Asking this question in strict propriety out of genuine curiosity, why is that in (American) English animal-related names are used for vulgar names for the private body parts? In fact, all of the examples I can think of, at least one vulgar term for each body seems to come from an animal. I am sure there are exceptions but even then, why are they so common? What is this fascination with having animal names as "dirty" words, i.e.
- Cock - A rooster
- Pussy - A cat
- Tits - A small bird
- Ass - A donkey - okay I see this so this can be taken out.
Is this only in America or does it happen in other parts of the English-speaking world as well?