Rat wheels: do rats need one, and what size?

Do rats need a wheel?

No, not in the way they need company, space and climbing. PetMD lists a wheel as optional, and plenty of rats never use one. Others run every night. The RSPCA's own list of rat enrichment is tunnels, ropes, hammocks, ladders and shelters, with no wheel in it at all; RSPCA Australia includes a wheel but sets strict rules for one.

What every rat does need is exercise beyond the cage. Humane World for Animals and Burgess both ask for at least an hour of play outside the cage each day, and PetMD gives 30 minutes as the bare minimum. A wheel can top that up but never replaces it.

So the honest answer: offer one if your cage has room for a properly sized wheel, and don't worry if your rats ignore it. Our guide to rat exercise wheels and alternatives goes deeper on choosing between them.

What size wheel does a rat need?

At least 30 cm (12 in) in diameter. Woodgreen calls 12 inches the minimum and says many rats need or prefer larger. Burgess also gives 12 inches, and the MSD Veterinary Manual says 12 to 14 inches (30 to 36 cm). RSPCA Australia doesn't give a number but sets the real test: the rat must be able to run without arching its back into a U-shape.

What makes a wheel safe for rats?

• A solid running surface, with no rungs, mesh or wire (RSPCA Australia, Woodgreen, PetMD).
• A smooth inside, with nothing that can pinch toes (MSD Veterinary Manual).
• No gap between the wheel and its stand where a tail can be caught as it turns.
• A sturdy stand or a firm mount on the cage side, so it doesn't wobble or tip.
• Big enough that the back stays flat.
• Easy to wipe clean; rats often wee while running.
• Quiet bearings if the cage is in a bedroom.

Never use an exercise ball. PetMD warns that rats' toes and feet get caught in them, and a rat inside can't stop, rest or reach water.

How to set up a wheel in a rat cage

1. Measure first. A 30 cm (12 in) wheel needs a little over 30 cm of clear height plus its stand, so check the gap between floor and shelf.
2. Put it low. Stand it on the cage floor or the lowest wide shelf, so a fall from it is short.
3. Fix it firmly. Bolt it to the bars or wedge the stand so it can't rock or walk across the cage.
4. Clear the swing. Keep hammocks, ropes and bowls well out of the way of the turning wheel.
5. Tempt them in. Put a treat inside and turn the wheel slowly with your hand while they watch.
6. Check the back. Watch a few runs. If the spine curves, swap to a bigger wheel.
7. Clean it weekly. Wipe the track with the rest of the cage; a litter tray under the wheel helps.

Wheels we'd look at

Why won't my rat use its wheel?

Most often the wheel is the problem, not the rat. These are the usual reasons, in the order we'd check them:

Better ways for rats to exercise

A wheel is one small part of a rat's day. These give more exercise and use their brains too:

• At least an hour of free-roam time daily in a rat-proofed room or playpen; see our free-roam safety guide.
• A tall cage with several levels, ropes and ladders to climb.
• A dig tray of coco soil or paper strips (Woodgreen).
• Food scattered in bedding or hidden in tubes, so they have to search (RSPCA).
• Cardboard boxes and tubes to explore, shred and rebuild.

Our rat cage setup guide shows how to lay out a cage so it works as a gym.

Rat cages on wheels: are they worth it?

Yes, for big cages. A tall rat cage is heavy and awkward, and castors let you pull it out to clean behind it, sweep up the bedding rats kick out, or roll it to a cooler room in a heatwave, which the RSPCA advises when summer temperatures rise. RSPCA Australia also wants the cage raised off the floor, away from cold and draughts, and a wheeled stand does that.

Two cautions. The castors should lock, so the cage can't drift when rats leap about inside. And keep the cage in one place day to day: the RSPCA says moving it around can be stressful. Use the wheels for cleaning and emergencies, not for wheeling rats from room to room.

Check the bars before anything else. Woodgreen wants no more than 1 cm (0.4 in) between bars, and RSPCA Australia says no more than 2.5 cm (1 in) for adults and less for youngsters. Some wheeled cages sold for rats have bars wider than either, and young rats and small females squeeze through.

For a full comparison of cages, with and without castors, see our guide to the best rat cages, and for everything else, our pet rat care hub and guide to rats as pets.