Fancy rats are a domesticated form of the brown rat, Rattus norvegicus also know as the Norwegian rat or Wharf rat. Breeding for the fancy began in 18th century Europe and has its origins in rat-baiting. More unusually coloured rats were spared from this horific fate and began to be bred and sold as pets. In the time since a wide variety of colours and coat types have been selectively bred. Dumbo rats are just Fancy rats with different ear placement, and can still be kept with normal, top-ear rats.
An adult Fancy rat averages around 9-11 inches long including tail with a weight of 350-450g for a female (doe) and 450-650g for a male (buck). The average lifespan is 2-3 years although they are sadly prone to a variety of ailments. Although they do tend to be demonized, there are in fact no associated health problems with keeping rats providing they are from an ethical source.
Fancy rats, like Fancy Mice are very social. Unlike male mice however, male rats can be kept quite happily together. Female rats tend to enjoy climbing and are more energetic, playful and 'pingy' than males. Male rats can be more affectionate towards their owners, some being perfectly happy to be shoulder rats known colloquially as a 'squish'.
Although your rats should enjoy human interaction and need a period of time to free-range each day, this cannot substitute for company of another rat. Young rats of under 12 weeks can be introduced to each other quite easily, but older rats can also be introduced. This needs to be done on neutral territory, see Further Reading for guides.
Rats do not need a complicated diet, although like many of the more common rodents they do require a more varied diet than just a simple commercial mix. Good rodent rescues can advise of diet and many rat breeders mix their own in bulk and so may be prepared to supply some of this for you. See Fancy rats - Diet for more information.
Rats cannot be kept in an aquarium due to the lack of ventilation, and must be kept in a large, barred cage. See details on Fancy rats - Environment.