Social media platforms and other internet sites may propagate inaccurate or misleading information. This misinformation encourages speculation, rumors, and mistrust in established science. In the current study, we attempted to determine whether biology and environmental science students at a small college are able to transfer their critical thinking skills to the assessment of online information. Students were presented with examples of internet-based information sources and asked to rate their reliability. Regardless of major, class standing, or experience with primary literature, students accurately rated the internet sources. Students also provided written rationales for their ratings. Although freshmen and sophomores had unsophisticated rationales, juniors and seniors were likely to base their rationales on the presence or absence of evidence, peer review, and publication in a scientific journal. Juniors or seniors with some experience in the analysis of primary literature were most likely to provide sophisticated, evidence-based rationales for their ratings.