When you think of a cat’s important attributes, you might envision their long whiskers, flickering tail, or bright eyes. But what about the swinging belly flap on the underside of a cat? A cat’s primordial pouch is excess skin and tissue under their belly, most prominently toward the rear.
A pouch might swing side to side on round cats, average kitties, and even slim ones. All cats are born with a primordial pouch, but it may not fully develop until they are adults. You cannot remove a primordial pouch or make it go away, as it is part of your cat’s anatomy.
So, what is the purpose of a primordial pouch? Experts say this mysterious feature may help your cat survive.
Here’s what we found out about a cat’s signature belly flap.
Why Do Cats Have a Primordial Pouch?
A cat primordial pouch is a belly flap of extra skin and tissue. Dr. Yui Shapard, DVM and medical director at Pawp, says the reason why cats have a primordial pouch is about as fuzzy as the pouch itself. While the pouch is not a common point of discussion in the veterinary community, there are some theories bouncing around:
- Protection. Dr. Shapard says one theory is that the primordial pouch adds a layer of protection for vital internal organs. Whether it’s a bunny kick or defense from a predator, the extra skin and tissue guard against an injury.
- Flexibility. The primordial pouch of a cat isn’t connected to the abdominal wall, giving the pouch its signature sway when a cat walks. The extra skin of the pouch is free to stretch and lengthen and may have a vital role in a cat’s flexibility.
- Genetics. All cats have a primordial pouch, but Dr. Shapard says the flap may be more pronounced in some breeds.
- Weight. Bigger cats will have a primordial pouch, but the pouch is looser than fat and will sag lower, sway more, and could have fat deposits in an overweight cat.
- Age. As cats age, their primordial pouch becomes saggier. “Just like with us, the skin loses its elasticity as a cat ages, contributing to a more prominent primordial pouch.” Dr. Shapard says.
- Energy. Some believe primordial pouches in cats store excess energy or food. It’s theorized that if a cat misses a meal, they can access the extra energy stored in the tissues of the swaying belly flap.
iStock/Anna Chaplygina
Do All Cats Have a Primordial Pouch?
All domestic breeds of cats have a primordial pouch, even if you think you haven’t seen one on your favorite feline. According to The International Cat Association breed standards, some domestic breeds of cats have a prominent primordial pouch, while others have a less noticeable pouch.
Cat Breeds Most Likely to Have A Prominent Primordial Pouch | Cat Breeds Least Likely to Have A Prominent Primordial Pouch |
Pixie Bob | Norwegian Forest Cat |
Egyptian Mau | Scottish Fold |
Siberian | Thai |
Snowshoe | |
Bengal |
Does Spaying or Neutering Cause a Belly Pouch?
A primordial pouch doesn’t develop when your cat is spayed or neutered—they’ve had their belly flap long before the procedure. But getting your cat fixed might cause them to gain weight. This weight gain, Dr. Shapard says, could cause a cat’s primordial pouch to become more pronounced.
If you’re concerned about spaying or neutering your cat due to weight gain, talk to your vet about maintaining a healthy weight after their procedure and throughout their lives.
iStock/BackyardProduction
Is My Cat Overweight?
While obesity is a serious health concern for cats, the primordial pouch is NOT health-related. Numbers on the scale don’t always tell the full story behind your cat’s ideal weight and body condition.
The best method of distinguishing between the primordial pouch and fat is an evaluation method that lets you visually assess your cat’s shape.
“There is a useful tool called the Body Condition Score, which can help you assess whether a cat is overweight or not,” Dr. Shapard explains. A healthy cat should have an hourglass shape from above and a tummy tuck with a thin, fat pad toward the front of the belly. Below is a chart to help you determine if your cat is overweight.
If they are overweight, your vet will help you create a diet plan and an exercise routine.
Signs of A Cat Who’s Overweight | Signs of A Cat at A Healthy Weight |
A thick, firm fat pad along the underside of the belly. | A primordial pouch that swings or sags. |
Round of the abdomen. | Visible waist when viewed from above. |
Unable to feel the ribs. | Ribs can be felt under a thin layer of fat. |
Fat deposits on the upper back. | Lumbar vertebrae have a thin layer of fat. |
Should my cat go on a diet?
A pronounced primordial pouch is not known to be linked to cardiovascular disease or diabetes, two common diseases associated with feline obesity.
If your cat is overweight, shedding a few ounces or pounds might lift the primordial pouch as a cat reaches a healthy weight, but losing this weight will not make it disappear.
Can You Pet the Primordial Pouch?
While touching your cat’s belly and pouch might be tempting, it’s the most vulnerable part of your kitty’s body. Unlike dogs, who often love belly rubs, most cats are fiercely protective and can get defensive if you try to touch them there.
“If they’re exposing their belly, it’s a sign that they’re relaxed, but it doesn’t necessarily mean they want you to touch [it],” explains Joey Lusvardi, a certified cat behavior consultant and founder of Class Act Cats.
Awareness of your cat’s body language and consent are key. “Tolerating a belly rub doesn’t mean they like it. It’s important you let them lead [and] listen to your cat if they try to walk away or push your hand away,” Lusvardi warns.
Remember, your cat’s stomach is just a single part of them. Lusvardi urges cat parents to remember the many other spots cats like to be petted.
iStock/SunRay BRI Cattery RU
When to Call A Vet
It’s good practice to regularly check your cat’s body, including their primordial pouch, for any unusual changes. Dr. Shapard says abnormal lumps or bumps could signal a few conditions:
- If your female cat is intact or spayed later in life, the lump in the primordial pouch could be a tumor in the mammary gland. Spaying before your cat’s first heat cycle stuns mammary gland development and reduces the risk of mammary gland cancer. Mammary gland cancer is less likely in males but has been reported.
- The lump could be a swollen lymph node, Dr. Shapard says. Caused by bacterial infections, fungal infections, or cancer, your cat will likely show other symptoms of illness.
- The lump could be another type of mass your vet should look at as soon as possible.
“If you notice a lump in the primordial pouch, I recommend scheduling an appointment with your veterinarian to have the lump checked,” Dr. Shapard says. “You do not want to take a wait-and-see approach with a lump because if this is cancerous, early diagnosis and treatment can significantly impact their prognosis.”
If the only concern you have about your cat’s primordial pouch is that it sags and sways side to side, Dr. Shapard says that’s okay and would recommend more kitty cuddles if your feline is up for it.