Fancy Rats

So, you want to learn about rats, because you think you might want some as pets. This article is a good place to start. We wanted to write an article giving potential adopters a basic history of how rats started to become pets. But, when we came across the Fancy Rat article on Wikipedia, we decided to not “reinvent the wheel.” Below is an excerpt of that page:

Fancy Rat

The fancy rat (Rattus norvegicus domestica) is the domesticated form of Rattus norvegicus, the brown rat, and the most common species of rat kept as a pet. The name fancy rat derives from the idea of animal fancy (the promotion of domesticated animals) or the phrase “to fancy” (meaning to like or appreciate). Wild-caught specimens that become docile and are bred for many generations still fall under the fancy type.

Fancy rats were originally targets for blood sport in 18th- and 19th-century Europe. Later bred as pets, they now come in a wide variety of coat colors and patterns, and are bred and raised by several rat enthusiast groups around the world. They are sold in pet stores and by breeders. Fancy rats are generally easy to care for provided plenty of research is done and are quite affordable, even compared to other small pets; this is one of their biggest draws. Additionally, they are quite independent, loyal and easily trained. They are considered more intelligent than other domesticated rodents. Healthy fancy rats typically live 2 to 3 years.

Fancy rats are used widely in medical research, as their physiology is very similar to that of humans. When used in this field, they are referred to as laboratory rats (lab rats).

Domesticated rats are physiologically and psychologically different from their wild relatives, and typically pose no more of a health risk than other common pets. For example, domesticated brown rats are not considered a disease threat,[4] although exposure to wild rat populations could introduce pathogens like the bacteria Streptobacillus moniliformis into the home.[5] Fancy rats have different health risks than their wild counterparts, and thus are unlikely to succumb to the same illnesses as wild rats.


The origin of the modern fancy rat begins with the rat-catchers of the 18th and 19th centuries who trapped rats throughout Europe. These rat-catchers would then either kill the rats, or, more likely, sell the rats to be used in blood sport. Rat-baiting was a popular sport until the beginning of the 20th century. It involved filling a pit with several rats and then placing bets on how long it would take a terrier to kill them all. It is believed that both rat-catchers and sportsmen began to keep certain, odd-colored rats during the height of the sport, eventually breeding them and then selling them as pets. The two men thought to have formed the basis of rat fancy are Jack Black, self-proclaimed rat-catcher to Queen Victoria, and Jimmy Shaw, manager of one of the largest sporting public houses in London. These two men are responsible for beginning many of the color varieties present today.[ Black, specifically, was known for taming the “prettier” rats of unusual color, decorating them with ribbons, and selling them as pets.

Rat fancy as a formal, organized hobby began when a woman named Mary Douglas asked for permission to bring her pet rats to an exhibition of the National Mouse Club at the Aylesbury Town Show in England on October 24, 1901. Her black-and-white hooded rat won “Best in Show” and ignited interest in the area. After Douglas’ death in 1921, rat fancy soon began to fall back out of fashion. The original hobby formally lasted from 1912 to 1929 or 1931, as part of the National Mouse and Rat Club, at which point Rat was dropped from the name, returning it to the original National Mouse Club. The hobby was revived in 1976 with the formation of the English National Fancy Rat Society (NFRS). Pet rats are now commonly available in stores and from breeders, and there exist several rat fancier groups worldwide.

Differences from Wild Rats

While domesticated rats are not removed enough from their wild counterparts to justify a distinct subspecies (compare Canis lupus familiaris), there are significant differences that set them apart; the most apparent is coloring. Random color mutations may occur in the wild, but these are rare. Most wild R. norvegicus are a dark brown color, while fancy rats may be anything from white to cinnamon to blue.

Behaviorally, domesticated pet rats are tamer than those in the wild. They are more comfortable around humans and known to seek out their owners while roaming freely. They have decreased reactions to light and sound, are less cautious of new food, and have better tolerance to overcrowding. Domesticated rats are shown to mate earlier, more readily, and for a longer period of time over their lifespan. Also, domesticated rats exhibit different behaviors when fighting with each other; while wild rats almost always flee a lost battle, caged rats spend protracted amounts of time in a belly-up or boxing position. These behavioral traits are thought to be products of environment as opposed to genetics. However, it is also theorized that there are certain underlying biological reasons for why some members of a wild species are more receptive to domestication than others, and that these differences are then passed down to offspring (compare Domesticated silver fox).

The body structure of domesticated rats differs from that of a wild rat as well. The body of a fancy rat is smaller, with larger ears and a longer tail than that of its undomesticated counterpart. They are generally smaller with sharper facial features as well.

Domesticated rats have a longer lifespan than that of wild rats. Because domesticated rats are protected from predators and have ready access to food, water, shelter, and medical care, their average lifespan is around two to three years, in contrast to wild R. norvegicus which average a lifespan of less than one year. However, wild rats generally have larger brains, hearts, livers, kidneys, and adrenal glands than laboratory rats. The fancy rat and wild rat also both face a multitude of differing health concerns; the former is at risk of developing a pneumococcal infection from exposure to humans, while the latter may harbor tapeworms after coming in contact with carriers like cockroaches and fleas.

Social Behavior

Generally speaking, rats are quite sociable and function best with at least one cage mate. It is generally ill-advised to keep a single rat unless there are severe behavioral problems. The earlier rats are introduced to one another, the better. Often, rat breeders will encourage new owners to take two or more rats of the same sex from the same litter for starters.

Particularly with males, there can be some fighting in the beginning, but once an alpha rat has been determined, the rats should get along well. Within two weeks to a month, the rats will most likely have adjusted and become friendlier with each other. Rats are generally very friendly to other cage mates. They will even sometimes help or take care of other sick rats.

Generally when two or more rats from the same litter are of the same sex, they live together with no disruptions but with the occasional friendly tussle and play fight. It is possible to integrate rats from different litters. This process can vary in difficulty, often measures have to be taken to provide security for both rats. Techniques for integration include bringing them to neutral ground so they do not become territorial. The process of integrating is easiest with two rats of young age, generally less than six months old. The process of integrating is most difficult with two or more adult male rats, as adult males are the least likely to accept new cage mates, especially after an alpha has been established. Unless there is an issue integrating rats together, owners should always keep them in a group of at least three, as rats live in packs and a pack starts with three animals.

Source: Wikipedia

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