# Tortoiseshell cat

Tortoiseshell cat

Multi-colored fur in cats

[\[image\]](https://en.wikipedia.org/wiki/File:Twenty-nine_the_Cat.jpg)

A [moggy](https://en.wikipedia.org/wiki/Moggy) tortie with a black brindled coat

**Tortoiseshell** is a [coat coloration](https://en.wikipedia.org/wiki/Cat_coat_genetics) in [domestic cats](https://en.wikipedia.org/wiki/Domestic_cats) named for its similarity to [tortoiseshell](https://en.wikipedia.org/wiki/Tortoiseshell) pattern. The coats of tortoiseshell cats, or **torties** for short,[\[1\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF2-1) are two colors other than white in an asymmetrical distribution, either closely mixed ('brindled') or in larger patches.[\[2\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Centerwall2-2) The two colors always consist of one [eumelanistic](https://en.wikipedia.org/wiki/Eumelanin) (black, blue, chocolate, lilac, cinnamon or fawn) and one [phaeomelanistic](https://en.wikipedia.org/wiki/Phaeomelanin) (red or cream) color. The most common tortoiseshell coloration is black tortoiseshell (black and red). Tortoiseshell can occur in combination with other cat coat patterns, such as [tabby](https://en.wikipedia.org/wiki/Tabby_cat) and [colorpoints](https://en.wikipedia.org/wiki/Acromelanism). Tortoiseshell cats with the tabby pattern in their eumelanistic color are tortoiseshell tabby cats, sometimes referred to as **torbies**.[\[3\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-fanciers2-3)

Like the tricolored tortoiseshell-and-white or [calico](https://en.wikipedia.org/wiki/Calico_cat) (in [North American English](https://en.wikipedia.org/wiki/North_American_English))[\[1\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF2-1)[\[4\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Oxford2-4) cats, tortoiseshell cats are almost exclusively female.[\[2\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Centerwall2-2)[\[5\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-5)[\[6\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-6)[\[7\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Colombo2-7) Male tortoiseshells are rare and are usually sterile.[\[7\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Colombo2-7)[\[8\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Atkins_2003,_p.1052-8) Tortoiseshell markings appear in many different cat breeds, as well as in non-purebred domestic cats.[\[9\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Syufy2-9) This pattern is especially preferred in the [Japanese Bobtail](https://en.wikipedia.org/wiki/Japanese_Bobtail) breed.[\[10\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-cat2-10)

## Pigmentation

Main article: [Cat coat genetics](https://en.wikipedia.org/wiki/Cat_coat_genetics)

[\[image\]](https://en.wikipedia.org/wiki/File:Mudball_(2017_photo;_cropped_2022).jpg)

A black tortoiseshell [moggy](https://en.wikipedia.org/wiki/Moggy) cat

Tortoiseshell coats result from an interaction between genetic, developmental, and environmental factors. Coat colors in domestic cats are produced by the interaction of orange-based [phaeomelanin](https://en.wikipedia.org/wiki/Phaeomelanin) (O) and black-based [eumelanin](https://en.wikipedia.org/wiki/Eumelanin) (B) pigments.[\[11\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-genmodel2-11) Tortoiseshell cats are bicolored and expresses a combination of both next to each other in their coat. The primary gene for cat coat color coloration (B) produces the brown-toned colors — black, blue, chocolate, lilac, cinnamon, and fawn. This gene can be masked by the co-dominant gene for the orange color (O), which produces the orange-toned colors — red and cream. The orange gene is located on the [X chromosome](https://en.wikipedia.org/wiki/X_chromosome) and has two [alleles](https://en.wikipedia.org/wiki/Alleles): orange (XO) and non-orange (Xo), that produce the orange phaeomelanin and black eumelanin pigments, respectively. Typically, the alleles are notated as an uppercase **O** for orange, or a lowercase **o** for non-orange.[\[11\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-genmodel2-11)

[\[image\]](https://en.wikipedia.org/wiki/File:Dilute_tortoiseshell_feline.jpg)

Cat with a blue ("dilute", "grey") tortoiseshell coat

### Pigment color overview

| Pigment | Allele[\[12\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-genmodel-12) | Gene[\[12\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-genmodel-12) | Basic (D) | Dilution (d)[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) |
| --- | --- | --- | --- | --- |
| **phaeomelanin** | orange | O |  | red | cream |
| **eumelanin** | non-orange | o | B | black | blue |
| b | chocolate | lilac |
| bl | cinnamon | fawn |

