How Long Do Pet Rats Live? 11 Tips to Extend Your Rat Lifespan

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Rat Lifespan – What Do We Know?

It is generally agreed that most wild rats will not reach their first birthday! This means that most wild rats die from predation, food shortages, and human control while they are still young and fit.

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Rat Lifespan – What Do We Know?

Pet rat life expectancy is better, and the average lifespan is around 2 years, though some rats will live to see their third birthday. However, you’ll notice that claims for longevity vary greatly.

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Rat Lifespan – What Do We Know?

The Guinness Book of World Records (1995 edition) puts Rodney the rat – who lived to be 7 years and 4 months – as the oldest verified rat. To put this in context, the oldest verified dog was 29 years and 5 months, while the average dog’s lifespan is around 11 years.

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Rat Lifespan – What Do We Know?

We also know that humans tend to have difficulty accurately recalling when events (like getting a pet) happen. This is called the telescoping effect.

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Rat Lifespan – What Do We Know?

That feeling of “knowing somebody forever” comes into play and it is common to find owners overestimating how long they have had a pet.

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1. Sourcing Your Rats Carefully (Minimizing Genetic Factors)

Genetic factors can be anything from the predisposition to illness, to poor immune system health. These issues mean the rat is more likely to end up with a life-shortening illness. In rare cases, obesity can also be down to genes, for example, in the Zucker strain.

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1. Sourcing Your Rats Carefully (Minimizing Genetic Factors)

More often the predisposition to put on weight is driven by changes to fat metabolism that occur when a juvenile rat is overfed. However, underfeeding and lack of protein during pregnancy and the first 8 weeks of life can also lead to an increased risk of early kidney failure and a shorter lifespan.

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1. Sourcing Your Rats Carefully (Minimizing Genetic Factors)

Choosing to buy rats from a well-informed, ethical breeder, who feeds a good diet but doesn’t overfeed, will mean that your rats are less likely to come to you with these issues. A good breeder will always breed from healthy parents, who are selected for the health and lifespan of their ancestors.

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1. Sourcing Your Rats Carefully (Minimizing Genetic Factors)

Of course, it’s always possible to hit lucky and buy rats with a strong genetic predisposition from a feeder bin or pet store, it’s just more of a lottery and one that may cause you great heartache.

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1. Sourcing Your Rats Carefully (Minimizing Genetic Factors)

There are other benefits to finding a great breeder, not least that they will have handled the babies from birth and provided them with an active and stimulating habitat, maybe even a wheel. We will come on to see why these things are helpful in promoting longevity in the following sections.

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2. Providing an Open and Active Habitat

Rats who are raised in an open and active set up, with the opportunity to engage in natural behavior such as climbing, balancing, foraging, and digging are not only set up for active adulthood but are also less likely to experience stress as babies.

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2. Providing an Open and Active Habitat

However, regardless of their upbringing, if you keep your rats in an active and open set up in a barred cage they are more likely to remain fit and active well into old age.

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2. Providing an Open and Active Habitat

Rats suffer from a number of conditions that can lead to hind leg weakness as they age, but the fitter they are and the more that is expected of them physically, the longer they can remain active once this problem occurs.

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2. Providing an Open and Active Habitat

Fitness – and particularly foraging for scattered food (rather than bowl feeding) – can help to maintain a normal weight throughout life. Since obesity is linked to shortened lifespan in rats, these practices can help increase longevity.

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3. Feeding a Range of Fruit and Vegetables

Like humans, rats have a need for antioxidants in the diet to reduce the inflammation and cellular damage associated with normal aging. The best way to give your rats antioxidants is by feeding a daily portion of nutrient-rich vegetables and fruit.

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3. Feeding a Range of Fruit and Vegetables

Antioxidants in your rat’s fresh vegetables and fruit end up in their bloodstream and circulate around the body, mopping up free radicals and reducing oxidative stress. Chronic oxidative stress is linked to many disease processes and aging.

