Preference for Light of Short Wavelengths in Hatchling Green Sea Turtles, Chelonia Mydas, Tested On Their Natural Nesting Beaches

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Abstract
Hatchling green sea turtles, Chelonia mydas, preferred blue and green stimuli to red when tested in a two choice situation on their natural nesting beaches. These stimuli when used singly were also more effective than the red in distracting turtles on their way to the sea. The preference for blues and greens over red was not simply dependent on overall intensity differences between the stimuli. There were in fact two components in the reactions of the turtles to light. There was a tendency to go to lights the more intense they were. Combined with this there was a tendency to go to lights of shorter wavelengths. Since turtles, if left unrestricted in these experimental situations, would rapidly reach the sea, the experiments were likely to have been testing some aspect of sea finding ability. HOOKER'S (1911) views on the importance of photic behaviour in sea finding are therefore generally confirmed, but whether the turtle prefers lights of short wavelengths because of their colour or because they appear brighter cannot yet be said. The relevance of these behavioural results to visual mechanisms in turtles is discussed, in particular the possibility of some shift in spectral sensitivity at a peripheral level in scotopic conditions.