Sorry, I don't know what happened to all of the images from this page!
Should we leave it here, and try to repair it? OK, we're going to try to
fix it and update it, while we're at it. Please check back later.
Leah Patton writes:
"Dun" in donkeys is currently being studied. The typical
coloration of many donkeys is "Gray-dun" or "Slate
gray". Although it resembles grulla (dun on black) in some ways, the
genetic action may be different. Most donkeys, even those who appear
"Black" have a dorsal stripe that runs from poll to tail. Nearly
all have a transverse stripe across the withers. This is called the
"Cross" in donkeys and mules. The dorsal is solid, and unbroken
except in the case of spotted donkeys, where the white masks out the underlying
base color and cross area. Some shoulder stripes will be WIDE (bold), some
are pencil-thin. The ends of the cross may taper, fade, or be
dashed. Ear marks, leg bars, inner leg zippers, dark anklet, collar
buttons (at the throatlatch), ventral stripes, and sometimes barring extensions
from the dorsal (ladder marks) are usually present on most animals.
In donkeys, therefore, the presence of a stripe does not always mean a
dilution, since it occurs on gray-dun, dark brown, sorrel (red), Light red
(pink), and even near-black. It is hoped that studying horse
dun, sooty/countershading, and donkey dun in relation to each other may help
determine genetic control for all.
Below are three donkeys. The first shows a dark brown/gray-dun
foal (sometimes called "Charcoal), with a distinct dorsal. Bred to
dark colors, this foal should produce mainly dark colors. The second is a
very dark brown which will shed off slightly darker, retaining the dark
cross. The third animal is frosted/spotted white. This is an
apparent combination of the Gray-ing type gene with spotted. Note that the
spotting pattern and cross are still visible even though the animal has grayed
Dun and Mules
Mules can come in any color a horse or donkey exhibits, with few
exceptions. The tobiano horse pattern comes through incomplete, and there
is no documented cream gene in donkeys, so cremello and perlino appearing mules
are usually the result of other factors (such as spotting). Dun is common
in mules, especially from dun mares. However, the cross and stripe can
appear on mules from chestnut mares mated to "black" jacks. This
is leading to further research as to whether the cross is genetically present in
even black-appearing donkeys. Mules often exaggerate all of the dun
factors, from wide shoulder stripes to zebra bars down the entire leg.