Obesity can lead to many feline health problems. If your cat no longer has a proportional figure (it loses its "waist"), check with your veterinarian whether your tabby is too tubby.read more
BY: -If your cat was only running and hiding under your furniture, then I would suspect feeling "scared" was the probable main reason. The combination of actions you describe, however, sounds like a more complex problem. It's quite possible that your cat is feeling scared, but it's probably because he's not feeling well. A trip to the veterinarian is in order to properly diagnose the problem. Based on what you've written, Patches may be suffering from two types of parasites: fleas and ear mites. Both can cause the body twitching, biting and head shaking that you describe. Clues to the presence of fleas are small black specks, also known as "flea dirt," in your cat's coat. Ear mites are a different parasite. They can live in your cat's ear canal and cause irritation if they are present in large enough numbers. Related excess scratching, infections and hematomas (blood blisters) can all result and may lead to permanent problems, so it's best that your cat gets examined by a veterinarian soon.
Cats reach full skeletal development when they are this old: