This thesis considers the roles of Snooks the cat, Bow-wow the mastiff, Silver Blaze the thoroughbred, Dryad the Newfoundland, Tanganrog the wolf, Hushwing the owl, Redruff the partridge, and Bella the parrot - all creations of Mary Elizabeth Braddon, Wilkie Collins, Arthur Conan Doyle, C. L. Pirkis, L.T. Meade, Sir Charles G.D. Roberts, Ernest Thompson Seton, and Margaret Marshall Saunders. Who are these creatures- and are they characters? The thesis takes as its starting point character studies in the humanist literary critical tradition in order to propose a new approach for reading animals in novels and short stories. The nineteenth century saw a rise in fiction writing and a proliferation of genres, many of which demonstrate a preoccupation with representing human psychology and interiority and a concomitant engagement with realism. At the same time, this period experienced an increasing number of discourses in science, politics, law, economics, and culture that viewed animals as "fellow-creatures" worthy of consideration. Methodologically, this thesis thus intervenes in, and moves freely between, two critical fields, animal studies and narrative theory, to provide a cross-disciplinary approach to understanding where "the animal" fits within theories of narrative. This thesis also expands the canon of Victorian literature itself by placing three prominent Canadian writers in conversation with their better-known British contemporaries to recover and revitalise the significance of the transatlantic nature of these debates about animal life. In this way, it offers new readings of canonical texts and illuminates minor works by major authors, largely forgotten bestsellers, Anglophone fiction from the country now called Canada, and the short story form. Its diverse corpus in turn provides the works under discussion with renewed critical attention. In addition to its literary close readings, this thesis draws upon scientific and medical writings and legal treatises in addressing a wide range of archival materials to emphasise how these fictional and non-fictional discourses on animals shaped one another. This thesis builds upon a growing body of criticism of animals in literature and culture while signalling the need for a sustained examination of animal characters in nineteenth-century literature that moves beyond canonical, realist texts. It underlines how many canonical works of realism, in their attention to "the human," often side-step or foreclose possibilities for animal participation entirely. It addresses this lacuna by examining the fraught relationship between literary character, realism, and animals across four genres: sensation fiction, detective fiction, the realistic wild animal story, and the animal (auto)biography. These all are closely related to realism but reveal different approaches to epistemological and ontological dimensions of animal life. Across its four chapters, this thesis shows how the writers under discussion used formal techniques, rhetorical structures, and narrative methods to account for new understandings of animals emerging from scientific and political discourses. As theories of literary character that extend consideration to animals have been limited by anthropocentric and humanist traditions, this thesis proposes a new approach to animal character that, when brought to bear on nineteenth-century fiction, illuminates the ways in which writers constructed realistic, interior-focused animal characters that challenge existing definitions. It demonstrates how in constructing Snooks, Dryad, Bella, and their kin, writers articulated both their individuality and importance to a larger collective social and narrative ecology. In doing so, this thesis attends to the ways in which evolving discussions about animal cognition, emotion, communication, and subjectivity are embedded within, explored, and refracted through these works. In this way, this thesis reveals how a reconsideration of literary character, a category seemingly inseparable from the ideological and socio-political positions of the subject, person, and human, can foster a more nuanced understanding of animals in literature and culture.