Otter Group (Tan: at-)

All four “shades” of otter became part of the official Rex standard inFeb. 2009

Full Color Concentration (C-)

Tan Patterns
Color A B C D E En
Black Otter at- B- C- D- E- enen
Chocolate Otter at- bb C- D- E- enen
Blue Otter at- B- C- dd E- enen
Lilac Otter at- bb C- dd E- enen
Black Otter Chocolate Otter
Blue Otter Lilac Otter

Chinchilla: The Martens (Cchd- )

Marten Currently, none of these are recognized in Rex.
Color A B C D E En
Silver Marten at- B- cchd- D- E- enen
Chocolate Silver Marten at- bb cchd- D- E- enen
Blue Silver Marten at- B- cchd- dd E- enen
Lilac Silver Marten at- bb cchd- dd E- enen

This is the color you get when you combine the shaded gene (cchd) with the tan pattern (at-). It's an otter without the red color along the borders. The chinchilla also makes the 'black' parts look slightly less black.

Marten Otter

Sable or Shaded (cchl-)

Sable Marten Currently, none of these are recognized in Rex.
Color A B C D E En
Sable Silver Marten at- B- cchl- D- E- enen
Sable Chocolate Silver Marten at- bb cchl- D- E- enen
Sable Blue Silver Marten at- B- cchl- dd E- enen
Sable Lilac Silver Marten at- bb cchl- dd E- enen

Californian or Himalayan (ch-)

Tan Himalayan Currently, none of these are recognized in Rex.
Color A B C D E En
Black Tan Himalayan at- B- ch- D- E- enen Possibly showable as a Californian (Black Himalayan) Would likely be faulted for poor point color.
Chocolate Tan Himalayan at- bb ch- D- E- enen
Blue Tan Himalayan at- B- ch- dd E- enen
Lilac Tan Himalayan at- bb ch- dd E- enen

Further Resources

Wild River Rabbitry has a lovely illustrated Shaded Mini Rex Guide.

Judith Graf, Color Basics 1991 (self-published booklet)

Glenna M.Huffmon, The Basics of Color Genetics in Rabbits (I have the 1995 third edition)