This paper discusses the applicability of theories about animal agency to studies of human–animal relationships in the academic disciplines of environmental history and archaeology. Both disciplines have a traditional epistemological stance that neglects the perceptual worlds of the animal. One example is presented of efforts to write from the other side of the epistemological chasm, on the environment of the animal, as well as Morten Tønnessen’s (2010) concepts of semiotic and ontological niches. There is also a critical discussion as to whether these concepts are applicable to the relationship between reindeer and humans. The second part of the text is devoted to an effort to recover the human presence in the scheme, with examples from sacrificial animals. It is argued that the human presence illuminates certain aspects of the animal agency, which theorizing on the animal Umwelt (environment) tends to neglect. In addition, these theories provide a heuristic foundation where species-specific environments, in all of which the reindeer dwells, provide a multiangled view of the limits of animal agency and the ways in which species, humans included, affect each other’s behavior in animal-to-animal and human–animal settings.