On the eastern edge of the Cascade Mountain range in Washington State, high school biology students have a unique opportunity to study the elusive cougar ("Felis concolor"), a large cat native to the area. Nestled in the Cascade foothills is the city of Cle Elum, a small rural community that is expected to soon experience considerable growth from development of a large resort. The community provides an excellent model for scientific study of native animals; students can study and compare the cougar's habitat and behavior before, during, and after resort development. From an instructional perspective, the study of cougars provides an ideal way to engage both introductory and advanced biology students in interdisciplinary science inquiry and problem solving. In this article, the authors describe the design and implementation of the Cougar Conservation Project (CCP), a problem-based learning (PBL) curriculum that provided students and community members with valuable interdisciplinary learning experiences. (Contains 2 figures.)