What is the proccess of a rat dieing of old age

I was just wondering how you can tell if your rat died of old age or of something else after the age of one.

I've had around 200 rats in 11 years, and so far around 100 have died.

Depending on genetics, some rats are old at 1.5 years, while others are still young at 3.0 years.

http://www.ratbehavior.org/ratyears.htm...

No one dies of old age. Aging is a process, not a disease in itself. Usually when your rat dies "of old age," it means that he or she succumbed to one of the diseases common in it's later years.

The process of old age in rats:

http://search.yahoo.com/search?search=th...

http://search.yahoo.com/search?search=ol...

Caring for old rats:

http://www.rmca.org/articles/oldrats.htm...

http://www.dapper.com.au/articles.htm#ol...

I have concluded that most rats do not age gracefully, very much like us humans, they are plagued with a meriad of old-age related ailments.

Old rats suffer from myco, arthritis, kidney failure, liver failure, heart failure, cancer of every organ, digestive disorders, strokes, pituitary tumors, and the list goes on. Most of the time you never know that these organ failures are happening until the rat suddenly dies. Rats are stoic animals, they hide their diseases well until it's too late to do anything about it.

Old rats get thin, the coat thins, some get grayer if their coat is already silvered, they get weak and wobbly, and some get dementia.