This is a big NO. Pet rats are intelligent creatures that make fantastic companions, but you need to think twice before keeping cats and rats together as pets. Cats can frighten a cat even though they were brought together from birth. If you have to, keep an eagle eye. 'Accidents' can happen as rats are too small.
The good news is, cats are rats repellent. The mere presence of a cat can scare the rats away. A rat looking for a new 'room to rent' will avoid a home that has a residence feline. You should consider one if you live in an area infested with rodents. Rats are know to carry more than 30 different diseases dangerous to humans. If they don't make you sick, they will steal food and will also chew throughh cables. This will expose you fire and leaks.
However, if your cat does get into a fist fight with wild rats, do take it to your vet especially if there is any bites or scratches. Neglected cuts can kill.
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