Why Do Cats Have Belly Pouches?

Chubby cats are adorable, but not every cat that looks like it has a big belly is overweight.

Although the part of a cat's underside that sways when it walks may look like a belly, it isn't actually a belly at all. So what is it?

That little piece of skin, fur, and fat is a protective layer known as the primordial pouch. It runs along the length of a cat's abdomen. These pouches are completely normal and healthy, says José Arce, president-elect of the American Veterinary Medical Association. All cats have primordial pouches, but they vary greatly in size; some are barely noticeable. A small pouch is easiest to spot when it sways back and forth while the cat is walking.

There are three main theories as to why cats have primordial pouches, according to Arce. The first holds that it protects the internal organs during a fight by providing an extra layer between claws or teeth and the cat's internal organs.

A second theory suggests that the pouch allows cats to move more quickly. It stretches when running, giving cats added flexibility and the ability to cover more ground with each stride — qualities that can help them evade predators or catch prey.

Another possibility is that the pouch serves as extra storage space for food after a large meal. In the wild, cats don't get two square meals a day; they eat when they can and are able to store the fat from a big kill in their pouch to sustain themselves days later.

Primordial pouches are not unique to domestic cats. Big cats, such as lions and tigers, have them for the same reasons, says Arce. In domestic cats, the pouch begins to develop at around 6 months of age, in both males and females.

It is important that you can tell whether your cat has a large primordial pouch or is overweight. Just as in humans, excess weight can lead to heart problems, diabetes, and high blood pressure, according to Arce. Being overweight can also increase a cat's risk of arthritis and certain types of cancer, he added.

One way to distinguish between the two is by the shape of the cat, according to Arce. Overweight cats have a rounder body than healthy-weight cats with large pouches. When you stand above the cat, you should be able to see an indentation at the hips, which represents the cat's waist. An obese cat's belly starts at the top of the underside and extends all the way down, whereas primordial pouches begin further down and are angled toward the hind legs. If you can only feel your cat's ribs with difficulty, your pet is likely overweight. And finally, bellies do not sway the way pouches do when cats walk or run.

«If you suspect your cat is overweight, consult your veterinarian. They can recommend a low-fat, high-fiber diet«, according to Arce. To keep your cat healthy, make sure it reaches the recommended goal of 15 minutes of exercise per day by encouraging it to play with toys. If your cat is not used to being active, start slowly. If it pants, it is likely overexerting itself.