The Tailtag System: Tracking Multiple Mice in a Complex Environment Over a Prolonged Period Using ArUco Markers

Despite recent advancements, safely and reliably tracking individual movements over extended periods, particularly within complex social groups, remains challenging. Traditional methods like colour coding, tagging, and RFID tracking, while effective, have notable practical limitations. State-of-the-art neural network-based trackers often struggle to maintain individual identities in large groups for more than a few seconds. Fiducial tags like ArUco codes present a potential solution by enabling accurate tracking and identity management, yet their topical application on mammals has proven difficult without frequent human intervention. In this study, we introduce the Tailtag system: a non-invasive, ergonomic tail ring embedded with an ArUco marker. This system includes a comprehensive parameter optimization guide along with practical guidelines on marker selection. Our Tailtag system demonstrated the ability to automatically and reliably track individual mice in social colonies of up to 20 individuals over a period of seven days without performance degradation, facilitating a detailed analysis of social dynamics in naturalized environments.