In Annie Proulx's interview with Charlie Rose, she states that her stories come "from place." Ecocriticism has been the predominant lens with which to understand Proulx's work; however, ecocriticism's nebulous tenets and theoretical deficiencies perpetuate sentimental pastoralism of geographical determinism. The shaping impact of Wyoming's environment in Proulx's work lends itself to an evolutionary perspective. Proulx's fiction, like evolutionary theory, examines humanity's unique, reciprocal relationship with nature. The evolutionary approach provides readers with a framework to understand the human relationship to our environment, a theme Proulx's work examines. This approach also augments current criticism that notes the importance of place but does not utilize the relevant framework of evolution. Current evolutionary theory provides the theoretical framework necessary to shed light on the relationship between Proulx's colorful characters and the environment that shapes them. Utilizing this evolutionary framework and textual analysis, I examine two short stories, "The Half-Skinned Steer" and "Wamsutter Wolf."