Before you invest any time, money and potential heartache on any pet you must ask yourself a few questions ahead of time. When considering a rat as a pet you should make an effort to understand the social behavior of the species as well as what the animal will require as far as care is concerned. So before you run off to the breeder or pet store, here are a few things to consider.
Are you will to buy more than one rat? Rats are very intelligent and social animals. Since it is impossible for you to devote all of your time to you new pet, getting more than one will provide your rat with the social structure he will need to be happy and healthy.
Do you have time to keep the enclosure clean? It is preferable to remove waste from the rat's cage at least once a day, in addition to a thorough cleaning once a week. And a periodic complete cage bleaching can be beneficial as well.
Do you have time to play? Since rats are very active and social animals they will require a minimum of one hour of "playtime" daily to keep him happy with his home. An unhappy rat is more likely to develop health problems, so playtime is essential. Whether you're busy, feeling ill, or just not in the mood, socializing with your rat will still need to be done.
Do you have the resources to take a sick rat to the vet? This is not usually a problem; rats are generally very hardy and robust creatures. Most of the time they will require little to no medical care, but if they do, can you afford it?
Can you provide a safe, large living space? 2 or more cubic feet of space is the absolute minimum for an adequate amount of room (double for a pair of rats). Of course, the bigger the better. Bigger cages also allow more modifications to be made to keep the environment stimulating for your rat.
Once you're sure that you can provide a good home for a rat, its time to find the right one for you. The first obstacle here is whether to choose a boy or a girl. From personal experience, and from other opinions I have heard, boys tend to be more laid-back and less active. Whereas females tend to be more active, intelligent, and curious. If this rat will belong to a small child, a gentler male would probably be the better choice. The male rat would be more tolerant of a rowdy child; a female might get agitated more easily. Also keep in mind that males tend to mark their territory. So if this is concerns you either get a female or only allow the male rat to play on a towel of sheet to protect your carpet and furniture.
Once you get to the breeder or pet store, be ready to interact with a few rats to find the one that gets along with you the best. Some rats will be more outgoing than others, talk slowly and softly and leave you hand in the cage for a few minutes; a few rats should seek you out and sniff you. Once a few rats have shown interest in you, have the breeder or store employee take one or two out of the cage for you. Let them crawl around on you a bit and see how they interact with you. You don't want a rat that is scared, intimidated, or aggressive toward you in any way. The rat should not bite you, no matter how cute he may be, a biter will only cause you more problems in the end. It is a normal fear reaction for a rat to defecate on you, once their used to your presence this should no longer be a problem. It's normal for the rat to become comfortable with you and crawl all over you in a few minutes. If after a few minutes he is still cowering, you may want to consider getting a more curious and out-going rat.
Most importantly, choose a rat that you know you can be happy taking are of for a few years. The natural life span for a pet rat is 2-3 years. You and your pet can have a wonderful relationship in that time, and I have no doubt that once you get the first there will be others. Rats are truly remarkable little critters that can have a lasting bond with their humans.