LONG RANGE NAVIGATION IN ANIMALS

The physical and sensory basis of navigation in fish, turtles, birds, and bats has been examined theoretically and by experiment. The stars are found to be superior for several reasons to the sun as potential cues in visual navigation. The advantage of non-visual over visual navigation increases rapidly with increasing size of the sense organs, which may help to explain certain differences in homing behaviour between small and large animals. Methods are suggested to differentiate between navigation systems based on measurements of (a) the altitude of the stars, (b) the altitude of the sun, (c) the position of celestial radio sources, (d) the inertial forces experienced during the outward journey prior to homing, (e) the intensity of gravity, (f) the intensity and direction of the Coriolis force, and (g) the intensity and direction of the geomagnetic field. Some results of such tests and of other experiments are reported. (Author) Available only for reference use at DDC Field Services. Copy is not available for public sale.