Why Do Pet Mice Poop So Much?


Many first-time mouse owners are shocked to see so much poop in their pet mouse’s cage. So, they tend to wonder if something is wrong with their new pet.

Mice poop so much because they eat a lot of food for their size. Mouse owners also tend to overfeed them, due to which they become overweight. Overweight, pregnant or lactating mice eat far more food than usual, and hence poop a lot more as well.

The Reason Mice Poop so much

Mice have a high metabolic rate, so they need to eat a lot more food in proportion to their body weight. Since mice eat a lot of plant matter, they poop more as well.

Mice also use their urine and faeces to mark their territories.

Adult mice poop anywhere between 0.25 gram to 1 gram per day, which is about 1% of their body weight. How much pet mice eat and poop also depends on where they are in the life cycle. A very young mouse can transition into an adult within weeks, so we don’t realise that it needs more food now.

Changes in a mouse’s body take place very fast. Consider the fact that their entire lifespan is about 2 years. They are born, spend some days drinking their mother’s milk, transition to eating solid food, grow older, breed and continue growing into their old age – all in about 2 years!.

Also, a pregnant or lactating mouse will eat a lot more food than usual, and consequently poop a lot more as well.

How Much Food Do Mice Eat?

Mice eat about 3 grams of food daily, which is about 10% – 15% of their body weight. They eat this amount little by little, nibbling on the food 10 to 15 times per day. They also tend to store some of the food within nooks and crannies around their enclosures.

Caring for an Overweight Mouse

Mice are prone to getting overweight. You need to keep an eye on your mice. You can use a kitchen weighing scale to measure your mice periodically, say once a week.

Take the weight before feeding them anything in the morning. If you take the weight after they have eaten, the scale won’t show the correct weight.

If your mice are overweight, stop feeding them seeds (especially Sunflower seeds). Seeds are very high in fat and will make your mice fat in no time.

Change the mouse’s diet. Swap the seed or grain mix for pellets or a mix that has lots of vegetables.

You need to ensure that your mice are getting plenty of exercise. They need a mouse wheel (or two) in their enclosures. You can also scatter their food in the cage so that they need to forage for it, just like kin the wild.

How to Control the Bad Smell in Mice Enclosures

The nasty smell that mice are infamous for comes from their urine. Given their massive appetites, mice pee and poop a lot.

Add that to the fact that they are social creatures and need to be kept in small groups; the problem of smell becomes magnified.

However, it is possible to control this odour. Keep in mind that there will always be a faint smell near the mice enclosure. But we can take steps to stop the smell from becoming overpowering.

We can replace the enclosure with a bigger one. There will be more space for bedding, which will absorb more urine and its smell. You can also use the extra space to place more litter trays for your pet mice.

Replace dirty bedding at least once a day. If you have many mice or the smell is still unbearable, you may need to replace it twice daily. Faeces don’t matter so much while controlling odour. You just need to remove any wet bedding, since urine is the main culprit here.

Mice may use the same spot as the toilet frequently, which will make cleaning a lot easier. If this is the case, consider placing a mouse or rat litter tray in that spot. It is possible to litter train some mice, as we shall see below.

Mouse enclosures need to be thoroughly cleaned once a week. If there are too many mice in a small enclosure, it will need to be cleaned twice a week.

Remove the mice from the cage. You can place them in another temporary enclosure or tub from where they cannot escape.

Wash the cage with warm water and dishwashing liquid. Be sure to give it a thorough rinse, as we don’t want any soap to be left on the cage. Then dry the cage using a specially designated towel.

Then, replace any cardboard or destructible toys and used bedding. Now the mice can be returned to their homes.

How to Litter Train Mice

It is a good idea to litter train mice. If they always poop everywhere in their enclosure, it can be hard to determine how much they are pooping.

The litter box should be shallow and heavy enough to not be tipped over by the mice. Small litter boxes for corners are also available and will help save space.

If your mice have already picked a spot in the cage where they frequently pee and poop, that is the best place to keep the litter tray.

Place some litter in the litter box, along with some of the mice’s poop and bedding that is soiled with pee. Mice tend to visit the same spots again and again.

So they will smell the toilet inside the litter box and will realise that they are supposed to go there. When you notice them using the litter tray, give them a little treat – a small fruit piece of a piece of seed. Now, you shouldn’t expect mice to use the litter tray every single time. But if they go there even half of the time, it will save you time and effort while cleaning the enclosure. And they will also pee around in the enclosure to mark their territory.

Syed Baseeruddin Hyder

I’ve been keeping fish and invertebrates in aquariums for over 5 years. Over the years, I’ve kept more than 15 different species of fish and invertebrates. Through ParadiseInATank.com, I hope to guide new and experienced fish keepers alike with as detailed information as I can get.

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