Once I was caving in Greene County, Mo., with a group of friends and acquaintances. Some passageways of the cavern were pretty tight and we had to crawl on our bellies. 
We emerged from one such tunnel into a good-sized room. It was nearing dusk outside and we were considering whether or not to continue into one of two or three tunnels that opened before us when we heard a sound like a strong wind, followed by high-pitched screeching.
What the heck? I think the answer dawned on us all at the same instant: Bats!
Hundreds, probably thousands, of bats poured out of the tunnels and flew over our heads and past our faces. We scrambled and clumsily ran back the way we came, flailing our arms about us like one of those big inflatable guys you see at used car lots.
We ducked into the narrow tunnel we had just slithered out of, and did our best impersonations of Marines under heavy fire as we crawled on our bellies as fast as we could in the very limited space of the tunnel.
The army of bats were with us all the way. They flew through our hair and brushed against our heads and bodies as they followed their ancient daily routine of waking up to feed for the evening.
We finally poured out of the mouth of the cave, amidst a dark cloud of furry flying mammals. It gave us the willies at first, but it wasn’t long before we were all laughing so hard we cried.
