This article is from the WSSF 2016 AFRMA Rat & Mouse Tales news-magazine.

By Karen Robbins

  

From our files
Q I’d like to find out if the Hairless rats have problems with cold, and what are the specific things you need to know about caring for them?

I have the same sort of questions about Tailless rats as well. Also, do they have any problems climbing? Are there any genetic problems with the gene that causes the absence of a tail (for example Tailless x Tailless)? I do know that it is a recessive gene. What is the history of them? Are they recognized in all colors?

And what about the Dumbo rat? Is this a recognized breed? What is their history?

Sarah Kane, RVN, England, e-mail
Q My name is Sarah Kane (I am the retired Kitten Co-Ordinator of the Yorkshire Rat Club). I am a qualified Veterinary Nurse and I am currently studying for my Degree in Advanced Veterinary Nursing at the University of Lancashire.

I am enquiring as to whether you can assist me with one of the essays I have to write whilst on this course. Part of the course is Ethics, Law and the Veterinary Nurse and the assignment is a 3000 word essay on an ethical dilemma of my choice. For my dilemma I have chosen the breeding of certain varieties of rats, namely the Dumbo, Tailless, and Hairless and whether it is ethical or not. I have been trying to research these varieties and attempting to find scientific papers and articles published in journals and books which analyse and discuss the potential medical problems associated with these varieties. By referencing these papers in my essay I can support my arguments of ‘for and against’ the variety (I have to argue both sides of the dilemma). One of the main problems I am facing is that the papers have to be current papers and have to have been published within the last 10–20 years.

I hope you will be able to make some suggestions as to which papers, journals, and books to look at and to use in my reference list and to cite in my essay.

Many thanks for all your help and any advice you can offer.

A Answer to both questions:

Tailless Rats

AFRMA has several articles online on the Tailless rats in regards to fanciers breeding them, including the problems associated with the gene (the first one is from a research article in 1915), that should answer both questions:

• Taillessness in the Rat (was written in 1915 but is the first reference we know of for Taillessness in the lab
• Tailless Rats (article on Tailless rats in general)
• Breeding Tailless Rats (article geared specifically to breeding Tailless)
• Troubles With Tailless (article about some of the health problems with Tailless)
• 5-week-old Tailless Rat with Bladder Stones
• Tailless Rats (some breeding problems with female Tailless rat, also urinary tract problems)
• C-Section Information (has mention of a female Tailless not being able to have babies)
• Creating Tailless Rats (how to make more Tailless using a Tailless male)
• Creating Various Coat Colors; Dumbo Rex Tailless Siamese? (making Tailless in other colors)

A more current research article on Tailless: Genic Interaction Causing Embryonic Mortality in the Rat: Epistasis between the Tal and grc Genes. Daniel J. Schaid, Heinz W. Kunz, and Thomas J. Gill III. Genetics, 100: 615–632 April, 1982

While a few responsible breeders have been able to breed healthy Tailless, they have many problems associated with being Tailless that must be taken into consideration before breeding them. It is not a variety for the beginning breeder. The best breeding method our breeders have found is to use a Tailless male with a tailed female (that was out of Tailless). There have been very few Tailless x Tailless breedings due to the fact the females should not be bred, but I do know of one breeder that did this and her female had no problems with the pregnancy, delivery, or raising of the litter and she got a Tailless in the litter.

The first Tailless we had in AFRMA did not have health problems, but once they became more popular and inexperienced breeders/pet shops got them, then we started seeing/hearing of problems that we had heard of N.F.R.S. breeders encountering.

Tailless are just as agile as a normal rat; however, their lack of tail can be a problem in hot weather so they must be carefully watched for signs of overheating. They can be produced in any color/coat type.

Hairless Rats

While we don’t have any specific articles on Hairless, we have many general articles on their different problems:

• Hairless Rats (question on eye drops for Hairless rats, general info)
• Flaky Rat (a Hairless with dry skin)
• Pep-Boy’s Problem (a Hairless male with health problems)
• Hairless Rat With A Rash (a Hairless with a rash)
• Bumps on Hairless Rat’s Stomach (a Hairless with bumps on stomach)
• Hairless Help Needed (question on female Hairless nursing and raising babies)
• Hairless Rat Babies (female Hairless having trouble raising babies)
• Hairless Rats–Special Care? (general question on Hairless)
• Blue Hairless Rats? (question on getting Hairless from Blues)
• Siamese Rats & Hairless Rats (question on if Hairless are fragile)

There are several research articles you can look into on different Hairless genes:

