Dolphins, whales, and sharks are some of the world’s most iconic animals. Yet, many people will only ever see these animals via the media. The media, then, hold significant power in creating, modifying, or reaffirming the imaginaries around various species which, in turn, influences how much concern is given to matters related to their welfare and conservation. Given the environmental and ecological concerns presently facing the ocean, protecting, conserving, and preserving the marine ecosystem is vital, and time is of the essence. Through the work of activists, three specific marine wildlife issues have received a lot of publicity across various forms of mainstream media: the killing of dolphins in Taiji, Japan for their meat; Antarctic whaling; and the practice of shark-finning. Three activist films, namely The Cove (2009), Whale Wars (2008-), and Sharkwater (2006), are centred on these issues, and filmmakers attempt to compel viewers to support the activists’ protectionist cause. In order for this goal to have a chance of coming to fruition, rhetorical arguments must be carefully crafted. Yet, the study of rhetoric in animal-focused activist films is still an understudied research area. This thesis contributes to this area of research by using the aforementioned films as case studies by applying Aristotle’s rhetorical proofs of ethos, pathos, and logos to analyse the rhetorical arguments. Ethos is demonstrable when the activists construct themselves as credible, moral heroes and the animals as possessors of positive traits worth protecting, and the hunters as immoral villains. The graphic imagery of animal death appeals to pathos to stir strong bodily and emotional responses such as sadness, and disgust in order to mobilize audience support for cause. Lastly, these films appeal to logos through the use of culturally authoritative discourses such as those of biology, western conventional medicine, and the legal system. This thesis essentially argues that these texts work rhetorically and discursively to persuade audiences to feel a connection with and sympathy towards the animals; to be supportive of the activists; and to prompt antipathy towards the hunters and industry spokespeople.