Editing Fancy rat (section)

== Varieties ==
{{For|varieties bred as lab animals|Laboratory rat#Stocks and strains}}{{For|other rat varieties|List of rat varieties (disambiguation){{!}}List of rat varieties}}<!--

Before changing COLOUR to COLOR please refer to WP:ENGVAR. The fancy rat originated in England, so it is fitting to keep British spellings in this article.

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[[File:Americanblue.jpg|thumb|left|The American Blue is one of several standardized coat colors]]
As in other pet species, a variety of colors, [[Coat (animal)|coat]] types, and other features that do not appear in the wild have either been [[Selective breeding|developed]], or have appeared spontaneously. Fancy rats in themselves are a subspecies and as such do not have distinctive breeds. Any individual rat may be defined one or more ways by its color, coat, marking, and non-standard body type. This allows for very specific classifications such as a ruby-eyed cinnamon Berkshire rex Dumbo.<ref name="MMratdoc">{{cite episode|title=Rats|url=http://www.tv.com/modern-marvels/rats/episode/1195778/summary.html?tag=episode_tabs;overview|series=[[Modern Marvels]]|credits=Writer: Kaylan Eggert Narrator: Max Raphael|network=History Channel|url-status=dead|access-date=2009-02-09|archive-date=2009-08-18|archive-url=https://web.archive.org/web/20090818074746/http://www.tv.com/modern-marvels/rats/episode/1195778/summary.html?tag=episode_tabs;overview}}</ref>

=== Coloring ===
While some pet rats retain the [[Agouti gene|agouti]] coloring of the wild brown rat (three tones on the same hair), others have solid colors (a single color on each hair), a trait derived from rats with black coats. Agouti-based colors include agouti, cinnamon, and fawn. Black-based colors include black, beige, blue, and chocolate.<ref name="ratgen" />

Eye color is considered a subset of coloring, and coat color definitions often include standards for the eyes, as many genes which control eye color will also affect the coat color or ''vice versa''. The [[American Fancy Rat and Mouse Association]] (AFRMA) lists black, pink, ruby, and [[Heterochromia iridum|odd-eyed]] (two differently colored eyes) as possible eye colors, depending on the variety of rat shown.<ref name=afrma-std /> ''Ruby'' refers to eyes which at a glance appear black, but on closer observation are a deep, dark red.

Color names can vary for more vaguely defined varieties, like lilac and fawn,<ref name="ratgen">{{cite web|url=http://afrma.org/ratgenpart3.htm|title=Rat Genetics, part 3|first=Nichole|last=Royer|publisher=AFRMA|access-date=9 January 2009}}</ref> while the interpretations of standards can fluctuate between (and even within) different countries or clubs.<ref name=afrma-std>{{cite web|url=http://afrma.org/fancyrm.htm|title=American Fancy Rat and Mouse Association standards|publisher=AFRMA|access-date=21 November 2006}}</ref><ref name=carol>{{cite book|title=Rats|last=Daly|first=Carol H.|url=https://archive.org/details/ratseverythingab00daly|url-access=registration|quote=international rat standard.|publisher=Barron's Educational Series|year=2002|isbn=978-0-7641-2012-1|edition=2|page=[https://archive.org/details/ratseverythingab00daly/page/15 15]}}</ref><ref name=nfrs-std>{{cite web|url=http://www.nfrs.org/varieties.html|title=National Fancy Rat Society standards|publisher=NFRS|access-date=21 November 2006|url-status=dead|archive-url=https://web.archive.org/web/20061209133238/http://www.nfrs.org/varieties.html|archive-date=9 December 2006}}</ref>
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=== Markings ===
[[File:Rat siamese.JPG|thumb|<!-- Do not change to Siamese, the picture is misnamed -->Himalayan rats have a unique color and marking variation]]

Further dividing the varieties of fancy rats are the many different markings. Fancy rats can appear in any combination of colors and markings. The markings are typically in reference to the patterns and ratios of colored hair versus white hair. Two extremes would be a ''self'' (completely solid, non-white color) and a Himalayan (completely white except blending into colored areas at the nose and feet, called [[Point coloration|point]]s, as in a [[Himalayan cat]]'s markings).<ref name="rsa-standards">{{cite web|url=http://ratsocietyofamerica.org/standards2.html|title=Standards|publisher=Rat Society of America|access-date=3 February 2009|url-status=dead|archive-url=https://web.archive.org/web/20090126204510/http://ratsocietyofamerica.org/standards2.html|archive-date=26 January 2009}}</ref>

