Comment: Regulation of moose populations by wolf predation

We discuss regulation of moose (Alces alces) populations by wolves (Canis l upus) in the context of a recent article by Eberhardt (L.L. Eberhardt. 1997 . Can. J. Zool. 75: 1940-1944), who contended that the killing rate of moos e by wolves was constant. Further, he argued that wolf population size was proportional to prey density, and that wolf predation exerted a regulatory effect on ungulate-prey numbers. We argue that this combination of function al and numerical responses results in density-independent predation that ca nnot regulate prey numbers. We discuss the present understanding of wolf-mo ose interactions and conclude that there is evidence suggesting density dep endence in both functional and numerical responses. Further, we conclude th at predation by wolves is density-dependent, at least at low moose densitie s, and therefore can act as a regulatory factor.