This page documents my project to develop silvermanes.
An import from Canada in 2016 brought (among others) a potentially distinctive new variety caused by a dominant gene, silvermane, to the UK. This new gene affects the coat, causing the ends (approximately 3/4 of the length) of the hairs to be silver (probably in fact translucent in structure), with more and more hairs affected as the rat ages, meaning that the adults can look quite striking with pale bodies and darker muzzles and ears, similar to an argente rabbit. A silvermane rat can be of any colour, but the effect looks most dramatic on dark varieties. I am keen to help establish the variety by developing a new line here employing a non-cull approach.
The silvermane gene mutation first appeared in 2012 amongst rats belonging to a feeder breeder, and since then more have been bred and passed on to further breeders in America and Canada, and more recently, Europe. Understandably, given their roots, these rats do not yet have particularly good genes in general, and the imported rats will not bring just the silvermane gene with them, but also various health, temperament, and type problems as well which will need to be overcome. There are several breeders in the UK who will be working independently to develop their own silvermane lines.
Initial plan: I will be improving them by crossing with the most robust rats from my own lines, probably creating mostly chocolate based silvermanes in self and agouti, as well no doubt as some who are american mink based. Since silvermane is dominant, I will be able to dilute the other imported genes by a factor of two with each subsequent generation by mating silvermanes with rats from my standard Zephyr lines each time. Also, by using silvermane bucks wherever possible, I can postpone the mating until they are old enough to have exhibited any hormonal issues, thus allowing me to select the best bucks to use. Once I am reasonably happy with the quality of the kittens being produced, I will test mate by inbreeding to reveal what recessive genes have been carried through. If the test litter proves satisfactory, then I will move on to my normal method of line breeding, and be able to focus on improving the silvermane coat.
Revised plan: Following the first litter, given the relatively low expression in most of the silvermanes, and because there were no immediate significant health concerns, an inbreed was planned to discover whether better expression could be expected from homozygous silvermanes. It would seem that stronger expression is more likely, so to balance this with increasing their 'zephyrness', future litters will be divided between silvermane inbreeds, and matings with a standard Zephyr. I'm currently going to aim for bases of agouti, american cinnamon, and chocolate.
Initial plan: The kittens from this development line will not be available to new pet homes until and unless they reach acceptable levels of both health and temperament, which may take several years. In the meantime, I will probably be keeping all of the silvermane buck kittens, and will be relying on the much appreciated help of experienced friends who are willing to deal with the potential issues that might arise to take the other kittens.
Revised plan: The first litter have largely proved to be delightful pets, with the only issues being that 2 does became over dominant with cagemates and were spayed, this may possibly have been due to the lack of a strong alpha in the group. Therefore, kittens from future litters which are crossed with standard Zephyrs will be available to a wider set of homes, although still not to brand new owners. Kittens from inbred silvermane litters will still be restricted to the most experienced homes.
In order to differentiate this development line from my other rats, I shall be naming them after artists rather than songs. The first generation (F1) will be from the 1950s, the second (F2) from the 1960s, and so on.
The imported rats arrived in the UK at the start of June 2016, and after fathering some litters for another breeder, one of the bucks, Mr. Bungle, came to live here at the start of September. He is an agouti based silvermane dumbo (although it is hard to see the silvermane effect visually), his colour is unknown and could be carrying any number of other genes (some unusual kittens have appeared in his other UK litters). The imported rats have come from Canada with just the coat on their backs: no name, no date of birth, no family tree. I estimated Bungle's age to be roughly 18 months on arrival, but have no clues to what genes he might be carrying.
Mid September - I believe Bungle has a sweet core, he shows some interest when I approach him, but is still shy and he doesn't like being handled. So far he has shown no sign of wanting to chew the plastic base of the cage he is currently in. He hasn't ventured into the hammock (unlike another imported rat who had a brief stopover here), so may not be the sharpest in terms of brain power or bravery. His left eye is shrivelled (a common problem where he came from), and I doubt that he can see much if anything through it. He has been tried with other bucks but will not accept them (a side effect of having lived his whole life as a stud buck), and loses condition rapidly when kept with does, but once I have some confirmed silvermane kittens, Bungle will be neutered and introduced to some companions.
Early October - having moved into half an explorer cage, after a few weeks of getting used to his new surroundings I introduced Bungle to the concept of cuddles, and now, once I have scooped him up, he relaxes and enjoys strokes and head massages causing him to brux and lick. He doesn't yet approach me or ask to come out, but doesn't always move away either. At this stage, caution regarding the temperament of his offspring is still advisable, but it won't surprise me if they turn out to have perfectly acceptable pet temperaments. He has developed a slight mask since arriving, and his coat has a particularly silky feel.
