Littermate Syndrome: Why Raising Siblings Isn’t Always Twice the Fun

Getting two puppies from the same litter can sound like the dream - double the cuteness, built-in playmates, and they’ll never get lonely, right? But for many well-meaning dog owners, that dream can turn into a behaviour nightmare. This is where something called littermate syndrome comes in – and it’s something we’ve seen first-hand at Canine & Co.

What is littermate syndrome?

Littermate syndrome refers to a range of behavioural issues that can develop when two puppies from the same litter are raised together. The symptoms can start young – think clingy behaviour, extreme separation anxiety, hyperactivity – and often get worse with time. In adolescence, things can escalate into fights, reactivity, and anxiety, even towards people or other dogs.

The underlying cause? An intense codependency that stunts both dogs’ ability to develop independence, confidence, and proper social skills. It’s not about bad dogs – it’s about an overwhelming bond that interferes with healthy development.

Common red flags:

• Crying or panicking when separated (even for a moment)

• Wild play that often escalates into fights

• One sibling growing anxious, while the other dominates

• Trouble interacting with other dogs

• Difficulty focusing during training

• Possessive behaviour over people, toys, or food

But we love them both – isn’t there a way?

While some owners do successfully raise siblings together, it’s rare – and takes serious dedication. The pups need to be trained, exercised, fed, walked, and socialised separately for at least the first 8–12 months. That means living almost completely independent lives under one roof. Most households simply aren’t set up for that kind of structure (and that’s okay!).

If you already have littermates and things feel manageable, we recommend getting professional guidance early and starting separation work now – before problems begin.

If you’re considering adopting two puppies at once, we gently suggest starting with one. You’ll both have a better chance at bonding, building confidence, and getting the most out of training and social experiences. You can always adopt a second dog later on – once your first pup has found their paws.

How Canine & Co can help

At Canine & Co, we’re here to support healthy socialisation and confident independence for all dogs – littermates included. We offer:

• Day Stays for gentle exposure to new environments

• Social Club for carefully structured socialisation and learning to be part of a pack

• Advice and support from staff who’ve seen it all (and then some!)

If your dogs are showing signs of littermate syndrome, or you’re unsure how to give them the best chance to thrive, reach out. We’re happy to chat, point you in the right direction, or refer you to a trusted behaviourist if needed.

Final thoughts

Raising two dogs together isn’t always a problem – but littermate syndrome is common, under-diagnosed, and very real. It’s not about failure – it’s about recognising what our dogs need to feel safe, calm and confident in the world. Sometimes, the kindest thing we can do is give them space to grow on their own.