There are many reasons why a cat’s belly trembles while lying down. The specific reasons can be divided into the following situations:

1. Indigestion or hair ball disease

It may be caused by the cat not eating hair removal cream for a long time or indigestion, which may cause the cat to vomit and cause abdominal convulsions.

2. Respiratory system diseases

For example, cats often cough, pant, etc., which will cause their diaphragms to contract and cause the cat’s belly to twitch.

3. Parasitic infection

If there are parasites in the cat, it may also cause abdominal pain and convulsions.

4. Feeling cold or scared

It may also be caused by the cat shaking because it feels cold or scared.