An unusual dilution has been observed in Morgan horses that looks similar to one seen in Arabian horses.
In the first volume of the Equine Tapestry series, I talked about two cases of unexpected dilute foals. The first was a Dutch Draft filly, Marinka van’t Heereind. The second was the Alt-Oldenburg filly Gaja. There is further information in the upcoming volume that covers the light breeds, where similar horses have been born to purebred Arabians. More recently, an entire family of Morgans has been documented that appears to have this same as-yet-unidentified dilution. Laura Behning has put numerous pictures up with photographic pedigrees on her Morgan Colors site. I highly recommend visiting her page!
There are also photos of the Arabian family with the similar dilution on the New Dilutions website.
The color has been called “light black” for lack of any better term, since it appears to dilute the black hair more strongly than the red hair. Because both the Morgans and the two Arabians are closely linebred, and because none of the parents are unusual in color, it is believed that this might be a recessive dilution. It should be noted that these horses have all tested negative for the known dilutions.
In appearance, many have looked like the Laura Behning’s Morgan mare, Positively Charmed (“Charli”), who is pictured at the top of this post. Charli is a tested smoky black with the silver dilution. That particular combination produces a body color like milk chocolate, while the skin tends to have a purplish cast. Many of these horses also have paler eyes, but I have not yet seen a silver smoky that had eyes quite as pale as those seen in this Morgan family.