Few people left in the human, more animal!))))
Yes, at one time it was just a craze called his girlfriend( loved Man) bunny, fish, pussy. ..
Under certain circumstances, it is very juicy rescued man - it was not necessary to memorize the names of the changing "attachments" for fear of inadvertently called Olga and Masha(Petya Vanya) or vice versa, "bunny", "kitty". .. rescued and protected from stormy scenes of jealousy.
Perhaps another reason this situation has become more and more urban dweller removal of the natural world.Living deep in the subconscious of every human relationship with all living things in this world that's compensated with such an artificial way, because to have a real live cat, a dog, a hare or a rabbit in a city apartment is not available to everyone:)