Penguins...

 

Bart rushed into a bar and ordered a double whisky.  With a worried look, he asked the bartender, "Do you happen to know how tall penguins grow?"

"Between 2 and 3 feet tall" answered the bartender.

"Are you sure?" Bart asked.

"Positive" said the bartender.

"Damn" Bart muttered.  "I think I just ran over a nun."