A strong genetic background for longevity can't be discounted. Given proper care, nutrition, and regular veterinary visits, a cat kept indoors can live as long as 21 years or more. (The average age of cats is 12-15 years) This is, of course, barring any serious medical conditions or untimely accidents.
Cats that are indoors-outdoors usually don't last to the the average age because of traffic accidents, fighting with other cats, intentional acts of violence, poisoning (accidental or intentional), diseases caught from other cats, being picked up by animal control and subsequently euthanized if not claimed, and death caused by predators.
"Stray cats" AKA "feral cats" usually don't live more than a couple of years because of starvation or all of the above.
Oldest Cat Trivia:
- The Oldest Living Cat
According to the Guinness World Record (of 2002 - no longer available online), the oldest living cat was then a cat from Victoria, Australia, named Kataleena Lady. She was born in 1977, making her 25, a mere youngster, compared to other claims.
- One source says the longest-lived cat was in Devon, England; a tabby named Puss, who passed on shortly after his 36th birthday, in 1939
- In 2007, a black cat named Baby in Duluth, MN was claimed to be 37 by his owners.
- Manx and Siamese have been mentioned as being among the longest-lived pedigreed cats.
- The Jaguar is said to be the longest-lived species of cat, sometimes reaching 30 years.