This post first appeared on October 2, 2012
Readers probably remember this horse from a post made back in August. At the time there was some discussion about whether or not this might be the result of a somatic mutation, or if it was caused by a reaction to something applied to the coat. Because the outline of the markings give the look of a horse smeared with an ointment, quite a few readers thought some kind of reaction to a topical substance must be the cause.

Since that post, the photographer has been in contact with the owner. The horse is named Cherokee, appears to have had the markings at least since he was a yearling, since they are noted on his passport from that age. His name would tend to suggest that his unusual markings were present in some form from quite early. His owner said that his is supposed to be an Irish Draught and Thoroughbred cross, though she mentioned that he does pace so the cross might be with a Standardbred.

But even more intriguing, another reader found a horse with a similar type of marking. This time it is a purebred Arabian mare. Her owner, Sami Alhassoun, kindly gave me permission to share her photos here.

Her name is Duja Alforsan and she is of local Egyptian breeding. Sami says that she was born with a white spot on her shoulder about 2 centimeters across. It grew as she matured, but stabilized at its present size when she was fully grown. She has had six foals, none of which have had this type of marking, nor have they produced it in their offspring.

The similarity to the markings on Cherokee is quite striking. It does not sound like either case involved anything applied to the coat, so it seems increasingly likely that this is some kind of somatic mutation. That might explain the unusual, non-organic outline. As I mentioned in the original post, the markings on Cherokee – and now Duja – are reminiscent of the odd white striping that some horses have.

And a hat tip to Maria Hjerppe for coming across Duja and putting me in touch with Sami. One of the best parts about doing this blog is the wide network of people out there looking for unusual horses. I have come to believe that one unusual horse is almost never the only one!