This modelling study aims at identifying the relative importance of proprioceptive feedback and internal body models for estimating the posture and motion of animals during locomotion. We use detailed natural whole-body movement data of walking stick insects to model sensory feedback from different proprioceptors on the legs. How well are body posture and movements estimated from distributed proprioceptors alone? Does an internal body model, which takes the geometry of the animal into account, improve purely sensor-based estimates? Picture: Schematic of a hairfield model.