The wolf population might overshoot equilibrium levels in a manner analogous to the irruptive pattern commonly observed for ungulate populations colonizing from low densities. The density reached by wolves in their initial period of rapid growth may indeed be very high, but this says little about the nature of the equilibrium that will be attained perhaps decades hence. We are confident that form and function of the Yellowstone ecosystem will change because of wolf recovery. What next for Yellowstone?