Amid growing enthusiasm for documentary filmmaking as a more‐than‐human research methodology, particularly in geography, I interject a cautionary reflection on the possibilities and limitations of this medium, emphasising documentary film production's effects on nonhuman life. From one of the first films ever made, in which Thomas Edison electrocutes Topsy the elephant, to contemporary wildlife documentaries that observe the lives and deaths of animals, film's affective potential to electrify, animate or enliven has existed in tension with its reliance on an encounterable, killable and invade‐able animal life. Accordingly, this paper first briefly reviews the emerging context of filmmaking as a research tool for more‐than‐human or animal geographies, focused on the relationship between animal documentary film and affect. I then complicate this lively energy through an examination of the conditions of production for animal film, particularly wildlife documentary, underscoring the speciesism that positions animals as disposable objects. Drawing on historical and contemporary examples as well as my own ambivalent experience making a short research film on wild animals circulating within global live wildlife trade, I show that a reliance on an encounterable animal, and a persistent taking of or impinging on animal life, underpins wildlife documentary film's ability to bring animals to life on film screens. At a time when documentary filmmaking is poised to become a dominant method in more‐than‐human geography and animal studies more broadly, this long history of violence, or film's lethal energies, must be considered more centrally.