PART 1 - CHOOSING YOUR RAT
You need to decide first off whether you want them to breed or not. If you don't want them breeding then you need to choose only one sex. Either male or female. Both genders typically get along well with each other, but there is always a hierarchy. One rat will be dominant. They will "battle" for dominance, but it is almost never true violence. They tend to wrestle or box more. Once you decide on your sex, decide how many you want. Rats are social animals and will not survive alone. I highly recommend a minimum of 4 rats. The more rats you get the better their health will be. Both physically, and mentally. They need the companionship of other rats to survive. DO NOT GET YOUR RATS FROM A PET STORE THAT SELLS THEM AS FEEDER RATS! Those rats are typically sick and not cared for at all. Get your rats from a reputable breeder. They are pet rats that will survive more than a few days and act as pets should.

PART 2 - RAT BEHAVIOR AND MENTALITY
As said already there will always be a hierarchy. Dominance will often be challenged and you will see your rats battling it out. But just because they are chasing each other and wrestling doesn't mean mutiny. They are very playful animals. They romp and run just like children. They are actually quite entertaining to watch. They are also extremely smart animals. They remember like an elephant. If you mistreat them they remember it and will not trust you. If you are kind to them they will like you better.

They love to explore. New surroundings mean new places to see. But unless you buy a rat ball, or a rat pen, this is not a good idea to let them do. A full grown rat can squeeze through a hole the size of a quarter. Once they do that, they are most likely gone for good.

Rats are nesters. They need a lot of material to build a nest. In the wild a colony can have up to 100 rats that are constantly maintaining the colonies nest.

They sleep a lot. They burn a lot of energy when they are playing, and tend to wear themselves out fairly quickly. It's not good for their health to try to play with them when they are trying to sleep. Wait until they wake up on their own.

Typically rats don't bite or claw, unless they feel threatened. If you don't present yourself as a threat you will do fine, but you do need to present yourself as the dominant one. If they feel that they are dominant over you, you will never be able to handle them. Some rats do bite. They might have been mistreated previously and are afraid. It's all down to the individual rat's personality. They can be a*****es just like people can.

Rats will however, give you a very light nibble from time to time. This is what's known as a rat kiss. It's the same as when a dog licks you. It's a sign of affection, and nothing to be afraid of. They will also take a hold of your finger with their paws frequently. This means that they want your attention. If they do that, it's a sign that they love you.

PART 3 - RAT HOUSING
There are many types of housing choices for rats. You can get what are called "rat cities", which tend to run $200-$300 typically. These are what I personally use. Or you can get a simple wire cage or aquarium. If you go with any kind of wired cage make sure the bars are no more than ½ inch apart. If they are more than that, the rats will escape. I recommend an aquarium for beginners, because rats are extremely skilled escape artists. Depending on the number of rats you get would determine the minimum size of aquarium you need. It would be best to base it by rat. A typical aquarium for example is 20 gallon. With 4 rats, that's 5 gallons of space per rat. That's a decent base to start. I would highly recommend going bigger, but aquariums can be extremely expensive, so your budget may not allow it. Also try to get an aquarium with more floor space than height, so they have a bigger area to run around on.

You will need to have a very secure way of keeping their habitat secure so they don't get out and run all over. Clips on an aquarium lid work well. The clips can slide off when you need to open it, but can be difficult to get off. So you may have to slip something under the clip top to lift it such as a screwdriver or a heavy blade knife. Doing this however, can bend the clips out of shape and render them useless. So it would be best to work at sliding them off instead.

Rats need something to chew and gnaw on. They have a natural instinct to chew, and their teeth grow continuously through their entire life, never stopping growing. So they need a way to grind it down. If they don't have something steady to chew on, they will start chewing on each other. They will go after the weakest link in the chain. Then you'll lose one of your babies. The best thing is an edible shelter. A good brand is SnakShak. But those can be hard to find, even at high end pet stores like Petsmart. Other good ones are Ediblogz, which can be found at just about any Walmart and run about $6 a piece. It doesn't have to be anything super fancy, but you need something that would stand up to however many rats you get for a bit of time while they chew it up. If it doesn't last at least a little while, you will be spending a lot of money replacing them.

Rats need exercise. Just romping in their home doesn't do it. You need to get them a wheel. Or two if you prefer. These are great for letting them run to their hearts content and keep them in shape.

The type of bedding you choose matters a lot. There are a lot of bedding's you will see at your pet store. You will see everything from wood chips, to pebbles, to sawdust, to paper. For rats, get the paper. Wood chips are dangerous for rodents. They can get splinters, or pieces of wood stuck in their teeth, which can cause a lot of problems. The pebbles would also cause health problems since you can't just clean out the pebbles and put new ones in when you clean their cage. And if they were to eat them, it would kill them. The healthiest for them, and your wallet is the paper.