The (B) and (O) genes can be further modified by a recessive dilute gene (dd) which softens the basic colors.[\[12\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-genmodel-12)[\[14\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-14) Red becomes cream, black becomes blue, chocolate becomes lilac, and cinnamon becomes fawn.[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) All tortoiseshells form a combination of either two basic colors — red combined with black, chocolate or cinnamon — or two dilute colors — cream combined with blue, lilac or fawn. Therefore, a tortoiseshell cat may be a _chocolate tortoiseshell_ (chocolate and red) or a _blue tortoiseshell_ (blue and cream) or the like, based on the alleles for the (B) and (D) genes.[\[15\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-15) However, due to [genetic dominance](https://en.wikipedia.org/wiki/Genetic_dominance), the most common tortoiseshell coloration is _black tortoiseshell_ (black and red). Various terms are colloquially used for specific colors, for example, black is also called "brown", blue is also called "grey", red is also called "orange", "ginger", and "yellow".[\[16\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Centerwall-16) Even though there exist three dilute tortoiseshell colors, blue is sometimes colloquially referred to as "dilute", which is the most common dilute coloration.

### Sex linkage

Female cats are [homogametic](https://en.wikipedia.org/wiki/Homogametic) (XX) and undergo the phenomenon of [X-inactivation](https://en.wikipedia.org/wiki/X-inactivation),[\[17\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-17) in which one of the X chromosomes is turned off at random in each cell in very early embryonic development.[\[18\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-18) The inactivated X becomes a [Barr body](https://en.wikipedia.org/wiki/Barr_body). Cells in which the chromosome carrying the orange (O) allele is inactivated express the alternative non-orange (o) allele, determined by the (B) gene. Cells in which the non-orange (o) allele is inactivated express the orange (O) allele. Pigment genes are expressed in [melanocytes](https://en.wikipedia.org/wiki/Melanocytes) that migrate to the skin surface later in development. In bicolored tortoiseshell cats, the melanocytes arrive relatively early, and the two cell types become intermingled; this produces the characteristic brindled appearance consisting of an intimate mixture of orange and black cells, with occasional small diffuse spots of orange and black. Tortoiseshell cats have a combination of orange-based O and black-based o on two XX-chromosomes; labelled as XOXo, indicating O-gene [heterozygosity](https://en.wikipedia.org/wiki/Heterozygosity).[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) Orange and black females have homozygous O-genes; labelled as XOXO (orange) and XoXo (black).

[\[image\]](https://en.wikipedia.org/wiki/File:Sex-linked_cat_colour_genetics.jpg)

Schematic overview of the sex linkage of the orange (O) and non-orange (o) allele

[\[image\]](https://en.wikipedia.org/wiki/File:A_tortoiseshell_cat's_speckled_paw-pads.jpg)

Typical combination of black- and red-based areas on the paw-pads of a tortoiseshell cat, in this case, in a mottling pattern

Male cats, like males of other [therian](https://en.wikipedia.org/wiki/Sex-determination_system) mammals, are [heterogametic](https://en.wikipedia.org/wiki/Heterogametic) (XY).[\[19\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-19) The single X chromosome does not undergo X-inactivation, ergo coat color is determined by which O-gene allele is present. Accordingly, the male cat's coat will be either entirely orange (O; XOY ) or [melanistic](https://en.wikipedia.org/wiki/Melanistic) black (o; XoY).

[Leonard Doncaster](https://en.wikipedia.org/wiki/Leonard_Doncaster) was the first to prove [sex linkage](https://en.wikipedia.org/wiki/Sex_linkage) of the tortoiseshell coat coloration; i.e. that tortoiseshell is the female heterozygote of orange and black (XOXo) with the corresponding male being orange (XOY). In the course of his studies he discovered that the rare tortoiseshell male is often sterile.[\[20\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-20)[\[21\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-21)

