Pet Mice and Pet Rats: Can They Live Together?

In some peoples’ minds, rats and mice are kind of the same thing, but they are completely different animals! Both are rodents. The type of mice and rats that people keep as pets are called “fancy mice” and “fancy rats.” Yes, that is really their species name.

Fancy mice are domesticated house mice. Fancy rats are domesticated brown rats. The term fancy doesn’t come from the meaning of formal, but more from the meaning of “to fancy” something. People that have mice and rats as pets certain tend to fancy these endearing rodents!

Can Pet Rats and Mice Live Together?

Both rats and mice are social creatures and would be the happiest living with another member of their own species. Mice should only live with mice and rats should only live with rats. In fact, you may consider only keeping one type of these rodents in your house, even if you have separate cages for them.

Rats are much larger than mice. Pet mice are usually between two and three inches long and weigh up to 1.5 ounces. Pet rats are between eight and 10 inches long and weigh up to a pound. Not only are rats larger than mice, but they are also very territorial. They often compete with mice for the same resources, so they instinctually kill mice, and sometimes even eat them. In captivity, these instincts do not usually go away. Mice are scared of rats and won’t live a very happy life around them. Rats will try to hunt and kill the mice if they have the chance.

If you do decide to keep mice and rats in the same household but in separate cages, keep the cages very far from each other, preferably in different rooms. Never let out both your rats and your mice at the same time to avoid any gory accidents.

How to Socialize Your Pet Rats and Mice

Rats and mice do enjoy living with other members of their species. Multiple males sharing the same cage may fight unless they were introduced at a very young age. You may also want to separate mice and rats by gender. Otherwise, you may end up with a surprise litter of rat or mice babies!

Can Any Pet Rodents Live Together?

It isn’t recommended for any pet rodents to stay together in the same cage. In nature, different types of rodents do not cohabitate. They don’t usually get along in captivity.

Differences and Similarities Between Pet Rats and Pet Mice

Besides their size, there are other differences between these two animals.

• Lifespan: Pet mice live for between 18 and 30 months. Pet rats live for up to three years.
• Gestation: Pet mice pregnancies last for 19-21 days. Pet rat pregnancies last for 21-23 days.
• Sexual Maturity: Pet mice reach sexual maturity at 4-7 weeks old. Male pet rats reach sexual maturity at 10-12 weeks old. Female pet rats reach sexual maturity at 8-9 weeks old.
• Litter sizes: Pet mice give birth to between 4 and 12 babies. Pet rats birth between 8 and 18 “pups”.
• Diet: Both pet rats and mice are omnivores. However, in the wild, mice eat mostly plants. In captivity, mice require some commercial pet food and some fresh fruits and veggies. Avoid giving mice lettuce because it can give them diarrhea. Rats also require commercial rat food plus fresh fruits, vegetables, grains, cooked eggs, and seeds.
• Foragers: Both mice and rats are foragers. They may enjoy having their food scattered all around their cage or having it in a large bowl so they can handle it with their paws. Rats especially enjoy nibbling food while holding it.
• Poop-eating: Yes, you read that right. Many rodents, including both rats and mice, eat their fresh poop. It helps them to get all the nutrients they require. Don’t stop this behavior even though you may find it gross!

How to House Your Pet Rats

Rats need to live in a rat cage. They are small and cages prevent them from getting out and getting into trouble. The cage needs three layers of bedding. A soft underlayer to protect the cage from poop and urine, litter to absorb excrements, and a top layer of nesting materials so your rat can have a cozy bed.

The bottom layer can be made of shredded paper, cardboard, coconut husks, or hemp. The middle layer is just litter, and the top layer can be anything. Rats may enjoy making their own by shredding a roll of toilet paper. You can also provide them with newspaper shreds or fleece fabric cut into strips to make their beds out of.

Some people use wood shavings for rat bedding, but these are not the best. Some may have chemicals that cause health issues in rats, and they are also very dusty and can get messy.

How to House a Pet Mouse

Pet mice can live in cages specifically designed for mice, but since they are so small, you must make sure they can’t slip through the cage. Some people house their pet mice in an aquarium with a mesh grate on top to allow for airflow. Similar to rats, mice need a bottom “substrate” layer of material in their cages, and then a top layer of bedding to make it cozy.

Both mice and rats need toys to keep them entertained. Popular options include a wheel for running, tree branches, toilet paper tubes, and other household objects that you can turn into a fun game for a rat.

Can Mice and Rats Go Outside of Their Cage?

Rats need at least an hour per day outside of their cage to live their happiest and most fulfilling life. Mice don’t necessarily need time outside of their cage but they may enjoy it. Because mice are so small it may be more dangerous to let them out. They can easily slip through small cracks in walls or go under furniture and become lost.

Rats are bigger so you still have to be vigilant, but there is less of a chance of escape. Even so, make sure to close windows, block the bottom of the door if there are any gaps, and make sure wires are protected so your rat doesn’t bite through them. As always, don’t let pet mice and pet rats roam outside of their cages at the same time.

The photo featured at the top of this post is © Sergey Bezgodov/Shutterstock.com