Many species of rodents are social animals, social meaning that they should be housed in pairs or groups. In the wild, social animals would live in large family groups, therefore, keeping them in pairs or groups in captivity gives them more natural, happy lives. Some species of social animals includes:

1. Mice (Though some males may fight after reaching adulthood, but there are things that their humans can do to help encourage them to live together happily)

2. Rats

3. Dwarf Hamsters

4. Gerbils

5. Chinchillas

6. Cavies (Guinea Pigs)

7. Degus

8. Jirds

Syrian hamsters are NOT social animals, they are solitary animals, and that means that they should NEVER be housed with other hamsters. The two hamsters will never get along. It doesn't matter if they are brothers, it doesn't matter how much space they have, they can never be housed together after the age of eight weeks, because this is the age that their solitary instincts starts to kick in. In the wild, hamsters live alone in burrow systems that they dig and never interact with other hamsters except for when mating.

When buying a social pet, it's always best to buy them a cage mate (or cage mates) at the time you buy them, and preferably a relative. (Two sisters or two brothers, or a mother and daughter, etc.) There are ways that you can introduce some animals, but it can be rather difficult so it's always best to buy them a cage mate from the same cage they lived in at the breeder, pet store, or wherever you buy them.

Male Mice

It's a common argument amongst mice fanciers whether male mice should be housed together or not. Though most people will agree that their humans should do all that they can to encourage the mice to live together happily.

In order to make it comfortable for insanely territorial male mice to live together it's best to give the mice as much space as you possibly can. A tank or cage at least 2 ft long and 1ft wide is best for groups of 2-6 male mice. But remember, that's the just the MINIMUM, a bigger tank or cage would always be better!

Another thing you can do is give them each their own nest box. (Plastic houses, tissue boxes, shoeboxes, etc) Example: If there are five mice living together, give them five nest boxes, this way they can each claim their own territory if they wish to.

Give them lots of toys. More than one wheel in the cage usually helps settle fights over the wheel. Lots of tubes (Toilet paper tubes work wonderfully), and lots of other things to play with and hide in helps keep them busy and prevent fights.

Usually males CAN live together if given a big cage, their own private "rooms" and lots of toys. ALL mice are extremely social animals, not just females. Therefore every measure should be taken to let them have a friend to live with.