When you think of sheep, you will usually have an animal with white, curly fur in mind. But there are always a few black sheep that particularly stand out in a white herd. Their wool cannot be dyed as well as the wool of white sheep. That is where the proverbial "black sheep" comes from as a term for an outsider. But otherwise, black sheep do not differ from the white. They are just as intelligent, playful, and sociable and have a very good memory.