Littermate Syndrome
National Adoption Week (July 20-26) is a wonderful time to welcome a new pet into your family. If you’re considering adopting two puppies or kittens together, here are a few things to know before you decide.
Adopting Pairs: Puppies vs. Kittens
Have you ever seen two puppies or two kittens in the shelter and wanted to give them both a loving home? You’re not the only one. If you’re able to adopt a pair of companions, it can be incredibly rewarding with the lifelong joy they bring to your life.
Although you may have heard the term littermate syndrome circling around the web… Here’s what it means, our staff’s recommendations on it, how to prevent it, and in what circumstances it may be beneficial to adopt a pair.
What is littermate syndrome?
Littermate syndrome is a way to describe the phenomenon that can occur when two puppies—from the same litter or similar ages—are raised in a single household (PennState Extension, 2024).
Littermate syndrome is often seen in growing puppies as (PennState Extension, 2024):
- Displaying anxiety or distress when separated
- Being aggressive toward each other
- Fear (seen by hiding away or aggression) toward new people, experiences, or other animals
- Difficulty training or forming a bond with you
As adorable as puppy pairs are, our staff generally does not recommend adopting two littermates or same-age puppies at once. Puppies develop best when they can build a strong individual bond with their human family. That said, if you already have two puppies, don’t worry as we’ll discuss ways to prevent littermate syndrome.
What about kittens? Littermate syndrome typically only occurs among pairs of puppies because “Cats are naturally more independent than dogs and typically don’t have problems with socializing or bonding as pairs” (Catster, 2025). More on cats below!
How can you prevent the behaviors associated with littermate syndrome?
If you have a pair of pups, it may seem convenient to use shared supplies, train them side by side, and socialize them together—both during quality time with you and out in public. This is okay from time to time. Being together constantly and having no time apart is when littermate syndrome can occur.
The best practice is to have sufficient alone-time when training and socializing your young doggos.
- Take each pup on a walk outside or in a store to meet other animals and people.
- Set aside some one-on-one time so each of your puppies can learn to sit, stay, lay down, and more.
- Finally, spend some quality time with each of your fur babies, giving your undivided attention and affection to them.
Your pups will have plenty of time to socialize with each other, but it is very important that they each have time to learn about the world and people around them without fear.
Is it okay to adopt a pair of kittens?
The answer is yes! (With a few points to consider.)
Taking home two kitties who have similar temperaments or are part of the same litter can be beneficial for their socialization, mental health, and physical health. Some pros include (The International Cat Association, 2025):
- Fun and natural enrichment! Two playful, active kittens will tucker each other out and stay mentally sharp—two wins, one play session.
- Learning manners. Your two kitties will teach each other how much play, biting, and scratching is enough—consequently, saving you a few Band-Aids.
- Settling in with less stress. If your young felines have interacted together as litter mates or in the shelter setting, they’ll find it easier to adjust to their new home.
- Having a lifelong friend. Adopting two cats together plants a seed for a deep bond to grow between them, and for your heartfelt relationship with them to bloom!
To really reap these positive experiences, it is best to:
- Adopt a pair who share personality traits or tend to gravitate toward each other.
- Have enough supplies (litter boxes, food bowls, beds, etc.).
- Make time for one-on-one moments and together time—snuggling, gentle pets, play sessions, and, of course, biscuit-making time!
Whether you’re wanting to adopt a tail-wagging pup or a pair of prancing kittens, our staff is here to help with any questions you may have!
Check out all our adoptable pets here or join us in person for National Adoption Week at our Everyday Adoption Center at Northpointe PetSmart, 9950 N Newport Hwy.