VISION IN ECHOLOCATING BATS
a doctoral thesis - Johan Eklöf Zoology dept. Göteborg university 2003
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The use of ultrasonic echolocation (sonar) in air is seriously constrained by the attenuation of high frequency sounds and unwanted echoes from the background (called clutter). Therefore, in many situations, echolocating bats have to rely on other sensory cues. The aim of this thesis is to investigate the use of vision by echolocating bats.
One of the most fundamental roles of the eyes is to register the amount of ambient light, in order to establish photoperiodic cycles. Some tropical bats avoid too bright conditions, i.e. moonlit nights probably due to increased predation risk, a behaviour not found in high latitude species.