Theyre a hybrid breed of domestic and serval cats. They are categorized by "filial generation (f)" which is used to indicate how many generations it is from a serval ancestor If a cat is F1 then that means one of its parent cats was serval. If a cat is F2 then one of its grandparent cats was serval. If a cat F3 then one of its great grandparent cats were serval, so on and so forth The largest of the cats (F1) weigh 17-25 pounds if male, and 13-19 if female [spoiler]as for the cat in the picture, i dont know what generation it is but i think it does a great job demonstrating their size[/spoiler]