Markings have a strict standard, with detailed terminology, for showing in fancy rat [[pet show]]s. However, many domestic rats are not closely bred to any color standard; many of those found in pet shops will have ''mismarkings'' from a formal breeding perspective, which are defined as variations in markings that are not recognized as conforming to a [[breed standard]] published by a rat fancier organisation.{{Citation needed|date=March 2024}}

Commonly recognized standards include:
* Berkshire – colored top, white belly
* Hooded – color runs in a ''saddle'', a single, unbroken line from the full head down to the spine and possibly partly down the tail<ref name=nfrs-std />
* Capped – color on the full head only
* Blazed – colored head (capped) or body (Irish, Berkshire or self) with a triangular wedge of white fur over the face.
* Variegated – any form of mismatched oddities in the fur. Can be anything from a broken or spotted hood to a misshaped blaze.
* Irish or English Irish – In England, the Irish is standardized by the NFRS as an [[equilateral triangle]] of white with a side that begins at the chest, or between the front legs, and where the point ends mid-length.<ref name=nfrs-std /> In the United States and elsewhere, clubs like the AFRMA distinguish this marking as the English Irish and allow for another standardized Irish in which the rat may have white of an even or symmetrical nature anywhere along its underside.<ref name=afrma-std /><ref name="fox">{{cite book|last=Fox|first=Susan|title=The Guide to Owning a Rat|publisher=TFH Publications|date=August 1997|page=[https://archive.org/details/guidetoowningrat00susa/page/12 12]|isbn=978-0-7938-2157-0|url=https://archive.org/details/guidetoowningrat00susa/page/12}}</ref>

Other marking varieties include spotted or Dalmatian (named for the spotted [[Dalmatian (dog)|Dalmatian]] dog), Essex, masked, Himalayan (typically a [[gradient]] of color along the body, darkest at the base of the tail and nose as in [[Siamese cat]]s), and [[Down Under rat|Down Under]] or Downunder (an Australian variety that has a solid color stripe on the belly or a color marking there that corresponds to the markings on the top).<ref name="rmfe">{{cite journal|last=Hemberg|first=Yvette|author2=Cindy Sautchuk|year=2000|title=A New Rat Variety Down Under|journal=Rat and Mouse Fancy Report|volume=1|issue=1|url=http://rodentfancy.com/pets/wp-content/uploads/2008/01/downundr.pdf}}</ref> {{Clear}}[[File:Fancy Rat Dalmatian.jpg|thumb|Dalmatian Fancy Rat]]

=== Ear and Body type ===
[[File:Velvet small.jpg|thumb|right|A male Dumbo rat, a variety with ears placed lower on the head]]
Two of the most prominent and standardized physical changes applied to rats through selective breeding are the development of the Manx rat and Dumbo rat. The Dumbo rat, whose origins are in the United States, is characterized by having large, low, round ears on the sides of its head, versus the smaller and less prominent ears seen on a standard eared rat. Dumbo ears are caused by a recessive mutation, and was named for its resemblance to the fictional character [[Dumbo]] the Flying Elephant. The Manx rat is tailless due to a [[genetic mutation]], and was named for the [[Manx cat]] which shares this feature,<ref name=afrma-std /> though not necessarily due to the same mutation. Breeding Manx rats does raise some ethical and health concerns however, as rats use their tails for both balance and [[thermoregulation]].<ref>{{Cite journal|url=https://cdnsciencepub.com/doi/abs/10.1139/y65-025|doi = 10.1139/y65-025|title = The Tail of the Rat, in Temperature Regulation and Acclimatization|year = 1965|last1 = Rand|first1 = R. P.|last2 = Burton|first2 = A. C.|last3 = Ing|first3 = T.|journal = Canadian Journal of Physiology and Pharmacology|volume = 43|issue = 2|pages = 257–267|pmid = 14329334}}</ref>

