Two vampire bats sitting in a cave, one turns to the other one and says "I am starving, just gonna pop out for something to eat."
The 2nd bat says "OK, I will join you in about 20 mins."
So off he goes, anyway 10 mins later the 1st bat comes back blood dripping from his mouth and from his teeth, 2nd bat says "Jesus man, that was quick, what happened there?"
1st bat says "Come here and I will show you", so they go to the edge of the cave and 1st bat says "see that tree there?" pointing into the woods.
2nd bat says "Well yes", 1st bat says "I didn't".