Very rarely (approximately 1 in 3,000[\[22\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-22)) a male tortoiseshell is born; these typically have an extra X chromosome (XXY), a condition known in humans as [Klinefelter syndrome](https://en.wikipedia.org/wiki/Klinefelter_syndrome), and their cells undergo an X-inactivation process like in females. As in humans, these cats often are sterile because of the imbalance in sex chromosomes.[\[23\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-23) Some male tortoiseshell cats may be [chimaeras](https://en.wikipedia.org/wiki/Chimaerism), which result from fusion in early development of two (fraternal twin) embryos with different color genotypes; these torties can pass only one color to their offspring, not both, according to which of the two original embryos its testes are descended from. Others are [mosaics](https://en.wikipedia.org/wiki/Mosaic_(genetics)), in which the XXY condition arises after conception and the cat is a mixture of cells with different numbers of X chromosomes.

## Variations

### Color and distribution

Tortoiseshell cats have particolored[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) coats; either bicolored with parts of various shades of orange and non-orange pigments, or tricolor in which tortoiseshell is combined with white spotting. The size of the patches can vary from a fine brindled pattern to large patched areas of color. Typically, the higher degree of white spotting a cat has, the more distinct the different colored patches are. In general, the markings on tortoiseshell cats are [asymmetrically](https://en.wikipedia.org/wiki/Asymmetrical) distributed.[\[24\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-fanciers-24) Dilution genes modify the coloring, lightening the coat coloration from red with either black, chocolate or cinnamon to a mix of cream with either blue, lilac or fawn. These three dilute tortoiseshell colors can be affected by a dilute modifier resulting in apricot mixed with their three caramel variants. Furthermore, the all tortoiseshell colors can occur in combination with the silver inhibitor gene, resulting in their respective silver tabby or smoke versions.

### Tricolor (tortoiseshell-and-white)

Main article: [Calico cat](https://en.wikipedia.org/wiki/Calico_cat)

Black tortoiseshell cats sporting different pigment distributions

[\[image\]](https://en.wikipedia.org/wiki/File:Short-haired_tortoiseshell_cat_(cropped).jpg)

"brindled"

[\[image\]](https://en.wikipedia.org/wiki/File:Бассинда_(13823156184)_(cropped).jpg)

"patched"; In this case, the patches resulted in a double-centrefold face marking resembling a [checkerboard](https://en.wikipedia.org/wiki/Check_(pattern)) pattern. Centrefold markings are often confused with [chimaerism](https://en.wikipedia.org/wiki/Chimaerism); however, in most cases, it is rather a less typical distribution of the tortoiseshell pattern.

In tricolor[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) cats, also known as tortoiseshell-and-white[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) or in [North American English](https://en.wikipedia.org/wiki/North_American_English) as [calico](https://en.wikipedia.org/wiki/Calico_cat),[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13)[\[25\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Oxford-25) a separate gene interacts developmentally with the tortoiseshell coat color genes. This [white spotting gene](https://en.wikipedia.org/wiki/Cat_coat_genetics)[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) produces white, unpigmented patches by delaying the migration of the melanocytes to the skin surface. There are a number of alleles of this gene that produce greater or lesser delays. The amount of white is divided by [cat registries](https://en.wikipedia.org/wiki/Cat_registries) into the categories _mitted_, _true bi- or tricolor_, _harlequin_, and _van_,[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) going from almost no white to almost completely white. In the extreme case, no melanocytes make it to the skin and the cat is entirely white, known as "epistatic" or "dominant white" (genetically different from [albinism](https://en.wikipedia.org/wiki/Albinism)).[\[12\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-genmodel-12) In intermediate cases, melanocyte migration is slowed, so that the pigment cells arrive late in development and have less time to intermingle. Observation of tricolor cats will show that, with a little white color, the orange and black patches become more defined, and with still more white, the patches become completely distinct. Each patch represents a clone of cells derived from one original cell in the early embryo.[\[26\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-RROB-26)

[\[image\]](https://en.wikipedia.org/wiki/File:Tortie-white-spotting_(no_text).jpg)

Schematic presentation of how white spotting affects tortoiseshell color distribution. As the amount of white spotting increases, the tortoiseshell color becomes less brindled and forms distinct patches of color. This is related to the migration rates of pigment cells across the surface of the embryo.

