Well, where did the word cat? Here we must appeal to the reasoning of the philologist A. Dolgopolova. He writes that the Egyptian cat name translated in English very clearly - "meow". So the Egyptians to the European name of a domestic animal relations do not seem to have. But the ancient Berbers who lived in North Africa, the word "cat" called wild cat. It was assigned to the domestic cat and has entered the lexicon of the Romans. The Romans and the Greeks gave the name and the cats themselves to other peoples of Europe.
But that's what hitch: "cat" and "cat" - a word, a little similar. Why "cat"and not "cotija" or something else? I think that is an affectionate diminutive of the word "cat" (ancient Slavs spoke "Kotka) was born in the conversations of children. And another detail: the origin of the word "kitten" is not very strong threads associated with the word "Okolitsa". For Okolitsa the lion and the goat, and the DOE-rabbit.