Blue Rat Support Group Article

DUMBO RATS: A New Wave of Rattie Cuteness

What's as smart and friendly as a rattie, has the ears of an English show mouse scaled up to rattie size, is usually as calm and sweet as a sleepy rattiebaby, and is taking the US rat world by storm?

Dumbo rats!

A dumbo rat is simply a normal domestic rat, Rattus norvegicus (same species as almost all pet rats), with a mutation that enlarges and widens the ears and places them lower on the head. Somewhere along the line most of these rats appear to have been heavily selected for a docile temperament. They suffer no disadvantage due to their unusual ear set and size and slightly broader, flatter heads. In fact, their winsome sweet faces appear to be largely to their advantage when it comes to out-cute-ing the competition, whatever the species......

Now, let's lay two falsehoods to rest.

1. All dumbo rats are calm to the point of being comatose.

Incorrect. There is a TENDENCY for dumbos to be calmer than usual, but I have seen hyper ones. There's a lot of overlap between activity levels in standard-eared rats and dumbo rats. As in any variety, there are exceptions who do not follow the tendency--I have a beautiful young blue rex dumbo girl, MNM Oceana, who has always been very twitchy and fearful; fortunately her breeder socialized her carefully and I was able to build on that good foundation to establish trust with her and get her calmed down. Now she will actually step off a high ledge to my hand and run down my arm to my shoulder. She will come when I call her. But this has taken several months of daily work. On the other hand, the vast majority of dumbos I have worked with (my rattery, AristoRats, specializes in marked and siamese dumbos, so I have some experience) have been generally friendlier and sweeter/cuddlier/calmer than the standard rats I have worked with, many of whom have also been excellent.

2. Dumbo rats are deformed and should never be bred.

I guess that depends upon how you define "deformed". This could get into a whole big can of worms; let me say, though, that the simple recessive dumbo gene is in my experience less detrimental to survival of the individual rat than some other genes, such as blue (which can result in slightly smaller size), and pearl (which, when doubled up, causes smaller litters due to prenatal/postnatal mortality, pearl being a lethal gene in its homozygous state). I have observed no such disadvantages to the dumbo rat. This is one reason why I have chosen to breed dumbos--that wonderful temperament, those adorable faces, and all without any accompanying disadvantages.

To the best of my knowledge, the dumbo variety seems to have mainly come from the Northwest US, with fairly large populations in Washington State, Idaho, Oregon, etc. from what I have been told. In the last several years they spread first to California, and then to the east coast. Shortly after their arrival in the east, I cooperated with another local breeder in importing a shipment from Blue Ridge Rattery in Washington State and Opaline Rattery in Idaho. They wanted to send me some Dumbos and Japanese Elephant Ears, a related variety, but I was skeptical. Wasn't that a deformity? What kinds of health problems did they have? I was told that they were perfectly healthy. I doubted it but since the price of shipping in rats was only minimally affected by the number of rats shipped and several people wanted rats in the shipment, I approved their addition to the shipment. I will never forget my reaction when we opened the shipping containers. One of the first was a baby self black dumbo later named BR Bonaventure. OH MY GOSH WAS HE CUTE!!!! He looked like a faintly rattie English show mouse--or like Fievel from Steven Spielberg's animated movies such as "Fievel Goes West"--beautiful baby rat face with big black eyes and HUGE ears that gracefully curved down around his was an "AWWWWW! How CUTE!" moment. I know I am going on and on, but if you had seen him you would too.....

Anyway, we examined the other rats of the shipment and I ended up falling in love with the dumbos, keeping several of them, and breeding them. That was the beginning of the dumbo variety in the Midwest states of the US.

Dumbo rats are standardized, as far as I know, by the Rat and Mouse Club of America and by NRMCI. I am not sure of the other clubs. Dumbo rats are shown according to their color/marking/variety. The ears, according to RMCA club founder Mary Ann Isaksen, should be moderate in size and free from folds. There is quite a bit of variation in ear size and shape. Personally, I don't care much about ear shape or size; rather I focus on temperament and health first, and use factors like ear shape/size and color and so on to make final selections. Shhh! Don't tell.

I am happy to correspond with people in regards to Dumbo rats, and indeed in regards to anything rattie at all. I can be reached by email at, and my site (which features pictures, links, and genetic info) is at

Sarah Shuman
AristoRats Rattery
Illinois, USA

Genetics Info Regarding Dumbo Rats

The dumbo mutation (which I call Du for my own convenience, because I have never seen any reference to any "official" designation), is a simple autosomal recessive trait. This mutation alters the design of the head somewhat, broadening and slightly flattening the head and changing the shape and position of the ears. The ears of a dumbo rat are wider, larger, and placed lower on the head (appearing to grow from the back of the cheeks rather than from the top corners of the head as in a standard rat. The mutation has no impact on fur color or any other dimension of the rat's body. As previously stated, it is recessive and is extremely reliable in this way in terms of expressing consistently, unlike the genetics of manx (tailless) rats. In my opinion, after a fair amount of experience with this variety, there is no adverse impact on the dumbo rat from its unique appearance. They can be bred in any color variety. This variety can be successfully combined with hairlessness, but from what I have been told it is not possible (at least so far) to breed a tailless dumbo--there is some sort of incompatibility, genetically, the nature of which I am not informed enough to guess at.

Sarah Shuman