American Fancy Rat & Mouse Association

This article is from the WSSF 2007 AFRMA Rat & Mouse Tales news-magazine.

The Pearl Rat

By Ann Storey, N.F.R.S., England

From Pro-Rat-a, No. 154 July/Aug. 2006, the N.F.R.S. journal. Permission given to reprint article.

STANDARD To be palest silver, shading to creamish undercolour. Each hair to be delicately tipped with grey evenly over the whole animal. Belly fur pale silver grey. Foot colour to match top. Eyes black.

  • Points
  • Top colour
  • Belly colour
  • Feet
  • Remainder – general conformation
  • Total


The Pearl would appear to be a development of the NFRS as, despite extensive research, I have not been able to find any record of them in the previous rat fancies. However, the Mink, which is closely related to the Pearl, certainly predates the modern fancy. There are records of rats called Blues in the early 1900s which had a habit of moulting into chocolates. These may well have been Minks. The first real record of Minks occurs in a Fur & Feather article of 5 February 1932. This article, entitled “A London Rattery” by John Wilton-Steer (previously president of the National Mouse Club, which also catered for rats, in 1905), describes a visit to the rattery of one Thomas Adams, a rat fancier who appears to have had a most impressive establishment. Mr Wilton-Steer comments, “Still more novelties – smokes. What a beautiful shade, I should imagine that with careful selection Blues may also be obtained from these.”

The first Mink I ever saw was for sale at an insect exhibition held at the then flagship comprehensive Holland Park School in London (Tony Benn’s son, Hilary Benn, went there) in 1973. The rat had been bred by the school, and I bought it (without parental consent) for the large sum of 50p. She was a Hooded doe called Bonnie.

When I joined the NFRS and exhibited at the 1976 London Championship show, one of the highlights of the show was the AOV class, there being no unstandardised class then. King of the unstandardised breeders was the Love family, also known as Genesis Stud, and they had entered a large number of rats in this class, both Minks and Pearls. Albert Collins, who was judging, gave the following report: “The next two rats were unstandardised, but what smashing rats . . . a deep cream undercoat blending to a silver cream top then topped with black.” I was there, I saw them, and they were dark Pearls. At that time neither they nor the Mink had a name.

For the next couple of years Clive Love and the rest of the family dragged their heels about standardising these rats. In the end, another strain of Pearls, also bred out of the widely available Mink and belonging to Jackie Chapman, were the ones standardised (1978). This, I may add, was due to pressure placed on her by the then committee, not because she wanted to get one over on Clive. Minks were standardised sometime later and were given their name by Gill Cooke, wife of a then mouse fancier Tony Cooke.

For some reason both Pearls and Cinnamon Pearls became rare within a year or so of being standardised. I have to say they were not spectacularly robust. I have only seen prolapsed uteri in two breeds of rat and that was in the early Pearls and the early Siamese. They required more cossetting and better feeding than most of us had access to in those days. Eventually the whole lot had dwindled down to a couple of bucks, a Cinnamon Pearl called (I believe) Tarl Cabot owned by Nick Mays and a big maloccluded buck owned by Sara Handley called Jasper. It is from Jasper’s mating with a Cinnamon Hooded doe (Anna Maria) with exceptional type that all the modern Cinnamon Pearls and Pearls come.

They were described in the scientific literature by Roy Robinson in 1994 with stock obtained from the fancy.

The early Pearls had the following faults: thin tails, cobby bodies, small size, small ears, short blunt heads, long coats, and aggression. Most of these traits have been bred out, although they do have a tendency to cobbiness and short heads. Another common fault is an Irish type white mark on the chest which is also found in Cinnamon Pearls. Ironically, it often occurs in rats with the best type and colour. The temperament of Pearls nowadays is very good.


Genetically, Pearls are Mink (mm) (Cinnamon Pearls are also mm) rats heterozygous for the Pearl gene (Pepe). Pearl is a lethal dominant which means that rats that have two doses (that is homozygous) of Pearl, either die in utero or possibly very shortly after birth. [In my experience, it is very rare for homozygous Pearls to come to term and when they do, they appear to be stillborn rather than dying after birth. Veronica Simmons] This means that litters of Pearls also generally produce Minks. Although Pearl is dominant to Mink, it does not express itself on any other colour with the possible exception of Russian dove, most of which are actually Russian Minks. The pearl-like gene responsible for Powder Blue and also seen in Chocolate is a different, recessive, gene.

One odd thing about the pearl gene is that it does not always express itself. This means that some Mink rats are not Minks but Pearls. This means that it is possible to breed Pearls from two supposed Minks, which is how they were first bred. The Pearls bred this way tend to be dark and are sometimes called dark phase Pearls.

Merles are Pearls (it also occurs in Cinnamon Pearls) with splashes of Mink. They used to crop up fairly commonly years ago but this was bred out. I once had one where half the head was Mink and the other half Pearl. The actual cause is unknown but as Pearl seems to be a relatively unstable gene, it is most likely caused by reversion mutations (as happens in variegated plants) in some of the early colour producing (melanoblast) cells migrating from the embryonic spine. As far as I know, there are no breeders breeding Merles in the UK at present but they are available in the USA.


A good Pearl has a wonderful pale silvery-grey coat and beautiful black eyes. The tail, ears, and feet are covered with fine grey hairs. The underside is a greyish shade although the standard does not describe it particularly well. The undercoat should be white with a hint of cream. They tend to be darker on the nose and feet, which is why in the early days before we had real Siamese some people thought that’s what they were. Good kittens are common and always do well on the show bench as they are very attractive and good at catching the judge’s eye. The trick is keeping them like that. Pearls need very level and optimum growing conditions. They need good quality feeding and no sudden temperature changes. If they do, then the colour tends to patchiness. It is important to remember that after the third or fourth moult, rats do not undergo complete moults but moult out in patches. With some varieties, including Pearls, if there are any changes in the environment, then these patches will be darker than the surrounding fur. These darker patches spoil the rat for showing and are one of the reasons why many beautiful kittens are never seen again on the show bench. In fact, over-showing as a kitten can precipitate this. These dark patches are not to be confused with Merles. Sootiness, that is where a rat is too dark due to an increase in length of the coloured hair tip, is also a serious fault and tends to occur with time in any strain of Pearls, although it can be increased by crossing with Minks. It must be rigorously selected against. Because of the tendency to sootiness, the Mink outcross is not to be recommended. Pearls are best bred with either other Pearls or occasionally Cinnamon Pearls.

Apart from the colour, the other striking point about Pearls is the eyes, which must be big, bold, and blackberry black. Previously I have said that Pearls always have good eyes, however, some I have seen recently have had quite small eyes. This is a serious fault in this variety and must be selected against.

Pearls have always had a number of dedicated breeders, including those who do little else. Of recent years Kropotkin [Veronica Simmons], Darkstar [Melanie Goulder], Holywood [Nicky Jones], and of course Serendipity [Paul & Sue Threapleton], have been successful in keeping this variety winning. *

English Pearl Rat
An English Pearl buck owned and bred by Karen Robbins, Karen’s Kritters.

Go to The Cinnamon Pearl Rat

Back to top

Updated December 28, 2018