A senior cat is one that is aged between 11 - 14. Most felines don’t outlive their senior years. However, there are the rare few that manage to make it into their geriatric years, which are considered to be 15 - 25 years.  During their senior and geriatric years, cats usually experience more health problems than they did in their younger years, so it’s important to keep a keen eye on your cat during this time.