Lowell Was Right! - Galileani 2

One of the most important things for any civilization is the ability to manipulate items to make things and the ability to carry things. Galileani can use their two thumb hooks over branches and bars, or rest their wings on the ground, freeing the two foot-hands for manipulation. In either mode, the tail acts as the third point of the tripod, and the tails are quite solid and strong.  In flight, items are carried in the feet and belly-packs. The thumb hooks are able close enough to grasp things, and are strong enough to support the whole body.

Galileani form temporary harems of about 1-6 females per male each breeding season, with the fittest males getting the largest harem, and many males - especially younger and undistinguished ones - not finding mates. Sexual selection plays a huge role in their society - with the definition of "fittest" changing as they became civilized. It isn't just physical fitness that matters now, as inventors, scientists, performers, and the like find mates with no problem.

Galileani are not at all territorial - they like getting up close and personal in huge breeding roosts - and are a naturally communal society. Tending and spreading their preferred fruit trees is an important part of their lives. As the Galilean moons get their light from the sun, but most of their heat from Jupiter, they migrated inward as Jupiter cooled. They are a highly technological civilization. Some of their preferred fruits grow on vinelike plants with gas-filled bladders that drift in the light gravity of the moons.

Their civilization first started with pieces of woven leaves tied between tree limbs to form enclosed volumes, heated by warm air rising from fires set in pits on the ground.  Drying fruit over the fires for preservation was been one of their first innovations.   Now they have cities with large open latticework buildings with jungle-gym like interiors.  There are no horizontal-surface floors, the lower surfaces of rooms funnel down into catch-basins for debris (their ancestral fruit bats are messy eaters, and traditional building layouts tend to persist). Food is now transported into the cities from the surrounding countryside.