Optimizing distal landmarks: horizontal versus vertical structures and relation to background.
During hoarding excursions, golden hamsters use distal landmarks and dead reckoning (updated signals derived from locomotion) to find their way back from a food source at the centre of a circular arena to their nest at the periphery. The preference for particular landmarks was assessed by setting landmark panoramas in conflict with dead reckoning. The hamsters tended to prefer horizontal landmarks to vertical ones when these landmarks were presented alone. However, in combination with a continuous background pattern including a single apex, vertical landmarks were more effective than horizontal ones. A panorama consisting of a vertical cylinder or bar and the background pattern was optimal provided the vertical landmark was aligned or superimposed on the apex of the background. The impact of a landmark panorama therefore depends on its particular components as well as on their mutual relationship.