Prowling Wolves is a world event added in Update 1.1.2. The events were removed in Update 2.0.0 in preparation for The Taken King, though the event at the Rubicon Wastes on Mars is still present. Petra Venj gives bounties that are for killing specific Fallen Majors in certain sections of a world map (ex: killing a Wolf Baroness in the Forgotten Shore on Earth). These "events" bear similarity to the Blades of Crota introduced in The Dark Below, as they are not considered a "public event," nor are they set between specific dates. Instead, they randomly occur in specific areas in a world. The worlds involved currently are Earth, Venus, and the Moon.