Skip to content

Guide To Littermate Syndrome In Dogs: Everything You Need To Know | Pupford

December 27th, 2023

Filed under Pet Parenting

Featured Image

Two dogs are twice the fun for most pet parents (and twice the work). But when those pups are siblings from the same litter, problems such as littermate syndrome can pose challenges to the puppies' social development.

Most pet professionals recommend you only get one puppy at a time to help them grow as independent, confident individuals. While it isn't impossible to successfully raise two well-adjusted dogs simultaneously, it's a lot harder, and you'll have to be careful to avoid a common cause of stunted emotional growth: Littermate Syndrome.

This guide has everything you need to know:

  • What Is Littermate Syndrome?
  • What Are The Most Common Symptoms Of Littermate Syndrome?
  • How Does Littermate Syndrome Affect The Puppies' Relationship With Their Pet Parents?
  • Does Littermate Syndrome Go Away?
  • How To Prevent Littermate Syndrome
  • Can You Manage Dogs With Littermate Syndrome
  • When Do Your Dogs Need Professional Help?


what is littermate syndrome in dogs

The term 'littermate syndrome' refers to behavioral issues that arise when two or more sibling puppies are raised together. Potential issues include separation anxiety, neophobia (fear of the unfamiliar), and aggression. Littermate syndrome affects dogs over 8-10 weeks of age, which is typically when young puppies join their forever homes.

Dachshunds, Terriers, Border Collies, and Shepherds are often cited as having a high propensity for littermate syndrome. Still, there is no clear scientific evidence that certain breeds experience littermate syndrome more or less than other breeds.

Dog psychology and brain chemistry, much like our own, are complicated. Each dog is an individual with their own experiences and quirks, which shape how they regard and cope with the world around them.

The breed might influence this, but it shouldn't be a factor in considering whether or not to adopt two siblings of a certain breed.

Not every pair of dog siblings will experience littermate syndrome, but there is no way for a potential pet parent to know that.

In some cases, dog siblings may have bonded in a way that makes sense for them to be raised together. Dog adoption of any kind is a very big and complicated undertaking that is better handled on a situation-by-situation basis. Adopting any dog pair must be done with as much care, thought, and preparation as possible.

If you do or already have adopted dogs from the same litter, you must be prepared to put in extra time and training, so your dogs live their best lives.

🐶 Looking for extra dog training resources? Sign up for the 100% free online course 30 Day Perfect Pup. Sign up here! 🐶


symptoms of littermate symptoms in dogs

When two puppies are raised together beyond their first 3 months, they can form a deeply co-dependent relationship that separates them from the outside world. Whenever some new, scary thing presents itself, your dogs retreat to the safety of their bond and fail to grow through their new experiences.

Here are five common symptoms of Littermate Syndrome in dogs:

  1. Extreme co-dependence
  2. Separation anxiety
  3. Poor social skills
  4. Fear of strange dogs & people
  5. Difficulty training

Let's look at each one below. ⤵️


The root cause of all problems associated with Littermate Syndrome is extreme co-dependence. Any time there's a new, stressful stimulus, your dogs may retreat to the comfort of their relationship, unwilling and unable to deal with anything new.


Extreme co-dependence leads to separation anxiety, which sometimes gets so severe that the dogs can't even be walked separately just a few feet apart without complete emotional meltdowns.


You'd think two dogs who grew up playing together constantly would be great at socializing, right? But that's not always the case. They may only know how to play with each other and haven't been exposed to how other dogs play.

It's like they developed their own language. Outside their bond, other dogs don't speak the same language.


Co-dependent pups neglect to explore and understand the world around them. When dogs don't understand something, their instinct tells them to fear it. As a result, dogs with Littermate Syndrome are fearful of anything new, including both dogs and people.


It's crucial you begin training your puppy from an early age, even as soon as 8 weeks of age. And the sooner you can start, the better. But training any puppy is challenging.

What makes training littermates exponentially harder? There are two things:

  1. Your co-dependent dogs struggle to pay attention to anything else. Outside of Littermate Syndrome, training two dogs is at least twice the work. And you need to be extra vigilant about training sibling pups to establish their independence.
  2. Sibling Aggression. Aggression isn't as common as the others on this list, but it's definitely the most serious. It's more common with same-sex littermates and usually arises when there's a bullying relationship where one dog is dominant over the other. As your littermates age to become full-sized dogs, those aggressive outbursts can become dangerous.
🐶 Looking for extra dog training resources? Sign up for the 100% free online course 30 Day Perfect Pup. Sign up here! 🐶


how does littermate syndrome affect dogs relationship

As mentioned, one or both puppies can fail to bond with the new parents. But there are other problems it can create as well. For example, both dogs may develop an extreme fear of people in general and other dogs. That can result in leash aggression and other behavioral issues. What's even worse is that these behavior problems intensify in older dogs.


