Primordial Pouch (Cat Belly Flap) in Cats

Last Updated on February 13, 2021 by Julia Wilson

What is the primordial pouch?

The primordial pouch is a loose flap of skin which runs along the length of the cat’s belly but is most pronounced towards the rear. It can often be seen swaying from side to side when the cat walks or trots.

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


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

1) The primordial pouch acts as a protection to the internal organs during a fight or attack. 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 which could potentially damage these vital organs. 

2) Allows cats to stretch out when running at high speed or jumping.

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.

In the video below, you can see my own cats Norman and Melody on the deck. Melody has quite a large primordial pouch which sways when she moves. Norman’s primordial pouch is much smaller.

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.

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.

This is an obese cat

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.

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?

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

Cat 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.

Pixie-bobANCATS breed standard (page 98)

The Pixie-Bob is an American breed which is said to be a cross between a wild bobcat and a domestic cat. In reality, it is a breed which was developed from a domestic cat with a naturally bobbed tail.

Egyptian MauCFA breed standard

The Egyptian Mau is the oldest domestic cat breed and is thought to have descended from the African Wild cat due to their remarkably similar appearance.

Bengal – CCCofA breed standard

The Bengal is was created by Jean Mill who by crossed an Asian Leopard Cat with domestic cats to create wild-looking cats with a domestic temperament.

Other names for the primordial pouch

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

Frequently asked questions

What age do cats develop a primordial pouch?

The primordial pouch usually begins to develop around six months of age, when the cat moves into adolescence.

Is a primordial pouch dangerous? 

No, a primordial pouch is not dangerous to cats.

Why does my cat have a belly after being spayed? 

The primordial pouch develops from 6 months, which coincidentally is the same time many cats are spayed or neutered. This may explain why many people attribute spaying and neutering to the development of the primordial pouch. But this is purely coincidental.

Do male cats have a primordial pouch? 

Yes, male cats have a primordial pouch, in fact, it is common in both sexes.

Why is my cat getting so fat? 

If your cat is getting fat, schedule an appointment with a veterinarian to determine the cause. Common causes of weight gain in cats include overeating, not enough exercise and pregnancy.

Why is my cat’s primordial pouch so big?

Each cat is individual and the size of a cat’s primordial pouch can range from small to large.

Is it normal for a cat to have a hanging belly?

It is completely normal for a cat to have a primordial pouch, which must be differentiated from a hanging belly due to obesity. If you have any concerns about the size or shape of your cat’s belly, speak to a veterinarian.

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

18 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.

    • I love Singapuras, we had a beautiful Singapura boy called Levi who we lost in 2017. He had a primordial pouch too.

      • 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.

  5. How can you determine whether the cat’s pouch is this, worms, or serious health issues like cancer and so forth. I got my cat at 9 months old (she’s now 4 1/2 years old). She was a rescue as she was previously abandoned by her previous owners. She’s always had this pouch. I’ve never seen it on a cat before. She’s a mostly black with small amounts of white domestic cat.

    • The pouch is quite literally an excess area of skin and fur and should feel soft and squishy. Cat worms would have no effect on the look or feel of a primordial pouch. The best way to evaluate for worms is to have the veterinarian run a fecal flotation test to look for eggs. My chocolate Oriental (in the short video on this page) has quite a prominent PP and you can see it jiggles from side to side when he runs.

  6. I have a male and female from the same litter but they have the same father because they look nothing alike my male has the pouch and is 20 lbs the female doesn’t have a pouch and is 8lb


Leave a Comment