Dumbo is an ear type from a recessive gene. Gene: dudu
There are some common myths that surround Dumbos. Dumbos are not any sweeter, larger, etc... They are also not a different breed of rat. Dumbos are still fancy rats, that same as standards. It is just a different ear type and nothing more.
Dumbo is simply a gene that affects the ear type and placement. You can learn more on my page on Rat Varieties.
There are only two ear types in rats the first is called Standard and the other is Dumbo.
You can not have a half standard/half dumbo rat, this usually would just be a rat with poor ear type that doesn't fit the standard.
Description: Large rounded ears set on the side of the head.
Dumbo rats to be shown in any recognized color, marking, or variety. The distinguishing feature being their low ear set. The ears are large and round, set low on the sides of the head. Head to form an equilateral triangle when viewed from above.
An important note is that it is a bit difficult to get the perfect ideal Dumbo ears. Some breeders even loathe them because of this! You often get folded or pointy elf looking ears. It is awful.
Most of my lines are Dumbo. I love standard ears but Dumbo steals my heart.
It is easier to list those lines that are not dumbo:
BEW (will likely be Dumbo in the future)
In baby rats you can tell if it will be dumbo by checking the angle & location of the ear. If the top of the ear lines up with the middle of the eye, then it is dumbo!