One of the appeals of Savannah (and Bengal cats) is their wild patterning. These hybrid cats get this from their wild ancestor (the Serval for the Savannah and the Asian Leopard Cat for the Bengal). The Serval typically has a clear gold or tawny coat with small inky black spots, while the Asian Leopard cat has patterns of rosettes like a larger leopard.
The breed standards for both detail what type of spotting is permitted in the cats (for show purposes). For Savannahs, they can be penalized for having Rosettes in their coat, as the breed standard (according to TICA) for coat pattern is "SPOTTED PATTERN ONLY. The spotted Savannah pattern is made up of bold, solid dark-brown to black spots, which can be round, oval, or elongated. A series of parallel stripes, from the back of the head to just over the shoulder blades, fan out slightly over the back and the spotting pattern follows the line of the stripes from the shoulders continuing the length of the body. Smaller spots will be found on the legs and feet as well as on the face. In the black Savannah ghost spotting may occur. A visible spotting pattern on the smoke Savannah is preferred. In all divisions, any visible pattern must be spotted."
The reason rosettes show up in Savannah coats, is that when the breed was started, Bengals were sometimes used as outcrosses. They are no longer acceptable in the breed, but, some lines carry strong markings that give away their Bengal lineage.
For me personally, I love the bengal heritage. I think it is largely because Nimar (who was born in 2006) had a Bengal cat for a mother, his face and build were very much Savannah, but he had a bit of an orange tinge to his coat and a few hints of rosettes in his patterning. He was beautiful and perfect to me, and I admit freely that I loved those rosettes.
Siada has lots of rosettes, and a pattern that looks like lace on her shoulders. It is unlikely that she would have been chosen by someone as a breeder, but we were looking for a certain personality, giant ears and a pretty face. Rosettes, despite being unwelcome in the breed, were actually a bonus for me.
TICA Standards for Savannahs: http://tica.org/cat-breeds/item/260-savannah-introduction
TICA Standards for Bengals: http://tica.org/cat-breeds/item/184
Savannah Caretaker who is honored to do the job.