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Re: pterosaurs, bats, flying theropods (fwd)



Nicholas Jainschigg wrote:
> Curiously, owls are very maneuverable flyers,
> as well as being silent and able to see in conditions that are as close to
> pitch blackness as nature provides outside of a cave. This is what lets them
> prey on bats.

Here in Australia, diurnal raptors will also prey on bats. They hover
around the entrance to the bats' cave around sunset, when there is
enough light for them to see, but it is dim enough for bats to emerge.
Snakes will also perch themselves on rock walls at the cave mouth, and
strike out at the bats as they fly past. 

I'm guessing that if becoming largely nocturnal was a response to
predation, then that was not the only strategy employed. Sheer numbers
seem to help keep bats safe from predators far more effectively than
being nocturnal does (especially since flying foxes roost in trees, and
will often fly about during the day). Perhaps some became nocturnal not
to avoid being preyed upon, but rather so they didn't have to compete
with diurnal predators for prey (or roosting sites, come to think of
it).

-- 
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Dann Pigdon                   Australian Dinosaurs:
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/
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