This article is from the WSSF 2015 AFRMA Rat & Mouse Tales news-magazine.

By Karen Robbins

Lori Broadwater, CA, Facebook
Q Short eared mice (Cobbie) . . . does anyone know where I can find any? Some are in Utah, are there any here in California?

A P.E. White Satin American Fold (short-ear gene) owned by Christian Diaz. Photo ©2001 Karen Robbins.

A I haven’t heard of anyone working on them other than you and other San Diego breeders a few years ago. You might try asking on some of the mouse forums/groups to see if anyone still has any.

American Fold is the term we came up with for these mice since everyone thought Cobbie was referring to the body shape. We had tentative standards for when they were shown in the Unstd. class many years ago at AFRMA shows and are listed in the Mouse Color Standards book. These are not ones to be standardized though due to their skeletal problems referenced in the research articles.

This is a recessive gene (se) that affects the whole skeleton. The smaller ears are a result of defective cartilage. There are other tweaked ear genes that you can read about in the AFRMA Mouse Genetics book.

Following are some research articles on short eared mice (Bmp5: bone morphogenetic protein 5; se) for those wanting to learn more about them:

• Short Ears an Autosomal Mutation in the House Mouse, The American Naturalist, Vol. 55, No. 640, Sep.–Oct. 1921
• Inheritance in the House Mouse, the Linkage Relations of Short-Ear, Hairless, and Naked by George D. Snell, Genetics. 1931 Jan; 16(1): 42–74.
• A search for some effects of the ‘short-ear’ gene on behavior in mice, American Naturalist, 1950 Vol. 84 pp. 393–399
• Mechanism of the pleiotropic effects of the short-ear mutant gene in the mouse, Journal of Experimental Zoology, Volume 167, Issue 2, pages 129–150, February 1968
• Molecular Genetic Analysis of the Dilute-Short Ear (d-se) Region of the Mouse, Genetics, 112: 321–942 February, 1986
• The mouse short ear skeletal morphogenesis locus is associated with defects in a bone morphogenetic member of the TGF beta superfamily, Cell. 1992 Oct 30;71(3):399–410
• Jackson Labs: Craniofacial mouse models (there are many tweaked ear genes)

Some history on them from the American Rat, Mouse & Hamster Society of San Diego, CA, newsletter, Spring 2000, by Lori Wuebker (now Broadwater): Cobbie Mice were brought in from St. Louis, Missouri, in 1994. To the best of my knowledge, these are the first ones in California. I traded a few small-eared mice (Cobbies), and Cobbie carriers for a red Mini Rex rabbit. Some of the colors were cream/white, Brindle/white, golden brindle, silver Brindle, Chocolate, Silver, and Fawn. Cobbies, for the most part, are unique because of their tiny ears and their very outgoing personality.

Cassi Anderson, Facebook

Photo from Cassie Anderson.

Q Does anyone have the old article on ear-less mice??? Not sure on the term, but basically has no ears, just a tuft of fur. Someone said they were even shown in the 1990s. We have three females (from two separate lines) with virtually no ear. Thanks.

A We know of several research articles for the short ear gene in mice (see previous answer). The ones shown here in California in the late 1990s to early 2000s with the clubs (Cobbie/American Fold) all had small ears, so the info in the articles refers to those type of mice. Not sure if there is anything on actual ear less. Try the Jackson Lab or MGI site.

Ed. Note: There are many deformities in rodents and while some things are cute, it doesn’t mean they should necessarily be perpetuated as many have underlying physical abnormalities that you can’t see that harm their health and well-being. Please breed responsibly.

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