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Getting two puppies at once from the same litter is not a decision to be taken lightly. Yet, it's so tempting to bring home an extra puppy, especially when the puppy in question appears to be pleading to be taken home along with his sibling, and you start thinking: "Why not?" After all, your puppy will have another play mate to play with, so what's to lose?

A multitude of problems though may await you. Littermate syndrome in puppies is an umbrella term often used to depict a variety of issues that may arise when getting two puppies at once.

The insidious part is that some of the biggest problems may not start from the get-go, but only later on, as the puppies mature. 

However, as the saying goes, "forewarned is forearmed," therefore knowledge is power when it comes to major decision making, or if you happen to have already made the decision, recognizing the early onset of problems. 

 What is Littermate Syndrome in Dogs?

Also known as sibling syndrome or puppy sibling rivalry when considering possible conflicts, sibling syndrome in dogs is an umbrella term used to encompass a variety of problems associated with getting two puppies at once.

One important factor to consider is that, despite its name, sibling syndrome in dogs may also affect puppies who aren't from the same litter. 

Due to the potential for sibling syndrome in dogs, in general ethical breeders, shelters and rescues don't advocate releasing two puppies at once unless the owners meet some specific qualifications (experience, time, financial resources, ideal settings).

So what is littermate syndrome in dogs, what potential problems does it encompass, and most of all, what can be done to reduce the incidence of problems? Following are some issues that are often encountered when raising two puppies close in age at once. 

Issues With Over-Attachment

One major issue when getting two puppies at once is the potential for the two puppies bonding heavily. 

Sure, its cute when two puppies play and sleep together and develop a tight-knit attachment, but this over bonding and co-dependency may lead to the puppies relying more on each other than the owner, leaving him out of the equation. 

When two puppies are playing or engaging in some other activity together and the owner intervenes to redirect them, the owner may be perceived as "the party pooper," or worse, the puppies may even ignore the owner's requests.

Of course, owners of households with multiple dogs can argue that any dogs living together are prone to bonding and depending on each other, but it appears that the issue may be worse when puppies are young and going through some delicate stages of development. 

Onset of Anxiety and Fears

On top of overattachment, when it comes to littermates, one must also factor in the potential onset of anxiety when the puppies are separated after relying so much on each other. 

This can turn problematic that day when one dog may be taken to some doggy event or in the unfortunate case of one dog being hospitalized. 

Used to living and possible sleeping together, one dog or both dogs may become prone to feeling stressed and even severely anxious when separated from the other.

Something else to consider is that too much playing together, sleeping together and walking together may also pave the path to a hyper attachment which ends up hindering the pup's socialization with humans and other dogs. 

This can ultimately lead to nervousness/suspicious behaviors towards strangers such as new people or dogs. 

Littermate puppies tend to develop a strong bond between each other. 

Littermate puppies tend to develop a strong bond between each other. 

"Half Dog Syndrome"

Often, one puppy develops to be a little more confident, while the other remains rather shy. As this latter puppy develops, he or she risks becoming overly dependent on his brother or sister. 

It's as if one or both puppies fail to develop to their full potential, becoming incapable of blooming as they would if they were to be the only dog. 

"I cannot remember a single dog who was raised with her mother to adulthood who could be successfully trained for a Guide Dog. Where two littermates are raised together in the same home we have had the same results," points out Clarence Pfaffenberger in the book: "The New Knowledge of Dog Behavior."

He then further adds: "In the case of two littermates raised together, one becomes a successful candidate for Guide Dog work and one fails, even if their aptitude tests were equal.”

Feeding Off Each Other's Emotions

Puppies raised together from a young age tend to greatly influence one another. In particular, the shy puppy may feed off the more confident dog's emotions. 

For example, when the more confident dog spots a dog on a walk, he or she may become reactive and his sibling will eventually back him up. Soon, you'll have two reactive dogs who are difficult to control and walk.

Of course, this applies as well to any dogs living in the same household, but in littermates their hyper attachment may cause the situation to escalate.

Fights Along The Way 

While young puppies may get along during their first months, relationships may start deteriorating once both dogs mature. 

Fights among two female dogs have been found to be the worse, according to research. Conflict often arises over priority access towards resources such as food, toys, sleeping places and owner attention. 

Double the Trouble

Many new puppy owners struggle with all the care, attention and time commitment one single puppy needs, imagine doubling all of that up!

 When potty training, you may find yourself cleaning one pee mess, while your other puppy is pooping at the opposite side. When you find an accident, you won't be able know which puppy did it and therefore you're left with no clue on which puppy still needs to go potty outside.

One puppy getting into mischief may be enough upsetting to dog owners, imagine two. One puppy may be therefore chewing your shoes, and as you put the shoes away, your other puppy will be chewing the kitchen table's leg. 

Socializing and training two puppies is also not without its challenges. The distraction of each other creates challenges as the pups may pay attention more to each other rather than you.

This therefore impacts the level of influence you may have over your pups' attitude and behavior towards training and exposure to stimuli.

Can littermate syndrome be owner-induced? 

Can littermate syndrome be owner-induced? 

No Black and White, Just Shades of Grey

Of course, it goes without saying, that not all littermates will go on to develop littermate syndrome. 

