I remember seeing film of fuit bats soaring and I've just bumped into a ref
about soaring flight in a "Flying Fox", a fruit bat. The site says, "It flies
with a slow wing-beat, frequently glides and can also soar on thermals."
http://www.animalinfo.org/species/bat/pterlivi.htm
Here's a photo: http://ibis.nott.ac.uk/Action-Comores/batflight2.jpg
Cheers,
--Mike Habib