Did you know that gerbils need sand baths and "sing" when they are happy? That wet-tail in hamsters isn't a disease, it's a symptom of many diseases that must be diagnosed by your vet to make it go away? Or that rats need a diet low in protein and need special diets very different from that of hamsters? That chinchillas can be stressed to the point of death if their daytime sleep is interruped too frequently?
The first and most important step in welcoming any new pet is learning how to care for his or her species. Rodents aren't little dogs and cats--they have special needs far beyond what a pet store clerk can tell you in a conversation. Check out our care sheets, then choose a few books from the reading lists to study what you'll need to know to be a responsible guardian. There are great books on the care of Chinchillas, Gerbils, Hamsters, and many more.
Websites are helpful, but books are key. Check out our website links to check out some sites that can point you in the right direction.