Feature Archive 4 - Last quarter 2000
Tailless rats have been available overseas in the US,UK & Europe for some time now.(Although in England the NFRS forbids their breeding, and in Sweden the authorities forbid it.)
In 1999-2000 Australians saw the appearance of our first Tailless rats, arising from spontaneous mutations in a number of different breeding lines. Even more recently, Tailless have appeared in New Zealand, having come through the lines exported there from Australia.
While this is a very exciting time for the fanciers who've found these little surprises in their litters, the general knowledge of Tailless and the issues involved with breeding them, is largely misunderstood or unknown by most people here. This would undoubtedly be the result of us not having had this breed in the past.
Tailless rats come in a range of 'types'. Rumpy, Rumpy riser, Stumpy, shorties & tailed carriers. Here in Australia ANRA recognise the Tailless as a standardised breed, Rumpy's are the only ones able to be exhibited While it's the norm, to breed with the other types. So far the genes responsible for them here appear to be recessive ones.
Rumpy Tailless have complete absence of all tail vertebrae, some even have an indentation where the tail would normally start. Rumpies have a slightly shorter body than normal tailed rats and a rounder body shape(Pic A4.1). This is natures way of compensating for the lack of tail. Most rumpy Tailless rats exhibit a different gait to normal, almost a bunny hop fashion. All the rumpy Tailless I have known personally have no problems with balance. In fact they're more active than a lot of tailed rats, climbing around like little monkeys.
Rumpy Riser Tailless also have complete absence of all tail vertebrae, but these have the normal body shape. This makes the back half of their body, end in a pointed shape and sometimes an upturned look. Because of having a normal body shape, they are generally considered to be safe to breed from.
Stumpy Tailless have between 1 & 6 tail vertebrae. This is usually straight, but can sometimes be kinked or even curled in a bobtail like fashion. Stumpy's are usually the Tailless type of choice for breeding.
Shorties are like Stumpy's only they have more than 6 tail vertebrae, but not as many as a normal tailed rat. These are not as popular among fanciers, and don't occur as often as the other types. It would seem that these could be harder to re-home due to the fact that some of them do look like they've had an accident to acquire their shorter than normal tail(Pic A4.4). This type can be the result of a mating between a stumpy and a tailed carrier, they're not used for breeding as much as the former two types.
Tailed carriers look like regular tailed rats, they're just carrying the gene or genes for the tailless trait. (Pic A4.5). In a minority of tailed carrier rats the tail can appear to be slightly shorter than normal in relation to their body length, but it usually takes an expert used to looking at Tailless types to pick this out .
Some rats can be Tailless through accidents(non-genetic tailless). Mum may have been overzealous in cleaning her newborn and eaten some or all of the tail. Or another rat may have grabbed and bitten some of it off. It's tail may have gotten caught somewhere and broken off, or there could even be the issue of disease to cause it, in the example of ring-tail. There is also a nutritional condition that causes siblings to mutilate themselves and each other, and the tail appears to be one of the first places they start.
NOTE:- there is one other way a rat can become Tailless. 'Docking'. While this practice is largely frowned upon by most fanciers,(including myself), it is practiced by some breeders. Said to improve the saleability of the babies, tails are docked when the pups are under a week old. There can be problems associated with this practice, one of which is the mothers not accepting their 'mutilated' babies back into the nest, and in turn harming them or worse.
There is also the issue of the animal itself, having either balance, walking or movement problems due to it's unnatural lack of tail.
I personally feel that docking is a very cruel act. Not just in Rats, but in any animal. Having been a vet nurse for years, I've often had to assist the surgeon with tail docking procedures done on dogs(puppies) before. I now refuse to assist in such procedures, and have also been involved in organisations here, to ban the unnecessary and cruel habit of taildocking among dogs. There are now some canine clubs here that will accept dogs of certain breeds (ie. Doberman, Cocker spaniel, Rottweiler) in their natural tailed state.
