Pets, Pets, Pets...
Cats may own the Fountain of Youth. They are masters at disguising their age. So much so, that vets have trouble estimating how old stray cats are. There are only a few times in a feline's life when age is relatively easy to pinpoint. The teeth are the benchmarks of youth; whereas eyes are a clue to senior status.
Dogs fall apart like us. They show their age. Canines slow down and gray faster than their feline friends. Not as dignified, dogs are more apt to engage in hobbies, like Frisbee or rock chewing, that wear down their teeth. The puppyish exuberance in a mature dog seems to go long before the kittenish flexibility of the adult cat. Many felines in their twilight teen years can still jump with ease. Dogs have usually stopped attempting the old leaps by then. In addition, more cats survive into their 20s than dogs. The oldest cat in the Guinness Book was "Crme Puff" of Austin, Texas who turned 37 in 2004.
So how do you guess the age of a found cat with no history? Kittens are much easier to judge than cats. First look at the teeth. Kittens do not start getting baby (deciduous) teeth until they're 3-4 weeks old, and all baby teeth are in by 8 weeks. By the time the kitten is 6 months old, the baby teeth have been replaced with adult teeth. After that, most folks try to estimate As the pet ages, the size of the reflection gets larger. They claimed it was the first realistic method for mature cats, and twice as accurate as dental assessment in dogs more than 4 years. I recall reading about this then, but have found little to verify how reliable this technique is.
Cats have also discovered a fountain of Miss Clairol. The graying process on the face varies from cat to cat but is so subtle that it goes undetected. Perhaps the various feline multicolor patterns help camouflage the gray. Dark dogs lose pigment early. White faces on Golden retrievers and Irish setters age them prematurely. My black longhair cat died at 13, still as dark as can be, but my 2 year old Afghan hound already shows slight gray on her muzzle. Graying is not a determinant when guessing a cat's age.
With better veterinary care and responsible owners, life expectancy in cats is now better than ever. The biggest variable is whether the cat lives indoors or outdoors. Indoor cats generally live from 12-18 years with many surviving into their early 20s. The average age for outdoor cats is around 4-5 years because there are so many dangers. Outdoor cats are often victims of trauma like car accidents and dog attacks. They are also more susceptible to infections, parasites and viruses from altercations and prolonged exposure