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

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

first in aquatic and then in terrestrial habitats in which orientational cues may be expected to differ

. The possibility that an individual amphibian utilizes a multisensory system rather than a single cue for orientation was first proposed in 1971 by D. FERGUSON who, together with his associates, initiated studies on amphibian orientation in the early 1960s. This and subsequent research clearly demonstrate that a wide variety of cues - including landmarks, odors, sounds, celestial cues including polarized light, magnetic field parameters, and possibly a kinesthetic sense - can, under appropriate circumstances, be employed. However, we are only beginning to understand how these cues are integrated or are given hierarchiai weight. In this brief review, recent research on polarized light and magnetic cues as well as extraocular receptors will be emphasized. Fig. 1. Compass orientation in representative vertebrates. Toads and tadpoles collected at a pond move along an axis parallel to their natural Y-axis when released outdoors in the center of a circular aquatic test arena; toads and tadpoles move in opposite directions according to group-specific directional preferences. The terrestrial toad, for example, moves in a compass direction in the arena that would return it to its home shore were it in the pond. The solid dots along the arena wall represent a typical set of data, marking the points where each toad contacted the wall. Similarly, salamanders and fish trained in a tank with an artificial shore move along an axis parallel to their trained Y-axis when released in the same test arena. Notice that the animals being tested do not move in a direction that would return them home (i.e., they are not homing); instead they move in a compass direction parallel to the natural or trained Y-axis. The test arena walls exclude all landmarks but the arena is in full view of a clear sky; tests indicate that these animals use celestial cues for guidance in the arena. The large arrows showing transfer of animals to the test arena are depicted as broken ones since the magnitude of these displacements does not affect the guidance mechanism. Adapted from ADLER (1976) NATURAL POND [natürlicher Teich] TRAINING TANK [Dressurzisterne]