### Pattern

Apart from the different color combinations the tortoiseshell pattern also occurs in combination with other genetic cat coat patterns. The [phaeomelanistic](https://en.wikipedia.org/wiki/Phaeomelanin) red and cream colors will always show a [tabby](https://en.wikipedia.org/wiki/Tabby_cat) pattern, even if they are genetically "solid" or "self" (meaning non-[agouti](https://en.wikipedia.org/wiki/Agouti_coloration_genetics), i.e. non-tabby).[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) The [eumelanistic](https://en.wikipedia.org/wiki/Eumelanin) color (black, blue, chocolate, lilac, cinnamon, and fawn) makes it possible to visibly determine whether a tortoiseshell cat is tabby or solid. The tortoiseshell tabbies are often called _tortie-tabby_, or _torbie/y_ for short.[\[13\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-WCF-13) In North America the combination of calico and torby, _caliby_, is used for tortoiseshell tabbies with large white areas.[\[24\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-fanciers-24) Tortoiseshell coloring can also be expressed in combination with one of the [colorpoint](https://en.wikipedia.org/wiki/Acromelanism) restriction patterns, colloquially referred to as a _tortie point_.[\[24\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-fanciers-24)

## Folklore

[\[image\]](https://en.wikipedia.org/wiki/File:Chocolate-tortie-mink.JPG)

Chocolate tortoiseshell mink [Tonkinese cat](https://en.wikipedia.org/wiki/Tonkinese_cat)

In the folklore of several cultures, cats with tortoiseshell coloration are believed to bring [good luck](https://en.wikipedia.org/wiki/Luck).[\[27\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-folklore-27) In Ireland, tortoiseshell cats are considered to bring good luck to their owners.[\[27\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-folklore-27) In the [United States](https://en.wikipedia.org/wiki/United_States), tortoiseshells are sometimes referred to as _money cats_.[\[28\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-28) In Japan, tortoiseshell cats are considered to bring good luck against shipwrecks.[\[27\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-folklore-27) There are some additional interpretations of the luck of tortoiseshell cats, such as the one in England that describes an announcement of misfortune when a strange tortoiseshell cat enters a house.[\[27\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-folklore-27) In England, if a woman dreams of a tortoiseshell cat, it can be interpreted as a warning that she should take care around her so-called friends.[\[27\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-folklore-27)

## Behavior

Some studies have found that people believe tortoiseshell cats are more likely to be aggressive and with stronger prey interest[\[29\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-wilhelmy2-29)[\[30\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-30)—the slang term "[tortitude](https://en.wiktionary.org/wiki/tortitude)" was coined in reference to this perceived behavior.[\[31\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-anthrozoos2-31) There is, however, little existing scientific evidence on the matter.[\[31\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-anthrozoos2-31)[\[32\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-32) One study found that there was not a relationship between coat color and tameness.[\[33\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-33) Based on various study results, assumptions cannot be made between cat coat color and personality or temperament.[\[34\]](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_note-Vonk2-34)\[_[page needed](https://en.wikipedia.org/wiki/Wikipedia:Citing_sources)_\]

## Gallery

*   [\[image\]](https://en.wikipedia.org/wiki/File:Tortoiseshellshorthair_(2013_photo;_cropped_2022).JPG)

    Black tortoiseshell ("tortie")

*   [\[image\]](https://en.wikipedia.org/wiki/File:路邊閒晃的貓_(49953930706).jpg)

    Black tortoiseshell tabby ("torbie/y")

*   [\[image\]](https://en.wikipedia.org/wiki/File:British_shorthair_with_calico_coat_(2).jpg)

    Black tortoiseshell-and-white tricolor ("calico")

*   [\[image\]](https://en.wikipedia.org/wiki/File:Black_tortoiseshell_tabby_and_white_cat_side_(cropped).jpg)

    Black tortoiseshell tabby-and-white tricolor ("caliby")

*   [\[image\]](https://en.wikipedia.org/wiki/File:Smudge_9472_(8467111276).jpg)

    Blue tortoiseshell tabby and white

*   [\[image\]](https://en.wikipedia.org/wiki/File:Tortie-point.jpg)

    Black colorpoint tortoiseshell ("tortie point")

*   [\[image\]](https://en.wikipedia.org/wiki/File:GIP_HU_Alba_Regia_Ganxsta_Gizi_(Gizi)_BUR_h_female_EX1_CAPS_NOM.JPG)

