Muggles' Guide to Harry Potter/Magic/Kneazle

Overview
Kneazles are small creatures that look like large cats, but have spotted fur, large ears and a tail like a Lion. An independent, intelligent creature, capable of aggression which it shows occasionally, a kneazle will make a great pet, if it likes you! It can be relied upon to guide its owner home if they should get lost. A kneazle requires a license for legal ownership.

Extended Description
Apparently Kneazles can interbreed with cats; the resulting cat/kneazle hybrid is relatively intelligent and larger than the ordinary cat. Crookshanks, Hermione's cat, is probably just such a cross-breed. We are led to believe that old Mrs. Figg is actually making a living by creating such hybrids. While we are told that it is necessary to have a license to own a Kneazle, nothing is said about licensing requirements, if any, for cat/Kneazle hybrids. If Crookshanks is one, we can safely assume that no license is required, because Hermione would be certain to get one.

Analysis
It could be said that the author's introduction of the Kneazle and its ability to cross-breed with cats is perhaps less than honest with the reader, that we should know about the possibility of Crookshanks' being not just an ordinary cat. There is no mention of Kneazles in the principal seven books, and thus no mention of the possibility that Crookshanks may be a hybrid. However, it is certainly true that in Harry Potter and the Prisoner of Azkaban, Crookshanks acts far more intelligent than an ordinary cat, and introducing the hybrid idea, even if it is done after the fact, may be necessary to explain that intelligence.