Bleuming Tails Rattery

The Plush Perfection of Velveteen Rats

A group of small mice with various fur colors—black, gray, white, and spotted—are huddled together in a transparent container. Calm and resting closely together, they resemble potential pet food ingredients ready to be included in a balanced diet for some animals.

The Plush Perfection of Velveteen Rats

A group of small mice with various fur colors—black, gray, white, and spotted—are huddled together in a transparent container. Calm and resting closely together, they resemble potential pet food ingredients ready to be included in a balanced diet for some animals.

ABOUT THE AUTHOR

With more than a decade of professional experience in the animal industry and the owner of Bleuming Tails, Abby has a deep interest in the science behind our beloved pets, and what that means for their care.

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Exploring the Velveteen Coat Type in Rats: What You Need to Know

If you’ve ever admired the soft, luxurious fur of a rat and wondered about the different types of coats they can have, you’re in for a treat. One of the most fascinating and sought-after coat types in the rat world is the Velveteen coat. At our rattery, we’re excited to confirm that we now have Velveteen rats in our breeding program, and we can’t wait to share all the details about this unique and stunning coat variety.

What is a Velveteen Coat?

The Velveteen coat is characterized by its dense, wavy curls that set it apart from other curly-coated varieties. Unlike the Rex coat, where the curls tend to clump together, Velveteen curls are more defined and separate, giving the coat a softer, more plush feel. While the fur is dense, it doesn’t get overly thick or coarse. The overall texture is soft and velvety, much like the fabric it’s named after.

As babies, Velveteen rats look like little lambs with a fluffy coat, but as they mature, the fur softens and the curls lose some of their tight wave, though they remain full and thick. Around the time of the five-week molt, the coat may lose a bit of its wave, but it will still maintain its density. One thing to note is that when Velveteen rats inherit two copies of the gene, they don’t lose hair like Rex rats but instead develop a thicker, plusher, and more curly coat. Velveteen rats are known for their long, forward-curved whiskers.

The Velveteen gene is often associated with the Curly-1 or Curly-2 gene variations on chromosome 5, leading to the genotype “Cucu” being used for the variety. Velveteen is an incomplete dominant gene, which means it only takes one copy to produce the distinct coat, but will exhibit a third phenotype when the gene is doubled. While it’s not yet standardized or widely recognized in breeding registries like AFRMA, many breeders who work with the variety.

 

Velveteen vs. Rex Coat

To understand the Velveteen coat, it’s helpful to compare it to the more common Rex coat. Both the Velveteen and Rex coats are curly-type coats and are known as rexoids, but there are key differences between the two:

  • Velveteen Coat: The Velveteen coat is softer and more plush. The curls are more tightly defined, and the overall feel is smoother and velvety to the touch. The fur is dense but often shorter than the Rex coat, and the curls are finer. The Velveteen gene is an incomplete dominant, meaning that if a rat inherits one Velveteen gene, it will have the velvety texture, but if it inherits two, the fur will be short and dense, resembling a freshly shorn sheep.

  • Rex Coat: Rex rats also have curly fur, but their coat has a rougher texture with looser curls. The Rex gene is also an incomplete dominant, but it behaves differently than Velveteen. While a single copy of the Rex gene results in a curly coat, a rat with two copies of the Rex gene (homozygous) typically develops a sparse coat, sometimes even becoming completely hairless. This is due to the way the Rex gene affects the hair follicles, causing them to produce less hair overall.
Proving a Variety: The Importance of Test Breeding

When it comes to confirming a new coat type or genetic variety, breeders often rely on a method called test breeding. Test breeding is a systematic process used to verify the genetic traits of rats and distinguish one variety from another, especially when it comes to similar traits like the Rex and Velveteen coat types.

In the case of Velveteen, the only surefire way to differentiate between this unique coat and the more common Rex coat is by observing how the coat type behaves when the variety is doubled. Both Rex and Velveteen are incomplete dominant genes, which means that if a rat inherits one copy of the gene, it will exhibit the curly coat. However, the way the coat behaves when the gene is doubled (homozygous) is what makes them distinct.

The Double Effect: Rex vs. Velveteen

For a Rex rat, when it inherits two copies of the Rex gene, the coat typically becomes much curlier and can even lose hair in some cases, resulting in a sparse or patchy coat. On the other hand, when a Velveteen rat inherits two copies of the Velveteen gene, the coat doesn’t lose hair. Instead, it becomes even thicker, denser, and more curly, while maintaining its soft and plush texture. This is the key distinguishing factor between the two coat types, and it’s only observable after breeding and letting several generations grow out.

How Test Breeding Works

Test breeding is a multi-step process that typically takes several generations and months of waiting to confirm. The first step is to start with a foundation pair of rats, one that carries the Velveteen gene (or is suspected to carry it) and another rat that may carry the same or a different coat gene, such as a standard coat or Rex. These rats will produce the first generation (G1) of offspring.

