Niven is, as you probably noticed from his pictures, a rather standard black&white cat.
However, we've learned that this sort of cat actually has several names.
They are occasionally, but incorrectly, called "Jellicle" cats, from the T.S. Elliot poem "The Song of the Jellicles" which has a line
Jellicle Cats are black and white,
but apparently T.S. Elliot was saying that Jellicle cats are black, white, and everything inbetween.
They are sometimes called "Jonny Cat®", because they look like the cartoon mascot of the cat litter.
But, the name we like best and use ourselves is "Tuxedo cat".