Are Your Mice Fighting? (Reasons, Signs & Solutions)

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If you have pet mice at home, it might be challenging to find out if they are playing or fighting. 

Mice can fight each other for different reasons. For example, they can fight each other after starting to play.

Like humans, they can fight because of territory, mates, power, etc. 

In this article, I’ll go into detail about why mice do usually fight and how to handle them. Let’s continue reading below.

4  Reasons Why Your Mice Are Fighting Each Other

Mice Are Territorial

Mice are highly territorial animals. This means that they fight to protect their space. 

The urge to protect their territory is powerful in male mice. They will fight with others to ensure the safety of their family and space.

When two males who are not related are kept in a cage, this could cause a problem. 

Males are more aggressive than females. In male mice fighting, you may not be able to prevent it as they will always fight.

Male mice prefer to have less competition in their group. Male children and male mice can live together peacefully as there is no competition involved. 

Not Enough Living Space

Not having enough cage space might be another cause for your mice to enter a fight.  Mice need a lot of space for entertainment. So, an overcrowded cell will cause your mice to fight among themselves.

As said before, mice are territorial and will do anything to protect their nest.  Putting several mice together means the males and females are going to fight to claim the space. 

Just like humans, mice, too, need their personal space, and if they don’t get it, they will feel suffocated. It is in their instinct to fight if there are too many mice in a cage.

Not Enough Food

Lack of food can also make mice fight each other for food. Food security is one of the biggest reasons why your mice can be seen fighting. 

Their survival instinct will kick in whenever you feed them if the food is not enough. Every living creature needs food to survive, and pet mice are no different. 

But even though wild mice can look for food, caged mice cannot. Your mice can react to this food shortage by attacking their cage mates.

Female mice start most fights over food as they are prone to be very protective. 

The female mice will look for food for themselves and their babies. Unable to pick enough food, they will attack others instinctively.

Too many mice in a cage with insufficient to a small amount of food can cause severe problems in the colony. 

The mice can become wounded, and the babies can be harmed. This is a serious issue to be dealt with by the caregiver.

Introducing New Mice to the Cage

Getting new mice to be settled in the cage with the old ones is bound to cause problems. With the older members, the existing colony will not accept the new addition. 

However, you can follow the tips given below to make it happen.

  • Ensure that the cage is spacious enough. There will be fewer fights if there is enough space for new mice.
  • Make sure you keep enough food inside the cage. It will stop the fight that takes place because of the lack of food.
  • You should always introduce more females to the group. Keeping too many male mice together can lead to fights. 
  • Give your mice some time to accept each other. In the meantime, observe their behavior and gestures. 

However, there are some cons of introducing new mice to the cage.

The mice would want to throw the new mice out and may fight to the death over claiming the cage. The new mice may also take time to adjust to the new living conditions. 

Even if the older mice accept them, the newer ones can fight to claim power.

Power is a factor in the mice world, and they will hurt each other to claim dominance. 

If you put new mice in a cage full of mice and pray that they will get well with each other, it won’t happen.

Signs That Your Mice Are Fighting (and Not Playing!)

Below are the 4 visible signs indicating that your mice are not playing but fighting.

Hair Fluffing

Like cats and dogs, when mice fight each other, their hair will stand on end. The hair will start getting fluffed on every part of the body. 

This is one of the first and most obvious signs that the mice are getting into a fight. However, hair fluffing is difficult to notice in groomed mice as they tend to have longer-looking hair.

Tail Rattling 

Mice ready to fight will flutter their tails side to side. This behavior is also very identical to cats and dogs. 

The rapid tail wagging is like a warning signal to the other participant of this fight.


Before a fight, the mice circle around or near the other mouse. 

The mice also take short steps toward the opponent with its body hunched upward. 

It is also seen as a warning behavior used to scare others away.

The Actual Attack

When mice fight, they bite each other a lot, along with scratches. The mice will wrestle rapidly, and some can show signs of running away.

If one of the mice runs away while fighting, the other will chase after the runaway. When the mice chase and positively catch up, they bite and scratch, wounding the other.

He will run away again from the victorious mouse when one is wounded or beaten. If the cage has sheltered spaces or hiding spaces, it will go into hiding. 

While fighting, mice make a shrill squeak sound and stand on their hind legs.

Keeping Mice from Fighting (What To Do)

It is really easy to keep your mice away from fighting. You just need to be extra cautious, that’s all.  Below are the 3 primary ways to ensure your mice’s safety.

Provide Enough Shelter

Keeping your mice crowded in a single enclosure causes a major problem. To avoid mice fighting over territory and personal space, keep mice separated and in lower numbers. 

The cage provided should have enough room for the number of mice you want to house. The cage should also be spacious enough for them to play.

Mice like to build a nest for themselves, hiding spaces, and playing areas. Ensure your cage fits all of these, including the feeding area. 

You should provide them with an additional feeding area and personal space to enjoy their treats.

Enough Supply of Food and Water

Providing enough food and water is a must for every pet. They will keep fighting unless you provide your mice with enough food and water. 

But at the same time, you should be careful not to overfeed them.

The well-fed mice are happy and will only engage in friendly fights. 

Food and water play a big role if the cage has young ones. The mothers of the cage will fight with others to get enough food for their children.

Keeping Male Mice In Different Cages 

Keeping males together is a big no in the case of having mice as pets. Male mice are highly territorial, and keeping them together in a cage calls for problems. 

Even keeping two male mice together can be a huge risk. It would be best if you pair male mice with male babies. Male mice see no competition in the children and hence will not attack.


Why Are My Female Mice Fighting?

Female mice are less aggressive than male mice. They only seem violent when they have babies. In the case of babies, they become super protective. 

They will prevent other females from getting closer. The female mice also fight to get food and shelter for their baby. 

Hence, the only time they fight is when they’re with babies. When the babies grow up, the females do not feel the need to protect them.

Why Are My Male Mice Fighting?

Male mice can fight over anything because they are territorial and aggressive in nature. 

They will also fight when they feel they need to establish order. The male mice want to control and claim everything. So it is essential to separate the males as much as possible. 

Why Do Wild Mice Fight?

The territorial behavior is more evident in the wild mice. The wild mice will kill each other when they need to claim territories. 

Wild mice also tend to fight a lot in the mating seasons. They fight to attract the attention of the female as well as to reduce their competition.


When you have pet mice, it might seem like a lot of work to figure out if they are fighting. But all you need to do is to understand the behavior of your mice. 

Mice are territorial creatures. They will fight if you put all of them in a single cage. This is one of the most common reasons they fight. They also fight if there is not enough personal space, food, and water. 

There are several reasons to detect mice fighting, like mincing, tail-wagging, and fluffed-up hair. 

To ensure their safety, you should put male mice separately. Enough supply of food and water and a large housing will also ensure fewer fights among your pet mice. 

Wait, does that mean mice can’t live in groups, or else they will fight? Read Do Mice Live Together? to find out!

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