This analysis case study is based on an article that appeared in Science entitled “Wolves, Moose, and Tree Rings on Isle Royal,” by B. E. McLaren and R. O. Peterson (1994). Although developed for a sophomore ecology class, this case has been taught in upper-level classes in ecology and wildlife management. The case assumes that students are familiar with the terminology and concepts fundamental to ecology, and it may be used to introduce the use of predators as control agents.