Does can be introduced at any age. Introduce new rats on neutral territory, and if there is no serious fighting, put them in a clean cage containing hiding places for each animal. Rats love coming out of their cage to play and explore their environment, but they are not usually compatible with other small rodents, cats, dogs or birds. Rats also tend to gnaw things and so should not be allowed out without close supervision. Rats enjoy crawling over their owners and exploring pockets, and will not usually bite unless mishandled or hurt.
Rats live to around two years of age.
It should be easy to clean, and should be cleaned out once or twice a week. Cages should be kept out of direct sunlight and draughts, as sudden changes in temperature can cause health problems. Untreated wood shavings and hay or shredded paper make suitable bedding. In the UK, wood shavings are of spruce. Rats are very clean animals and will spend a lot of time washing and grooming their coats.