It’s normal for indoor only cats to “nap” for 14-16 hours a day, although older cats and cats who get a lot of play or other stimulation will naturally sleep even more. If you think your cat is sleeping excessively, closely monitor him or her for any signs of illness. Vomiting, diarrhea, reduced energy or stiffness when awake, reduced appetite, weight loss, or a poorly groomed haircoat are signs that something else is going on and you should schedule a veterinary appointment. If your cat is not showing any signs of illness, it may be that he or she is just bored. See The Ohio State University’s website for tips on environmental enrichment and how to alleviate your indoor cat’s boredom--http://indoorpet.osu.edu/cats/.