[[File:Dwarf rats sleeping.jpg|thumb|alt=Two Dwarf rats sleeping|Two Dwarf rats sleeping. Dwarf fancy rats are much smaller than standards.]]
Another body type variation that has risen to prominence more recently in the hobby is the Dwarf rat. Dwarfism arose as a mutation among Sprague-Dawley rats kept for research in the 1970s.<ref>{{Cite journal|title=Molecular mechanism of growth hormone(GH) deficiency in the spontaneous dwarf rat: detection ofabnormal splicing of GH messenger ribonucleic acid by thepolymerase chain reaction|year=1990|first1=Takashi|last1=Takeuchi|first2=Hitoshi|last2=Suzuki|first3=Susumu|last3=Sakurai|first4=Haruo|last4=Nogami|first5=Shinichi|last5=Okuma|first6=Hiroshi|last6=Ishikawa|journal=Endocrinology|volume=126|issue=1|pages=31–38|doi=10.1210/endo-126-1-31 |pmid=2152867 }}</ref> Adult dwarfs are considerably smaller than their standard counterparts, with males between 100 and 130g as opposed to 300g or more. This strain of dwarfism is caused by reduced production of growth hormone, and this has other effects in addition to changed overall body size. Important for pet-keeping, it reduces the incidence of pituitary and mammary tumours and nephropathy (kidney disease), with the result that Dwarf rats live 20–40% longer in males and 10–20% longer in females than their standard counterparts.<ref>{{Cite journal|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1447-0594.2009.00559.x|doi=10.1111/j.1447-0594.2009.00559.x|title=Spontaneous dwarf rat: A novel model for aging research|year=2009|first1=Kazunao|last1=Kuramoto|first2=Shoichi|last2=Tahara|first3=Toru|last3=Sasaki|first4=Shigenobu|last4=Matsumoto|first5=Takao|last5=Kaneko|first6=Hiroshi|last6=Kondo|first7=Makoto|last7=Yanabe|first8=Shohei|last8=Takagi|first9=Tadashi|last9=Shinkai|journal=Geriatrics and Gerontology International|volume=10|issue=1|pages=94–101|pmid=20102388 }}</ref> However, they may also show some cognitive impairment. <ref>{{Cite journal|url=https://www.jstage.jst.go.jp/article/endocrj/58/4/58_K11E-006/_article|doi=10.1507/endocrj.K11E-006|title=Hippocampus-dependent spatial learning and memory are impaired in growth hormone-deficient spontaneous dwarf rats|year=2011|first1=Endan|last1=Li|first2=Dong Hyun|last2=Kim|first3=Mudan|last3=Cai|first4=Sungyoub|last4=Lee|first5=Yumi|last5=Kim|first6=Eunjin|last6=Lim|first7=Jong Hoon|last7=Ryu|first8=Terry G.|last8=Unterman|first9=Seungjoon|last9=Park|journal=Endocrine Journal|volume=58|issue=4|pages=257–267|pmid=21350302 }}</ref>

=== Coat types ===
There is a relatively small variety of coats compared to the number of colors and markings, and not all are internationally standardized. The most common type is the normal or standard, which is allowed variance in coarseness between the sexes; males have a coarse, thick, rough coat, while females' coats are softer and finer.<ref name=afrma-std /><ref name=nfrs-std /> Other standardized coats include: rex, in which all the hairs are curly, even the [[Vibrissae|whiskers]]; velveteen, a softer variation of the rex; satin or silky coat, which is extra-soft and fine, with a sheen; and Harley<!--If this is not named after someone identifiable, it should not be capitalised-->, characterized by wispy long straight hairs.<ref name=afrma-std /><ref name=nfrs-std /><ref name=ratspacnw-std>{{cite web|url=http://www.ratspacnw.org/rat%20standards.htm|title=Rats PacNW standards|publisher=RatsPacNW Rat Fanciers Club|access-date=12 January 2009|url-status=dead|archive-url=https://web.archive.org/web/20090427192925/http://www.ratspacnw.org/rat%20standards.htm|archive-date=27 April 2009}}</ref> Remaining coat types are not defined by the hair itself, but rather by the lack of it, such as hairless rats.

