Dave, Albino Buck - 23m had been suffering from lung tumour and huge abscess on side of neck, both treated successfully but passed away, possibly pneumonia.

Barry, Dave's brother, Brown Hooded Buck - 24m - suffering respiratory problems, passed away unexpectedly when taken to vet did not respond to resusitation

Miranda, Cream/Pale Beige and White Hooded Doe - 10m - Cause of death unknown, began to vomit blood and passed away suddenly

Melissa, Brown Doe, Miranda's sister - 34m - Passed away in sleep unexpectedly

New Rat, 6 weeks old, Brown - Bought with his brothers from pet shop but passed away the following day sadly before we got to know and accordingly name him.

Rattastic 7m Dark Brown with small white stripe on tummy, Buck - Cause unknown

Georgie 8m Dark Brown and White Buck - went to sleep fine, was cold and limp the following morning nothing vet could do, passed away within the hour.

Daphne Beige and White Hooded Doe - 6 weeks, Christmas present bought with her sister Niamh from pet shop, died in sleep just 8 days later, Niamh had 10 babies the following day

2 Babies, both the littlest of Niamh's litter but both got to 4 weeks of age, died suddenly despite having been playing, eating and being lively.

My previous guys...

Willard - Black hooded male (friend bred feeders, saved this one for me) - 10 months, unknown, passed in his sleep
Scabbers - Mismarked Black Berkshire (breeder who worked at a pet store. Her private rat) - 30 months, tumor
Wormtail - Black hooded male (same breeder, different time) - 67 months, expected to just be old age. Crawled away, went to sleep, never woke up...

Current guys:

Remy - Black hooded male (pet store that aforementioned breeder used to work at) - 2.5 months...so far so good
Emile - Blue capped Dumbo (breeder that pet store now buys rats from...Remy's half brother) almost 2 months...again, so far, so good!

My poor Charrlotte baby was only 4-6 weeks from a pet store. Sweetest little angel! Gave kisses, cuddled, and fell to sleep in your hand. She died 10/11/07 while I was at school. Death unknown, but suspected brain tumor or stroke. Maybe trauma to the spine.

Aurora - agouti hood, intact female, just under a year, streppococcal pnuemonia
Nimbus - mismarked smeezie, intact female, 8 months I believe?, streppococcal pnuemonia
'Mygy - PEW, intact female, approximately 1.5 years, streppococcal pnuemonia
Pickles - fawn berk, intact female, between 2.5 and 3 years, pituatary tumor
Namless - black hood, intact female, 3-4 months, myco

Courtney +/- 18 months female - Tumor  (PEW feeder rescue)
Duncan   +/- 2 years female - Tumor (private adopyion as an adult. Not sure of original source - we had her about a year.  Agouti)
Bailey     +/-  9 months female - unknown causes (suspwect heart problems) private adoption.  Agouti
Smidge   2 years+ - Hairless dumbo female - old age (we adopted her when her breeder retired her)
Muffin    +/-  2 years female  - tan hooded - petshop resue
Frankie   +/- 2 years female   - tan self - older petshop resue - we think her breeder sent her off as a feeder rather than retiring her honorably.  grrrr
Dartanion +/- 18 months male - Siamese - stroke.  He was a private adoption (owner went to college but came to visit him every so often)

our living ratties:
Puppy  +/- 2 years and going stong - second of three from our college bound friend - PEW male (my cuddler)
Athos  +/- 2 years - Agouti male the third adoption (had been Dartanion's cage mate. 
                            He's sleeping alot but he and Dartanion were killers, so I can't put a companion in with him)
Blaggutt +/- 12 month PEW male - Feeder rescue
Dante    +/- 10 months - chocolate hoolded male - feeder rescue
Tempest +/- 6 months - brown hooded male - pet shop purchase (too cute!)
Maverick +/- 6 months - brown variegated male - pet shop purchase (ditto!) we are pertty sure Tempest and maverick are litter mates
Lewis +/- 6 months - brown self male - feeder rescue
Smudge +/- 1 year - hairless female (possible kin to our other hairless - same breeder)
Angel +/- 4 months PEW female - feeder rescue
Tyrant -  5 weeks dumbo variegated female (accidental litter rescue)
Andy   - 7 weeks dumbo agouti female (ditto)
and four more on the way (2 females this Sunday and two males the following Saturday)

Hmmmmm   hello i am new to this forum and i have only had  three rats  but i would like to participate in this survey.

Lester - We had Lester for 3 years and he ate all the worst things you can give a rat - he died of cancer finally
Zoe - Many years after Lester i bought Zoe from a pet store. I had Zoe for 4 years and finally she also developed cancer i had to have the vet put her down cause she was barely moving around and couldn't eat anymore

Now I have little Iban he is about five weeks old. I own a dog grooming salon in the same building as a pet store. He was the runt of his litter and his mom was beating up on him. The store owner put him in with a snake but the snake didn't want him. So, the whole time really didn't know what was going on until i saw him in the snakes cage and he was so skinny and sick looking. So, i pulled him out and started feeding him formula and he's doing great we'll see how it goes though.

Stella = 36 mths, female, suspected stroke => hand fed and cleaned her for last 2 mths of life => an incredible girl, pet store
Lucy and Ethel = 4 mths => died same day for unk reasons => pet store
Berries => 2 mths => died from a careless fall => reptile shop (feeder rat, absolute angel)

Two rats to add:

Zuko: lived 1 year and 8 months.  Passed of unknown causes, but he had a tumor once before so my guess is he had another tumor in his brain or some other neurological problem.

Vaughn: about 2 months.  Died of unknown causes several hours after a successful surgery to drain an abcess and castrate him.

Winston 5yr (Back legs went had to be put to sleep)
Jasper 5 months (bleed on the brain)

jane - 3 months (possibly a seizure or pneumonia)

Tallulah-Belle, my gorgeous agouti self girl. 20 months, suspected stroke.  Got her from a private owned pet shop, that I know the owner from, and who adores her ratty-babies.  She had a benign mammary tumor successfully removed around 13 months.

Meatloaf, male Rex rat, 25 months, incurable pneumonia, cause of death euthanasia

Clyde - 7 months old - had a chronic respiratory infection - I think he got a secondary respiratory infection and wasnt able to breath

 shadow - petco rat- became blind after 11 months from illness lived another 10 months before she was put to sleep