While petting your cat, you feel a squishy lump on their belly. Could they have a hernia? Cat hernias are relatively uncommon, but they can happen. The good news is that hernias are easily treated with surgery — and if your cat was born with a hernia, it can be repaired during a spay or neuter procedure. Here's what you should know about this condition.
A hernia occurs when there's an abnormal hole in the muscle wall of the abdomen or diaphragm. Fat or internal organs can protrude through the hole, causing a squishy lump noticeable from the outside. The classic cat hernia is located over the area where your cat's bellybutton would be. Usually the lump isn't painful, and it may disappear if you gently push on it. If this occurs, it's because the hernia is reducible, meaning the contents of the hernia can be pushed back into the body. Not all hernias are reducible.
A cat hernia is usually not life-threatening. However, on rare occasions, internal organs such as intestines can protrude through the opening in the muscle wall. If this cuts off an organ's blood supply, it can be life-threatening.
If the hernia only contains fat, then you probably won't see any other signs other than the lump. If the hernia contains any abdominal organs, then you may observe a large swelling that's painful or hot and your cat may vomit, lose their appetite, have bloody urine and/or have less energy.
If a cat has a hernia, they're typically either born with it or it's the result of some type of injury. Physical trauma, weak abdominal walls, pregnancy and birth defects are the most common causes of hernias in cats. Extreme or repeated constipation that requires straining to defecate has also been reported to cause hernias in cats.
Hernias are classified by where they occur in the body. There are three types:

If you suspect your cat has a hernia, it's important to have a veterinarian check it out as soon as possible. Most cat hernias can be diagnosed by physical exam alone, except for hiatal hernias, which can only be diagnosed with an X-ray or abdominal ultrasound. If the hernia is very hard or large, your vet may order an X-ray to determine if any abdominal organs are trapped.
Treatment depends on the hernia's size and location. If the hernia is small, your cat might not need surgery. If they have a larger hernia, then surgery is required to keep internal organs from slipping out of the hole. If internal organs are trapped in the hernia, then emergency surgery is needed right away.