Do Mice Have Bladders? (Dispelling the Myth)

Do mice have bladders? Is it one of the many mice myths that they do not have a bladder?

It’s not as strange a question as you might think. I’ve heard people say this before but seeing as they are mammals it didn’t really make sense.

While researching this I found numerous sources that think mice, and other rodents, don’t have bladders. Mainly due to the fact that they urinate a lot and often.

I can tell you without a doubt however that mice do in fact have bladders.

Mice urinate as a form of communication and marking their territories like a lot of animals do.

So, it can look like they have no control over their bladders, or don’t have a bladder, but they do. Aligned with standard mammal anatomy.

Why Do Mice Constantly Urinate?

As I mentioned above, mice urinate to mark their territory with their scent. This turns out to be peeing quite often to keep their scent up, and in all honesty is one of the downsides to owning mice as pets.

This is why you have to clean out their cage and change their bedding once a week at least.

Their pee doesn’t smell too bad or strong when it’s new or for a week on so in their cage.

But if you leave it too long it will start to smell, and you’ll get that whiff of ammonia and turn your nose up for sure.

Male mice urine smells a lot stronger than females. There will also be a hierarchy formed within a group of mice, and the dominant mouse will do most of the marking (source).

Here are some answers to other questions I’ve heard related to this topic:

Do Mice Pee When They Run?

Yes! Mice can pee while they are running. You might even see long lines of pee as an indication that you have mice in a certain area of your home.

What Does Mouse Urine Look like on Carpet?

I don’t know how to explain it any better than it looks like a small wet patch on a carpet.

Another tell-tale sign that it’s mice pee is that there will almost certainly be some droppings/poop nearby.

Mice poop a lot as well as pee’ing a lot. I’ve covered how to identify mice droppings before, as well as other signs to look out for if you think you have mice in your home.

Is Mouse Urine Harmful to Humans?

Mouse urine is potentially dangerous to your health. Always take care when cleaning mouse urine and droppings and do so as soon as you see any.