Rat cage setup for happy rats

First things first, rats are highly intelligent and cannot live in small and/or boring cages and thrive.

The absolute minimum for a rat cage is 90/60 and 120 in height (if anything is sacrificed, it should be the height rather than the floor space).

Cages of this size or bigger:

Smaller cages do not allow for enough enrichment, neither for a normal rat behavior.

The optimal space between the bars is around 1 cm. It can be up to 1.5 cm for adult males, or 0.8 mm - 1 cm for the babies.

While fleece covers might look pretty, they are not the best option to use instead of a substrate. Rats require a deep (at least 10 cm, but the deeper, the better) layer of safe substrate to dig and forage.

Hemp
It is absorbent, great for digging, has a pleasant natural smell. Keeps a cage from smelling for quite a while, especially when the layer is thick. It is not too dusty, but I prefer to
A small downside is that it easily gets out of the cage, cause it is lightweight.

Non-aspen hardwood (alder, beech – except for red) chips can be an addition to the main substrate, but they are pretty hard on rats’ feetsies when used alone.

Aspen bedding is widely used for rats and it has a look and feel of hemp more than anything else, but it doesn’t have the same natural smell. Aspen can be a good option, but it greatly depends on quality of a particular brand, as some are very dusty. There’re dust-extracted products, which are an amazing option.

Cardboard is loved by some and hated by others. Cardboard could be a nice addition for another type of substrate for variety of textures, but it can get smelly. The good thing is that it isn’t dusty at all. I use it for my girls sleeping box, it gets wet fast, cause they love peeing on it, so I change it daily.

Paper bedding is not recommended as the main substrate due to its low ability to hold ammonia. It gets smelly very fast. Depending on the brand, many paper-based substrates are dusty. But it can be used in particular places in the cage, if it is changed every day (or in a dig box).

Kiln-dried pinewood is also used widely, it’s affordable and considered safe (kiln-drying is the process that is supposed to release the phenols that would otherwise cause harm for rats’ respiratory organs). The safety of this type of bedding is still debated in rat community, so you’d need to make a choice for yourself.

Corn is not the best option as it can be contaminated with mold. Mycotoxins are extremely damaging to rat health. Corn also has extremely high absorbency, so much so that it can dry the air in the cage. Rats are sensitive to the level of humidity, if the air is too dry, it can cause respiratory problems.

Cedar is toxic to rats and other small animals due to phenols.

Pine is toxic as well (unless kiln-dried).

Bioactive setup is currently pretty popular in the rat community. This, I believe, is the case for two reasons:

• it is supposed to be self-cleaning (in practice, many people report that they are not able to achieve the point where the substrate never needs to be at least partly changed);
• rats absolutely love it.

The substrate itself is a mix of coconut coir, fiber and chips. What makes it bioactive is the addition of CUC (clean-up crew). CUC is a name for tiny bugs that eat all the stuff that would make the substrate smelly or unsafe for rats, like mold, decaying organic matter, etc. The most popular choice is springtails, but some people use isopods. There’s a slight difference in the dietary preferences of these creatures.

The substrate must be kept slightly damp at all times, otherwise it gets very dusty.

There’re downsides to using this type of setup, such as, for example, it can attract other insects. Fungus gnats are huge fans of moist soil, for one. They are small and pretty harmless, but it is not pleasant to have an infestation.

Fleece covers have one or a few absorbent layers inside. The fleece layer is supposed to wick liquids away from the surface and into the absorbent layer. In practice, even then the fleece has a good ability to wick the urine, the smell will still be there and it gets worse pretty fast too. At the same time, some covers are simply not good at it and the urine sits on top of the cover, allowing rats to walk on it. Fleece covers get chewed.

I believe that fleece covers have its place, some people choose to cover ramps or shelves. If changed regularly (ideally, daily), it is an option. The downsides are that most owners go through these covers fast due to them being chewed and washing them so often is not really an eco-friendly option, because you do need a long cycle to get all the smell out.

Fleece covers are great for rats after surgeries, they help to keep dust and small particles from the bedding from getting into the stitch. Another option would be a Vetbed. It has a great ability to wick the urine away and keeps a rat warm and cozy, but does require to be changed often. I would recommend to change it twice a day for a rat in recovery after a surgery.

