The pet rat is a domesticated breed of the brown rat (rattus norvegicus). Rats have been domesticated for over 200 years. Selective breeding of many generations of Norway rats over all those years has produced the domestic rat of today which comes in many different colors and markings. Rats are intelligent, affectionate, clean animals with lots of personality and enjoy spending time with people. They are curious and adventurous. Pet rats – like their ancestors – are very social and should be kept in pairs or more (same sex unless neutered or spayed!).
Rats live in colonies in the wild and therefore should be kept in at least (same sex unless neutered or spayed) pairs as pets. They groom each other, play and sleep (often piled up) together. Since you are part of the rat pack too, don’t be surprised if your rats start grooming you too! They might check your ears, nose, eye brows, lips and teeth. Be proud and enjoy!
Normally, male rats get bigger than females, have coarser fur and can have a slightly “musky” smell (some people describe the smell as warm corn chips). Rats reach puberty at around 5-6 weeks of age, but they reach social maturity at around 5-6 months of age. At this age, male rats in particular start to behave more aggressively toward each other. They shift from harmless play fighting into more serious adult fighting. They establish their hierarchy. This might look scary but don’t interfere unless there are injuries involved. Females have softer fur (sometimes their fur has a pleasant sweet smell). They tend to be more active, hardly sit still and always have places to go. Older rats do calm down, though. Rats don’t see well (especially pink eyed rats). You might see your rat swaying his head from side to focus on an object and to help the rat figure out how far away various objects are. They rely heavily on their nose and whiskers rather than on their eyes. Rats can hear and produce ultrasound. They communicate with each other at frequencies we humans can’t hear. Sometimes you will hear the occasional squeak. As a general rule, audible vocalizations are signs of protest, pain or stress.