In recent years, Jim regularly made fun of our cat, Lucy. She wasn’t fat, but my husband often commented on her sagging belly that looked like a “flag waving in the wind” when she walked. I just attributed that loose skin to her increasing age but in truth, that undulating flap of skin is called a primordial pouch.
No doubt you’ve seen it: Fluffy saunters across the room with her belly gently swaying to and fro. You shake your head and wonder when she picked up that extra blob of fat, and what can be done now to get that lazy kitty back in shape!
Good news! Your cat doesn’t need to go on a diet. That extra “flab” is completely normal. It’s called a primordial pouch and may appear at any age.
The Primordial Pouch Has a Purpose
Cats in general possess looser skin than many other animals. When you scruff a cat behind its neck, you can feel it. So the primordial pouch shouldn’t come as such a big surprise.
Many people think the pouch is due to weight gain, but this belly flap happens to most kitties. Whether or not the animal is spayed or neutered makes no difference. The pouch may become more pronounced as a cat grows older.
Cat experts believe the pouch, which sits on the belly just in front of the animal’s back legs, helps protect her from predators in a fight. When cats fight, they often use their back legs to kick and claw their opponents. The flap of skin provides an extra layer of protection for their internal organs.
When my fur-boys, Jake and Chico, used to play, they often used their back legs this way and had they fought that way as adult cats, some serious tummy damage could have occurred. Jake was a Bengal-mix and Chico was a Snowshoe Siamese-mix, and both proudly displayed their belly pouches as young adult cats.

The flap also allows a cat to stretch out when she runs at high speeds or jumps without harming or stressing her body.
Feral cats often go days without eating. The extra pouch allows them to overeat when they find food and store extra fat in the primordial pouch.
Is My Cat Fat Or Is That a Primordial Pouch?

Make sure you distinguish between obesity and the primordial pouch. If you look down at your pet from above, you can immediately tell if she is overweight, but you likely won’t see the pouch.

If you can feel your cat’s ribs when you gently run your hands down them, you can assume the soft flap of skin behind the ribs is a primordial pouch, not fat. Watch her walk and if the extra flap back of her ribs sways from side to side as she moves, that’s not fat.
Some Breeds More Likely to Display a Pouch
Oriental cat breeds tend to possess the primordial pouch more than others. The most evident pouches may be seen in Bengals, Pixie Bobs, and Egyptian Mau breeds. Our Lucy is a Siamese-mix, and that extra skin swinging back and forth as she moves is clearly the pouch, not a sign of obesity.
Even Wild Cats Develop Primordial Pouches

Look at the drawing of the tiger in the image above. The blue circle surrounds the big cat’s primordial pouch. This genetic characteristic may be found in cats of all types.
Don’t Worry! It’s Normal
Look at your cat objectively. From above, can you see an indention just back of her ribs? If so, she’s unlikely to be overweight. Do the rib test from the sides of her body. If you can gently feel her ribs as you run your hands down the length of her body, she’s not fat. Do you see that extra loose skin just back of her ribs? Does it feel like loose skin? Don’t despair. That’s her primordial pouch. Your kitty’s extra piece of skin is perfectly normal. She isn’t overweight. She’s just a normal feline, sometimes with an extra wiggle to her waddle.