As with the genes causing Tailless traits in other animals (ie cats & mice) There can be lethal outcomes to breeding Tailless rats.
In Cats the gene causing the taillessness is the dominant gene M. Tailless cats are called Manx due to the origins of the first of this type. (the Isle of Man). Homozygotes (MM) die inutero. called a prenatal lethal. All manx cats are heterozygotes (Mm). Manx cats can be affected by a number of anomalies of the lower vertebrae and anal region. This leads to some of them displaying a stiff-legged or stilted gait because of pelvic defects.
In the US they have produced a longhaired variety of tailless cat, called Longhaired Manx or "Cymric". This type unlike their shorthaired relative has no original connection with Wales
There is another type of cat with an irregular tail. These are the Japanese bobtail cats. These far Eastern Cats are affected by a gene which causes tail shortening very different from the standard manx gene in cats. The tail is never absent, only shorter and sometimes kinked or curled. There are no overt signs of any abnormality with this variety.
I have personally bred Tailless mice since 1994, and while we are fortunate that the problems that can arise, never have in our lines, we still take great care with selection of breeding pairs. The gene causing our Tailless mice is a recessive one & I have my theories about whether or not there are any lethalities associated with it at all. It would appear though, from having talked to breeders of Tailless rats overseas, that the undesirable traits & resulting problems, that can arise when dealing with Tailless genetics, occur more frequently in Tailless rats than do in Tailless mice. As I haven't had any such deformities or problems in my own Tailless rats to date, I have to go on the experience of other breeders at this time.
There are two known genes causing Taillessness among fancy rats. One is a dominant gene, the other a recessive one. So far the genes mutating here appear to be recessive. The combinations of genes causing taillessness in Rats are a complicated issue, there is a lot of polygenic factors to consider.(also sometimes referred to as modifiers) These factors are sometimes not even fully understood by dedicated fanciers who have bred them for a long time and often not even fully explainable by geneticists. What we do know is that the shortening of the spinal cord(effecting the absence the coccygeal vertebrae of the tail) can go too far sometimes, leading to the rat exhibiting such conditions as spina bifida (S.B.)
Other documented conditions include birthing problems in rumpy Tailless females, due to skeletal deformity of the mother, which can lead to the death of the pups, the mother or both. Some of the problems that can occur are; the birth canal being too narrow, thus making birth impossible, The pelvic area being fused in places & so unable to move normally during the birthing process and the pelvis itself being too loosely connected to the spinal column, thus the pressure of labour can damage this area, leaving the female paralysed.
There have even been rare cases of pups born to Tailless parents that have absence of some joints and bones altogether, resulting in paralysis issues, and loss of voluntary bowel and urinary function.
While Tailless rats do have the risk of being born with deformities or S.B not all Tailless develop these problems, in fact they are definitely in the minority. There are breeders that have bred generations of tailless rats for years, that have never had S.B. occur in their lines. It's all a matter of responsibility, paying close attention to even the most minute details of every animal and keeping comprehensive accurate records.
If you're really serious about breeding Tailless rats, you must be willing to take the time to research the breed thoroughly and breed to strict rules, governing which animals are selected to strengthen the line and reduce the risk of problems.
The percentages of S.B. occurring in Tailless rats is in fact lower than that of some other lethalities occurring in other varieties of fancy rats. (Megacolon being just one example).
There are some other issues that have been brought up with this breed. One of them has to do with bodily temperature regulation. Because rats like so many furred animals, don't have the ability to perspire like humans do, they lose excess body heat via their tail, ears and paw pads. This begs the question, that if they don't have a tail, then their body heat escape routes are greatly minimised.
Only fairly recently however this theory has been under question, with Tailless rat breeders who are living in hot climates, not reporting any such problems. Maybe the temp. regulating problems some breeders feel are there are also a polygenic factor, affecting some lines but not all.
Because of the lethal problems associated with the genes of this breed, inbreeding, and linebreeding are not usually recommended, with outcrossing being the sensible and humane way of approaching a Tailless rat breeding programme.
