Alien Professor Xargle teaches his class of extraterrestrials about the quirky behavior of a favorite earth animal "Good morning, class. Today we are going to learn about Earth Hounds. Earth Hounds have fangs at the front and a waggler at the back. To find out which is which, hold a sausage at both ends." Dr Xargle is instructing his class of small fellow aliens on the nature and habits of the earth creatures known to humans as "dogs," in this hilarious follow-up to Dr Xargle"s Book of Earthlets.