Hamsters are popular pets, but there’s a lot to learn before bringing one home.

If you’re considering more than one hamster, be aware that two males or two females housed together may fight over territory. On the other hand, a male and a female are likely to mate and have babies.

A hamster’s diet should be mostly commercial hamster food, but a bit of fresh greens, fruit, veggies or nuts is fine now and then. Hamsters also need safe materials to chew on to help keep their teeth from overgrowing.

Hamster balls are a great way for these little guys to get exercise. Wheels can work too, but they need to be the right size—not too large for hamsters and not so small that a hamster has to overarch its back to run.

Just like other pets, hamsters need routine wellness exams. That’s a good time to ask about nail and teeth trims, too.