10 Pet Rat Facts to Keep in Mind When Caring for Rats

by Alison Blyth
10 Pet Rat Facts

Rats aren’t just adorable and engaging pets. They are also genuinely amazing creatures and the more we know about them, the better we can look after them. Here are 10 things I’ve learnt in nearly 20 years of rat care.

1. Rats can get lonely and depressed

Many people think mental illnesses and even emotional states are unique to humans, but they happen in animals too. They are not exactly the same as in people, and we should be cautious with talking about them using human terms – but the disruption to the animal’s quality of life is real.

In rats, these problems are most often seen when a rat is suddenly left alone by the death of a cage mate. The rat can:

  • become subdued in their behaviors,
  • show stress responses such as barbering their arms, and
  • in extreme cases, they can stop eating.

The good news is that I’ve yet to meet a case that can’t be cured by introducing new friends. Sometimes it can take some time and effort in finding the right friend, sometimes a rat might need neutering, but for rats having friends to snuggle up to is a healing thing. In fact…

2. Rats really need companionship

Pet rats need companionship

In nature, Rattus norvegicus (the species our fancy rats belong to) live in large family groups. They are naturally social animals and they use behavioral cues from their friends to understand whether a situation is safe, or whether a food can be eaten. The latter is why the food belonging to another rat is always the most interesting – that bit of food is proven safe and yummy, and therefore is the best food around.

Rats, just like many people, also get comfort and companionship from having others around. Put two rats in a slightly scary situation (like a car trip to the vet for the first time) and they’ll snuggle up together for reassurance. It’s so routine that I actually use car trips as a bonding technique during intros – it’s hard to stay hostile towards someone you’ve used as a security blanket!

Keeping rats alone is possible, but it is very rarely in their best interests. Read more in our post “Can Rats Live Alone?“.

3. Rats are prone to respiratory infections

Rattus norvegicus as a species are very tough. However, as pets they can be surprisingly prone to ill-health. Part of the problem is that in many commercial breeders and rodent farms they are bred for looks rather than health.

The most common illnesses are respiratory infections, often caused by mycoplasma bacteria. All rats carry this bacteria from birth and most of the time it causes no problems. However, if a rat is under stress

  • due to another illness,
  • a change in living conditions,
  • a shock due to a sudden change in temperature

then the infection can flare-up, and treatment with antibiotics may be needed.

Respiratory infections are also made more likely by poor cage hygiene or ventilation as the ammonia from urine irritates the lining of the lungs. Similarly, rats shouldn’t be exposed to cigarette smoke or scented products as it can hurt their respiratory systems.

4. Rats produce red “snot” when ill or stressed

It’s actually not real snot. Rats have glands around their nose and eyes that produce a red substance called porphyrin. All rats produce a bit, but normally you won’t see it as they clean it up straight away. However more is produced when a rat is unwell or very stressed.

If a rat has visible red staining round their eyes or nose then it is a good indication that something is wrong. It could be a minor irritation, or a sign they feel very ill, so it is best to examine them closely, think about their other behavior or if anything else is “off”, and if in doubt, have them checked by a vet.

5. Rat incisors grow throughout their lives

Rats have two types of teeth. At the back are molars and pre-molars that they use to crush food. These teeth grow when they are young and then stay in the mouth for life.

However, at the front of the mouth are their famous incisors. These have a hard layer of orange enamel on the front and softer dentine on the back, which gives the teeth a chisel shape. The enamel is so hard that rats can gnaw through plastic, wood, aluminium, and sometimes even through cement.

These incisors never stop growing. Rats wear them down and keep them in good condition by grinding the top and bottom teeth against each other. If they didn’t do this, then the teeth would grow by inches each year.

It is important to keep a close watch on your rats’ teeth as if they become misaligned, the teeth can’t grind down properly, and can overgrow, causing damage to the rat’s mouth.

6. Rats grind their teeth to show happiness or stress

Rats have to grind their teeth to keep them healthy, but they also do it to communicate. The noise of a rat grinding its teeth together is called bruxing. If they do it really vigorously, then the movement of their jaw muscles causes their eyes to wobble in and out! This is called boggling. Miss F, a one eyed rat I owned a few years ago could boggle even in the absence of an eyeball!

Bruxing is usually a sign of happiness in rats. They do it when they are relaxed and enjoying something – you’ll often see both bruxing and boggling while cuddling and stroking your rats.

However, because rats brux when happy, they also sometimes do it to comfort themselves when unhappy or feeling ill. That makes it important to look at the rest of your rat’s behavior while bruxing. Are they relaxed or are they sitting tense or huddled? Are they doing it during something they enjoy like being stroked, or is it during a stressful event, like driving to the vet when they are sick? Getting to know your rats well can help understand their behavior.

7. Rats use their tails as a fifth limb

Rats use their tails as a fifth limb

One of the least popular features of rats is their long scaley tail – to the extent that some breeders have tried breeding tailless rats.

However, to the rat, their tail is an absolutely essential part of their body. It is as important to them as a limb is to us.

  • They use it to balance when they climb, whipping it from side to side or wrapping it partly around things.
  • As it doesn’t have thick fur, it is used to regulate their temperature, giving out heat when they are too hot.
  • Tails are also used for communication with the way a rat holds it indicating whether they are relaxed, hostile, about to attack etc.

8. Rats can live to be over 4 years old – but usually don’t

The oldest fancy rat I’ve ever owned lived to be just over 4 years old. The oldest of my wild-born Rattus rattus lived to be around 4 and a half. There are reports of rats living to be 5 or in one case, even 7.

However, most pet rats are viewed as “old” if they live to be two. Why is that?

As with their susceptibility to respiratory infections it probably comes down to the influence of poor breeding, which makes rats more likely to develop potentially fatal illnesses; and poor husbandry, such as feeding unhealthy foods, not providing an environment where rats can be active, and not taking animals to the vet early enough when they first get ill.

I’m not suggesting it’s an individual owner’s fault if their animal dies young – I’ve been there myself – rather that as a community we could be doing more, both in the breeding of our animals and in popular standards of care to promote practices that will help maximize their life-spans.

9. Rats can breed at 5-6 weeks old

Rats breed like… well, rats. Males and females both become fertile at around 5 weeks old, and females can become pregnant again immediately after giving birth. That’s one of the reasons rats have become so successful as wild animals that we call them pests.

It also means that in pet homes we have to make sure they can’t reproduce, otherwise we’ll end up with a lot of rats very quickly. If boys and girls are kept in the same home then either one sex should be neutered (I neuter all my boys), or care needs to be taken that sexes are housed apart, and can’t come into contact during free-range. Supervision is not enough – rats can mate far quicker than we can move to stop it.

10. Male rats shouldn’t eat citrus or mango

Rats are omnivores, which means they can eat an enormous range of foods (although can doesn’t mean should – high fat and sugar foods and processed meats that are unhealthy for people are unhealthy for rats too). However, as well as toxic foods like green potatoes that neither humans nor rats should eat, there are a couple of things to be careful of in male rats.

Citrus fruits and mango contain a compound called d-limonene. This doesn’t seem to cause any problems in female rats but has been implicated as a cause of kidney problems and cancer in males. How big a risk is it? We don’t really know.

Personally, I prefer to err on the side of caution as there are so many yummy foods we can feed our rats, so missing a couple out does no harm. You can learn more about the foods rats can eat in our post about a healthy rat diet.

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