Littermate Syndrome is a behavioral phenomenon that can occur when two puppies from the same litter (or sometimes just two puppies of the same age raised together) are raised in the same household.
What It Is
Instead of forming strong, independent bonds with their humans, the puppies bond primarily with each other. This can create developmental, training, and behavioral problems. It’s not an official veterinary diagnosis, but it’s a well-documented pattern observed by breeders, trainers, and behaviorists.
Common Signs
- Hyper-Attachment to Each Other: Puppies may panic when separated, even briefly.
- Underdeveloped Social Skills: They may fail to learn how to interact properly with humans or other dogs outside their sibling. All our puppies are heavily bonded with me however if you have two puppies they may find it hard to bond with their new humans. Cavoodles however are a very loving, human friendly breed so this may not be as much of a concern as in other breeds
- Poor Training Response: They often ignore owners during training, paying more attention to each other than to commands.
- Aggression & Rivalry: Littermates can develop intense sibling rivalry, sometimes leading to fighting as they mature.
- Anxiety Issues: Separation anxiety, generalized anxiety, or nervousness around new environments and people is common.
Why It Happens
During the critical socialization period (roughly 6–16 weeks), puppies need to form bonds with humans, learn boundaries, and build confidence independently. When raised with a sibling 24/7, they can rely on each other for security, stunting that development.
Prevention & Management
If someone does raise two littermates, it requires:
- Separate Training: Each pup should have individual training sessions without the other present.
- Separate Socialization: Take them on individual outings, walks, and experiences.
- Crating Separately: Encourage them to sleep apart at least part of the time.
- Individual Bonding Time: Each needs one-on-one play and affection with humans.
The Reality Check
Many breeders and trainers actually advise against adopting two puppies at once, especially from the same litter, unless the owner is experienced and ready to commit to essentially raising two dogs in parallel. Done right, they can grow into well-adjusted companions—but if mishandled, littermate syndrome can make life miserable for both dogs and their humans.
🐾 Step-by-Step Guide: Raising Two Puppies Together
1. Day One: Set Boundaries
- Give each pup their own crate, bed, and feeding area.
- Avoid letting them share everything (food bowls, crate, constant cuddle piles).
- They can play together, but you want to teach them independence right from the start.
2. Crate & Sleep Training Separately
- Separate crates — ideally in different rooms (at least part of the night).
- This teaches them to self-soothe and prevents dependency panic.
- Alternate nights where crates are further apart until they’re comfortable.
3. Training Sessions: One-on-One
- Do short daily sessions with only one puppy while the other is crated or distracted with a chew.
- Commands to focus on early: sit, stay, come, leave it, settle.
- This builds the human-dog bond, not just the sibling-bond.
4. Individual Socialization
- Take them out separately to new environments — coffee shops, vet visits, car rides, puppy playdates.
- Each dog should build confidence in the world without their sibling as a crutch.
- Goal: they can each walk into a new space and not panic without the other.
5. Bonding Time with Humans
- Every day, spend at least 10–15 minutes per pup in solo play, cuddle, or walk.
- Rotate who feeds, grooms, and trains each pup so they bond with multiple humans (if possible).
6. Manage Playtime Together
- Allow them to play, but monitor for signs of bullying or one always being dominant.
- Interrupt play often with training commands so they learn to check back in with you.
- Don’t let them form an “us vs. the world” mindset.
7. Prevent Rivalry
- Feed separately.
- Avoid giving high-value chews or toys when both are loose together — unless you’re supervising.
- Reward calm behavior when the other dog gets attention, so jealousy doesn’t take root.
8. Teenage Phase (6–12 months)
This is where littermate syndrome tends to explode.
- Keep up separate walks, training, and outings.
- Expect pushback: barking, ignoring commands, or fighting. Stay consistent.
- If they fight, separate immediately, reset, and give both space to calm.
9. Consistency is Key
- Think of it as raising two dogs individually, who just happen to live together.
- The goal: they are best friends but also fully functional, confident dogs on their own.
10. Pro-Level Tip
If time or energy is tight, stagger their schedules:
- Morning = walk/train Dog A.
- Afternoon = walk/train Dog B.
- Evening = a bit of supervised playtime together.
This way, they never become a two-headed puppy monster you can’t separate.
✨ Bottom line: Two puppies at once is double the work (and honestly, sometimes triple). But if managed properly, they’ll grow into independent yet bonded dogs who enrich each other’s lives — not compete for yours.
Kareema
Healing Energy Animals
Kareema is the owners of Healing Energy Animals where devil dogs, horrible horses and crazy cats are turned into perfect pets using Relationship Animal Training and over 50 years of experience training a wide variety of animals.
Healing Energy Animals provides owners and pet professionals assistance with with common pet behavior training, feeding and grooming issues such as barking, escaping, scratching, aggression and fleas. Kareema consults and writes widely on a range of pet care issues for owners and also assists pet care professionals in setting up and growing their businesses by the provision of customer handling advice, sales and marketing strategies and up to date product information that allows for the differentiation of their pet care business from their competitors.
Healing Energy Animals is an Australian business but operates worldwide via the provision of virtual services.