The general rule is 'never breed from a rumpy female'. If you want to have a rumpy parent, then breed a rumpy male to a 'safe' female.
If you are prepared to have your rumpy Tailless females x-rayed, and the results show that the skeletal form is normal in structure and size - In particularly her hips, pelvis and birth canal, then it is probably safe to breed from her. The Stumpies, shorties and tailed carrier females are the better choices for breeding, and in some cases rumpy risers.
Because the possible complications with this breed, can be so severe, and the results being quite shocking, Tailless is a controversial breed. Opinions among fanciers vary, from open acceptance to complete non-acceptance.
There are people out there doing the wrong thing, breeding for financial gain or to be the first one with something new to sell, along with other unacceptable reasons. While we as responsible fanciers cannot control these bad breeders, what we can do is control our own breeding practices & ethics, so that our lines of these more exotic breeds of rat, will be sound and well bred. By doing this we decrease the likelihood of problems occurring in our own rats and to a degree in their future offspring to other breeders.
In conclusion - Tailless is only a recent mutation in Australia and it's future here is largely unknown as yet. While there is plenty of interest in Tailless rats here, the general knowledge of their health, is poor at best. This coupled with the Australian public's view of rats in general, (which needs a serious overhaul) means that for breeders like myself, there is definite cause for concern with abuse issues, should they fall into the wrong hands.
For these reasons, I have chosen to develop the line of Tailless I presently have, keeping all of the offspring for the first 4 generations at least, after which time, should the line prove to be sound, I will consider offering de-sexed rats for adoption.
The thought that later on down the track, someone may be indiscriminately breeding from stock originally from my line, is a large weight to bear and one I'm not sure I want to be responsible for. Only time will tell.
I consider myself very fortunate to be among the small group of fanciers in Australia, to have had Tailless babies just show up in litters. First in a line of bareback rats we had. (Line was closed for other health-related problems - not anything to do with the taillessness. - see main rat article, esp. part about "Besos")
Imagine my surprise upon discovering the little guy "Maverick", and my relief at realising 'he' was a male, rather than a female, which up until then, had been the result of all the other Tailless rats occurring in litters to other fanciers.
Second, in our DU line(at least three other breeders I know have also had Tailless mutate from their DU lines), a little female rumpy riser(with a skin tag)"Sarabi"-pic A4.6. An Agouti Down Under Hooded, born 28th December 2001.
In 2002, we adopted two little Tailless girls from a friend who was moving.
Baci-PicA4.7 - a rumpy(with a skin tag)black DUSpotted &
Flower-PicA4.8 - a rumpy Dove DUHooded.
Both these girls came to us with the news that they were infertile, as the previous owner had tried to breed them on a number of occasions. It was a very great surprise then, not to mention a great worry, when we found Flower looking very pregnant. There was only one possibility for the father, that being Avatar, our Opal hooded boy, as both Flower & Baci have routine 'bouncing' time, when-ever I'm cleaning anyone. Not usually with males however, only this day Avatar & his lady friend Flot were having a wander while I cleaned their home. So it's obvious what happened, an embarrassing mistake on my part.
Never assume a rat is infertile, even if she appeared so at one stage.
I'm very relieved to say though that Flower gave birth to her litter, 7th October 2002, & nursed them with no problems. All the babies do have tails.
One of these babies "Rumpus", went to Robyn & Al of Dapper Rat here in Brisbane. & we have kept the rest.
On the 18th April (2003) we bred a litter from this line, again keeping all 9 babies. So these 2nd generation babies, bring us half way to what I hope will turn out to be a sound line. So far, so good.
Below I've included a couple of pages from Maverick's family photo album. Our first Tailless rat.
'Maverick' at 3 days old.
'Maverick at 9 days old.
'Maverick' at 4 months.
I'm always looking to learn more about Tailless rats & as such, would love to chat to other breeders of Tailless, or anyone interested in them.
Yours in Rodents