    Chocolate tortoiseshell sepia [Burmese](https://en.wikipedia.org/wiki/Burmese_cat)

*   [\[image\]](https://en.wikipedia.org/wiki/File:Cat_in_Krasnodar,_July,_2012_(square).jpg)

    Black smoke tortoiseshell domestic longhair

*   [\[image\]](https://en.wikipedia.org/wiki/File:KURILIAN_BOBTAIL_Femmina_Jasmin_(cropped).jpg)

    Black tortoiseshell silver blotched tabby [Kurilian Bobtail](https://en.wikipedia.org/wiki/Kurilian_Bobtail) Longhair

*   [\[image\]](https://en.wikipedia.org/wiki/File:High_content_black_tortie.jpg)

    A female tortoiseshell cat with high black fur content

## See also

*   [Calico cat](https://en.wikipedia.org/wiki/Calico_cat)
*   [Deaf white cat](https://en.wikipedia.org/wiki/Deaf_white_cat)
*   [Tabby cat](https://en.wikipedia.org/wiki/Tabby_cat)

## References

1.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF2_1-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF2_1-1) ["Glossary of terms"](https://wcf.de/en/glossary-of-terms/). _wcf.de_. [World Cat Federation](https://en.wikipedia.org/wiki/World_Cat_Federation). Retrieved 2026-03-03.
2.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Centerwall2_2-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Centerwall2_2-1) Centerwall, W. R.; Benirschke, K. (1973). "Male Tortoiseshell and Calico (T-C) Cats: Animal models of sex chromosome mosaics, aneuploids, polyploids, and chimerics". _Journal of Heredity_. **64** (5): 272–278\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1093/oxfordjournals.jhered.a108410](https://doi.org/10.1093%2Foxfordjournals.jhered.a108410). [PMID](https://en.wikipedia.org/wiki/PMID_(identifier)) [4798734](https://pubmed.ncbi.nlm.nih.gov/4798734).
3.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-fanciers2_3-0) ["Cat Colours FAQ: Common Colours"](http://fanciers.com/other-faqs/colors.html#white_markings). _Fanciers.com_. Retrieved 19 December 2015.
4.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Oxford2_4-0) ["Calico cat"](https://www.oxfordlearnersdictionaries.com/definition/english/calico-cat). _oxfordlearnersdictionaries.com_. [Oxford Learner's Dictionaries](https://en.wikipedia.org/wiki/Oxford_Learner's_Dictionaries).
5.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-5) Centerwall, W. R.; Benirschke, K. (1975). "An animal model for the XXY Klinefelter's syndrome in man: Tortoiseshell and calico male cats". _American Journal of Veterinary Research_. **36** (9): 1275–1280\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.2460/ajvr.1975.36.09.1275](https://doi.org/10.2460%2Fajvr.1975.36.09.1275). [PMID](https://en.wikipedia.org/wiki/PMID_(identifier)) [1163864](https://pubmed.ncbi.nlm.nih.gov/1163864).
6.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-6) Atkins (2003), p. 61
7.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Colombo2_7-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Colombo2_7-1) Noli, Chiara; Colombo, Silvia (2020). _Feline Dermatology_. Cham, Switzerland: Springer. [ISBN](https://en.wikipedia.org/wiki/ISBN_(identifier)) [9783030298364](https://en.wikipedia.org/wiki/Special:BookSources/9783030298364). [OCLC](https://en.wikipedia.org/wiki/OCLC_(identifier)) [1159164563](https://search.worldcat.org/oclc/1159164563).
8.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Atkins_2003,_p.1052_8-0) Atkins (2003), p.105
9.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Syufy2_9-0) Syufy, Franny. ["More Cat Colour Patterns: Calicos, Tortoiseshell, Tuxedo Cats"](https://www.thesprucepets.com/breeds-domestics-and-color-patterns-554862). _thesprucepets.com_. Retrieved 27 January 2025.
10.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-cat2_10-0) ["Breed Profile: Japanese Bobtail"](https://web.archive.org/web/20070612084729/http://www.cfainc.org/breeds/profiles/japanese.html). [Cat Fanciers' Association](https://en.wikipedia.org/wiki/Cat_Fanciers'_Association). Archived from [the original](http://www.cfainc.org/breeds/profiles/japanese.html) on 12 June 2007. Retrieved 2 June 2007.
11.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-genmodel2_11-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-genmodel2_11-1) ["Genetic Model"](https://wcf.de/en/genetic-model/). _wcf.de_. [World Cat Federation](https://en.wikipedia.org/wiki/World_Cat_Federation). Retrieved 2026-03-03.
