All the witches need a BLACK cat?

I myself adore cats and I had one who was living with our family for 17 years and died because of senility. The cat was black and white, with green eyes. If I were a witch I would have definitely considered him to be my magical cat :) And he was, I believe, not an ordinary one.
More than the brooms and the cauldrons the witches have to own ... a black cat. How it happened that this fluffy fellow became a favorite tame animal among the wizardry folks? What is the role of it in all the process at last? And do all the witches need particularly a black cat?

The witchcraft is much more complicated matter than as it is presented in popular culture. The black cats are being one of the inalienable characters of  the witchcraft as a simple interpretation of it. The book of  1964 "Ugh, Ugh, Touch Wood" (Tьфу, Tьфу, чтоб не сглазить) by V. Ostrovsky was one of my favorite read. The book is not just about the witchcraft but it gives kind of atheistic point of view on the human's beliefs, including magic. Look at the cover - the black cat is crawling among the letters!

Why black? Because this color is traditionally considered to be a color of witchcraft and we keep this in out mind too.We know that the cats were worshiped in ancient Egypt, and when mummified had to accompany their owners in the other world. It is mentioned in "The Encyclopedia of Witchcraft, Witches and Wicca" that the black cats at the same time were associated with darkness and death in the Egyptian mythology (b). 

 In the same book is said that "according to lore every witch, sorcerer, gypsy was supposed to have a cat. During (the XVI century) witch hunts, the cats were familiars, they embodied the demons who performed the witches' tasks of maleficia against their neighbors". The book then gives an example of a  convicted witch Elizabeth Francis who said she kept white spotted cat named Sathan, which whenever it performed a job for her, demanded a reward of a drop of her blood". The cat isn't black in this story, is it? However during the same XVI century the black cats were said to be the Devil himself and many of them were hunted and burned. Is it some kind of a "black color phobia"?

The Love Potion by Evelin de Morgan

   "Though the black cat is associated with witchcraft, it is considered a good luck own one in parts of Europe, England and  the United States. But having one's path crossed by a black cat is always bad luck," -says the above mentioned Encyclopedia. So the belief in black cat's dark powers is relative. All the cats were bestowed somewhat supernatural powers like seeing ghosts, being able to sense danger and so on.

What about the black cat in modern witchcraft tradition? As Encyclopedia says " In Wicca, the cat is favored companion or familiar, valued for its psychic sensitivity and assistance in magic and ritual". However it is not mentioned in any of special rules that the cat a witch owns has to be necessarily black. I found such statement "black cats are just double the witchiness! The black cat is one of the most common Wicca symbols, to outsiders" on one of the Wicca sites.  I consider that such perception of the black cat by modern Wiccans is based on an ancient thinking of which I told about earlier in this post: witchcraft - black color.
The concept of the particularly black cat as a companion of any witch can be an archetype (Carl Gustav Jung's term) which is being popularized in our century and got a second life. So seven are left still? ;)
What we can conclude is that the cat was an enigmatic animal even centuries ago, it continues being such nowadays too. We value cats for their ability to be sensitive, tender, create a homely atmosphere and make our life a little more happy, no matter if they are black or of any other color.

 Yours sincerely,
Witchcraft and Literature