==== Hairless rats ====
[[File:Hairless rat Lhassa.jpg|thumb|Even though this rat is hairless, [[pigmentation]] indicates that it is a hooded rat.|alt=|left]]

{{See also|Laboratory rat#Hairless rat|l1=Hairless laboratory rats}}

Hairless rats are a coat variety characterized by varying levels of hair loss. One type of hairless rat is bred from curly-coated rexes. These range from having areas of very short fur to being completely bald. Since rex is a [[dominant trait]], there only needs to be one rex parent to produce curly rex-coated offspring. However, when two rex parents are bred, two copies of the trait may be present in the offspring. This causes varying levels of hairlessness, and has earned the colloquial name "double rex". The other type of hairless rat is sometimes referred to as a "true hairless". This is caused by a different gene, and is distinguishable from a hairless double rex by the absence of whiskers. Unlike a double rex, this type of hairless rat is incapable of growing hairs on any part of the body. One additional subset of semi-hairless rats, patchwork rex, constantly lose their hair and regrow it in different "patches" several times throughout their life.<ref name=afrma-std /><ref name=nfrs-std /> Hairless rats may be prone to more health problems than their standard- or rex-coated counterparts, including a reduced tolerance for cold, kidney and liver failure, more prone to skin injury, skin conditions, and shortened life span.{{Citation needed|date=March 2024}}{{Citation needed|reason=Reliable source needed for last sentence.|date=June 2019}}

=== Ethics of selective breeding ===
There is controversy among rat fanciers in regard to [[selective breeding]].<ref name="nfrs-breeding">{{cite web|url=http://www.nfrs.org/geninfo.html|title=General Information – Advice for the Novice Breeder|date=3 May 2008|publisher=National Fancy Rat Society|access-date=14 November 2008|url-status=dead|archive-url=https://web.archive.org/web/20160909021538/http://www.nfrs.org/geninfo.html|archive-date=9 September 2016}}</ref><ref name="rmca-breeding">{{cite web|url=http://www.rmca.org/Articles/breeding.htm|title=Breeding: Can YOU Live With It?|last=Isaksen|first=Mary Ann|date=January 1999|work=Rat & Mouse Gazette|publisher=Rat & Mouse Club of America|access-date=14 November 2008}}</ref> On one hand, breeding rats to "conform" to a specific standard or to develop a new one is a large part of [[#History|what the fancy 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—the latter referred to as [[culling]].{{Citation needed|date=March 2024}}

There are concerns as to whether breeding hairless and tailless rats is ethical. The tail is vital for rats' balance and for adjusting [[Thermoregulation|body temperature]]. Tailless rats have greater risk of [[Hyperthermia|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]].<ref>{{cite web|url=http://www.afrma.org/taillessrats.htm|title=Tailless Rats|last=Royer|first=Nichole|year=1998|work=AFRMA Rat & Mouse Tales|publisher=American Fancy Rat and Mouse Association|access-date=14 November 2008}}</ref> Similarly, hairless rats are less protected from scratches and the cold without their coat. Groups such as the [[National Fancy Rat Society|NFRS]] prohibit the showing of these varieties at their events and forbid advertisement through affiliated services.<ref>{{cite web|url=http://www.nfrs.org/banned.html|title=Banned varieties|publisher=The National Fancy Rat Society|access-date=11 November 2008|url-status=dead|archive-url=https://web.archive.org/web/20081018171106/http://www.nfrs.org/banned.html|archive-date=18 October 2008}}</ref>
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=== Availability ===
{{Anchor|Accessibility}}<!--Old heading name.-->Because ''[[R. norvegicus]]'' and related species are seen as pests, their intentional import into foreign countries is often regulated. For example, the importation of foreign rodents is prohibited in [[Invasive species in Australia|Australia]],<ref name="aqis">{{cite web |url=http://www.daff.gov.au/aqis/cat-dogs/other |title=Other Pets – DAFF |publisher=Australian Quarantine and Inspection Service |access-date=3 March 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090225171457/http://www.daff.gov.au/aqis/cat-dogs/other |archive-date=25 February 2009 }}</ref> and so various coat types, colors, and varieties have been bred separately from foreign lines, or are just not obtainable within that country (for example, hairless and Dumbo rats do not exist in Australia). In other areas, like the Canadian province of [[Alberta]], which is considered rat-free,<ref name="Bourne">{{cite web|last=Bourne|first=John|title=The History of Rat Control in Alberta|work=Agriculture and Food|publisher=Alberta Department of Agriculture|date=1 October 2002|url=http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex3441|access-date=1 December 2007|archive-date=25 September 2014|archive-url=https://web.archive.org/web/20140925063521/http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex3441|url-status=dead}}</ref> the ownership of domestic fancy rats outside of schools, laboratories, and zoos is illegal.<ref name="Bourne" />