Introducing Your Cat To Your New Rats.
As many pet owners know,
introducing a new pet to one who's lived alone for a while is tough, but it can be done. With patience, love, treats, and careful teachings, your pets will be playing together in no time.
Do not attempt this if you are not completely comfortable with taking action if the animals decide to fight. It is a cat's natural instinct to attack a small rodent and a small rodent's natural instinct to defend itself.
Let's Get Started
Disclaimer: Please bear in mind that every animal is different. Some animals, like my cat (Fernando) and my rats (Cordelia and Annabelle) will manage to get along. While others, like my mothers late dog (Levi) and any other dog would simply fight at every encounter. DO NOT under any circumstances force any animals to "get along". This will only cause stress between the animals, which will worsen any problems you come across.
I understand that a rat is not an ideal playmate for a cat of any age, but if you're going to own both of them in one household, there's no harm in attempting to introduce them to each other, so long as you know what you are doing.
Set up the rat cage. (CAGE, not tank. Rats are extremely susceptible to respiratory infections, having them in a tank will increase their chances of coming down with one.) Find a place high enough that no small children / animals can reach it, but low enough that you can monitor what you new pets are doing. Make sure the cage isn't on a ledge or shelf where it would easily fall when the rats play / tumble around. Keep in mind that rats are intelligent creatures who love to explore their surroundings, so make sure that you don't have anything you don't want them chewing near the cage. (They will pull anything that can fit through the bars into the cage.)
Bring your new fur babies home and introduce them to their new cage. After the rats have become acquainted with their cage, take them out and get acquainted with them yourself. While you're playing with the new babies, allow your cat to sniff around the cage. Let him / her poke around the outside of the cage as well as sniff a few of their toys.
Once everyone's had a nice 'sniff all the things' moment, allow the animals to sniff each other. (PLEASE make sure everyone is in a good mood first. An irritated cat is more likely to lash out and attack its new potential playmates, and vice versa.) Take your new rat and hold him / her out in front of the cat while softly speaking something like "Wanna meet your new friend?", "Be nice.", "Play nice now.", ect. Make sure you have enough control over the situation to get the smaller animals to safety if anyone decides it's snack time. If everything went well, no one nipped / bit at anyone else, hand out a small treat to the animals. This will encourage them to get along.
Continue step 3 every day until you feel comfortable with letting the rats run around freely around the cat. Of course, you need to keep in mind that that cat does have natural instincts to prey on small rodents... so you'll have to monitor every action when they're playing together, taking care to reprimand everyone for nipping / biting / clawing / ect. You should have a happy fur family in no time!