American Fancy Rat & Mouse Association

This article is from the Winter 1997 AFRMA Rat & Mouse Tales news-magazine.

Colors & Coats

Mystery Mice; Merle Hooded; Odd-Eyes

By Nichole Royer

Mystery Mice

Melissa Fredrickson, Tempe AZ
QI took a female Siamese, bred her to a black and white, and ended up with almost peanut butter colored mice with black tips. Have you ever had this color? If so, what color would they be considered?

AWithout a picture, it is very hard to make a positive ID on your mice; however, I can make a guess. It sounds to me like your peanut butter mice with black tips are Agoutis or Sooty Fawn (Sable). Try breeding your Siamese to a different colored mouse and see what happens. Agouti and Fawn are dominant to almost everything else, so try breeding with a non-Fawn, non-Siamese male and see what you come up with. This is one of the fun things with breeding mice you don’t know the background of—you often get colors totally different from either parent!

Merle Hooded

Chris Faron, Millers Creek, NC
QI’ve enclosed some photos including a few of our Hooded Merle, “Merlene,” Merle Hooded rat who I believe was a mutation. I’ve never had Merles, and her dam has always bred as pure for Black/Agouti (i.e. doesn’t throw any dilutes of any kind, no Blues, Beiges, etc.) and if Merle is dominant in rats like it is in dogs, then this definitely popped up out of nowhere. The rest (of the pictures) are all assorted ones from my cap-stripe breeding programs. I’m getting lots of blazes and now a lot of rats that aren’t even really cap-stripe, but rather have patches of color on the head and along the spine. Baby Merle rats I call them “patched” for lack of a better description. They are different from Dalmatian in that the color is in specific areas and is usually fairly symmetrically distributed.

AThank you for the pictures. The one of Merlene is very interesting. She is different than the Merles we have here, and it will be interesting to hear what she produces when bred. Patched is a very good discription of your spotted rats, they do look different from Dalmatians. I have seen these markings rather often in Odd-Eyes. They may be simply cap stripes selected for broken up markings, or the Odd-Eye gene may have something to do with it. No one really knows.


Chris Faron, Millers Creek, NC
QIs it possible that the odd-eye gene(s) (which I guess are some sort of recessive or threshold trait and/or affected by coat color), is visible in a non-odd-eye rat carrying the odd-eye gene. That Odd-Eye Rats is, the normal eye is incompletely dominant? I ask this because I have three rats from the same line that produced the Odd-Eye that are black cap-stripe, but with each, one eye has a very definite red cast to it. The first time I saw it I thought the rat had an eye injury.

AI have also seen this on occasion with stock which produces Odd-Eyes. Often the difference is so slight between the eyes that I wonder if I am imagining things. Since other people have also had this experience, I have to assume that these animals really do have different colored eyes. We do not know a lot about the genetics involved in Odd-Eyes, but I would say your theory is a reasonable one and would be a good working hypothesis for further breeding experiments. *

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Updated December 13, 2014