The Three Creatures of the First Canto

Dante's just beginning to realize as Virgil is about to tell him that he must descend before he can ascend and sure enough of this threshold on this change of direction that he had no sense that he would be invited to undertake Virgil appears who's going to be his guide through hell and through the purgatory. But nonetheless he has a work rushes towards the hill in the hope that actually he's almost at his journey's end. So he steps towards the hill but immediately he's confronted by the famous three creatures of the first Canto. This is the dancing leopard, the strong lion and the lean and hungry she-wolf. I think that what these stand for is three