Rats needs to have opportunities to do lots of things in their cage: forage, dig, run, climb, gnaw, jump, problem-solve and, of course, rest and sleep comfortably. That’s why a good cage is a busy cage. Let’s explore the types of things one would need to get for their rat’s enclosure.

Rats are in their foraging mode almost all the time and things in the cage must support it. Other than a deep layer of substrate and scatter-feeding, lots of foraging toys will help to support and encourage their natural behavior. Hiding food in different locations throughout the cage stimulates rats to move around and explore.

While rats should always have appropriate substrate that allows digging, it’s a good idea to have a few options with different materials. For example, cardboard or coconut coir. Any box can be used for cardboard or paper, but only water resistant for the coir (or coconut chips) as it needs to be slightly damp (otherwise it’s dusty).
Digging box for coconut fiber should have a lid with big wholes for access, without a lid the coir will get thrown out of the box. The coir should have CUC (like springtails) and rat-friendly herbs can be planted there. Without a CUC damp coconut coir is going to get moldy.
New springtails will need to be added regularly, cause the urine from rats doesn’t create the best environment for them. But partial substitution of the coir with additional springtails will help to maintain freshness.
The box should be monitored for anything moldy. If the cage allows it, it can be there at all times, but if it takes too much space, it can be taken in and out. Or just used during free-roaming time.

Rats need enough space to be able to run around. A great way to keep the space free and at the same time provide even more space for running is hiding a long tunnel under the substrate. It will require regular cleaning, because rats will pee there, but it’s very fun for them and is worth it.

Climbing is natural for rats and they are quite good at it. To provide many opportunities for climbing – use thick ropes. The ropes for rats must be from natural materials, the best options are:

• jute
• sisal

Cotton ropes are sometimes used as well but require caution, because it is not safe for rats to chew on things with long threads.

Ropes are perfect for rat cage setup. They provide opportunity for balancing. They also can partly serve as fall-breakers (but you will need to get the actual fall-breakers too, as falls from height are extremely dangerous to rats.

You will find lots of ropes in parrot sections in the stores.

Gnawing is necessary for rats and many other rodents because their teeth never stop growing. If rats don’t get the appropriate items to gnaw on, they will find something themselves and can even start biting the cage bars. It’s important to fill the cage with safe wooden sticks and gnawing toys, so they have a choice (all rats have preferences about what they like most).

Safe wood for gnawing (small branches without sharp tips, cleaned, dried well):

• Apple
• Arbutus
• Blackberry
• Black currant
• Cork oak
• Artichoke (topinambur)
• Willow
• Grapewine
• Crab-apple
• Bamboo
• Coconut shell
• Aspen
• Hardy kiwi
• Pear
• Hazel
• Hawthorn
• Cottonwood
• Mulberry
• Beech
• Dogwood
• Ash
• Lilac
• Rowan
• Whitebeam
• Sugar and silver maple (others are not safe)
• Magnolia
• Pecan
• Poplar
• Alder (BUT red is not safe)
• Linden
• Rose hip

For making a nest rats require materials like shredded paper, kitchen towels, toilet paper or/and shredded cardboard. These will get peed on, so require to be changed often, preferably – daily.

For nesting rats will use:

• sputniks
• hammocks
• tunnels
• igloos
• cardboard boxes

All of which should be provided for them to have a choice.

Many rats will enjoy filling their own nests, so you can provide them with kitchen paper towels and cardboard.

Fall-breakers are a must in any rat cage. Falls from height can be extremely dangerous for rats.

Let’s quickly go through mistakes a rat parent could make:

• inappropriate cage (not enough floor space or height, too wide bar spaces);
• mesh shelves (can lead to trauma or bumble foot);
• too many shelves (prevents activity and climbing, takes space that could have been used for enrichment);
• fleece instead of substrate;
• not enough enriching “clutter”; empty cage;
• only one water-source;
• changing water less than daily;
• no changes in the cage (rats are highly intelligent and thrive in interesting environment, they need to experience something new often);
• lack of fall-breakers (can lead to dangerous falls).