Why do Pet Mice Fight? How to Stop Them Fighting?

Inevitably, your pet mice might start to fight with each other, especially the adult mice. In a lot of cases, it can be easily prevented. Owners often make several mistakes when keeping the mice at home that can cause them to fight with each other.

Male mice are especially more inclined to fight each other, especially in certain conditions. That’s partly because of their aggressive nature and competitiveness, but also due to living conditions that can trigger the fighting.

Fighting between pet mice can sometimes be less severe. In other cases, it can be more severe and cause serious injuries to the fighting mice, and even death.

That’s why it’s important to know what you can do to prevent the fights in the future, and to prevent the injuries that might happen to your pet mice.

Here, we’ll take a look at the most common reasons for pet mice fights and how to prevent these fights from happening in the future.

5 Most Common Reasons Why Pet Mice Fight

Here’s what you need to know about pet mice fights and why they happen. It’ll give you a better understanding of how to prevent them in the future, too.

Reason #1: Male Mice Will Always Fight

In some cases, you just won’t be able to prevent fights. Boys will be boys, as they say when young men make reckless decisions. The same goes for mice, only that these male mice might start to fight over no particular reason.

Sometimes, it might be due to competitiveness. Some male mice can be very territorial, and will try to protect their area for all costs.

This can spur even more fights, and can cause the male mice to get harmed. To prevent this, it might be better to keep your male mice in separate cages or habitats.

Reason #2: Overcrowded Cage

An overcrowded cage can be one of the leading reasons for mice fights. We can easily prevent this from happening by buying another cage or tank. If the tank is overcrowded, it’s only natural to see more fights in the cage, especially between the male members.

They’ll become far more territorial, as they’ll get intimidated and will start to worry about their personal space. This is often the fault of owners that stick too many mice into a small cage. It’s an easily avoidable issue.

Reason #3: Not Enough Food

Food scarcity is one of the prime reasons for fights. The natural survival instinct will start to kick in, which is a natural reaction that almost every creature in this world would show.

And so will mice, and even the female mice will start to fight for their survival, and the survival of their babies.

If you don’t feed your mice in the cage enough, you will start to see fights over the food. Make sure every mouse gets more than enough food to survive, but keep a balance – don’t overfeed.

Reason #4: New Pet Mouse

If a new player enters the game, there is bound to be some problems. First of all, the pre-existing members of the cage are unlikely to accept the new mouse if you introduce it aggressively.

Secondly, the new mouse will take time to adapt to the new living conditions, and to get acquainted with the mice already in the cage.

That’s why it’s crucial that you gradually introduce the new mice to the cage. Even if the mice were already a part of another cage before, start slowly. Don’t just put the mice in the cage and pray for the best.

Reason #5: Mice will Sometimes Just Play

In some cases, the mice will look like they are fighting, but they are actually just playing around. It’s a common form of playing between the mice, even though it will appear like they are fighting. You’ll notice the distinction between fights and playing quickly.

Playing will be more spontaneous, the mice won’t be as aggressive and won’t try to harm each other. When the real fights kick in, there might be injuries and mice can get harmed.

Learn the difference between fights and playful behavior. Make sure it’s not playing before you act.

Can Pet Mice Kill Each Other?

Some mice fights can turn pretty nasty. Mice can be pretty aggressive in some cases, especially when it comes to survival. That’s why it’s not unusual to see pet mice kill each other if you’re doing something wrong.

In most cases, deaths and fights are easily preventable. If you follow the tips above, you’ll be highly unlikely to experience pet mice deaths due to fights.

But, in case of overcrowded cages, food or water shortages, or other things, the mice can actually kill each other. Prevent this by following the tips in this article.

How to Stop Pet Mice from Fighting?

The good news is that fighting can be easily prevented with a few simple steps. It might take you some money that you’ll invest in another cage or tank, but it’ll be worth it. After all, you don’t want to see your pet mice harmed or even killed because of fights.

Pet mice fights will most commonly occur between two mice males that are stuck in the same cage. Separating them makes sense, which can massively decrease the chance of fights happening.

Do Pet Mice Squeak When Fighting?

When mice fight, they’ll let you know by making squeaking noises and a lot of noise overall. That’s how you can distinguish fights between just playful behavior.

If you notice this, then the mice are most likely fighting, and you’ll have to do something about it.


Pet mice will fight with each other, and there are a few simple reasons for that. Mostly, male mice will start fights, but that’s not exclusive to males.

Females can also start fights, especially if it’s about survival. Shortages of food and resources can encourage fighting, as can close proximity to other mice.

avatar Jane
Jane is an experienced animal care specialist with a focus on rodents and small mammals, with over 10 years of experience in the pet industry. Her articles provide practical guidance on choosing the right pet and managing common health issues. Jane is an advocate for animal welfare and supports organizations dedicated to protecting wildlife. read more...

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