Re: Why does a bat hang upside down?

Hi there,

Good question!  You reminded me to switch my bat calendar from October to 
November, so now I'm being watched by a Honduran White Bat.  Thanks!  

I wanted to make sure I had the right idea before responding to your 
question, and was very surprised to find that very few bat information 
resources answer this question directly.  However, some technical reports 
got to the anatomical/scientific explanation, and the Bat Conservation 
International web page "Frequently Asked Questions" provided just the 
answer you need.  Basically, bats' knees face backwards (compared to ours), 
which helps them steer when flying, but would make it hard for them to 
perch "upright" (like birds).  

Here's the more complete explanation from BCI:

"Why do bats hang upside down? 
     Unlike the bodies of other animals, a bat's body is best adapted for 
hanging upside down. Its hind limbs have rotated 180 degrees so that its 
knees face backwards. This rotation aids in the bat's ability to navigate 
in flight and to hang by its feet. Bats actually have specialized tendons 
that hold their toes in place so that they are able to cling to their 
roosts without expending any energy. In fact, bats must flex their muscles 
in order to let go of the roosting surface. These adaptations are quite
helpful for a flying mammal since bats only need to let go of the roost in 
order to drop into flight. Hanging upside down also provides bats with 
roosting space away from predators in safe places on the ceilings of caves, 
in trees, and buildings that few other animals can use because they have 
not evolved to hang upside down by their feet. "

Here are some good bat resources on the Web:

Bat Conservation International (includes many amazing bat photos) http://www.batcon.org/

The Lubee Foundation, a bat conservation center http://www.lubee.com/

Organization for Bat Conservation http://www.batconservation.org/

Ranger Rick's Bat Page http://www.nwf.org/nwf/rri
ck/batbs96.html

The Bat Conservation Trust http://www.bats.org.uk/default.ht
m

The more I learn about bats, the more they fascinate me.  Enjoy exploring. 
 
Sincerely,

Ruth