Celestial Compass Orientation in Juvenile American Alligators (Alligator mississippiensis)

The use of celestial cues for compass orientation was investigated in juvenile American alligators. Animals entrained to new shoreline directions in outdoor training pens moved toward the land end of their y-axis when celestial cues were available. Under overcast skies no significant departure from a uniform circular distribution was apparent. Alligators were able to use solar, stellar or lunar compass mechanisms in this directed movement. The solar compass was time-compensated as indicated by phase-shift tests. Orientation was shifted in the predicted direction after a 6 hour advance in the L:D cycle. The stellar compass was neither time compensated nor bidirectional, as has previously been shown for amphibians, which suggests that the orientation may be based on stellar patterns. Adaptive advantages for celestial compass mechanisms may include predation avoidance, thermoregulation and increased foraging efficiency.