Question: what is the difference between f1 and f4 savannah cats?
Answer: F1 generation Savannahs are always A, since the father is a nondomestic outcross (the serval father). The F2 generation can be A or B. The F3 generation can be A, B or C. The F4 generation is the first generation that can be a "stud book tradition" (SBT) cat, and is considered "purebred".