International awareness of the role of indigenous knowledge in resource management is of recent date. This article is based on interviews with Cree Indians of Whapmagoostui (James Bay, Canada) compiled by the authors in 1994, in the context of a social and environmental impact assessment of the proposed Great Whale River hydroelectric project. One Cree hunter, disturbed by the many gaps he had identified in the developer's environmental impact assessment document, made a concerted effort to convey his knowledge and world-view. His systematic analysis, of which data concerning the beaver are focused upon here, highlights the ecological relationships that interconnect humans, mammals, birds, and fish, including the species-specific needs of human and non-human beings for habitat, food, and shelter. Transcending the compartmentalised view of Western science, his vision combines the material, aesthetic and ethical while taking into account the impacts of human action on both natural and spiritual worlds. Furthermore, it demonstrates the predictive capacity of Cree knowledge and thought, as well as their relevance and legitimacy as assessment tools.