OPTIMIZING VISUAL LANDMARKS - 2-DIMENSIONAL AND 3-DIMENSIONAL MINIMALLANDSCAPES

When hoarding food within a circular arena, golden hamsters, Mesocrice tus auratus W., return along a direct path from the feeding place at t he centre to their nest at the periphery. The homing direction depends on dead reckoning (updated internal signals derived from locomotion) and, if available, on landmarks outside the arena. This study was aime d at defining the conditions under which a landmark panorama predomina tes over dead reckoning during conflict situations. In agreement with previous results, this was found to be the case only when the panorama contained at least one prominent vertical feature aligned with the ap ex of a two-dimensional, continuous background pattern. The minimal la ndscape that controlled homing was a solid cylinder presented in front of the background pattern, or its two-dimensional projection on the p attern itself. Contrary to a previous hypothesis, depth did not appear to be a critical factor in an effective landmark panorama.