Above image, owned by Melissa Miller, of her two dogs, 1 month apart in age, playing.

Littermate Syndrome

Many people who bring home two puppies at the same time, or around the same time, will likely be warned about the potential for Littermate Syndrome. There is much back and forth between the canine community, even amongst professionals, on what the cause is as well as the actual likelihood of seeing Littermate Syndrome dogs.

After a lot of research, time taken to talk to other dog care professionals in different fields as well as months of dedication of dissecting this “Syndrome” to the best of our abilities we believe we have the answers.

Almost 6 year old Littermates
Owned by Zoe Elizabeth

What is Littermate Syndrome?

Littermate Syndrome is a non-scientific term used among the dog community to describe a multitude of behavioral issues between dogs who are brought home around the same time, most commonly between siblings from the same litter.

But they aren’t related.

Littermate Syndrome is not necessarily between littermates. It can also be between two young dogs gotten within 6 months of each other from different litters. While it is more often used when it comes to actual littermates, getting dogs too close together in age while still puppies can still leave the dogs susceptible to the behaviors associated with Littermate Syndrome.

The dogs in these two photos, owned by Ashley Hawkins and her family, developed Littermate Syndrome and needed to be placed in separate homes. Since separation, both dogs have been able to thrive.

Will every pair of puppies get Littermate Syndrome?

No. There are many families, owners, breeders and trainers that never experience the negative behaviors associated with Littermate Syndrome even when having two (or more) puppies from the same litter.

What are some of the behaviors associated with Littermate Syndrome?

When is comes to Littermate Syndrome there are many behaviors that come to mind, some more mild than others. These symptoms usually include one, or both, puppies becoming shy or timid, anxious/fearful of new things, separation anxiety from each other, bonding more to each other than the people in the household, aggression toward other people and other dogs/animals especially when separated and on the more severe side becoming aggressive with each other.

The aggression with each other is often the biggest, as well as the most concerning symptom experienced when it comes to Littermate Syndrome. This aggression often starts as small sibling scuffles and can quickly escalate to knock out, drag out fights that can leave both dogs seriously injured. In some cases this aggression can end in one dog killing, or coming close to killing, the other.

Unfortunately, in many cases where aggression has come into play it often ends in heartache, either being forced to make the decision to rehome, learning to “crate and rotate” the dogs, or one of them seriously injuring/killing the other. Sometimes, an unfortunate combination of these options.

Double Trouble.

Littermates
Owned by Annabelle Connely

When deciding to bring home two puppies it is often an emotionally charged decision rather than a logical one. Some of the reasons we have heard in regards to getting more than one puppy at once, from pet owners, are:

• They will keep each other company

• What’s one more?

• We couldn’t leave the last one all alone

• We have always had multiple dogs/always had siblings

What many people don’t think about is what this actually translates to, Littermate Syndrome aside:

• Double the food bill

• Double the vet bill, preventative medication(fleas, ticks, intestinal parasites etc).

• Double the training, house training, puppy antics

• Double the teething, destroyed items, accidents

• Double everything puppy

Yes, you get double the kisses, cuddles and puppy cuteness but it doesn’t take long for that puppy cuteness to fade out to unsavory teenage and adult dog behaviors. You also get double the issues when it comes to two puppies and double the cost all around. These are things often forgotten when bringing two cute puppies home, until you are already attached and trying to figure out how your food, toy, and vet bills all got so high.

Owned by James Childress.
These two are only 5 days apart in age from 2 different litters, and get on great.
Picture of them playing.

How to prevent Littermate Syndrome.

Not all littermates, or puppies of similar age, develop Littermate Syndrome. In fact, many breeders, trainers, and owners with working dogs are successful in raising multiple puppies -even from the same litter- simultaneously. How come these people rarely-if ever- experience Littermate Syndrome while companion dog owners have a much higher chance of having puppies that develop these symptoms associated with Littermate Syndrome?

The universal key seems to be with time and training.

Making sure that each puppy gets more individual one-on-one training and time than the puppies get together. Building the bond with the handlers/owners rather than to each other. Many of these owners are experienced with owning multiple dogs at the same time and understand the importance of one-on-one time and a dedication to training separately.

Ideally, each puppy will need individual one-on-one training, socialization and bonding with each puppy. They will need more individual time with their owners, learning to be confident and secure with themselves and by themselves than they do with each other. Teaching the puppies to exist together (See Existence Socialization entry), rather than constantly interacting, and limiting their play sessions to designated times only.

Two Puppies, One Goal

Siblings owned by Dawn Tracey

When it comes to raising two confident, obedient puppies at the same time and to eliminate the chances of Littermate Syndrome, it does take some work but is possible.

When raising two puppies with the goal of having confident, obedient adult dogs, it is important to look at them as individuals. Getting them their own separate crates with a clear divider between them, or placing the crates in completely different rooms helps. Most things typically need to be done separately; crate training, feeding in separate areas, training lessons/classes, walks separate and so forth.

Teaching “Existence Socialization” can help a great deal and also help ease your stress by teaching the puppies to just be able to exist with each other without the need to interact with each other. This method of socialization helps a great deal in preventing many different undesirable behaviors as well.

The goal is to not allow the puppies to become too attached to one another while still giving them each the structure and confidence building, as well as socialization that they need in order to eliminate the potential for Littermate Syndrome to take effect.

Different Levels

Playing Dobermans owned by Riley Seth

Littermate Syndrome is not always expressed with knock-down, drag out fights. Although, when addressing Littermate Syndrome, this is often the biggest concern because two dogs who had previously been “fine” together now are literally trying to kill each other. This can result in serious injury and even death in the worst cases.

Littermate Syndrome can present itself in much subtler variations as well, which are overlooked by most pet owners until specific situations arise, such as:

• Not being able to be apart/Separation Anxiety

  • This can be as “simple” as screaming/howling/barking/whining when separated, or pacing

  • This can be as “difficult” as tearing apart/breaking out of crates, eating through walls/doors, and more dangerously destructive behavior

• Not being confident away from one another

  • This is often seen when a perceived confident puppy turns into a very anxious, fearful, shy puppy when separated

• Being Aggressive/reactive when away from one another

  • This is often seen when an otherwise friendly puppy growls, lunges, barks at people or other dogs while by themselves. Many times this is a fear based response.

• Not bonding to their owners/human family

  • Or bonding more strongly to their canine counterparts rather than their owners.

Siblings from different litters. They were amazing together, but that changed quickly and now cannot be loose around each other without bad fights. Even with training and a ton of work.
Owned by Sam Jones

To conclude…

It is important to note here that even if you prepare for the worse and stack the odds in your favor by following the guidelines here there is no guarantee that your pups will not develop Littermate Syndrome. Some dogs/families just are not suited to live together after maturity, and there is nothing wrong with that.

There also is not a guarantee that your pups will develop Littermate Syndrome if you do not do these things, but it will help you to stack the odds in your favor to prevent it.

Even if you are not concerned with Littermate Syndrome developing the steps to “preventing” Littermate Syndrome are all great strategies to helping your puppies have the foundation to becoming well rounded, confident and well trained dogs as they mature.