Primordial Pouch (Cat Belly Flap) in Cats

What is the primordial pouch?

The primordial pouch is a loose flap of skin which runs along the length of the belly but is most pronounced towards the rear, just in front of the hind legs. It can often be seen swaying from side to side when the cat moves.

Pet owners often attribute the primordial pouch to weight gain, but it is common on cats of all shapes and sizes, even slim ones.

Does spaying and neutering cause the primordial pouch?

No, cats either have a primordial pouch or they don’t it has nothing to do with spaying or neutering. Entire cats, as well as spays and neuters, can all have a primordial pouch.

What purpose does the primordial pouch serve?

We don’t know for sure, but the most obvious theories are that it serves four purposes.

1) To protect the vulnerable internal organs in the event of a fight. If you have ever seen cats in a fight, you may have noticed that they often kick each other with their hind legs and their sharp claws.

Primordial pouch

2) To enable the cat to stretch out when running at high speed or jumping.

Primordial pouch

3) For greater stomach expansion if a cat gorges on a large meal.

4) To provide a fat reserve in the event of leaner times. I’m not convinced about this because the primordial pouch is mostly loose skin and fur.

What’s the difference between a primordial pouch and an overweight cat?

Obesity is a serious and growing health concern among domestic cats. It is our responsibility to keep a close eye on our cats to make sure they don’t gain too much weight.

  • The primordial pouch is a loose flap of skin, and you may notice it jiggles from side to side when a cat trots towards you. It is located on the underside of the belly, and if you look down on the cat, it will be difficult to see.
  • The obese cat’s belly has an overall rounder shape, that will not jiggle from side to side the way the skin of the primordial pouch does. You should be able to feel the ribs when you run your hands along the cat’s sides; if you can’t, the cat is overweight and should seek veterinary advice on ways to help the cat get down to a healthy weight.
Obese cat
This is an obese cat

The cat directly above is severely obese and runs the risk of developing several diseases due to her weight. Obesity is an overall increase in the cat’s size compared to the primordial pouch, which is confined to the underside of the belly and most prominent in front of the rear legs.

Primordial pouch removal

Primordial pouch removal
Primordial pouch removal

It is not possible to get rid of the primordial pouch with weight loss, and it would be unethical to surgically remove it. In no way does the primordial pouch have a detrimental effect on the cat.

Do all cats have a primordial pouch?

Not all cats have a primordial pouch
Not all cats have a primordial pouch

No, not all cats have a primordial pouch. It is very common in both domestic breeds of cat as well as several pure breeds.

It’s not only domestic cats, but the photo below also shows that even big cats can have a primordial pouch.

Primordial pouch

Breeds permitted to have a primordial pouch

Some cat councils/associations permit the primordial pouch in certain breeds. What that means is the primordial pouch is an allowance that has been written into the breed standard for those particular breeds.

Other names for the primordial pouch

  • Belly flap
  • Spay sway
  • Apron
  • Fat pouch
  • Belly bag

Julia Wilson is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. She enjoys photography, gardening and running in her spare time. Full author bio Contact Julia

14 thoughts on “Primordial Pouch (Cat Belly Flap) in Cats”

  1. I have 2 cats, both female. I’ve been told that it common in females, particularly those who have been spayed. Its actually endearing, particularly when my younger cat runs and it swishes from side to side.

    • I have one female and three males, and all four of them have one. It’s most obvious on the oriental, and like you said, it’s endearing when it swishes from side to side.

  2. Thank you for this information.
    I’ve had two Singapuras who died at 18 and 20 years. The male was pouched while the female was not. Due to allergies, I now have two obviously pouched Oriental Shorthairs. I always called it their ‘power pack’ and thought it was due to being ‘fixed’.
    This is new to me, thanks.

      • Recently was worried about this pouch, as i have an orange tabby around 9 months old and have only noticed this “pouch” in the last month or so. I honestly thought he was getting fat because he is a house cat. I was also worried it could be some type of tumor. Ive had many cats and never seen this before. Thanks for the article

        • I jut spent the last day and a half agonizing over this very thing! I’ve even set up home visit vet appointments for tomorrow thinking something has been seriously wrong with my cat. Now I’m starting to think it’s just this! If so… How relieving! She’s 7-8 months old And was fixed about three months ago… Did you find that your cat developed this shortly after being spayed?

          • Three of my four cats were adopted as adults, and I can’t remember with the cat we adopted as a kitten. Sorry, I wish I could help. Does your cat’s pouch look like the ones in the pictures?

    • I had an Egyptian Mau who lived to be 22 and Jasmine had the pouch. Cheddar, one of our current cats has it also. Picasso, a Maine Coon does not.

  3. My old girl has had kittens few years ago then got her spayed after the kittens were rehomed j always thought it was from being pregnant xx

  4. MY Lydia was brown tabby with tux markings. her sides were tabby and her pouch was white. I used to say she wore a tabby dress with a white petticoat.


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