If the Sorting Hat sent you to Slytherin in first year, no doubt you'll be charmed by these two fabulously scaly serpents, who seem almost to wriggle right off the pages of Ulisse Aldrovandi's 1640 volume on snakes and dragons. Fear not if you're not a fan of Slytherin's mascot: the common Aesculepian snake (left) and the black Aesculepian snake (right) aren't venomous. Aldrovandi reopens the debate about snake generation in this book, puzzling over the suggestion that snakes come from the eggs of a rooster. Is there a Parselmouth in the house? We'll just have to ask.