Those committed to raising a pair should ensure that the puppies spend significant portions of every day apart so each learns how to be alone—a key lesson in any well-thought-out puppy program. This means feeding, walking and training separately, with individual crates in different parts of the home. Even trips to puppy socials and the vet should be separate so they learn to incorporate these episodes into their respective psyches without being overly dependent on their littermate. This separate-but-equal arrangement is timeconsuming, exhausting and seems to defeat the original intent of acquiring siblings. Wilde notes that planned separations must begin immediately. “I’ve been called into homes where four-month-old siblings have been sleeping in the same crate for eight weeks and not purposefully separated by the owners, who had the best intentions but were unaware of littermate issues. Even getting the puppies to sleep in separate crates right next to each other is traumatic for them.”
Dunbar, too, is adamant that one of the key lessons a puppy must master is how to be content with being alone, which is all but impossible with two siblings. “Once we’ve done that, yes, he can live with other dogs and have free run of the house. But if you don’t teach puppies early on how to be alone, and especially with siblings who have always been together, it will be catastrophic when one dies.” Dunbar encourages multiple dog households— “I always like having three dogs”—but the timing, temperament and age that each enters the home is paramount.
Most people have never heard of littermate syndrome, finding out about it while researching their dogs’ problematic behaviors. Increasingly, however, trainers and behavior professionals recognize that the cons of adopting siblings far outweigh the pros. “The only advantage I can think of is a short-term gain of the puppies being less lonely in the first month of life,” says Dunbar. “Everything else is a loss.”
Exceptions and Hope
While there are indeed struggles in raising siblings—including ongoing aggression and fighting often seen between same-gendered littermates— there are also well-adjusted cohabitating pairs. A common thread seems to be that littermates are more likely to thrive when introduced into a household with an older dog, who perhaps acts as an arbiter and stabilizing influence.
Myriad factors affect dog behavior, including genetics, early life experiences and owner engagement. As University of California, Davis, veterinary behaviorist Dr. Melissa Bain points out, “Two fearful littermates very well may be genetically predisposed to fear.” Bain is less inclined to apply the term syndrome to the set of symptoms. “It makes you think all littermates have problems, which is not the case.” She also emphasizes that the level of owner involvement is key, saying, “The symptoms escalate when the owners treat them as one dog with eight legs.” When conflict ensues between the pair, Bain believes it’s due to the dogs being similar in size, age and gender. “This uniformity makes it difficult for the siblings to delineate a hierarchy,” she said.
After one of the siblings had been rehomed, I received an email from the owner describing how the remaining puppy began to thrive under a remedial socialization program. “Dora has blossomed in the last three months into a delightful household companion, and she continues to improve. She now approaches people out of curiosity. We know she would still be fearful had we not separated the two before it got any worse. Dora has become more confident with all kinds of dogs, and successfully completed a group obedience class.”