• Three variations of hairlessness associated with albinism in the laboratory rat. Ferguson FG, Irving GW 3rd, Stedham MA. Lab Animal Science. 1979 Aug;29(4):459–64.
• The Charles River ‘Hairless’ Rat Mutation Maps to Chromosome 1: Allelic With Fuzzy and a Likely Orthologue of Mouse Frizzy. K. Ahearn, G. Akkouris, P. R. Berry, R. R. Chrissluis, I. M. Crooks, A. K. Dull, S. Grable, J. Jeruzal, J. Lanza, C. Lavoie, R. A. Maloney, M. Pitruzzello, R. Sharma, T. A. Stoklasek, J. Tweeddale, and T. R. King. Journal of Heredity, (2002) Volume 93, Issue 3, pp. 210–213.
• Fuzzy, a hypotrichotic mutant in linkage group I of the Norway rat. Palm J, Ferguson FG. Journal of Heredity, 1976 Sep–Oct;67(5):284–8.
• Genetic mapping of the athymic nude (RNU) locus in the rat to a region on chromosome 10. Cash JM, Remmers EF, Goldmuntz EA, Crofford LJ, Zha H, Hansen CT, Wilder RL. Mammalian Genome, 1993;4(1):37–42, January 1993.
• Shorn (shn): a new mutation causing hypotrichosis in the Norway rat. Moemeka AN, Hildebrandt AL, Radaskiewicz P, King TR. Journal of Heredity, 1998 May–Jun;89(3):257–60.
• The rat shorn mutation (shn) maps between D7Got143 and D7Rat94. R.R. Chrissluis, T.A. Stoklasek, J.A. Loman, A. Guariglia, and T.R. King. Molecular Genetics and Metabolism, 76 (2002) 335–339.
• Further Studies of Linkage in the Third Chromosome of the Rat. W. E. Castle. Journal of Heredity, Volume 46, Issue 2, 1 March 1955, pp. 84–86.

Breeders and pet owners will house their Hairless with furry rats so they don’t get cold. You do need to watch the type of bedding used with them as some types are very drying and can dry out their skin.

The Hairless we have seen on the show bench and from our breeders have been healthy, but they do have their own unique problems that must be taken into account by anyone who breeds them. The most common is some females not being able to raise/nurse their young so it is always advised to have a foster mom on hand when breeding them.

There are also different ways to get Hairless—one is by breeding Rex to Rex and selecting for the least amount of hair. These will have fuzzy face and feet. The way to tell if you have a Rex Hairless is if this is bred to a normal-coated (Standard) rat, all the babies will be Rex. The other way is to get one of the recessive Hairless genes. These can range from completely Hairless with just their curly whiskers, to having some fuzz on the face and feet. When bred with a Standard rat, you just get Standard babies that carry the Hairless gene. The first Hairless rats we saw being shown were from the Rex to Rex breedings (always had fuzzy face and feet), then one of our members got a true Hairless (had no fuzz) and everyone started breeding those instead. Since then we have seen many versions of the Hairless being shown.

Dumbo Rats

Dumbo rats originated in a breeder’s stock in Northern California around 1991 and were confirmed in 1993. They made their way to one of the shows of the San Francisco based Rat, Mouse, Hamster Fanciers (RMHF) club that was around at that time where other breeders took an interest in them and began breeding them. They were standardized in AFRMA in 1998. They have a wide range of ear shapes and sizes and can be made in any color or coat type. To my knowledge, breeders have not had any troubles breeding Dumbo rats.

There are a couple research articles that tell more about the physical change to the skull to make them Dumbo:

• Expression of Msx1 and Dlx1 during Dumbo rat head development: Correlation with morphological features
• Deletion of a conserved regulatory element required for Hmx1 expression in craniofacial mesenchyme in the dumbo rat: a newly identified cause of congenital ear malformation

We don’t have any specific articles on Dumbo but have a couple general ones:

• Making Dumbo Rats
• Dumbo Rat Ears

Nicolas Salarí, Uruguay, Facebook
Q My name is Nicolás, I’m from Uruguay, and I breed rats for snake food. To my surprise yesterday with a pair of albino normal rats was born a Tailless. I did not know they existed, then looked for information and found your site. It is the first born Tailless rat in my breeding room, and that never happened with my provider of rats. My Tailless is a month old, he looks normal, and is no different than his brothers. Do you think it’s appropriate to raise my Tailless with some brother, or is it better with a rat not related? Thank you for your help.

A Tailless is a mutation that can pop up when you don’t expect it. Yes, you can raise him with his brothers. See the first answer for many articles you can read on Tailless. If he is healthy and does not have any physical problems from being Tailless and you were interested in trying to breed for more (make sure you read up on everything on Tailless before attempting to work on a Tailless line as they can have serious issues—we have several articles online), having a male Tailless is the best option as most females have problems with a pregnancy or delivery, so it’s not recommended to breed the females. You can breed him back to his mom or to his sisters. You could also repeat the breeding of his parents to see if another one might pop up. Just be aware that breeding Tailless has its risks as more physical problems are common with these than other types/colors of rats and should not be undertaken lightly. Be prepared to stop the lines if any of the physical problems show up.

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