12.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-genmodel_12-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-genmodel_12-1) [3](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-genmodel_12-2) [4](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-genmodel_12-3) ["Genetic Model"](https://wcf.de/en/genetic-model/). _wcf.de_. [World Cat Federation](https://en.wikipedia.org/wiki/World_Cat_Federation). Retrieved 2026-03-03.
13.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-1) [3](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-2) [4](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-3) [5](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-4) [6](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-5) [7](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-6) [8](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-7) [9](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-8) [10](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-9) [11](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-WCF_13-10) ["Glossary of terms"](https://wcf.de/en/glossary-of-terms/). _wcf.de_. [World Cat Federation](https://en.wikipedia.org/wiki/World_Cat_Federation). Retrieved 2026-03-03.
14.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-14) Crosta, Maria Cristina (2020), ["Coat Colour Genetics"](http://link.springer.com/10.1007/978-3-030-29836-4_2), in Noli, Chiara; Colombo, Silvia (eds.), _Feline Dermatology_, Cham, Switzerland: Springer International Publishing, pp. 23–66, [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1007/978-3-030-29836-4\_2](https://doi.org/10.1007%2F978-3-030-29836-4_2), [ISBN](https://en.wikipedia.org/wiki/ISBN_(identifier)) [9783030298357](https://en.wikipedia.org/wiki/Special:BookSources/9783030298357), retrieved 17 September 2023
15.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-15) Moran, Chris; Gillies, Chris B.; Nicholas, Frank W. (1984). ["Fertile male tortoiseshell cats"](https://academic.oup.com/jhered/article-lookup/doi/10.1093/oxfordjournals.jhered.a109964). _Journal of Heredity_. **75** (5): 397–402\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1093/oxfordjournals.jhered.a109964](https://doi.org/10.1093%2Foxfordjournals.jhered.a109964). [ISSN](https://en.wikipedia.org/wiki/ISSN_(identifier)) [1465-7333](https://search.worldcat.org/issn/1465-7333).
16.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Centerwall_16-0) Centerwall, W. R.; Benirschke, K. (1973). "Male Tortoiseshell and Calico (T-C) Cats: Animal models of sex chromosome mosaics, aneuploids, polyploids, and chimerics". _Journal of Heredity_. **64** (5): 272–278\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1093/oxfordjournals.jhered.a108410](https://doi.org/10.1093%2Foxfordjournals.jhered.a108410). [PMID](https://en.wikipedia.org/wiki/PMID_(identifier)) [4798734](https://pubmed.ncbi.nlm.nih.gov/4798734).
17.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-17) Ahn, J.; Lee, J. (2008). ["X Chromosome: X Inactivation"](http://www.nature.com/scitable/topicpage/x-chromosome-x-inactivation-323). _Chromosomes and Cytogenetics_. 1(1):24. Nature Education. Retrieved 21 March 2011.
18.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-18) Lyon, Mary F. (22 April 1961). ["Gene action in the X-chromosome of the mouse (_Mus musculus L._)"](https://www.nature.com/articles/190372a0). _[Nature](https://en.wikipedia.org/wiki/Nature_(journal))_. **190** (4773): 372–373\. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_(identifier)):[1961Natur.190..372L](https://ui.adsabs.harvard.edu/abs/1961Natur.190..372L). [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1038/190372a0](https://doi.org/10.1038%2F190372a0). [ISSN](https://en.wikipedia.org/wiki/ISSN_(identifier)) [1476-4687](https://search.worldcat.org/issn/1476-4687).
19.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-19) Gould, Laura (1996). [_Cats Are Not Peas_](http://link.springer.com/10.1007/978-1-4684-6313-2). New York: Springer. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1007/978-1-4684-6313-2](https://doi.org/10.1007%2F978-1-4684-6313-2). [ISBN](https://en.wikipedia.org/wiki/ISBN_(identifier)) [9781468463156](https://en.wikipedia.org/wiki/Special:BookSources/9781468463156).
