption centers and shelters should know not to send two puppies home with the same pet parent and should be transparent about the risks. But that’s not always the case. If you realize that you already have littermates and it’s too heartbreaking to re-home one of the pups, there’s still hope. The best way to manage littermates is to make sure they spend significant portions of every day apart so they learn how to cope with being alone.

Here are some of the everyday activities that should be done separately:

Yes, even trips to the vet or the dog park should be separate. Start slowly by placing the pups in two separate crates right next to each other; then transition into keeping the crates in different parts of your home. This transition will be challenging for both you and the pups, but it’s important to begin the separation process as soon as possible if you plan on keeping both puppies. They’ll miss each other, but it’ll be worth it in the long run since it’ll be much easier to socialize your dogs. It is possible to have well-adjusted littermates, but it’s rare. Why take the risk if you can help it?

If you feel like you’ve tried everything, including dog behaviorists and trainers, and socializing them with other dogs, and you still have a littermate problem, it’s time to consider rehousing one of the puppies. Once separated, littermates often blossom on their own and become confident and independent adults.

The good news is that littermate syndrome awareness is on the rise. Some breeders and shelters are opting out of placing siblings together. Don’t worry-you can still have a multiple-dog household if you want to. Just be sure to consider timing, temperament, and the age that each dog enters your home. If you still have questions about littermate syndrome, Airvet is here to help. Our licensed veterinarians are available any time-no problem is too small.

Originally published at on May 10, 2021.



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