Actually, there is current debate over whether littermate syndrome is even a real thing, as there is little research and scientific literature to back it up. 

Most of the proof of its existence is anecdotal, with many dog owners and dog trainers having a story to share about it. 

Can Littermate Syndrome or Sibling Rivalry be Owner-Induced?

One may also start to wonder whether littermate syndrome in puppies may be something that is inadvertently owner- induced, as in the case of new puppy owners making various mistakes, not knowing how to tackle certain problems or even encouraging certain behaviors. 

Many dog breeders and dog trainers share many success stories of raising littermates. My first two dogs were two Rottweiler littermates, a male and and a girl and as a "full-time mom" I rolled up my sleeves and did everything I could to make things work out. 

The last littermates I fostered were two females, they played well and all, but at some point one started bullying the other when going out of doors, she was lunging and nipping blocking the other and often even pinned her down to the ground.

 I personally solved this issue by training them to sit before opening the door and then calling them to me so they would focus on me rather than each other. After several reps, the issue was solved, never to present again in the following weeks.

My Rottweilers too developed some issues at one point. As they matured, they started having squabbles over their bones. The issue was nipped in its bud by feeding bones in their crates, and then feeding them at a distance from each other while carefully monitoring them. By carefully managing their bone-eating sessions, no more fights occurred over bones for the rest of their lives. 

One may therefore wonder, whether littermate syndrome or sibling rivalry is more likely to occur to new puppy owners compared to more experienced dog owners. It can certainly happen to the experienced owners as well, but perhaps it's less likely. 

Now That You Know...

As seen, getting two puppies at once can mean some trouble down the road, although it is also true that often things may work out pretty well. 

It's therefore not easy to predict how things like this may turn out in the long run. Dog owners often ask me whether their littermates will get along. 

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I answer tell informing them that it's ultimately sort of like wondering whether a marriage will work out or not. It's hit or miss. Some dog owners have littermates getting greatly along, others are not that lucky.

So with all of this in mind, the million dollar question is: can you raise two puppies successfully? The answer is of course, yes, there are many success stories out there, but the task is not without any struggles.

 Following are some general tips for setting your puppies up for success. 

How to Raise Two Puppies Successfully

These are just some general guidelines to successfully raise littermate puppies. Of course, every case is different and therefore you will have different results. 

  • Keep the two pups separated starting early. For instance, take one pup on a walk while your spouse walks the other one. When you have to run to the pet store, leave one pup at home with a family member, while the other rides in the car. Organize separate training sessions, playing sessions, take them to puppy classes separately, gradually teach them to sleep separately and cope with being apart. 
  • Pick a boy and a girl. Statistics show that same-sex combinations are more likely to encounter problems. In particular, two females are more likely to not get along once socially mature compared to other combinations. 
  • Manage the environment. Prevent problems by providing space between the dogs when feeding long-lasting treats and bones or remove toys if they are a source of conflict. In other words, take steps to prevent conflict from arising and prevent rehearsal of problem behaviors.  
  • Consider it a full-time job. Dealing with littermates is for the most part a full-time job, so it's best if at least one person can spend time with the pups most of the day to prevent over bonding between the pups. 
  • Seek help from a family member. An even better solution would be having two people at home with the pups so that one can socialize, train and play with one puppy, while the other takes care of the other. This of course, is not always feasible.
  • Consider the risks. Most ethical, responsible breeders don't allow perspective owners to take two littermates at once because of the heavy workload and risks for potential problems. They may though make some very rare exceptions if the owner is experienced. If a breeder allows any potential buyer to purchase two puppies at once, that's often a sign of a poor quality breeder. This raises the risks for the puppies not having great temperaments which consequently ups the risks for problems along the road. 
  • Don't assume dogs can work things out. Sure, if it's just a little growl over something that is solved in a ritualistic manner (more noise than anything) that's good conflict resolution, but if your dogs go into attack mode, it's best to enlist the help of a professional for an assessment and subsequent plan. I know some owners who followed the common advice of "letting dogs work things out" leading to bloody messes and needs for stitches. Not to mention, the longer lasting emotional scars that can take time to effectively heal. 
  • Consult with the pros. It can be very tempting trying to solve behavior problems at home, perhaps using the advice found over the internet (which can sometimes be good, while sadly too often is bad). A good dog behavior professional (look for one using force-free methods) can provide important insights on the behavior. For example, you may think one dog is provoking the other, while in reality he may be responding to a provocation rather than being the actual trouble maker. 
  • Don't take the decision lightly! Think it over carefully. There are  several pros and cons of raising littermate puppies. Do you have the time, determination and experience to raise two puppies at once? What will you do if things don't go as well as planned? Do you have a back-up plan? Consider that unethical breeders who sell littermates too easily typically won't take any puppies back and may even never return your phone calls. 


A New Look at Interdog Household AggressionKathryn M. Wrubel1,PhD,Alice A. Moon-Fanelli¹,PhD, CAABLouise S. Maranda²MVZ, MSc, PhD, Nicholas H. Dodman¹, BVMA, DACVBDepartmentof Clinical Sciences¹Department of Environmental and Population Health²Tufts University Cummings Schoolof Veterinary Medicine200 Westborough RoadNorthGrafton, MA 0158

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