Poison frogs rely on vision for homing in natural environments

Neotropical poison frogs (Dendrobatoidea) can navigate back to their territories after large passive displacements. However, the underlying sensory mechanisms remain largely unknown. Dendrobatoids use simple visual stimuli for navigation in confined laboratory experiments, but larger movements under natural conditions are likely to be more challenging. Tropical forests have dense vegetation that creates cluttered and confusing visual environments. Here, we investigated visual cues and navigation of territory-holding male strawberry poison frogs (Oophaga pumilio) in tropical forests. First, we displaced frogs and blocked different aspects of their visual surroundings at the release site. To orient successfully, frogs required information from the lower half of the visual field, but not from the sky or canopy. Second, we displaced males in forested or open areas and characterized their homing trajectories according to visual information using 360° photos. Homing success was higher and faster in open areas, where frogs also showed better initial orientations and lower meandering. We show that low-level visual panoramas in open areas contain more directional information than in closed forests, which could explain these navigational differences. Our results shed light on the mechanisms by which frogs navigate natural environments.