Rats make excellent pets, and they will bring so much joy to your life. But one thing is certain: Their lives are just too short!
Have you ever wondered what your pet rat’s life expectancy is? Just how old can a store-bought rat get?
Pet rats usually live between 1.5 and 3 years. Some exceptional rats have been documented to live up to 7 years or more!
Let’s have a look at the factors that influence your rat’s lifespan, and what you can do to ensure that your rats live a long and happy life.
Average Rat Lifespans
How Long Do Wild Rats Live?
The rats we keep as pets are descendants of a species of wild rat called Rattus norvegicus (Norway rat). Wild Norway rats can theoretically live up to 3 years, too, but they rarely live to see their first birthday1.
This is due to food and water scarcity, diseases, and of course, natural predators.
How Long Do Pet Rats Live?
Pet rats are described as living between 18 and 36 months, so 1.5 to 3 years2. This is quite a wide span, but typically, a rat over 1.5 years old would be considered a senior rat.
Their life expectancy also varies depending on certain genetic traits. Dumbo rats (who typically have large ears set low on the side of their head) have been anecdotally reported to live longer than average, but this has never been scientifically proven.
Hairless rats and rex rats (with their curly fur and whiskers), on the other hand, often have shorter lifespans than other fancy rats. This is due to health problem that are linked to their genetic makeup.
So-called “feeder rats” often have a very short life, as they are bred solely for the purpose of serving as feed for snakes, so inbreeding is the norm.
What Is the Longest Living Pet Rat?
According to the Guinness Book of World Records of 1995, the oldest reported pet rat was named Rodney. Rodney died in 1990 at the whopping age of 7 years and 4 months3.
There are other reports of rats that lived up to 5 or 6 years, but these have never been verified4.
A large study conducted on rat longevity looked at thousands of rats and found that the maximum lifespan was 3.8 years (except for one female under caloric restriction, who lived to become 4.6 years old)5. It’s important to keep in mind, though, that these were laboratory rats. Their genetic makeup and the environment they live in differs strongly from pet rats.
Factors Affecting Your Rat’s Lifespan
As we’ve talked about, pet rats in the wild often perish due to predators or food scarcity. These factors thankfully don’t play a role in your pet rat’s life span. So, what is the reason for their short lives?
The most common diseases pet rats are diagnosed with are respiratory tract disease and tumours6.
Respiratory Tract Disease
Respiratory tract disease in rats usually occurs due to pathogens such as Mycoplasma, but environmental factors play a big role in facilitating the disease process7.
In many cases, respiratory tract disease becomes chronic and is frequently accompanied by an audible sound when your rat is breathing (called stridor). If the disease progresses, the rat may develop difficulty breathing.
Tumors
Mammary gland tumors are the most frequent tumors in rats6, but they are generally prone to developing all kinds of benign and malign tumours8.
If the tumors are benign, surgical removal can eliminate the problem altogether. Often, though, neoplasia tends to come back, or new tumors develop.
A tumor by itself does not mean that your rat’s life is over – even without surgical removal, rats can often live many months with their tumors. Euthanasia should be discussed when the tumor becomes so large as to impede movement significantly, or when it becomes ulcerated.
Unfortunately, rats seldom die peacefully of old age.
As they grow older, they can no longer move freely and may not be able to access food or chew it properly, and these may be signs your rat is dying. Waiting for a natural death in this situation can take a long time and causes unnecessary suffering. Therefore, euthanasia by your trusted veterinarian is often required.
Breeding
Another factor that affects your pet rat’s life span is breeding.
Inbreeding increases the chances of tumors and other diseases. But even two genetically identical rats will have different life spans if the environment they are kept in differs.
Which is brings us to what you can do to maximize your rat’s life expectancy…
How To Increase Your Rat’s Lifespan
Of course, you can’t extend your pet rat’s life by years; but by optimizing their environment, you can delay the onset of disease and ageing.
Weight & Diet
The one factor that has been proven time and time again to reduce longevity is obesity. In fact, restricted feeding has been linked to a longer lifespan9 and a decreased incidence of tumours10.
Make sure you choose a pellet food that is made specifically for rats. Enhance your pet rat’s diet with lots of fresh vegetables (daily) and the occasional piece of fruit (the lower in sugar the better – berries are great).
Even for training, stay away from high-sugar treats such as the beloved commercially available yogurt drops. Consider making your own high-protein training treats, for example by cutting a hard-boiled egg into small pieces.
Respiratory Health
Factors that contribute to the onset of respiratory disease are overcrowding (not enough space in the cage), poor ventilation, scented and dusty bedding, increased ammonia level in the cage, humidity and sudden changes of temperature7.
To promote your rats’ airway health, you should therefore keep their cage clean (but steer clear of scented or harsh cleaning products) and ensure proper ventilation without causing drafts. Under no circumstance should you smoke inside the house if you keep pet rats.