The short answer is no; littermate syndrome does not go away on its own. But the behavioral issues that arise from two sibling puppies being raised together can be addressed.

However, it may take a significant amount of effort on your part to help your dogs achieve proper socialization skills and good behavior.


preventing littermate syndrome in dogs

If you already have two young puppies, you can reduce the effects of Littermate Syndrome by teaching your dogs to do things separately — completely independent of one another. (It's best to start this immediately to help prevent Littermate Syndrome!)

There are too many small moments in the day to tell you how to handle every one of them, just make sure to keep it equal and fair for all dogs involved:

  1. Take your dogs on walks separately. This gets them used to going places without their sibling attached at the hip.
  2. Take your dogs on car rides separately. At first, it will probably be horrifying for them to experience alone. But they will start to look forward to these rides if you take them to fun places (like the park, a walking or hiking trail, or your kid's baseball game).
  3. Play catch with only one dog at a time. The other dog can be in a crate, a playpen, another room, or outside (or any other game for that matter).
  4. Feed your dogs separately using separate food bowls. You don't want to be the reason they have food aggression issues!
  5. Train your dogs with their basic puppy cues separately. Training them both at the same time takes much longer and is less effective — because you need to have each dog's undivided attention and be able to give rewards and hugs to only one dog at a time.
  6. Brush (or groom) only one dog at a time.
  7. Crate train your two puppies separately.
  8. Talk to your dogs separately.
  9. Enroll your dogs in puppy training classes separately.

That's not to say you can't ever interact with both of your puppies at the same time when they're less than 6 months old. But remember, the goal is to raise two secure, confident individuals who can succeed separately and thrive together.

🐶 Looking for extra dog training resources? Sign up for the 100% free online course 30 Day Perfect Pup. Sign up here! 🐶


What if you already have a pair of littermates? Is there anything you can do to prevent the problems between sibling dogs? Well, to start, you need a good plan, and there may also come a time when you need to consult a professional dog trainer or animal behaviorist too.

Assuming you aren't dealing with severe aggression, there are some things you can try.

The most important work, especially at the beginning, takes place when your dogs are separated to help them build their confidence and independence.

You can manage Littermate Syndrome in the following ways:

  • Deal with their separation anxiety

You can't work with each dog separately until they can be apart without freaking out. The best way to overcome separation anxiety is by teaching your dogs to be crated separately. Of course, this means you'll need two properly-sized crates. You can't just skip to locking them up in separate rooms. That's too traumatic and won't do any good. Instead, go slow.

Crate them separately, right next to each other. Your dogs can still see, smell, and touch each other, but they'll have a physical barrier between them. Slowly move them apart over the next few weeks until they can be calm in their respective crates on opposite sides of the room. When they're fine being crated separately for 30-60 minutes, you should try to crate them out of sight of each other.

If there are any setbacks, slow down and return to the edge of their comfort zones. When teaching your dogs to be OK without each other, the most important thing is to make their alone time fun. Dogs learn from repeated positive experiences, so give your separated dogs a favorite toy or high-value dog treat to distract them from their feelings.

  • Train them separately

Now that your dogs can deal with being apart, it's time to give them separate obedience training. There's no set timeline for how long this takes, but it can take over a year before unbonded littermates can be trained together. Your co-dependent pair may need more time.

  • Enable their independence

Beyond teaching them to be apart and training them individually, it's essential to approach each dog as a separate dog. Eating, playing, walking, vet visits — each dog should learn to do these things without the other.

  • Reunite them

Again, it isn't like your dogs never see each other during this process, but only after they can be content and train apart should you consider reintroducing shared activities like dog park trips and doubled-up obedience training.


two beagle puppies with littermate syndrome | Pupford

We know it can get overwhelming dedicating extra effort and time to care for your puppies. But cut yourself some slack! You can always reach out to a trusted veterinarian, registered animal behaviorist, or trainer to help you manage littermate syndrome.

After all, they are the experts—no shame in asking for their help.

But if you feel like it is going to be difficult to sustain this much training until the pups learn to be independent, you may want to reach out to a trusted relative or friend (whom you know will love the puppies too!) to help you care for at least one of the siblings.


The best solution to littermate syndrome is to prevent it by avoiding raising siblings together. Instead, if you want a pair of puppies, it's best to get them from different litters and space out, introducing them to their new home.

Make sure you bring each of your new family members home at least six months apart. That way, you can begin the potty training and socialization of one pup before the second dog arrives. Of course, you can also adopt adult dogs over a year old who have already developed independent personalities.

It may sometimes feel like treading on thin lines, but getting this far ahead in your research on caring for two or more puppies simultaneously.

🐶 Looking for extra dog training resources? Sign up for the 100% free online course 30 Day Perfect Pup. Sign up here! 🐶


Your Cart

Shipping & taxes calculated at checkout