Vision in echolocating bats - Fladdermus.net

to be precedence of vision over sonar. At short range, within that of
echolocation, bats may defer to visual cues in addition to sonar and
spatial memory to solve different tasks of orientation, especially when
there is conflicting information. Light conditions and time of the day may
determine the behaviour of the bats and thus which sensory cues will be
used.
There is an increasing amount of data suggesting that
vision might be of importance in some situations and some aspects of
foraging, especially for frugivorous and nectarivorous bats, which can
make use of differences in brightness and spectral composition, to find
different food items. But even in species traditionally considered to rely
heavily on echolocation, such as most insectivorous bats, vision seems to
play a more important role than has been recognised previously. The
gleaning brown long-eared bat (Plecotus auritus, Vespertilionidae),
known to forage mostly by using passive listening, detects prey more
readily by using vision than by using sonar, and the aerial hawking
northern bat (Eptesicus nilssonii, Vespertilionidae), use visual
information in addition to sonar to find large stationary prey in clutter.
Although echolocation is the key innovation that have made it possible
for bats to fly at night, vision is retained as an important complement; and
indeed bats use an array of different sensory inputs to solve the different
tasks of life.
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