Yes, Your Cat’s Belly Flap (aka Primordial Pouch) Is Adorable—But What Exactly Is It?

By: Monica WeymouthPublished:

primordial pouch
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Yes, Your Cat’s Belly Flap (aka Primordial Pouch) Is Adorable—But What Exactly Is It?

Admit it: You have a silly nickname for your cat’s belly. Whether it’s “jelly belly” or “coin purse,” you certainly wouldn’t be the first cat parent to do so! But did you know that your kitty’s “snack pack” already has a name?

That’s right—the jiggly, swaying, irresistible “love paunch” you so admire is officially known as a “primordial pouch.” Although all cats have them, many pet parents are unfamiliar with the term. From why they exist to why we love them, here’s everything you need to know about the cutest part of your feline friend.

What Is a Primordial Pouch?

So, what is a primordial pouch, anyway?

It’s simpler than it sounds. “Primordial pouch” is just a fancy name for the soft, saggy flap of skin under a cat’s belly, explains Dr. Chyrle Bonk, DVM, an associate veterinarian at Clearwater Valley Veterinary Clinic in Orofino, Idaho. It runs the length of the cat’s underside, but is typically more pronounced near the back legs.

“The primordial pouch is a mix of fat, skin and fur,” says Dr. Bonk. “All cats have primordial pouches—they are just different sizes depending on your kitty.”

Cats begin to develop stomach pouches during kittenhood, typically around 6 months old. And the feature isn’t unique to house cats, she notes. Big cats, including lions and tigers, have them as well.

Why Do Cats Have Primordial Pouches?

Primordial pouches are goofy and endearing—but they probably don’t exist solely to entertain us cat lovers. So, what purpose do they serve?

Veterinarians aren’t exactly sure why cats have stomach pouches, says Dr. Jamie Whittenburg, DVM, owner and director of Kingsgate Animal Hospital in Lubbock, Texas, but there are some theories about why this cat belly came to be:

  • Protection: One theory is that the pouch and its fatty cushion offer protection to the cat’s internal abdominal organs, which would be especially beneficial for wild cats. "This protection could be useful in fighting situations, as well as for injuries," says Dr. Whittenburg.
  • Flexibility: Another theory is that the pouch provides extra flexibility while running, enabling the cat to cover more ground with each stride. This flexibility could also aid a cat in cutting from side to side quickly when they are escaping predators, or while they are chasing prey.
  • Energy: It's also possible the primordial pouch comes in handy when food is scarce. "Some theorize that the pouch may act as a fat reserve, storing fat that can be later used as energy if reliable meals are unavailable," says Dr. Whittenburg.

Does a Primordial Pouch Mean My Cat Is Overweight?

Many pet parents assume the primordial pouch is akin to a kitty “spare tire.” However, even a sizeable cat pouch doesn’t necessarily mean your pet is overweight, explains Dr. Bonk.

“The size of the pouch has a genetic component, and can vary with breed, as well as with individual cats,” she says. “A healthy, lean cat can still have a large pouch.”

The following factors can influence the size of a cat’s primordial pouch, according to Dr. Bonk:

  • Genes & Breed: The size of a cat’s primordial pouch is largely based on genetics. Some breeds (including the Egyptian Mau, Japanese Bobtail, and Bengal) are known for having sizeable pouches. Most pet cats are mixes of various breeds, so their pouch sizes vary widely.
  • Weight: Your cat’s shape and weight distribution can affect how big their pouch appears. In fact, if your cat’s pouch looks especially large, it might actually indicate that your cat is in great shape. That’s because overweight cats tend to have bigger midsections in general, which can obscure the actual pouch, while a thinner cat’s pouch may appear more prominent compared to the rest of their body.
  • Age: Like humans, cats tend to lose muscle mass and skin elasticity as they age, potentially making the pouch hang a little lower.

Not sure if your cat is overweight or simply pouchy? Consider these signs, Dr. Bonk says:

Signs of an Overweight Cat
Signs of a Healthy-Weight Cat
Signs of an Overweight Cat

Round-shaped belly

Signs of a Healthy-Weight Cat

A visible waist indentation when viewed from above

Signs of an Overweight Cat

"Extra padding" (aka fat deposits) over the ribs

Signs of a Healthy-Weight Cat

A primordial pouch that swings when they walk


If you’re concerned about your pet’s weight, check in with your veterinarian, and find out more about pet obesity and weight management.

Why Is the Internet So Obsessed With This Pouch?

If you love cats with saggy bellies, you’re not alone. On social media—where, of course, cats have long enjoyed star status—admirers regularly post photos of their cats’ so-called “tum-tums” and “cookie pouches.”

Animal behaviorist Sarah-Jane White has a theory as to why we humans can’t get enough of kitty bellies.

“We have a built-in radar for anything baby-like, because during our evolutionary history, it was important to protect helpless infants,” she says. “When you witness your cat do something extra-cuddly, your brain simultaneously instructs you to safeguard it, and rewards you with happy hormones for doing so.”

Our natural instinct to nurture may render us defenseless to cute tummies, reasons White.

“Soft, fluffy bellies that we just want to snuggle with are part of our DNA,” she adds.

Evolution might have something to do with it, but let’s not forget the primordial pouch’s, uh, unique aerodynamics.

“No doubt about it, cat pouches are entertaining,” Dr. Bonk laughs. “Especially when your cat streaks across the room with it swinging side to side!”

The Many Names of the Primordial Pouch

“Primordial pouch” is a mouthful. Thankfully, creative cat parents have come up with plenty of cute nicknames for kitty bellies.

  • Jelly Belly: For the cat who's as sweet as a jelly bean.
  • Tum-Tum: With all due respect to “primordial pouch,” the much cuter and sillier “tum-tum” is far more fitting.
  • Cookie Pouch: One of the most popular terms, “cookie pouch” is just plain fun to say.
  • Snack Pack: If the primordial pouch’s fat provides backup energy, as some theorize, then “snack pack” is both cute and accurate.
  • Puddin’ Belly: Because this pouch is as sweet and jiggly as a bowl of pudding.
  • Fluff Armor: As silly as this one sounds, the primordial pouch may offer some fluffy protection from predators.
  • Jungle Pouch: You’ll also find primordial pouches stalking around the jungle… but it’s best not to snuggle those.
  • Coin Purse: Like a fanny pack for your cat (which should definitely be a thing).
  • Swiffer: Because if your kitty’s tummy hangs low enough, it can sweep the floor!
Like cats themselves, primordial pouches are a bit of a mystery. While we’re not sure exactly what they do or why we can’t resist them, one thing’s for sure—they’re adorable. Stay squishy, kitties!

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By: Monica WeymouthPublished:

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