After these rats mature, breeders will selectively pair them with other rats from different lines to observe how the traits manifest in future litters. The goal is to create Generation 2 (G2), which refers to the second generation of offspring that are two generations past the foundation pair. By this point, the genetic traits from the initial breeding begin to become more consistent, and the breeder can better understand how the Velveteen coat behaves across generations.

In the case of Velveteen, breeders are specifically looking for how the coat doubles. A G2 litter may include some rats with more pronounced velvety fur and others that show typical Rex-like traits, allowing breeders to see the full range of genetic expressions depending upon the genes at play. If the litters show consistent results where the doubled Velveteen gene creates the thicker, plush fur without patchiness, then the Velveteen variety is considered verified.

Patience and Precision

Test breeding is not a quick process. It requires careful planning, patience, and attention to detail. Generations must be bred and observed before conclusions can be made. A successful breeding program to prove a variety like Velveteen can take months of work, with multiple litters being carefully evaluated for coat consistency. It’s a lengthy but necessary process to confirm the genetic makeup and reliability of a new coat type.

We’re Excited to Have Velveteen in Our Rattery

We’re thrilled to have Velveteen rats officially added to our breeding program. As always, we’re committed to breeding for health and temperament, and we look forward to sharing these beautiful, curly-coated rats with other rat enthusiasts. This line is currently unavailable to the public as it’s still unestablished. Stay tuned for more updates and photos.

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Agouti and Black

A close-up of a brown rat with a sleek coat standing on a light surface. The text "BLEUMING TAILS RATTERY" appears in the left corner of the image. The background showcases minimalist decor.

Black and Agouti

A close-up of a brown rat with a sleek coat standing on a light surface. The text "BLEUMING TAILS RATTERY" appears in the left corner of the image. The background showcases minimalist decor.

ABOUT THE AUTHOR

With more than a decade of professional experience in the animal industry and the owner of Bleuming Tails, Abby has a deep interest in the science behind our beloved pets, and what that means for their care.

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Agouti is the natural color of wild rats. Each individual hair shaft is banded with yellow, red and black pigment vs being a solid-colored shaft. The typical Agouti color is a rich chestnut with dark slate at the base of the hair. However, domestic Agouti rats tend to be much brighter in color which can be furthered when the animal carries red-eye dilute or pink-eye dilute.

Found on the A locus
Chromosome 3

Genetics

Agouti has two alleles “A” Agouti, and “a” non-Agouti or Black. Dominant “A” produces the banding of hair we know as Agouti. Recessive “a” produces solid colored hairs. When on an animal without any other recessive, Aa and AA will all produce an Agouti animal. aa indicates the animal is black. Unlike any other recessive, every single rat has an active A locus. This means that all rats, regardless of final coloration, are either Agouti-based or Black-based.

If bred, an Aa rat can pass on either the Agouti allele or the non-agouti allele. In an AA rat, only the Agouti allele can be passed on to offspring. In an aa rat, only the Black allele can be passed on to offspring.

AFRMA Standard: The color to be a rich chestnut with dark slate at the base of the hair. Coat is evenly ticked with black guard hairs. Belly color will be silver gray. Eye color is black.
NFRS Standard: To be a rich ruddy brown, evenly ticked with black guard hairs. Base fur dark grey to black. Belly fur to be silver grey. Foot colour to match top. Eyes black.
United Rat Community Standard: TBD

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Keeler (1942) found significant differences in behavior between agouti and black rats, but no clear, sharp division between the animals of different coat color.

Temperament

In a series of studies, scientists tested the theory that Agouti-colored rats were more difficult to tame than their Black counterparts. Of course, temperament is a complicated beast and many other factors go into the general tameness of an animal.

Keeler (1942): agouti and black rats

The rats: Keeler (1942) acquired Agouti and Black rats by crossing albino laboratory rats with wild Agouti rats. The offspring were all Agouti or Agouti berkshires. These hybrid offspring were then crossed together producing rats that were either agouti, black or albino with solid, berkshire or hooded patterns. These rats were not handled post-weaning, and were not allowed to be socialized by experimenters.

The tests: Keeler put these second-generation Agouti and Black rats through a variety of behavioral tests to study how docile they were.

The results: When the rats were picked up and gently held for the first time, the Agouti rats were noticeably more likely to display untame behaviors than the black rats. More Agouti rats bit (40% of Agouti rats vs. 10% of Black rats), squealed (68% vs. 37%), laid their ears back (45% vs. 10%) and urinated (51% vs. 7%) than their black counterparts. In addition, only 1% of agouti rats showed no reaction upon being picked up, compared to 30% of black rats.

More agouti rats than black rats responded to mild annoyance. When their noses were tickled lightly with a fine brush, 86% percent of agouti rats bit compared to only 20% of black rats. Agouti rats were also much more reactive; only 15% of agouti rats showed no reaction to the brush, compared to 73% of black rats.