20.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-20) Bateson, W. (10 June 1920). ["Prof. L. Doncaster, F.R.S."](https://zenodo.org/record/1429638) _[Nature](https://en.wikipedia.org/wiki/Nature_(journal))_. **105** (2641): 461–462\. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_(identifier)):[1920Natur.105..461B](https://ui.adsabs.harvard.edu/abs/1920Natur.105..461B). [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1038/105461a0](https://doi.org/10.1038%2F105461a0).
21.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-21) ["OMIA:001201-9685: Coat colour, orange in Felis catus (domestic cat) - OMIA - Online Mendelian Inheritance in Animals"](https://omia.org/OMIA001201/9685/). _omia.org_. Retrieved 2026-03-02.
22.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-22) Spadafori, Gina. ["Feline Fallacies"](https://web.archive.org/web/20080612154655/http://www.veterinarypartner.com/Content.plx?P=A&A=2209&S=5). _The Pet Connection_. VeterinaryPartner.com. Archived from [the original](http://www.veterinarypartner.com/Content.plx?P=A&A=2209&S=5) on 12 June 2008. Retrieved 3 July 2008.
23.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-23) Foster, Robert A (2022). ["Disorders of sexual development in the cat: Current state of knowledge and diagnostic approach"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9052703). _Journal of Feline Medicine and Surgery_. **24** (3): 257–265\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1177/1098612X221079711](https://doi.org/10.1177%2F1098612X221079711). [ISSN](https://en.wikipedia.org/wiki/ISSN_(identifier)) [1098-612X](https://search.worldcat.org/issn/1098-612X). [PMC](https://en.wikipedia.org/wiki/PMC_(identifier)) [9052703](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9052703). [PMID](https://en.wikipedia.org/wiki/PMID_(identifier)) [35209773](https://pubmed.ncbi.nlm.nih.gov/35209773).
24.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-fanciers_24-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-fanciers_24-1) [3](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-fanciers_24-2) ["Cat Colours FAQ: Common Colours"](http://fanciers.com/other-faqs/colors.html#white_markings). _Fanciers.com_. Retrieved 19 December 2015.
25.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Oxford_25-0) ["Calico cat"](https://www.oxfordlearnersdictionaries.com/definition/english/calico-cat). _oxfordlearnersdictionaries.com_. [Oxford Learner's Dictionaries](https://en.wikipedia.org/wiki/Oxford_Learner's_Dictionaries).
26.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-RROB_26-0) Robinson, Roy (1991). _Genetics for Cat Breeders and Veterinarians_. Butterworth-Heinemann Medical. [ISBN](https://en.wikipedia.org/wiki/ISBN_(identifier)) [9780750635400](https://en.wikipedia.org/wiki/Special:BookSources/9780750635400).
27.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-folklore_27-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-folklore_27-1) [3](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-folklore_27-2) [4](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-folklore_27-3) [5](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-folklore_27-4) Bonnerjea, Biren (21 September 1935). ["Cats in Folklore and Belief"](https://global.oup.com/academic/product/notes-and-queries-14716941?cc=us&lang=en&). _Notes and Queries_. **CLXIX**: 201–205\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1093/nq/CLXIX.sep21.201](https://doi.org/10.1093%2Fnq%2FCLXIX.sep21.201) – via Oxford University Press.
28.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-28) Finegan, Edward; [Rickford, John](https://en.wikipedia.org/wiki/John_R._Rickford) (2004). [_Language in the USA: Themes for the Twenty-first Century_](http://www3.cambridge.org/uk/catalogue/catalogue.asp?isbn=0511206941&ss=fro). [Cambridge University Press](https://en.wikipedia.org/wiki/Cambridge_University_Press). [ISBN](https://en.wikipedia.org/wiki/ISBN_(identifier)) [0511206941](https://en.wikipedia.org/wiki/Special:BookSources/0511206941). Retrieved 22 January 2009.`{{[cite book](https://en.wikipedia.org/wiki/Template:Cite_book)}}`: CS1 maint: deprecated archival service ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_deprecated_archival_service))
