After that line, Vogon kept intermittently bursting into chuckles until the story wrapped up with "and no one knows how far the giant beavers will spread".
From The World: January 30, 2006:
Beavers in Chile threaten environment (5:45) (Listen in WMA format)
Beavers in southern Chile are gnawing their way north and causing concern. Biologists fear economic and ecological mayhem if something isn't done to stop them. Reporter Jen Ross has the story.