The mechanistic underpinnings of sustained attention, vigilance, and the ability to continue responding to critical stimuli over time, despite decades of research, are not well understood. Although sustained attention is vital for survival and is studied in many taxa, a lack of comparative work and a greater research focus on the high-level psychological aspects of human sustained attention performance have hindered progress in our understanding of it. We posit that an interdisciplinary approach between the biological and psychological fields, involving research on humans and nonhuman animals, will illuminate the biological mechanisms involved. A key obstacle to a comparative approach is the vast terminology used to illustrate similar phenomena across disciplines. We compare the research on sustained attention in humans and animals, showing that the comparative gap is not insurmountable. To resolve the communication issue, we outline the different terms used and suggest future directions to encourage productive engagement between the two fields. Additionally, we propose that an interdisciplinary perspective will be advantageous for developing countermeasures to declining sustained attention.