Like the foxes in the deserts, etc. The points of comparison are manifold. The fox is cunning (Luke 13:32, where the term is applied to Herod Antipas). It spoils the vine and its fruits (So 2:15); it burrows among ruins (Nehemiah 4:3; Lamentations 5:18).
So the false prophets were crafty, laid waste the vineyard of the Lord of hosts (Isaiah 5:7), made their profit out of the ruin of Israel, and made that ruin worse. The 'Reineke Fuchs,' in satirizing the monks and priests of the sixteenth century under the same comparison, presents a curious, though probably unconscious, analogue.
In Matthew 7:15 and Acts 20:29 wolves appear as the types of the false prophet.