29.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-wilhelmy2_29-0) Wilhelmy, Jacquelene; Serpell, James; Brown, Dorothy; Siracusa, Carlo (2016). "Behavioural associations with breed, coat type, and eye colour in single-breed cats". _Journal of Veterinary Behaviour_. **13** (1): 80–87\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1016/j.jveb.2016.03.009](https://doi.org/10.1016%2Fj.jveb.2016.03.009).
30.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-30) Stelow, Elizabeth A.; Bain, Melissa J.; Kass, Philip H. (2 January 2016). ["The Relationship Between Coat Colour and Aggressive Behaviours in the Domestic Cat"](https://escholarship.org/content/qt4hf2b2st/qt4hf2b2st.pdf?t=o17125) (PDF). _Journal of Applied Animal Welfare Science_. **19** (1): 1–15\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.1080/10888705.2015.1081820](https://doi.org/10.1080%2F10888705.2015.1081820). [ISSN](https://en.wikipedia.org/wiki/ISSN_(identifier)) [1088-8705](https://search.worldcat.org/issn/1088-8705). [PMID](https://en.wikipedia.org/wiki/PMID_(identifier)) [26467020](https://pubmed.ncbi.nlm.nih.gov/26467020). [S2CID](https://en.wikipedia.org/wiki/S2CID_(identifier)) [7645478](https://api.semanticscholar.org/CorpusID:7645478).
31.  [1](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-anthrozoos2_31-0) [2](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-anthrozoos2_31-1) Delgado, Mikel M.; Munera, Jacqueline D.; Reevy, Gretchen M. (2012). ["Human Perceptions of Coat Colour as an Indicator of Domestic Cat Personality"](https://gwern.net/doc/cat/psychology/2012-delgado.pdf) (PDF). _Anthrozoös_. **25** (4): 427–440\. [doi](https://en.wikipedia.org/wiki/Doi_(identifier)):[10.2752/175303712X13479798785779](https://doi.org/10.2752%2F175303712X13479798785779). Retrieved 2024-11-18. Tri-coloured cats (calicos and tortoiseshells) were ranked relatively high in aloofness and intolerance, and low in friendliness by the participants in this survey. The International Cat Association website describes them as follows: "They tend to have what the cat fancy calls 'Tortie-tude.' More than any other colour, these girls have an 'opinion' on everything" (The International Cat Association Southeast Region n.d.). A Google search for the term "Tortitude" (tortoiseshell attitude) brings up over 15,000 websites, many of which imply that tortoiseshell cats have unique personality traits including stubbornness, independence, and unpredictability.
32.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-32) Zielinski, Sarah. ["Judging a Cat (Wrongly) by the Colour of its Coat"](http://www.smithsonianmag.com/science-nature/judging-a-cat-wrongly-by-the-color-of-its-coat-97549864/?no-ist). _[Smithsonian](https://en.wikipedia.org/wiki/Smithsonian_(magazine))_. Retrieved 16 May 2015.
33.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-33) Umbelino, M. T. L. P. (2014). [_Evaluation of the relation between tameness and coat colour in cats_](https://core.ac.uk/download/pdf/62467987.pdf) (PDF) (PhD). [University of Évora](https://en.wikipedia.org/wiki/University_of_Évora). Retrieved 2024-11-18. Despite our efforts to gain a better understanding of this relation in domestic cats, our study showed no significant relations between tameness and coat colour. However, we do believe a new study, with a larger sample and particular adjustments to the measuring scales would possibly find a strong relation between these two variables.
34.  [↑](https://en.wikipedia.org/wiki/Tortoiseshell_cat#cite_ref-Vonk2_34-0) Vonk, Jennifer; Weiss, Alexander; Kuczaj, Stan A. (26 July 2017). _Personality in Nonhuman Animals_. Cham, Switzerland: Springer. [ISBN](https://en.wikipedia.org/wiki/ISBN_(identifier)) [9783319593005](https://en.wikipedia.org/wiki/Special:BookSources/9783319593005). [OCLC](https://en.wikipedia.org/wiki/OCLC_(identifier)) [999445759](https://search.worldcat.org/oclc/999445759).

*   Atkins, Carla. _Cats: An Owner's Guide_ (2003). San Diego, California: [Thunder Bay Press](https://en.wikipedia.org/wiki/Thunder_Bay_Press). [ISBN](https://en.wikipedia.org/wiki/ISBN_(identifier)) [1-59223-097-0](https://en.wikipedia.org/wiki/Special:BookSources/1-59223-097-0)

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