When you think about the important attributes of cats, you might imagine long beard, flashing tail, or bright eyes. But what about the swinging, sagging bag on the underside of a cat? Also known as the ventral flap, the primitive pouch is the skin and excess tissue under the cat’s abdomen, most prominently toward the tail.
A bag that can swing to the sides for round cats, medium cats, and even thin ones. All cats are born with a pouch initially, but it may not fully develop or go unnoticed by us until they reach adulthood. You cannot remove the original pouch or remove it as it is part of the cat’s anatomy.
Experts say the reason cats have this mysterious trait may not be just a cute swaying belly. In fact, the theory is that the primary pouch may play a vital role in the cat’s survival.
Here’s what we found out about a cat’s signature belly flap.
Why do cats have primitive pouches?
The cat’s protoplasm is a flap of the abdomen with extra skin and tissue. Dr. Yui Shapard, DVM and medical director at Pawp, which shows why cats have an original bag that is as translucent as the bag itself. While the carrier bag is not a popular point of discussion in the veterinary community, there are several theories surrounding it:
- Protection. Dr Shapard said one conjecture is that the primitive pouch adds an extra layer of protection to vital internal organs. Whether it’s the bunny’s kick or the defense from a predator, the extra skin and tissue will protect against injury.
- Flexible. The cat’s original sac is not connected to the abdominal wall, causing the pouch to wobble its characteristic when the cat walks. The excess skin of the pouch can freely stretch and lengthen — perhaps important for the cat’s flexibility.
- Genetics. All cats have a primitive pouch, but Dr. Shapard says the scab can be more pronounced in some breeds.
- Weight. Bigger cat there will be a primitive bag, but the bag looser than fat and will sag lower, sway more, and possibly accumulate fat in overweight cats.
- Age. As cats age, you’ll likely notice their sacs become more saggy – that’s normal. “Just like us, skin loses elasticity as cats age, contributing to a more prominent primary bag.” Dr. Shapard said.
- Energy. Another theory behind the primordial pouch in cats is that it stores excess energy or food. It has been hypothesized that if a cat skips a meal, they may be able to access the extra energy stored in the tissues of the swaying abdomen. Dr. Shapard does not believe in this theory, because of a cat’s sensitivity to miss a meal or two.
iStock / Anna Chaplygina
Do all cats have primitive pouches?
All in the country cat-like have a primitive bag, even if you think you haven’t seen one on your favorite cat. Based on International Cat Association breed standard, some domestic cat breeds have prominent primeval pouches while others have less noticeable marsupials.
| Cat breeds most likely to have a prominent primitive pouch | Cat breeds are less likely to have a prominent primitive pouch |
| Pixie Bob | Norwegian forest cat |
| Mau Egypt | Scottish Fold |
| Siberia | Thai language |
| Snowshoe | |
| Bengali |
Does talking or being unnecessary cause cats to have a primitive pouch?
The vesicles don’t develop when your cat is killed or neutered — they’ve patted their stomachs long before the procedure. But immobilizing cats can make them weight gain. Dr. Shapard says this weight gain can cause the cat’s primary sac to become more visible.
If you’re concerned about your cat’s fussiness due to weight gain, talk to your veterinarian about it Maintain a healthy weight after their procedure and throughout their life.
iStock / BackyardProduction
The difference between an original bag and an overweight cat
Worried that a gurgling noise in your belly could indicate that your cat is overweight? While obesity is a serious health concern for cats, the bag is not initially a sign of health. And the numbers on the scale don’t always tell the full story behind Cat’s ideal body weight and condition.
The best method to distinguish between the original bag and the fat is an assessment method that allows you to visually assess the shape of the cat. “There is a useful tool called Body Condition Score Dr. Shapard explains. A healthy cat should have an hourglass body from above and a sunken belly with a thin layer of fat toward the front of the belly.
When you feel the cat from the sides, you should be able to feel the ribs under a thin, firm layer of fat. If you can’t feel your cat’s ribs, they may be overweight. Remember, the fat will stick to the body, while the primary sac will sag and warp.
If you’re not sure if your cat is overweight, ask your veterinarian to demonstrate a Body Condition Score assessment at your cat’s next checkup. If your cat is overweight, your veterinarian will work with you to create a diet plan and an exercise routine.
| Signs of an overweight cat | Signs of a cat with a healthy weight |
| A thick and firm layer of fat along the underside of the abdomen. | A primitive bag can rotate or sag. |
| Waist circumference. | The waistline is obvious when viewed from above. |
| Can’t feel the ribs. | A thin layer of fat can be felt under the ribs. |
| Fat accumulates in the upper back. | The lumbar vertebrae have a thin layer of fat. |
Should my cat go on a diet to lose their primordial pouch?
The pronounced primordial pouch is not known to be associated with cardiovascular disease or diabetes, two diseases commonly associated with obesity in cats.
If your cat is overweight, losing a few ounces or a few pounds can lift the initial bag once the cat reaches a healthy weight. Excess weight can cause the belly to hang lower, but this weight loss won’t remove the cat’s primitive bag.
iStock / SunRay BRI Cattery
When to Call the Vet
When rustling your cat’s initial pouch, you should feel for any unusual changes such as lumps or bumps. Dr. Shapard says veterinarians should look at a tumor in a cat’s original pouch to be sure, but unusual lumps or bumps can signal a number of conditions:
- If your female cat is intact or has subsequently died, the tumor in the primordial sac may be an developed mammary gland or a tumor in the mammary gland. Spanking before a cat’s first heat cycle stuns mammary gland development and reduces risk breast cancer. Breast cancer is less common in men but has been reported.
- Tumor can be a swollen lymph nodesDr. Shapard said. Caused by a bacterial infection, fungal infection, or cancer, your cat will likely show other symptoms of illness.
- The tumor could be another type of tumor that your vet should look into as soon as possible.
“If you notice a tumor in the primordial sac, I recommend that you schedule an appointment with your veterinarian to have the tumor checked,” Dr. Shapard says. “You don’t want to have to wait and consider approaches to a tumor because if this is cancer, early diagnosis and treatment can significantly affect their prognosis.”
If your only concern about your cat’s original bag is that it sags and wobbles to the sides, Dr. Shapard says that’s okay and would recommend more cuddling and belly rubs. —if your cat likes it.