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3. Feeding a Range of Fruit and Vegetables

Make sure the fruit and vegetables that you choose are nutrient-dense, like berries, kiwi, nectarine, kale, dandelion greens, broccoli, carrot, red bell pepper, and beetroot. This way your rats are getting vitamins and minerals as well as antioxidants.

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4. Restricted Feeding With Some Fast Periods

One of the easiest, most effective aids to longevity that we can provide for our rats is restricted feeding. By this, we mean not having a bowl of food available to graze on throughout the 24 hour period. The opposite of feeding adlib.

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4. Restricted Feeding With Some Fast Periods

Rats, like humans, benefit greatly in terms of health and longevity from having fasting periods. One way of achieving this is to feed once a day and only feed the amount that will keep your individual group of rats at a fit lean weight.

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4. Restricted Feeding With Some Fast Periods

Try starting off with 15g of dry food plus about a tablespoon of fresh veg and berries per rat. Then tweak the volume depending on whether your rats look like they are a perfect weight or not. Intermittent fasting has been shown to significantly extend lifespan in rats

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5. Maintaining a Good Weight for Size

The adult weight of most rats – and whether or not they struggle with weight gain – is usually determined by how they are fed as youngsters. The following quote is taken from a study into dietary patterns that extend lifespan in rats:

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5. Maintaining a Good Weight for Size

“In general, an early adult death age is associated with a high food intake prior to adulthood particularly when coupled with a high efficiency of food utilization during the post-puberty period, a rapid growth rate and early attainment of mature weight. Deviations from this pattern serve to increase the duration of life of the individual.”

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5. Maintaining a Good Weight for Size

Source: Dietary habits and the prediction of life span of rats: a prospective test MH Ross, ED Lustbader, and G Bras. American Journal of Clinical Nutrition, Vol 41, 1332-1344

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5. Maintaining a Good Weight for Size

Put simply, rats should not be fed to their maximum capacity for growth. Adlib feeding encourages rats to eat as much as they want and grow rapidly to their adult size. Any intervention that slows their growth down – without negatively affecting their well-being is a good thing.

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5. Maintaining a Good Weight for Size

Obesity is frequently seen in rats, and those who are fed more as youngsters are often predisposed to weight gain as adults. This is because the feeding patterns of juveniles can actually alter fat metabolism for life.

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5. Maintaining a Good Weight for Size

Neutering also increases the obesity risk unless the intake of food is restricted. Obesity can negatively affect almost every system in the rat’s body and is linked to several illnesses that affect our rats:

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5. Maintaining a Good Weight for Size

• Mammary tumor • Kidney failure • Stroke • Ovarian disease • Fatty liver • Cancer

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5. Maintaining a Good Weight for Size

Being overweight can also affect the progression rate of the symptoms of other diseases, like the hind leg degeneration that occurs with kidney failure, demyelination disease, and osteoarthritis.

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5. Maintaining a Good Weight for Size

Keeping your rats at a good lean weight for size is one of the best things you can do in maintaining their health and lifespan. This is most easily achieved by a combination of: • a low-fat diet • scatter feeding • periods without food • plenty of exercises

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6. Wheel Running

The use of a wheel is controversial in some rat communities, but all potential issues are addressed by the size of the wheel (a 16-inch diameter is ideal). Wheel running has been shown to extend average lifespan in rats

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6. Wheel Running

To avoid spinal issues and tail curling, stay away from small wheels. A wheel needs to be big enough for the rat to run or bound in a normal horizontal position. For most rats, this is at least 16 inches.

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6. Wheel Running

Because of their rapid metabolism, exercise and activity can have a big impact on maintaining a rat’s healthy weight. A large running wheel and a tall barred cage that encourages climbing are two ways to achieve this.

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7. Veterinary Access and Expertise

Over the past two decades, as more people have started keeping rats as pets, the number of veterinarians with experience of treating rats has grown too. This has led to many new treatment protocols with a variety of medications that are not necessarily licensed for rats.

