Mice tails function in response to external and self-generated balance perturbation on the roll plane

Abstract

The functionality of mouse tails has been unexplored in the scientific literature, to the extent that they might seem to be considered as a passive appendage. Previous research on mouse locomotion has largely omitted tail dynamics, but hints at its potential use in balancing can be seen in the natural habitats and behaviors of these rodents. Here, leveraging high-speed videography, a novel naturalistic locomotory task and a simple biomechanical model analysis, we investigated the behavioral utility of the mouse tail. We observed that mice engage their tails on narrow ridge environments that mimic tree branches with narrow footholds prone to roll-plane perturbations, using different control strategies under two defined conditions: during external perturbations of the ridge where they primarily work to maintain posture and avoid falling, and during non-perturbated locomotion on the ridge, where the challenge is to dynamically control the center of mass while progressing forward. These results not only advance the existing understanding of mouse tail functionality but also open avenues for more nuanced explorations in neurobiology and biomechanics. Furthermore, we call for inclusions of tail dynamics for a holistic understanding of mammalian locomotor strategies. Author summaryWe describe and quantify the rapid mouse tail movements in response to external balance perturbations, possibly constituting a novel balance-compensatory motor program. Furthermore, we bring to light the consistent, context-dependent movements of the tail during increasingly precarious locomotion. The observations highlight the tail as an integral component of the mouse locomotory system, contributing to balancing and putatively movement efficacy, and call for inclusion of the tail in future works examining motor (dys)function.