# dwarf rat genetics?



## hannah (Mar 19, 2010)

Six monthes ago I purchased a supposed rex dumbo earred dwarf rat from a local breeder. I love the little guy, even though he is a rather, well, BIG guy. He is even larger then our standard sized male who is his cagemate, so Im wondering if dwarf genetics can skip a generation? I saw both his parents on site, and they were dwarf sized...


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## sorraia (Nov 10, 2007)

True dwarfism in rats is a simple recessive. What that means: If you breed two dwarfs together, all babies will be dwarfs.

What you have is probably a case of size variation NOT true dwarfism. Size variation is natural. You can have larger rats and smaller rats in the same family. Two smaller rats (that are NOT true dwarfs) can produce larger babies. Likewise two larger rats can produce smaller babies. Many of the "dwarf" rats people have are actually just small rats, not true genetic dwarfs.


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## ema-leigh (Jan 24, 2010)

I have seen breeders advertising small sickly rats as dwarfs, when often they were just the runts of their litter. Or the rats you saw were not actually their parents - if they were true dwarfs that is. Does this breeder have a website? 

The dwarf gene works as the rat is resistant to its own growth hormones. So the fact your rat grew tells you its not a genetic dwarf. If a dwarf is bred to a standard, the litter will be a mixture of both dwarfs and standards. I have never personally dealt with dwarfs, but I read it can be hard to tell who is dwarf and who is not until they are 6 weeks old.


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## hannah (Mar 19, 2010)

That would make sense, as the mother rat was small and the father was too but there was no proof that they were "true dwarves".. and the father might not have even been the true sire, but the babies were still in with mom when i picked mine up so I do know the mother was the real mother. Both parents were probably just small rats :] It doesnt matter to much to me anyways, I love Draefuss just the way he is!


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## ema-leigh (Jan 24, 2010)

Heres a pic to show you the size difference between a dwarf male and a standard sized male. Picture found at random on google search.


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