If you go with a wire cage, you need to put something soft on the bottom so they're not on wires all the time. A fleece blanket or sweatshirt is perfect. They will move it around to where they want it, and they will tear it apart, so you will need to replace it once it gets super torn up. I always keep a couple extra sweatshirts and fleece blankets on hand for my rats.

PART 4 - RAT NUTRITION
You need to get the right food for rats. Also you need to make sure it's age appropriate. There are many types of rodent food to choose from. But just because it's good for a mouse or a guinea pig, does not mean it's good for a rat. They have a different metabolism than other rodents, and need a food that is specifically formulated for them. I feed my rats Oxbow pellets. The pellets you buy will be enough, but I highly recommend giving them fresh fruits and vegetables with the pellets. Nothing canned or cooked. Stay away from soft fruits and vegetables such as tomatoes and grapes, or citrus fruits. They need something they can crunch and chew. Carrots, lettuce, and cabbage are good choices for vegetables. Apples, watermelon, or cantaloupe would be good choices for fruits. Make sure though, that you remove the seeds first, especially with the apples. Apple seeds contain cyanide, and while not lethal to humans in small doses, rats are more susceptible to the poison due to their size. Also they could choke on fruit seeds. You need to get them a food dish that is safe for them and that will hold enough food for them so that you don't have to refill it several times daily. Ceramic is an excellent choice. They eat a lot, so be prepared to be spending a good amount of money on food.

DO NOT EVER FEED THEM ONIONS OR ANYTHING CONTAINING ONION. ONIONS ARE LETHAL TO RATS WITHIN MINUTES.

Also be aware that you can over feed your rats. Over feeding can cause a lot of problems. Obesity, diabetes, and breathing problems just to name a few. So watch how much you feed them, and make sure they have a balanced diet.

You need to get water bottles that will survive their chewing. Plastic will have to be replaced regularly, unless they can be mounted on the outside of their cage. You can buy glass chew proof bottles. They are a few dollars more expensive, but will save you a lot of money in the long run. If you go with smaller bottles you will need at least one bottle per rat. If you go with larger bottles you won't need quite as many. Take for example a cage with 4 rats. With large bottles, I would need 2. For larger numbers dividing by 2 would be a bit impractical. For example if you had 10 rats, 5 large bottles would be a bit overkill.

You will need to wash their food dish at least once every few days. Rats don't try to aim any specific direction when they have to go, unless they're marking territory. So they will go in their food dish.

PART 5 - CAGE MAINTENANCE
When you clean their cage, don't just scoop the bedding out and put new bedding in. You have to get all the feces out, and wash not only the bottom, but the sides with soap and water. When rats pee, they tend to spray. This is how they mark their territory, the same as dogs. You will have it on every surface in your rats cage if you're using an aquarium. After washing it you need to make sure you get all the soap cleaned out of the cage before you replace the bedding and put the rats back in. Soap residue can make them sick if they lick it up. And scented soaps can be attractive to them. Don't use cleaners such as Windex or Pledge. Just use simple soap and water.

If you're using an aquarium, you need to check it periodically to make sure there are no breaks in it. If it gets cracked it will need to be replaced. They can easily crack it further which will allow them to have a way out, and also hurt themselves on the broken glass at the same time.

If you want, you can get a small heating pad to put under the cage. A small one would be enough. You don't want anything big, or extremely powerful, as if it's too hot, they can burn their feet. So I would recommend against it, but if it has a low heat setting that is VERY lukewarm, you can try it. Just remember to keep a close watch if you do.

PART 6 - RAT HEALTH AND LONGEVITY
Rats are very clean animals. If you watch them you will see them cleaning and grooming themselves quite a bit. But rats can also carry a lot of health problems if they're not cared for properly. They can have organ problems, bone problems, respiratory problems, or emotional problems. The symptoms range from small things such as mood changes, to self harm, to violence toward you and other rats. You just need to keep an eye on them to make sure everything is going good for them. You need to keep not only their cage clean but the area around them. Remember germs can jump.

Rats don't have the lifespan of animals such as dogs who live on average 12-15 years. Rats typically live between 2-3 years depending on the breed. So technically they don't live long, but they love hard.

PART 7 - MISCELLANEOUS
Contrary to what many will tell you, rats are very high maintenance. Their home has to be cleaned regularly, their food has to be specifically for rats, their water has to be clean, their home has to be sufficiently supplied for them to maintain their mental health, they have to be kept out of stressful situations, and above all they have to be loved. If you get rats and then lose interest in them, then that is cruel to them, because they will no longer be taken care of properly. You have to give them attention and love. Just because they live in a cage or aquarium doesn't mean they don't need you.

It will hurt when you lose them, the same as any of your other companions. But your life will be that much richer for having had them. They will always love you if you love them.