The intensity of the responses varied between the two colors as well. The squeals of the agouti rats were often loud and prolonged, while those of black rats were short and soft and tended to decline into a protesting whine. The urination of the agouti rats was a strong spurt or stream; the urination of the black rats was a slow emission of one or a few drops. Agoutis defecated three to five boluses of feces; black rats frequently defecated only a single bolus. Lastly, agouti biting entailed a series of six or seven forceful bites delivered with “machine-gun rapidity,” while in the black rat the bite was often a single, weak nip.

The response to handling wasn’t the only difference. Agouti rats were more cautious than black rats in emergence tests. When the cage door was opened, agouti rats took an average of 84 seconds to come out, while black rats took only 57 seconds. After three minutes, 49% of the agouti rats had emerged, compared to 73% of black rats.

Keeler (1942) found significant differences in behavior between agouti and black rats, but no clear, sharp division between the animals of different coat color. This is to be expected, because temperament is not a single-gene trait but is influenced by many genes.

Cottle and Price (1987)

The rats: Cottle and Price (1987) conducted a more complex experiment comparing the behavior of agouti and black rats. These rats were the descendants of six wild rats trapped in New York. Five generations later, the authors took 12 female and 10 male rats who were heterozygous for agouti (Aa), and bred them to produce agouti (A-) and black rats (aa). These sixth-generation rats therefore had a common genetic background, and were put through behavioral tests.

The behavioral tests and results: In handling tests, the agouti rats were more likely to exhibit defensive behavior and were more difficult to handle than black rats. Specifically, when an experimenter placed a gloved hand on the floor near the rat, a higher percentage of agouti than black rats attacked the hand, and exhibited jumping and running behavior. When the experimenter slowly approached a gloved hand and tried to touch, stroke, then catch the rat, agouti rats were more likely than black rats to attack the hand and were significantly more difficult to touch, stroke and catch.

All black rats could be touched by the second trial, but after five trials 15% of agouti rats had not been touched. All black rats could be stroked by the third trial, but after five trials 32% of agouti rats had not been stroked. The first time a rat was approached with the gloved hand, 76% of black rats could be caught, compared to only 25% of the agoutis. By the fifth trial, all black rats could be caught, compared to 75% of agoutis.

Cottle and Price also found agouti rats to be more active in an open-field test, and groomed slightly less than nonagouti rats when placed on a platform.

Citations

Experimental evidence: Coat color and temperament in rats. (n.d.). Retrieved February 11, 2021, from http://www.ratbehavior.org/ExperimentalCoatTempmt.htm

Grandin, T., & Deesing, M. J. (2014). Genetics and behavior during handling, restraint, and herding. Genetics and the Behavior of Domestic Animals, 115-158. doi:10.1016/b978-0-12-394586-0.00004-4

Chocolate and Chocolate Agouti

A person wearing a maroon sleeve holds a large rat with chocolate brown and white fur on their forearm. The background features a wooden fence.

Chocolate and Chocolate Agouti

Chocolate Agouti_Laughin' Place Rattery

ABOUT THE AUTHOR

With more than a decade of professional experience in the animal industry and the owner of Bleuming Tails, Abby has a deep interest in the science behind our beloved pets, and what that means for their care.

Share:

Chocolate was first bred in 1915 and was standardized in 1935 in the UK. In 1976, it was taken over by the NFRS but removed from standards in 1978. In 1981, Chriss Lown reintroduced the color and in 1983 it was again accepted in the NFRS standards. Chocolate was first scientifically described in 1932. Chocolate agouti is the agouti variant.

Genetics

Chocolate (or the agouti variant known as Chocolate Agouti) is caused by the recessive allele on the “b” locus or “brown” locus. The alleles found on this locus determine whether or not the eumelanin pigment in the hair shafts will be black (B) or brown (b). When an animal is BB or Bb, the eumelanin will be black, but if the animal is bb (has 2 copies of the recessive allele present), the eumelanin will be brown. Chocolate is a single-recessive color, so it’s created only by the b locus and not a combination of recessives.

It is a common issue that poor blacks resemble extremely dark chocolates and are often mistaken as such.

AFRMA Standard: A deep rich chocolate, as even as possible, devoid of dinginess and white hairs or patches. The feet to match top color. Eyes black. (English, N.F.R.S.)
NFRS Standard: To be a deep, rich chocolate, as even as possible, devoid of any dinginess and white hairs or patches. Foot colour to match top. Eyes black.
United Rat Community Standard: TBD – Chocolate Agouti known as Gingerbread

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The incomplete dominance shown by b in one strain could be a unique occurrence.

Color Variation

It has been suggested that a Bb Agouti animal may visually present as more “brown” than a BB counterpart. If true, this suggests a partial dominance or at least a strong penetrance. However, this may be strain dependent and one strain may have stronger penetrance than another. 

It has also been stated that, like the brown allele in mice, the brown allele in rats may promote larger body sizes. This hasn’t been studied extensively, but a small pattern was seen in a few 4-month-old Cinnamon rats being just slightly larger than their non-chocolate counterparts.

CItations

Robinson, R. (1965). Color Variation: Brown. In Genetics of the norway rat (pp. 14–14). essay.

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