At face value, it's obvious that it's anything involving animals, however, what about carnal endeavours with/featuring the following;
Furries
Pet-play (ie women/men wearing collars/tails, pretending to be animals)
Daemons
Space creatures
Aliens from other planets (bipedal or whatever, sentient or whatever)
Monsters from mythology (Valkyries, Djinn, etc etc)
Are all the above (and similar) now out? Official (site) clarification on the matter would be helpful.