For the definitive answers to all questions about Discworld, I would suggest getting hold of the New Discworld Comapnion, written by Sir Pterry and Steven Briggs. (Our local library has three copies). This is a valuable addition to anyone's collection and you know you are getting the definitive answers straight from the horse's mouth; so to speak.
Remember the Yeti in 'Thief of Time'? A form of troll. The Ice Giants surrounding the Hub are also considered a form of troll, according to Pterry.
For reference - Just in case anyone needs to ask in future... did you know there are thirty seven varieties of swamp dragon!
