Whats taking the US rat world by storm?

Dumbo Rats: Genetics:

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?"

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.

Dumbo Rats A New Wave of Rattie Cuteness