O. G. Dely szerk.: Vertebrata Hungarica 21. (Budapest, 1982)

Adler, Kr.: Sensory aspects of Amphibian navigation and compass orientation 7-18. o.

F VERTEBRA TA HUNGARICA TOM. XXI. 1982 p. 7-18 Sensory aspects of Amphibian navigation and compass orientation* ** BY Kr. ADLER Abstract: Amphibians use a variety of cues for long-distance orientation, including landmarks, odors, sounds, celestial cues including polarized light, magnetic parameters and possibly kinesthetic cues. Although it was originally thought that a given species utilized one particular cue, recent research suggests that orientation is dependent upon a multisensory system. Current research is directed at understanding how the sensory input is integrated, both functionally and developmentally, and on what basis an animal decides to weight the several orientation cues available at any given time. Beginning in the late 1940s with the pioneering work of KARL von FRISCH and GUSTAV KRAMER on honeybees and birds, respectively, many important discoveries have been made concerning longdistance orientation by animals. Although research during the last decade has firmly established the multisensory basis of orientation (reviewed in SCHMIDT-KOENIG& KEETON 1978, and ABLE 1981), this also has made us aware that orientation mechanisms are vastly more complex than previously thought. Some earlier theories that sought to explain the mechanisms involved in animal migration, navigation and other forms of long-distance orientation have been largely abandoned, partly because the discovery of new sensory modalities - which had not been considered in earlier tests - rendered many experimental designs uncritical. Thus, many of the "classical" experiments have had to be repeated under more carefully controlled conditions, often with dramatically different results. These tests have also underscored the critical importance of an animal's motivational state. Recent work suggests that magnetic cues may play an even more central role in animal navigation than believed earlier and may be involved in the "map" sense, or positionfinding (GOULD 1980). These discoveries have caused us to revise radically our notions as to animals' sensory capabilities and, ultimately, the mechanisms for orientation. Amphibians offer a particularly useful model system for the study of animal orientation. Since they do not move the great distances traversed by birds, their normal movements can be observed in natural or near-natural arenas without great expense In equipment. Moreover, it is relatively easy to maintain amphibians in the appropriate motivational state for orientation, even under controlled laboratory conditions. Since compass orientation and homing have been shown to exist in a variety of easily-obtainable wild species, objections to the use of captive-raised or highly-selected domesticated forms do not exist. Amphibians also are particularly well suited to a study of the development and integration of orientation mechanisms because many forms live * I dedicate this paper to the memory of my late colleague William T. KEETON, for his seminal contributions to our understanding of animal orientation and navigation. ** Paper presented by author at the First Herpetological Conference of the Socialist Countries on the 26th August, 1981 in Budapest.