Why do bats hang upside down?

It conserves energy by keeping warm blood in their head, where it's needed; they effectively "lock" their feet onto whatever they hold onto, and then most of the blood circulates between brain and heart while they sleep; the wings wrapped around them as they sleep serve as a sort of "blanket" to help conserve heat as well and need little circulation when not in use. The areas below the torso (when they're upright) need and get very little circulation while they sleep, meaning the heart doesn't have to work as hard to keep them alive.

They are all copycats.. they ape their elders, parents and forefather..

Besides, they believe that the world is upside down, and to see the world in straight way, they hang upside down.

Moreover, usually, they live together in millions in a congested-narrow place.. So, in order to save space and accommodate more they hang this way..

One more, It is easier and faster to take the flying start towards the gravitation power than in opposite direction, in case of unexpected incidents.So they hang facing the earth (upside down)

they like to see the world upside down. life seems much easier and fun like that :P

Cause their hands are converted to wings and have weak legs..so they grab a thing and hang to it

I was going to say that they evolved from the opossums...sorry just being silly like my contact Jesus. LMAO!

ye mean bass ball bats,I never knew that,the things ye learn on here,lol,

They simply have a different point of View.

http://asset1.cbsistatic.com/cnwk.1d/i/ne/p/2008/B...

I'm not sure but MAN what a phenomena

To prevent this guy from doing this to them

http://ts4.mm.bing.net/th?id=H.4713250864365851&pi...

Spandey's answer made me laugh