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7. Veterinary Access and Expertise

In some countries, rats are lumped together with exotic pets and specialists tend to be trained in exotics. Elsewhere, vets have come to specialize by learning on the job, through personal interest or because they service areas where rats are popular pets.

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7. Veterinary Access and Expertise

Finding an excellent rat vet can be key to helping your rat live a long life, as many rat ailments can now be treated with surgery or medication. If you don’t know where to begin looking for a good rat vet, try finding local recommendations online.

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8. Freedom From Environmental Toxins

There are a number of environmental toxins that are known to have the potential to shorten a rat’s life. These include cigarette smoke, phenols from untreated pine and cedar, and ammonia from the breakdown of urine over time.

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8. Freedom From Environmental Toxins

Rats should be kept in a smoke-free environment and if you smoke indoors they will need to be in a separate room with the door closed. Exposure to smoke regularly can cause respiratory problems and even tumors.

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8. Freedom From Environmental Toxins

Phenols are easy to avoid as you just need to purchase paper, card, hemp, aspen or kiln-dried pine products for use in your rats’ cage. Exposure to phenols can cause raised liver enzymes and tumors.

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8. Freedom From Environmental Toxins

Ammonia build-up can be avoided by changing the cage litter and bedding before any ammonia smell develops. How often you need to do this will depend on which litter you have chosen to use. Ammonia can cause inflammation of the airways leading to respiratory symptoms.

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9. Freedom From Severe Stressors

Rats, like all animals, suffer from stress as a response to fearful, uncertain or challenging circumstances. Biologically, the rat’s stress response is the same as ours. Understanding this can help us to understand why stress can shorten their natural lives.

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9. Freedom From Severe Stressors

While small, infrequent, day to day stresses (like a sudden noise) that come and go quickly can actually help to make a rat more resilient, prolonged or severe stress has been found to lead to symptoms that are similar to what humans describe as depression and PTSD.

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9. Freedom From Severe Stressors

Significant stressors are things like moving from home to home, changes in cage groupings, social stress (bickering, bullying and dominance struggles), illness, overcrowding, the death of a bonded cage mate or loss of a significant human (such as the main carer heading off to college or university).

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9. Freedom From Severe Stressors

Research has shown that social stress creates a stronger stress response in rats than negative experimental techniques such as immobilization and electric shocks. Never underestimate the impact of an unsettled cage group on the most vulnerable rats.

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10. Adequate Undisturbed Sleep

Chronic lack of adequate rest and undisturbed sleep is known to shorten a rat’s lifespan. It’s important to make sure that your rat has a dark, quiet sleeping area, where they can rest undisturbed by any sudden noise and harsh light.

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10. Adequate Undisturbed Sleep

Remember rats do about two-thirds of their sleeping during daylight hours and spend more time awake overnight. A cozy bed that screens out some light and a quiet environment for at least some of the day are essential for deep sleep and longterm well-being.

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11. Connection and Enrichment

Rats are social creatures and we would expect there to be health benefits from housing them in social groups. Research suggests that both positive social groupings and positive human handling (connection) can cause changes in the rat’s cells that reduce the rate of aging.

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11. Connection and Enrichment

Social connection is important to rats and those who are more isolated have been found to experience chronic stress, which can shorten lifespan. So connection and social enrichment can prolong a rat’s life by more than one mechanism.

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11. Connection and Enrichment

Positive noise stimulation (such as background higher-pitched classical music) has also been found to significantly reduce stress levels in rats. I am not aware of a musical study that has looked at lifespan, but many have looked at stress – and reducing lifelong stress would be likely to extend life.

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11. Connection and Enrichment

One study in mice did look at the lifelong impact of enrichment noise (in this instance, rain forest recordings) and found a positive impact on lifespan in the group exposed to the noise at around 20 kHz, which is the peak frequency that rats hear – but outside of the range of most humans.

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