Is wolf predation ratio-dependent?

The controversy over whether wolves (Canis lupus) can regulate ungulate numbers is difficult to assess, owing to data limitations, relaxation of predator control, and the fact that current predator-prey theory was developed from the study of invertebrate populations. A ratio-dependent predator-prey model appears to be supported by data on predation on ungulates, and the data indicate that wolves have a significant impact on numbers of moose (Alces alces), and thus can exert a regulatory effect on that species.