Fancy rat

The fancy rat is a domesticated brown rat, which is the most common type of pet rat.

Varieties

As in other pet species, a variety of colours, coat types, and other features that do not appear in the wild have either been developed, or have appeared spontaneously. Any individual rat may be defined one or more ways by its colour, coat, marking, and non-standard body type. This allows for very specific classifications such as a ruby-eyed cinnamon rex berkshire dumbo.

Colouring

While some pet rats retain the "agouti" colouring of the wild brown rat (three tones on the same hair), others may be black based colours (a single colour on each hair). Agouti based colours include agouti, cinnamon, and fawn. Black based colours include black, beige, and chocolate. Additionally, eye-colour is considered a subset of colouring, and coat-colour definitions often include standards for the eyes as many genes which control eye colour will also affect the coat colour. The American Fancy Rat and Mouse Association (AFRMA), a United States-based club, lists black, pink, ruby, and odd-eyed (two different types) as possible eye-colours depending on the variety of rat shown. Ruby refers to eyes which normally appear black, but are shown to be red under bright light. Colour names can vary for more vague varieties, like lilac and fawn,while the interpretations of standards can fluctuate between and even within different countries or clubs.

Ethics of selective breeding

There is controversy among rat fanciers in regards to selective breeding. On one hand, breeding rats to conform to a specific standard or to develop a new one is a large part of what the hobby was founded on. On the other hand, the process results in many rats who do not conform and are then either given away, sold as food, or killed—referred to as culling. Additionally, there are concerns as to whether or not breeding hairless and tailless rats is ethical. The tail is vital for rats' balance and for adjusting body temperature. Tailless rats have greater risk of heat exhaustion, poor bowel and bladder control, falling from heights, and can be at risk for life-threatening deformities in the pelvic region like hind leg paralysis and megacolon. Similarly, hairless rats are less protected from scratches and the cold without their coat. Groups such as the NFRS prohibit the showing of these varieties at their events and forbid advertisement through affiliated services.

Risks to owners

Keeping rats as pets can come with the stigma that rats transmit dangerous diseases to their owners. One fear is that all rats carry plague, when in fact R. norvegicus is not among the list of species considered a threat. In 2004, an outbreak of salmonella in the United States was connected to people who owned pet rats, however it has been determined that a pet rat's initial exposure to salmonella, along with many other zoonotic rat-diseases, typically indicates exposure to wild rodent populations, either from an infestation in the owner's home, or from the pet's contaminated food, water, or bedding. The pet rat is exposed to a wild rat with disease or contaminated products, and then passes that disease along to its owner.