Stimulation & Exercise
Studies have shown that an enriched environment increases rats’ life span11. This is great news because it’s so easy to keep your rats stimulated and entertained.
Give them plenty of opportunities to climb, explore, go through tunnels, dig, hide their food, and so on.
Consider teaching your rats tricks and offering them toys to play with, such as wooden balls.
Give them plenty of free-roam time where they can explore a secure area in your home and get some exercise.
Veterinary Care
Better veterinary care and diagnostics has improved pet rats’ life spans all over the world12.
If you can find a veterinarian that is trained specifically in treating rats, you can greatly improve your rat’s chances of surviving any illness they will inevitably develop.
Talk to your vet about optimizing the environment your keep your rats in, and always bring your rats in for a check-up at the first sign of something wrong.
How To Care for Your Older Rat
Even if you do everything right, your rats will inevitably grow older. As they age, their mobility will decline, their balance and coordination will worsen, and they will be less inclined to explore and play11.
Ageing is often accompanied by a reduced muscle mass and total body weight11.
To help your older rats, make sure that their food is easily accessible. All the floors they walk on (in their cage and in their free-roam area) should be grippy.
Older rats may need ramps to access higher areas of the cage. As their memory can suffer13, try not to change around the interior of their cage, and place everything back where it was after you’re done cleaning.
Some senior rats may be bothered by younger rats trying to assert their dominance. If this is the case, you could consider splitting up your mischief into older and younger rats, should this be feasible. Otherwise, try to give the older rats some moments of quiet and peace, maybe by doing a different free-roam time for the young energetic ratties.
When the time comes to say good-bye to your rat, spoil them with some treats and cuddles before bringing them to the vet’s.
Keep in mind that though rats’ lives are short, they tend to live them to the fullest – and they will be more than grateful for the wonderful times they have spent with you!
Resources:
1. An Age: The Animal Ageing and Longevity Database. AnAge Entry for Rattus norvegicus 2017. https://genomics.senescence.info/species/entry.php?species=Rattus_norvegicus.
2. MSD Vet Manual. Mice and Rats as Pets 2021. https://www.msdvetmanual.com/exotic-and-laboratory-animals/rodents/mice-and-rats-as-pets.
3. Guiness World Records. Oldest Rat Ever. https://www.guinnessworldrecords.com/world-records/70885-oldest-rat-ever.
4. Finch CE. Longevity, senescence, and the genome: University of Chicago Press, 1994.
5. Turturro A, Witt WW, Lewis S, et al. Growth curves and survival characteristics of the animals used in the Biomarkers of Aging Program. J Gerontol A Biol Sci Med Sci 1999;54:B492-501. https://pubmed.ncbi.nlm.nih.gov/10619312/.
6. Rey F, Bulliot C, Bertin N, et al. Morbidity and disease management in pet rats: a study of 375 cases. Vet Rec 2015;176:385. https://pubmed.ncbi.nlm.nih.gov/25745083/.
7. Benato L. Respiratory diseases in rats. Companion Animal 2012;17:47-50. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7162205/.
8. Gorbunova V, Seluanov A, Zhang Z, et al. Comparative genetics of longevity and cancer: insights from long-lived rodents. Nature reviews Genetics 2014;15:531-540. https://pubmed.ncbi.nlm.nih.gov/24981598
9. Richardson A, Austad SN, Ikeno Y, et al. Significant life extension by ten percent dietary restriction. Ann N Y Acad Sci 2016;1363:11-17. https://pubmed.ncbi.nlm.nih.gov/26695614/.
10. Tucker MJ. The effect of long-term food restriction on tumours in rodents. Int J Cancer 1979;23:803-807. https://pubmed.ncbi.nlm.nih.gov/468413.
11. Altun M, Bergman E, Edström E, et al. Behavioral impairments of the aging rat. Physiol Behav 2007;92:911-923. https://pubmed.ncbi.nlm.nih.gov/17675121.
12. Dutton M. Selected Veterinary Concerns of Geriatric Rats, Mice, Hamsters, and Gerbils. The veterinary clinics of North America Exotic animal practice 2020;23:525-548. https://pubmed.ncbi.nlm.nih.gov/32409159
13. Fahlström A, Yu Q, Ulfhake B. Behavioral changes in aging female C57BL/6 mice. Neurobiol Aging 2011;32:1868-1880. https://pubmed.ncbi.nlm.nih.gov/20005598.
Nina has a degree from the Veterinary School in Zurich, with a special focus on microbiological research. Nina has a passion for sports, nutrition and the outdoors and she loves all pets, but rats have a special place in her heart. When she’s not working or reading and writing about all things related to pet health, she loves to travel and surf.
As a small animal veterinarian, Nina is your go-to expert on pet health and nutrition.
