As they age, cats are not able to digest their food as well resulting in increased nutrition requirements. If their nutrition does not meet their requirements, they will lose muscle mass resulting in the ability to easily feel the bones of their spine and hips when petting them.

Why is my cat skinny and bony?

There are two main causes for a skinny cat: Either they aren't eating enough, or they're expending more calories than they are taking in. They may not be eating enough due to stress, dental disease, nausea or a host of other reasons.

Is it normal to feel my cat's bones?

Feel around your cat's spine

Again, you should be able to feel the bones, but not excessively. If the vertebrae feel very knobbly or like there's nothing on top of them, your cat is underweight. If they're difficult to feel, you have an overweight cat.