The ability of specific sensory stimuli to evoke spontaneous behavioural responses in the mouse represents a powerful approach to study how the mammalian brain processes sensory information and selects appropriate motor actions. For visually and auditory guided behaviours the relevant action has been empirically identified as a change in locomotion state. However, the extent to which locomotion alone captures the diversity of those behaviours and their sensory specificity is unknown. To tackle this problem we developed a method to obtain a faithful 3D reconstruction of the mouse body that enabled us to quantify a wide variety of movements and changes in postures. This higher dimensional description of behaviour revealed that responses to different sensory inputs is more stimulus-specific than indicated by locomotion data alone. Thus, equivalent locomotion patterns evoked by different stimuli (e.g. looming and sound evoking locomotion arrest) could be well separated along other dimensions. The enhanced stimulus-specificity was explained by a surprising diversity of behavioural responses. A clustering analysis revealed that distinct combinations of motor actions and postures, giving rise to at least 7 different behaviours, were required to account for stimulus-specificity. Moreover, each stimulus evoked more than one behaviour revealing a robust one-to-many mapping between sensations and behaviours that could not be detected from locomotion data. Our results challenge the current view of visually and auditory guided behaviours as purely locomotion-based actions (e.g. freeze, escape) and indicate that behavioural diversity and sensory specificity unfold in a higher dimensional space spanning multiple motor actions.