Mid October - I have introduced Bungle to a couple of elderly spayed does, and they have settled happily together.
Early January 2017 - Bungle's sons were introduced to his group without any issues.
March 2017 - Bungle remains fit and well, although an attempted mating has failed to result in a litter, so he may be losing fertility. He is now a fully integrated member of his group, and will come to the cage front of his own accord to greet me.
October 5th 2017 - Mr. Bungle sadly passed away today, he'd had HLD for a while but was managing well, he died peacefully in the cage. We'd recently discovered his date of birth was 21/07/15, so he made it to 26 months.
September 2016 - Zephyr Foxy Lady (standard Zephyr, chocolate american mink) was mated with Bungle.
14 kittens - 7 silvermanes, 6 selfs (so Bungle is carrying self), 2 black and 3 agouti (so Bungle is not expressing UK chocolate or american mink).
The silvermane kittens exhibited a pale point on their snout by two weeks of age, with the agouti buck's being the most prominent.
By the start of the kitten moult, the agouti buck's mask was very clear, but the selfs began silvering from their bellies up. Their coats are now very silky, easily distinguished by touch alone, regardless of how much silvering they have developed.
I prefer the effect on standard agouti, or on chocolate self. I suspect that Bungle is expressing a dominant chocolate gene, but later matings will make this clear. Some of the kittens have a brighter coat like Bungle does, probably due to a RED type gene being carried (aka 'dirty orange'), but this mutes the impact of the silvermane coat in terms of the facial mask.
Full picture history can be found on the litter page here, but these are the agouti and chocolate bucks at 7 weeks:
May 2017 - a mating between two silvermane kittens from Foxy's litter to investigate the relative degree of expression in homozygous silvermane: Zephyr Eartha Kitt (F1, black silvermane) was mated with Zephyr Elvis Presley (F1, agouti silvermane).
6 kittens - 3 silvermanes, all fully silvered as soon as their coats emerged, 1 american mink doe and 2 american cinnamons (buck has a stronger mask than the doe). I'm quite keen on the american cinnamon silvermane, even though the mask is not very distinct.
Full picture history can be found on the litter page here, but this is the american cinnamon silvermane buck (Paul McCartney, aka Macca) at 12 weeks:
July 2017 - a mating between Zephyr Carrie Ann (standard Zephyr, american mink dumbo carrying RED but probably not carrying chocolate) and Zephyr Bo Diddley (F1, chocolate irish silvermane) to test the chocolate gene and for silvermane selfs.
10 kittens - 5 silvermanes, none distinct as the coats emerged: an american mink buck and a chocolate doe who became very nicely silvered after their moult (they have gone to some breeders in Sweden), a black buck, and two chocolate does were not so well silvered. I chose to keep the worst because she has the best temperament and I intend to mate her with another silvermane. There were no chocolate looking non silvermane kittens, but one of the silvermanes looked more like a black than the others who all look chocolate, so for now I'm hoping that my chocolate silvermane keeper is a dominant chocolate - I plan to mate her with another chocolate as a further test.
Full picture history can be found on the litter page here, but this is my keeper (Cilla Black) and her mink silvermane brother, aged 8 weeks:
January 2018 - a test mating between Zephyr Bo Diddley (F1, chocolate irish silvermane) and Rivendell Elleth (black, known to not carry UK chocolate) to test the chocolate gene more rigorously.
16 kittens - 11 silvermanes, none distinct as the coats emerged: several became quite nicely silvered after their kitten moult (two will be exported to a breeder in France), 11 are clearly chocolate rather than black like the others proving that Diddley and they are dominant chocolates. One chocolate silvermane buck is also a satin, this was identifiable as a young kitten but looks the same as other silvermanes in adult coat. I kept the satin, a chocolate silvermane doe, and a buck and doe in non silvermane dominant chocolate for future test matings using this gene.
Full picture history can be found on the litter page here, but this is the satin silvermane (Donovan), aged 10 days and 10 weeks:
future matings planned are:
March 2018 - Zephyr Cilla Black (F2, dominant chocolate silvermane) will be mated with Zephyr Paul McCartney (F2, american cinnamon silvermane, possibly UK chocolate based), to produce visually stronger homozygous silvermanes with great temperaments.
October 2018 - Zephyr Marianne Faithful will be mated with Zephyr Mick Jagger (both F2, dominant chocolate, non silvermane) to investigate homozygous dominant chocolate, and potentially 'double chocolate' if they both carry UK chocolate.